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Biomedical subjects

H Takei

Publications and source records attributed to H Takei.

At least 163 records · Page 9Linked to original sources
PubMed1986

The effects of pyridinium salts, structurally related compounds of 1-methyl-4-phenylpyridinium ion (MPP+), on tyrosine hydroxylation in rat striatal tissue slices.

We had previously reported that 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), which produces Parkinson's disease in humans and animals, inhibited tyrosine hydroxylation, the rate-limiting step of dopamine synthesis, in striatal tissue slices after its conversion to 1-methyl-4-phenylpyridinium ion by monoamine oxidase. In this report, structurally related compounds of 1-methyl-4-phenylpyridinium ion (MPP+) were synthesized and tested for their ability to inhibit tyrosine hydroxylation in rat striatal tissue slices. The following pyridinium salts showed inhibitory effect on tyrosine hydroxylation: pyridinium salts that substituted the alkyl group for the methyl group of MPP+ (1-ethyl-, 1-propyl-, 1-isopropyl-4-phenylpyridinium ions); pyridinium salts that changed the position of the phenyl group (1-methyl-2-phenyl-, 1-methyl-3-phenylpyridinium ions); pyridinium salts that modified the phenyl ring at 4 position (1-methyl-4-tolylpyridinium ion, 1-methyl-4-(4'-methoxyphenyl)pyridinium ion); and N-methylisoquinolinium ion. In contrast, pyridinium salts in which the phenyl group was replaced with hydrogen, methyl or methoxycarbonyl group, paraquat (1,1'-dimethyl-4,4'-dipyridinium chloride, one of bipyridinium compounds and a widely used herbicide), and N-methylquinolinium ion, showed no inhibitory effect. Nomifensine, an inhibitor of dopamine uptake, prevented the inhibition caused by 1-methyl-2-phenylpyridinium ion. The result suggests that the effective pyridinium salts are taken up into dopaminergic neurons likewise MPP+ by the dopamine transport system and inhibit tyrosine hydroxylation in striatal tissue slices. N-methylisoquinolinium ion could be one of the candidates of endogenous or environmental factors that produce Parkinson's disease.

1-Methyl-4-phenylpyridinium↗
PubMed1986

The lumped constant in the deoxyglucose procedure declines with age in Fischer-344 rats.

Concentrations of [14C]2-deoxy-D-glucose ([14C]DG) and of glucose were measured in plasma of arterial and sagittal sinus venous blood from awake Fischer-344 rats at 3, 12, and 24 months of age, during continuous intravenous infusion of [14C]DG and after a steady-state arterial plasma concentration of [14C]DG was reached. Brain extraction, i.e., the difference between arterial and venous plasma concentrations divided by the arterial plasma concentration, was calculated for both [14C]DG and glucose. Because exchange of both substances between rat plasma and erythrocytes is slow, the ratio of the brain extraction of [14C]DG to that of glucose is identical to the lumped constant in the deoxyglucose procedure of Sokoloff et al. [J. Neurochem. 28, 897-916. (1977)]. This ratio equaled 0.502 +/- 0.015 (SEM) at 3 months, 0.456 +/- 0.007 at 12 months, and 0.418 +/- 0.006 at 24 months of age (n = 15); the means differed significantly from each other (p less than 0.05). The results indicate that the lumped constant declines between 3 and 24 months of age in awake rats, and suggest that many reported age reductions in regional cerebral glucose utilization, of 15-25%, are artifactual.

Aging↗
PubMed1986

Enhancement of anti-inflammatory effects of biphenylylacetic acid by its incorporation into lipid microspheres.

Using lipid microspheres (LM), average diameter 0.2 micron, and containing methyl and ethyl esters of biphenylylacetic acid (BPAA) in the carrageenan paw oedema tests in rats, it was found that their anti-inflammatory activities were enhanced 3 to 8 times over that of free BPAA. By electron microscopy, LM were seen to be taken up into the endothelial cells of the blood vessels and macrophages at the inflamed sites. In a study using dogs, after an intravenous injection of BPAA-methyl ester incorporated into LM (lipo-BPAA-Me), lipo-BPAA-Me rapidly disappeared from the blood and the BPAA serum level was gradually elevated. These results, together with previous findings, suggest that part of lipo-BPAA-Me was immediately transferred to the inflamed site and taken up by prostaglandin (PG)-producing cells as macrophages. It is considered that the anti-inflammatory effects of BPAA are enhanced by incorporating it into LM.

Animals↗
PubMed1986

Effects of Nd:YAG and CO2 lasers on cerebral microvasculature. Study in normal rabbit brain.

The effect of Nd:YAG and CO2 laser beams on cerebral microvasculature was examined in experimental animals. Soft x-ray microangiography and histological examination of the brain after Nd:YAG laser exposure revealed broad avascular or oligovascular zones in the irradiated and the surrounding edematous tissue, in which the surviving vessels were narrowed and tapered without significant leakage of blood. After CO2 laser exposure, a wedge-shaped tissue defect surrounded by layers of charring, coagulation, and edema was observed. The main finding in the surrounding coagulation and edematous layers was dilatation of the vessels. Hemorrhage was sometimes observed, mainly in the edematous layer. These findings seem to explain the effective hemostatic capability of the Nd:YAG laser and the occasional hemorrhage following CO2 laser exposure, especially at high energy output.

Animals↗
PubMed1986

[Spinal dural AVM--report of three cases].

A new type of spinal AVM is reported. The characteristics are as follows: All the patients are male over 50-years-old. Their symptoms are insiduous and progressive ischemic pattern. All the lesions locate at the thoracic and lumbar levels. Selective intercostal angiography shows a fistulous AVM adjacent to the intervertebral foramen fed by spinal dural branch and drain into tortuous veins on the spinal cord via radiculomedullary vein. No typical hair-pin configuration by radiculomedullary and spinal cord arteries contributes to the AVM. This type of spinal AVM must be distinguished from so-called singled coiled type spinal cord AVM since pathophysiological features presumably are different from each other; the former is "dural" on anatomical basis, whereas the latter is "pial". Embolization should be recommended as a first choice of treatment to spinal dural AVM.

Aged↗
PubMed1985

Parietal foramina complicated by meningocele.

Parietal foramina are symmetrical bone defects adjacent to the sagittal suture and are not usually associated with other malformations. A case is described in which scalp tumors protruded through the foramina and proved to be meningoceles. No such cases appear to have been previously reported. The possible developmental mechanisms are discussed.

Female↗
PubMed1985

Anomalous atlantoaxial portions of vertebral and posterior inferior cerebellar arteries.

In a review of the vertebral angiograms of 300 patients free from disease at the craniovertebral junction, we found atlantoaxial arterial anomalies in 2,3%. These were: 2 cases in which the vertebral artery ran in the spinal canal below C1, 3 cases of duplication of the vertebral artery above and below C1, and 2 cases of origin of the posterior inferior cerebellar artery at C2. Although these arteries ran in the spinal canal between C1 and C2, they never encroached upon the posterior third of the canal. From the survey of another 21 patients having bony abnormalities at the craniovertebral junction, the first type of arterial anomaly described above was seen in 4 patients and associated with failure of segmentation of the embryonic sclerotome such as occipitalization of the atlas or Klippel-Feil syndrome. It is possible to relate the development of these anomalous vessels to malarrangement of the embryonic segmental arteries. Our results indicate that one must be cautious with lateral C1/2 puncture or surgical exposure of the region.

Adult↗
PubMed1985

Enzymatic determination of serum ethanol with membrane-bound dehydrogenase.

In this enzymatic method for detecting ethanol in blood by use of membrane-bound microbial alcohol dehydrogenase (no EC no. assigned), the enzyme catalyzes the reaction irreversibly and the rate of oxidation can be monitored by spectrophotometry of the reduction of the indicator dye. No pyridine nucleotides such as NAD+ or NADP+ are used. The calibration curve is linear in the range of 0.1 to 4.0 g of ethanol per liter. Assays of 45 samples of serum having ethanol values ranging from 0.4 to 3.2 g/L by the described technique and a gas-chromatographic method gave respective means of 1.734 and 1.732 g/L (r = 0.954).

Alcohol Dehydrogenase↗
PubMed1985

[Experimental study of brain lesions after combined coaxial exposure to high-peaked pulse wave form CO2 and Nd: YAG lasers on the brain].

UNLABELLED: The CO2 laser is useful for cutting and vaporization but not for coagulation and hemostasis. On the contrary, YAG laser is effective for coagulation and hemostasis but not for cutting. The purpose of this study is to examine the effect of the exposure of combined, coaxial CO2 and YAG laser on the animal brain to supplement the advantages and draw-backs of each other. To compare these results, each of non-combined pulse wave form CO2 and YAG lasers was employed separately. MATERIALS AND METHODS: The lasers in this study were pulse wave form CO2 and YAG lasers, employed separately or simultaneously using 130 YZ of Nihon Infrared Industries Company. Japanese white rabbits were anesthetized with pentobarbital. Fronto-parietal burr holes were made, the dura was removed and then Evans blue solution was injected intravenously. The lasers were employed to the cerebral cortex without great vessels using a micromanipulator attached to the operative microscope with a distance of 30 cm. The spot size was 700 mu for CO2 laser and 1200 mu for YAG laser. The first experiment was to see the effect of nine combinations of simultaneous coaxial CO2 of 2, 4 and 8 watts and YAG lasers of 10, 20 and 40 watts, 1 sec on the brain. In the second experiment, also combining two lasers, the exposure time of YAG laser was elongated from 1 or 2 seconds into 2 or 4 seconds and the arrangement of powers was the same as that of the first experiment. The lesions were thus made in 18 different conditions.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1985

[Nidus embolization of cerebral arteriovenous malformation fed mainly by a pericallosal artery prior to surgical excision. Case report].

Nidus embolization of large arteriovenous malformation (AVM) by silastic spheres is not rarely performed prior to surgical excision of AVM. This technique is highly indicated for the large AVM supplied by the middle and the posterior cerebral arteries since silastic spheres injected into either the internal carotid or the vertebral arteries usually enter the middle or the posterior cerebral arteries due to less sharp angle from the main arteries. The authors report a case whose AVM, fed mainly by the anterior cerebral artery, was successfully embolized with silastic spheres using balloon catheter technique. On December 1, 1983, a 27-year-old man was admitted to our department with chief complaint of headache and clonic convulsion of the left upper and lower limbs. Convulsion began in 1973 and severe headache suddenly appeared two months prior to admission. He was neurologically asymptomatic on admission. Right internal carotid angiogram taken on admission showed a presence of large arteriovenous malformation in the medial portion of the right fronto-parietal lobe and corpus callosum fed mainly by the right pericallosal artery. Nidus embolization with silastic spheres was planned to make surgical removal easier. To prevent stray of silastic spheres into the right middle cerebral artery, balloon, introduced into the M1, was inflated for a few minutes, during which time, injection of 40 silastic spheres of 1.5 and 2.0 mm in diameter was performed via the right internal carotid artery. The nidus was significantly reduced and total removal of the nidus was successfully done 28 days following the embolization.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗