[Equipment and instruments for use in radiological protection. VIII. Characteristics and use of radiation protection apparatus (2)].
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Biomedical subjects
Publications and source records attributed to K Sogabe.
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The degree of skin flare 10 min after intradermal injection of histamine (0.06-2 micrograms in 0.1 ml saline) was evaluated both visually and by thermography in 6 healthy male volunteers. Intradermally injected histamine increased the skin flare area in a dose-dependent manner. There was a good exponential correlation (r = 0.963) between the flare area evaluated visually and that evaluated by thermography, indicating that the degree of underestimation of the flare area by visual inspection increased with increasing flare size. This could be due to the fact that the rather irregular shape of a flare was rounded by the eyes. Suppressive effects of an antihistamine, terfenadine (20, 40, 60, and 120 mg, p.o.), on the flare caused by histamine (2 micrograms/0.1 ml saline) were evaluated in a similar way in a single-blind, crossover controlled trial using 15 healthy male volunteers. The histamine skin test was evaluated both visually and by thermography before and 4 hr after administration of placebo or each of 4 doses of terfenadine. Terfenadine (20, 40, and 60 mg) suppressed the skin flare in a dose-dependent manner, but 60 and 120 mg had almost the same effect. In all cases the flare area evaluated visually was smaller than that obtained by the thermography, although the degrees of reduction of flare area by the drug were similar by both methods when expressed as a percentage of placebo. In conclusion, thermography could serve as a tool for the objective evaluation of the histamine skin test.
Of 164 patients with trigeminal neuralgia treated by percutaneous retrogasserian glycerol injections, we have studied the long-term outcome (one to four years) of 72 patients. 51 patients suffered from idiopathic trigeminal neuralgia, and of these 92% were freed from pain by the operation. 21 patients suffered from symptomatic trigeminal neuralgia due to multiple sclerosis or of traumatic or infectious origin. Of these, only 38% became free of pain. A further 8 patients with facial deafferentation pain who underwent treatment by retrogasserian neurostimulation with a permanently implanted electrode were included in this study. 4 of these patients were rendered free of pain by this procedure.
The responsiveness to vasoactive agents in the perfused hindlimb of DOCA-salt hypertensive rats was examined and compared with that of normotensive rats. The vasoconstrictor responses in the femoral vascular bed to norepinephrine and serotonin were markedly potentiated in DOCA-salt hypertensive rats as compared with those in normotensive rats, and no change was found in the responses to angiotensin II. On the other hand, the vasodilatory response in DOCA-salt hypertensive rats to isoproterenol was attenuated without any marked changes in responsiveness to acetylcholine, nitroprusside and papaverine. These results suggested that the reduced vasodilator responses as well as the increased vasoconstrictor responses occur to some specific vasoactive agents in DOCA-salt hypertensive rats.
The affinities of drugs for the postsynaptic alpha 2-adrenoceptors in the dog saphenous vein were examined and compared with those in human platelets or in rat brain. The pA2 or pD2 values in the vein were determined in the presence of phenoxybenzamine. The pKi values (dissociation constant) of drugs for binding to alpha 2-adrenoceptors in human platelets or in rat brain were determined by radioligand binding assay using 3H-yohimbine (YOH) or 3H-clonidine (CLO) as ligands. The binding of agonists to 3H-YOH binding sites was carried out in the presence of GTP. The pA2 or pD2 values in the vein had a good correlation with pKi values for YOH sites but not with those for CLO sites in rat brain. The pKi values for YOH sites in human platelets had a good correlation with those for YOH sites in the brain or with pA2 or pD2 values in the vein. These results suggested that the affinities of adrenergic drugs for postsynaptic alpha 2-adrenoceptors in the dog saphenous vein are similar to those in brain and in platelets, and it is probable that the adrenergic drugs produce their alpha 2-adrenoceptor-mediated effects on vascular tissues primarily through binding to a low-affinity form of the alpha 2-adrenoceptors.
The effects of nadolol on experimental arrhythmias were investigated and compared with those of propranolol and alprenolol. The arrhythmias were induced by either ouabain, holothane plus adrenaline or acute coronary occlusion in anesthetized dogs. All three beta-blocking drugs in a dose range of 10 to 200 micrograms/kg inhibited halothane plus adrenaline-induced arrhythmias. These drugs also attenuated coronary occlusion-induced ventricular arrhythmias as well as other electrical abnormalities such as electrical alternation and conduction delay. Among the three drugs, nadolol was the most potent in suppressing both types of arrhythmias. Contrary to the potent effects on these arrhythmias, nadolol was ineffective against ouabain-induced arrhythmias even in a dose of 3 mg kg, while propranolol and alprenolol were significantly effective in a dose of 100 micrograms/kg. It is probable that the anti-arrhythmic effect of nadolol is exclusively due to its beta-blocking activity.
Single crystals of 1- hydroxyxanthine have been X-irradiated at 77 K and studied by ESR at 300 K. A nitroxide radical formed by abstraction of a hydrogen atom at N1 is the primary species formed by the radiation. A nitrogen hyperfine tensor with principal values of 0.8, 2.6, and 13.6 G and a g tensor with principal values of 1.9985, 2.0031, and 2.0099 have been determined. These results indicate a spin density of 0.24 on N1. Pairwise trapping of the nitroxide radical was also detected and principal values of the dipolar coupling tensor were found to be 140.7, -69.4, and -67.8 G. These data indicate effective radical separations of 7.3 A and are consistent with molecular layer spacings of 3.5 A in this crystal structure.
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A case, a 18-year-old male, of an endodermal sinus tumor (yolk sac tumor) in the fourth ventricle, was reported. The patient had a month history of headache, vomiting and gait disturbance prior to the hospitalization, when he admitted to our service he was in lethargic condition with left cerebellar ataxia and horizontal nystagmus. Lumbar tap revealed clear CSF under normal pressure of 110 mm H2O with the CSF protein of 432.5 mg/dl and cell count of 147/3. The vertebral angiography demonstrated space occupying lesion in the posterior fossa. Plain CT demonstrated only disappearance of the fourth ventricle and slightly dilated bilateral ventricles and third ventricle. However diffuse high density area around the fourth ventricle was demonstrated and the wall of bilateral anterior horn was slightly enhanced, after injection of contrast media. There was no other abnormal findings around the pineal region. Suboccipital craniectomy was performed and the tumor was totally removed macroscopically. The tumor was situated in th floor of the fourth ventricle and infiltrated into the fourth ventricular wall and th adjacent cerebellar tissue. The tumor was with soft, greyish color and extremely vascular. Histologically the tumor was diagnosed as endodermal sinus tumor according to Teilum's classification. There were stellate cells arranged in a loose with vacuolated network which formed cystic cavities and a complicated network of honeycomb appearance with a system of communicating cavities and channels. Various size of intra- and extracellular PAS-positive hyaline globules were also seen. Glomerular-like structure (Schiller-Duval body) was not observed. Immunoperoxidase study clearly demonstrated the presence of intra- and extracytoplasmic alpha-fetoprotein granules in the tumor tissue. The amount of the serum alpha-fetoprotein, measured by radioimmunoassay, showed 400 ng/ml. After irradiation in the posterior fossa (5000 rad) the patient was discharged. Three months later, follow up CT demonstrated small high density area in the anterior horn of the left lateral ventricle, so he was rehospitalised. Irradiation in the whole brain was again administered. The tumor was very radiosensitive. CT, after 800 rad, demonstrated complete disappearance of the tumor. After irradiation totally (3000 rad), he discharged with left cerebellar ataxia.
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