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The purpose of this study was to examine the distribution of neuronal damage following transient cerebral ischemia in the rat model of four-vessel occlusion utilizing light microscopy as well as {sup 45}Ca-autoradiography. Transient ischemia was induced for 30 min. The animals were allowed to survive for 7 d after ischemia. In the animals subjected to ischemia, the most frequently and seriously damaged areas were the paramedian region of hippocampus, the hippocampal CA1 sector, and the dorsolateral part of striatum, followed by the inferior colliculus, the substantia nigra, the frontal cortex, and the thalamus, which were moderate damaged. Furthermore, the cerebellarmore » Purkinje neurons, the hippocampal CA4 sector, the medial geniculate body, and the hippocampal CA3 sector were slightly affected. {sup 45}Ca-autoradiographyic study also revealed calcium accumulation in the identical sites of ischemic neuronal damage, except for the frontal cortex. Regional cerebral blood flow during 10 min of ischemia was severely decreased in selectively vulnerable areas. The blood flow in the medial geniculate body, the substantia nigra, the inferior colliculus, and the cerebellum was less pronounced than that in the selectively vulnerable areas. The present study demonstrates that transient cerebral ischemia can produce significant neuronal damage not only in the selectively vulnerable regions, but also in the brainstem.« less

Regional water distribution in the rat brain was obtained autoradiographically by activation analysis. The autoradiogram obtained for the normal rat brain showed high accumulation of water in the areas of sensory-motor cortex, hippocampus, thalamus, and amygdaloid cortex, whereas corpus callosum and internal capsule showed low water contents as expected. The estimated values of water content were 78.6 +/- 4.9 weight % for gray matter, and 73.5 +/- 4.9 weight % for white matter, respectively. The mean values of the water content were consistent with those obtained by a conventional drying-weighing method.

Thirty-two patients with salivary gland tumors or sialadenitis were studied with Tc-99m pertechnetate and Ga-67 imaging and, in some instances, sialography. The diagnostic algorithm presented allows the correct categorization of the salivary gland pathology in the vast majority of patients. The patients were studied serially with Tc-99m pertechnetate, Ga-67 and in certain situations sialography (or CT-sialography). Use of the algorithm can distinguish benign salivary tumors from malignant tumors and malignant tumors from inflammatory disease. The limitations and pitfalls of interpretation are discussed.

Magnetron-sputtered Ta/sub 2/O/sub 5/ films on Si are analyzed for their applications to semiconductor devices. It is clarified that the transition region formed at the Ta/sub 2/O/sub 5//Si interface plays a significant role in determining electrical characteristics. This transition region formed during the initial stage of deposition consists of a mixture of Ta, Si, and O, and its thickness is in the range of 4 to 6 nm. The composition profile of this transition region and its thickness depend on two dominant factors: (1) oxygen partial pressure in the sputtering gas and (2) the surface oxide thickness on Si priormore » to deposition. Furthermore, it is initially indicated that 2.5-nm-thick surface oxide formed on Si prior to deposition produces a significant deterioration in leakage current. By reducing the surface oxide thickness to as low as 1.8 nm and adjusting the oxygen partial pressure, an optimum transition region is formed, which makes it possible to obtain high-quality Ta/sub 2/O/sub 5/ films with high dielectric breakdown strength exceeding 6 MV/cm and low leakage current of <10/sup -9/ A/cm/sup 2/ (at 1 MV/cm).« less

Endogenous and exogenous oxygen in the rat brain were quantitatively determined using an autoradiographic technique. The oxygen images of frozen and dried rat brain sections were obtained as /sup 18/F images by using the /sup 16/O (/sup 3/He,p)/sup 18/F reaction for endogenous /sup 16/O images and the /sup 18/O(p,n)/sup 18/F reaction for endogenous and exogenous /sup 18/O images. These autoradiograms demonstrated the different distribution of oxygen between gray and white matter. These images also allowed differentiation of the individual structures of hippocampal formation, owing to the differing water content of the various structures. Local oxygen contents were quantitatively determined frommore » autoradiograms of brain sections and standard sections with known oxygen contents. The estimated values were 75.6 +/- 4.6 wt% in gray matter and 72.2 +/- 4.0 wt% in white matter. The systematic error in the present method was estimated to be 4.9%.« less

SMS 201-995 (SMS), a synthetic analogue of somatostatin (SRIF) has been shown to be effective in the treatment of the hypersecretion of hormones such as in acromegaly. However, little is known about the effects of SMS on the secretion of thyroid-stimulating hormone (TSH) in normal subjects. In this study, plasma TSH was determined with a highly sensitive immunoradiometric assay, in addition to the concentration of SMS in plasma and urine with a radioimmunoassay, following subcutaneous injection of 25, 50, 100 ..mu..g of SMS or a placebo to normal male subjects, at 0900 h after an overnight fast. The plasma concentrationsmore » of SMS were dose-responsive and the peak levels were 1.61 +/- 0.09, 4.91 +/- 0.30 and 8.52 +/- 1.18 ng/ml, which were observed at 30, 15 and 45 min after the injection of 25, 50, and 100 ..mu..g of SMS, respectively. Mean plasma disappearance half-time of SMS was estimated to be 110 +/- 3 min. Plasma TSH was suppressed in a dose dependent manner and the suppression lasted for at least 8 hours. At 8 hours after the injection of 25, 50, and 100 ..mu..g of SMS, the plasma TSH levels were 43.8 +/- 19.4, 33.9 +/- 9.4 and 24.9 +/- 3.2%, respectively, of the basal values.« less

This paper reports the results of tests of the newly developed Varian EIMAC X2274 in the JAERI JT-60 ICRH system at pulse lengths up to 6 seconds at 131 MHz. It is our belief that these tests achieved the highest long pulse, or CW, power that has ever been delivered by a single power grid tube at frequencies above 100 MHz. Varian's EIMAC X2274, developed in conjunction with General Atomics and the US Department of Energy, uses an improved pyrolytic graphite grid configuration which provides significantly better vhf performance than the grids of the X2242 tetrode which was tested inmore » this system in 1989. The EIMAC X2274 combines the improved grids with a new anode design which reduces the required water flow approximately 50% and increases the maximum anode dissipation 80%. All tests were performed at 131 MHz, the system's highest operating frequency. Tests of both prototype EIMAC X2274s produced essentially identical results. The basic objectives of these tests were: to demonstrate that the system with the EIMAC X2274 can reliably produce 1.5 MW at 130 MHz at 5 second pulse lengths for the JT-60U tokamak and to collect data for use in the design of future high power ICRH systems. In these tests the tube and system produced up to 1.7 MW at pulse lengths up to 5.4 seconds: i.e, the EIMAC X2274 in this system can easily meet Objective 1. The remainder of this paper shows that Objective 2 has been fulfilled. In addition to the high power tests, operational range tests were performed under variable VSWR conditions. Unlike the EIMAC X2242 tests were rf current heating of the screen grid limited output power, system parameters, rather than tube parameters, limited the output power in the high power tests. Operational range tests were conducted at output power levels chosen to be well within the system's anode cooling capability.« less

Endogenous oxygen-18(/sup 18/O) content in the rat brain was determined as the /sup 18/F image by means of the nuclear reaction and the autoradiography (ARG). Endogenous /sup 18/O which contained 0.204% in total oxygen was converted to /sup 18/F by the /sup 18/O (p,n) /sup 18/F reaction. The rat brain slice(34..mu..m), the rat brain homogenate slices(34..mu..m) contained various percent of water (65,75 and 85%), and 24..mu..m polyester film (33% of oxygen) as a /sup 18/O standard were placed on the aluminum target holder cooled to -100/sup 0/C by liquid N/sub 2/. Proton beam(18MeV) was scattered and decayed to 5.35MeV andmore » Ti, Al foils, He gas and 100 ..mu..m polyester film to irradiate the target. The slices were irradiated for 30 min at 15 ..mu..A to need the enough activity for ARG. Uniformity of the beam density was also measured by 100 ..mu..m polyester film set to precede the target. Quantitative ARG of the slices were processed 3 hours after the irradiation to decay out the other radio-activities (/sup 11/C and /sup 13/N). /sup 18/F image which consists of both H/sub 2//sup 18/O and /sup 18/O in non-water materials in the rat brain was visualized. The ARG density and the oxygen content showed their linear relationship. This method will be useful to apply to the various brain studies (e.g. CBF study, water content in brain edema and the metabolism of /sup 18/O labeled compounds.)« less