Distribution of the blood flow supplied by the vertebral artery in humans as assessed by emission CT

Though unilateral blood distribution of the vertebral artery has not been studied in humans, it is significant when considering the ischemic events especially embolic occlusion in vertebrobasilar system. To clarify the blood distribution, Krypton-81m was continuously infused into the vertebral arteries of 10 patients. Radioactivity was recorded by a rotating gamma camera. The perfusion images, reconstructed by computer in the transaxial plane, were classified according to whether the distribution was equal, or predominantly unilateral. Overlapping of blood supply from each vertebral artery was studied. In addition, the perfusion from one of the vertebral arteries revealed four distribution patterns with respect to laterality. A) ipsilateral; B) contralateral; C) bilateral; D) mosaic. Images obtained following perfusion of the vertebral artery show less uniformity compared to that of the internal carotid artery, suggesting a complicated vascular supply of the vertebral basilar territory. This complex distribution can be classified by the use of continuous infusion of Krypton-81m.

A femocerebral catheter for middle-aged patients of relatively small stature

The authors describe a catheter for multi-artery studies in middle aged patients of relatively small stature. Experience in more than a thousand cases proved its special usefulness in selecting the left common carotid artery with tortuous aortic arch.

[Gonadotropin release following hypothalamic electrical stimulation of the Macaca fuscata]

The effect of electrical stimulation on hypothalamic nuclei was studied by using a stereotaxic operation and in vitro bioassay of luteinizing hormone (LH) in the macaca fuscata. The results were as follows: The serum LH level was increased when the arcuate nucleus or the ventromedial nucleus was stimulated at 250 mu A and 500 mu A. The serum LH level was not increased when the paraventricular nucleus or supraoptic nucleus was stimulated at 250 mu A and 500 mu A. When the medial preoptic nucleus was stimulated at 250 mu A, the serum LH level was not increased. However, the stimulation of 500 mu A increased the serum LH level. The stimulation of the lateral preoptic nucleus did not increase the serum LH at 250 mu A and 500 mu A. The half lives of LH were 35.4 min., 33.4 min., 48.4 min., 43.1 min. These results were different from the half life of human LH. The contribution of various hypothalamic nuclei to the release of LH was discussed.

A study of regional cerebral blood flow and hemodynamics in cerebrovascular diseases by selective continuous infusion of Kr-81m

A tomographic study of regional cerebral blood flow and hemodynamics was performed on 25 patients with cerebrovascular diseases by selective continuous infusion of krypton-81m (Kr-81m). Kr-81m single photon emission computed tomograms were superimposed on X-ray computed tomograms to assess topographically the perfusion of the entire brain. Study of cerebrovascular diseases using this method showed: (1) regional cerebral blood flow change; (2) perfusion distribution change; (3) the route by which blood reached the brain or the obstructed artery proximal to the circle of Willis; (4) development of a collateral system and its actual function; and (5) efficacy of surgical bypass after extracranial-intracranial anastomosis. This method is especially useful in hemodynamic assessment in patients with ischemic cerebrovascular disease.

Superimposition of Krypton-81m single photon emission CT and X-ray CT images for cerebral blood flow evaluation

Selective arteriographic infusion of krypton-81m was used to obtain cerebral single photon emission computed tomograms. These were then superimposed on X-ray computed tomograms to assess topographically the perfusion of the entire brain. This method enhances the detecting capability for abnormal perfusion areas and has been used in 21 patients with various brain diseases.

Krypton-81m single photon emission tomography and the collateral circulation in carotid occlusion: the role of the circle of Willis and leptomeningeal anastomosis

Cerebral perfusion images were investigated in patients with carotid artery occlusion, using single photon emission computed tomography with the infusion of krypton-81m into the internal, common carotid and vertebral arteries. The contribution of the circle of Willis and cerebral cortical anastomoses to the maintenance of adequate blood supply into the involved hemisphere was analysed. It was concluded that the cerebral perfusion image is superior to angiography in evaluating collateral circulation, and in the case of carotid occlusion, the circle of Willis is important in preventing infarction in the territory of the perforating arteries, while the cerebral cortex mainly receives its blood supply through the cortical leptomeningeal anastomoses, illustrating the major role of the leptomeningeal anastomosis as a collateral channel.

Interaction of aminoacyl-tRNA with bacterial elongation factor Tu: GTP complex: effects of the amino group of amino acid esterified to tRNA, the amino acid side chain, and tRNA structure

The present investigation was undertaken to see to what extent the alpha-amino group of the amino acid, the side chain of the amino acid of aminoacyl-tRNA, and the tRNA structure are involved in determining the affinity of aminoacyl-tRNA for bacterial elongation factor Tu-GTP complex. Various aminoacyl-tRNAs, mis-aminoacylated tRNAs, and formylated aminoacyl-tRNAs were prepared, and the dissociation constants of the ternary complexes of aminoacyl-tRNA with ET-Tu: GTP were determined by the RNase-resistance assay. The results indicated that the free amino-acid group of the amino acids in aminoacyl-tRNA is strongly required for binding with EF-Tu : GTP. In this concentration, the biological significance of formylation for Met-tRNAMetf species is discussed.

Interaction of initiator Met-tRNArMet (Escherichia coli) and Gly-tRNAIGly (Staphylococcus epidermidis) with bacterial elongation factor Tu:GTP complex

Jekowsky et al. reported recently that elongation factor Tu:GTP complex from Escherichia coli protected aminoacyl-tRNA from digestion by pancreatic RNase (I). On the basis of their finding, we have developed the "RNase-resistance assay" for determination of the dissociation constant of aminoacyl-tRNA from aminoacyl-tRNA:EF-Tu:GTP complex. By the use of this sensitive assay, the dissociation constants were estimated to be 3.6 x 10(-7) M for Ala-tRNA1Ala (Torulopsis utilis), 7.9 x 10(-8) M for Phe-tRNAPhe (Escherichia coli), 8.1 x 10(-7) M for initiator Met-tRNAfMet (Escherichia coli), and 5.4 x 10(-6) M for Gly-tRNA1Gly (Staphylococcus epidermidis) participating in cell wall biosynthesis. Moreover, using a relatively large amount of EF-Tu:GTP, we have been able to detect the ternary complexes of initiator Met-tRNAfMet and Gly-tRNA1Gly with EF-Tu:GTP even by the method of gel filtration.

Effects of exogenous stimuli and centrally acting drugs on galvanic skin responses in rats

Effects of physical stimulus and psychic stimulus on the galvanic skin response (GSR) in rats were evaluated. A significant change in the GSR was observed after exposing the rat to the noise of hand-clapping, and introducing another rat into the cage. The latter stimulus had a much greater effect than the former. Changes in GSR were measured after various animals were introduced into the test cage. A shift in the GSR in intrusion of guinea pig or rabbit was significantly greater than that in intrusion of Wistar rat, but no difference was observed in intrusion of rat and mouse. Changes in GSR were studied by introducing another animal into the test cage containing a single rat (isolated state) or a pair of rats (grouped state). The change in the GSR in the grouped state was generally smaller than that in the isolated state, but there was no difference in the score between these states when a rabbit was introduced. When the effect of drugs on changing of GSR was investigated, we found that elevation of GSR value, as induced by exogenous stimuli, was inhibited by tranquilizers such as chlorpromazine, carpipramine and diazepam. These tranquilizers in a remarkably small dose had an apparent effect on the psychic, mutual relation in GSR test in rats.

In vivo methylation of elongation factor Tu of Escherichia coli

A protein existing mainly in the supernatant fraction of Escherichia coli was found to be methylated by accepting the methyl moiety originating from methionine. The protein was identified as peptide synthesis elongation factor Tu (EF-Tu) by the following criteria. 1) The methylatable protein separated at the same position as purified EF-Tu on two-dimensional gel electrophoresis. 2) The methylatable protein interacted with antiserum specific for EF-Tu. Amino acid analysis of the methyl-labeled protein suggested that the site of methylation was an epsilon-amino group of lysine.