Thyroxine deiodination associated with NADPH-dependent (enzymatic) and Fe3+-ADP-catalyzed (nonenzymatic) reactions in hepatic microsomes.
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Adenosine Diphosphate↗
Biomedical subjects
H Fukuyama
Publications and source records attributed to H Fukuyama.
The persistence of high uptake of serum albumin in the olfactory bulbs of mice throughout their adult lives.
Brain to plasma concentration ratios of i.v. administered human serum albumin (HSA) in the olfactory bulb, frontal cortex and cerebellum were evaluated in DDD mice of different ages. We measured the brain uptake of serum albumin excluding intravascular content by using a double isotope technique and examined the time course of the brain uptake to evaluate the brain uptake at different time intervals. In young adult mice, the value was significantly higher in the olfactory bulb than in other brain regions 3-24 h after (125)I-HSA injection. It was about 2.3 times higher in the olfactory bulb than in the cerebellum (P < 0.01). The high concentration ratios in the olfactory bulb were observed in all 4-22-month-old mice. Moreover, the ratio in the olfactory bulb 24 h after (125)I-HSA injection was higher in 22-month-old mice than in younger animals. The high uptake of serum albumin in the olfactory bulb suggests that intravascular macromolecules can be transported into the olfactory bulb more easily than in other brain regions with tight endothelium, and the persistence of high uptake during adult life may be associated with age-related morphological changes in the olfactory bulb.
Journal Article↗
Epidural venous system (meningorachidian venous plexus) in juvenile amyotrophy of distal upper extremity: assessment with GD-DTPA enhanced volumetric MR study.
The epidural venous system (meningorachidian venous plexus) was analyzed utilizing gadolinium-diethylenetriamine pentaacetic acid (DTPA) (Gd-DTPA) enhanced volumetric magnetic resonance (MR) images in 11 patients with focal cervical spinal cord atrophy, clinically consistent with juvenile amyotrophy of distal upper extremity. In our series, all of the patients showed unusual posterior epidural venous enhancement at the C5-6 level, suggesting posterior epidural venous dilatation. Three patients also showed prominent dilatation of cervico-thoracic epidural veins surrounding the thecal sac. These MR findings were also demonstrated by spinal phlebography. Gd-DTPA enhanced MR images, especially high resolutional volumetric MR images, were efficient for evaluating these vessels. The observation of meningorachidian venous plexus along the disease course should be necessary for searching the pathogenesis of this disease.
Adolescent↗
Prevalence of type 2 diabetes mellitus and impaired glucose tolerance in a rural area of Japan. The Funagata diabetes study.
PURPOSE: To determine the prevalence of type 2 diabetes and impaired sucrose tolerance (IGT) among people aged 40 and over in a rural area, Funagata, Japan, by using a 75-g oral glucose tolerance test (OGTT), and to compare the prevalence to that obtained from a more urban area, Hisayama, Japan. METHODS AND RESULTS: Total eligible subjects for the Funagata study were 3526. Among them, 140 were confirmed to have diabetes judged by the 1985 WHO criteria. A 75-g OGTT was conducted, excluding the 140 known cases of diabetes. The 1985 WHO criteria were used to classify the current diabetes status of participants. The overall participation rate was 74.4%. The prevalence of diabetes (known and newly diagnosed cases combined) was 9.1% for men and 10.8% for women. The prevalence of IGT was 12. 0% for men and 16.5% for women. Age-adjusted prevalence (using 1990 Japanese census) of diabetes and IGT in men in Hisayama is two times higher than in Funagata (12.8% vs. 6.8% for diabetes, 19.5% vs. 10. 3% for IGT). Age-adjusted prevalence of IGT in women in Hisayama is significantly higher than in Funagata. CONCLUSIONS: The prevalence of type 2 diabetes among people aged 40 and over is approximately 10% even in a rural area of Japan. Prevalence of diabetes and IGT is much higher in an urban area than in a rural area in Japan.
Adult↗
High intensity areas on noncontrast T1-weighted MR images in cerebral infarction.
Among 46 noncontrast magnetic resonance studies on patients with cerebral infarction, 11 showed areas of high signal intensity of the involved brain on T1-weighted images. These areas were more frequent in cerebral or cerebellar cortical lesions. Lacunar infarcts in lenticular nuclei, internal capsules, corona radiata, or brain stem did not show any high signal intensity areas on T1-weighted images, whereas the thalamic infarcts did. Sequential studies revealed that these lesions displayed low signal intensity on T2-weighted images at first, and then a high signal intensity area appeared on T1-weighted images. We suggest that these high signal intensity areas on the T1-weighted images in cerebral infarction are caused by hemorrhagic changes at the periphery of the infarction, where blood flow is restored by recanalization or collateral supply.
Adult↗
White matter hyperintensities may correspond to areas of increased blood volume: correlative MR and PET observations.
A method for correlating positron emission tomography with magnetic resonance (MR) imaging enabled the authors to examine the high intensity white matter areas in T2-weighted images in patients with internal carotid artery occlusion. The high intensity areas showed increased cerebral blood volume compared with the ipsilateral and contralateral normal intensity white matter. This observation may have relevance in explaining some of the patchy white matter lesions seen in MR images.
Aged↗
Sympathetic nerve terminals in the tunica media of human superficial temporal and middle cerebral arteries: wet histofluorescence.
In specimens from the superficial temporal artery (STA) and middle cerebral artery (MCA), obtained during STA-MCA anastomosis, green fluorescent varicose fibers of sympathetic nerves were clearly visible with both formaldehyde-glutaraldehyde and sucrose-potassium phosphate-glyoxylic acid wet-histofluorescent techniques. These fibers were fairly thick, were densely packed and had a meshwork-like arrangement. Fluorescent terminals were seen both in the adventitia and in the outer muscular layer of the media in both STA and MCA specimens. They were more often observed in patients with prominent atherosclerosis in these vessels. The present study suggests the possible role of sympathetic nerve terminals in the development of vasospasm and occlusive lesions in cerebral vessels. It may also help to explain the marked constriction and transient occlusion following a STA-MCA bypass procedure.
Adrenergic Fibers↗
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.
Adult↗
Asymmetric tonic seizures with bilateral parietal lesions resembling frontal lobe epilepsy.
We performed long-term video/ EEG monitoring and a single photon emission computed tomographic (SPECT) study to clarify generating mechanism of bilateral tonic motor seizures resembling seizures generated by the supplementary motor area (SMA), in patients with bilateral parietal lesions. We describe 2 patients (age 24 and 32 years), with bilateral parietal lesions. Clinically, seizures were preceded by lightning sensation in the body, followed by asymmetric tonic posturing of both hands and thrashing movements of the feet, lasting for less than 1 min. Ictal rhythmic (7-15 Hz) activity at the vertex was observed on the EEG in 1 patient. Interictal SPECT in 2 patients showed decreased blood flow in both parietal areas, consistent with bilateral parietal abnormalities on T2- and T1-weighted MRIs. Ictal SPECT in 1 patient showed increased blood flow in the right parietal and frontopolar areas. The present 2 patients had clinically asymmetric tonic seizures, most likely resulting from spreading of the ictal activity from the parietal lesions via the superior longitudinal fasciculus to the SMA. Bilateral, homologous lesions in the parietal area might cause disinhibition on the unilateral epileptogenic side.
Adult↗
Spinocerebellar degeneration: qualitative and quantitative MR analysis of atrophy.
Magnetic resonance imaging at 1.5 T was performed in 27 patients with either the cerebellar or spinocerebellar form of spinocerebellar degeneration and in 10 control subjects. Neither T1- nor T2-weighted images (T1WIs and T2WIs) of the patients showed any abnormal intensity areas within the cerebellum or in any other structures of the brain. The T2WIs delineated normal configurations of symmetrical dentate and red nuclei. On T1WIs two patterns of atrophy were detected: (a) moderate to severe shrinkage of the basis pontis and the middle cerebellar peduncles associated with atrophy of the cerebellum, and (b) moderate atrophy of the cerebellum with a preserved basis pontis. The former morphological changes are consistent with the pathology of pontocerebellar atrophy (PCA) and the latter with those of cerebellar cortical degeneration (CCD). In 11 patients, only after a quantitative analysis of the images were we able to classify them in one of the two morphological categories (PCA or CCD). There was a significant correlation between atrophy of the cerebellum and atrophy of the basis pontis. Furthermore, in the PCA group the anterior portion of the body of the corpus callosum was significantly smaller in comparison with the control subjects.
Adult↗
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.
Adult↗