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Biomedical subjects

K Yaguchi

Publications and source records attributed to K Yaguchi.

36 records · Page 2Linked to original sources
PubMed1986

Left-right asymmetry in the temporal and parietal region based on the medullary pattern of cerebral white matter.

Left-to-right differences in cerebral structures of the posterior temporal and inferior parietal region were investigated in CT examinations from 500 cases, by anatomic analysis based on the medullary branches of cerebral white matter. On the left side, the planum temporale and middle temporal gyrus were positioned more posteriorly, the intraparietal sulcus was deeper and lower, and the folding of the inferior parietal lobule was more extensive. The lateralization of the planum temporale diminished gradually from 19 years of age downwards. An anatomic analysis of the medullary branches succeeded in revealing the cerebral asymmetry and is expected to be useful in magnetic resonance imaging.

Adolescent↗
PubMed1985

Surgically confirmed myelographic classification of congenital intraspinal lipoma in the lumbosacral region.

Twenty-four cases of histologically confirmed congenital intraspinal lipoma of the lumbosacral region were studied by means of myelography with metrizamide. The findings were compared with intraoperative observations. Myelography with metrizamide clearly revealed the detailed intrathecal structures and allowed a classification of intraspinal lipomas into four types, in terms of their insertion into the conus medullaris: dorsal type, either with direct or indirect (via an intrathecal stalk) insertion of the extrathecal lipoma into the dorsal aspect of the conus medullaris; caudal type; combined type; and filar lipoma. Based on our surgical experience in untethering and decompression of the lesions, the classification was found to be useful in designing a safe and effective surgical procedure which minimized all possible trauma to the intrathecal neural structures.

Adolescent↗
PubMed1985

Computed tomography of cerebral infarction along the distribution of the basal perforating arteries. Part II: Thalamic arterial group.

Computed tomographic (CT) manifestations of cerebral infarction along the distribution of the basal perforating arteries were reviewed and correlated with cerebral angiography. Infarcts in the territories of perforators were demonstrated individually based on knowledge of their three-dimensional distribution as shown by microangiography of cadavers. In Part II of the study, the posterior areas supplied by the thalamic arteries were examined. Infarcts in the area supplied by the thalamotuberal arteries involved the anterior pole of the thalamus; those in the area of the thalamoperforate arteries involved the medial portion of the thalamus, along the lateral wall of the third ventricle; those in the area of the thalamogeniculate arteries involved the posterolateral portion of the thalamus; and those in the area of the choroidal arteries of the lateral ventricle involved the most posterolateral and dorsolateral portions of the thalamus. Clinical and neuroradiological correlations are discussed.

Arteries↗
PubMed1983

Middle fossa arachnoid cyst: clinical, neuroradiological, and surgical features.

16 patients and 4 adult cases of small-or medium-sized middle fossa arachnoid cyst were subjected to various neuroradiological investigations and their results were analyzed in terms of possible mechanisms of cyst expansion. Based on the results of the investigations which strongly suggested that the cyst is an expanding lesion, all cases were surgically treated by the same techniques of craniotomy, excision of the outer cyst membrane, followed by a cystoperitoneal shunt, resulting in complete disappearance of the cyst concomitant with reexpansion of the surrounding brain and marked improvement in the clinical pictures of the patients.

Adolescent↗
PubMed1976

Temporal sequence of frequency specific and nonspecific effects of flickering lights upon the occipital electrical activity in man.

Human subjects were exposed 10 times to light flicker for a period of 10 sec, being altered with equal non-flicker periods. Four flicker frequencies were studied: the resting alpha frequency, twice the frequency, and 14 and 6 c/sec, which are both unrelated to alpha rhythms. The effect of flicker stimulation upon the occipital EEG was quantified in terms of integrated values per band over an epoch of 10 sec using a Walter-type frequency analyzer.

Alpha Rhythm↗
PubMedDate not supplied

Extent of cadmium accumulation and its effect on essential metals in liver, kidney, and body fluids.

Cadmium was injected sc into female Wistar rats at a dose of 3.0 mg Cd/kg body weight, 4 times a week for 1, 2, 3, 4, 5, and 6 wk. Cadmium and five essential metals in the livers and kidneys were determined simultaneously by inductively coupled plasma-atomic emission spectrometry. Concentration of cadmium in the livers increased linearly up to 3 wk, remained at an almost constant and highest value (440 micrograms Cd/g wet liver) for the following 2 wk, and then decreased. The difference between cadmium in the whole livers and cadmium bound to heat-stable proteins was wider during the plateau than during the other periods. Cadmium in the kidneys was close to a plateau after 6 wk of injections. Concentrations of zinc in the livers and copper in the kidneys changed dramatically with injections of cadmium, and the changes were related to the changes in concentrations of the two metals in plasma and urine. Concentration of iron in the kidneys decreased with injections of cadmium. The content ratio of calcium to magnesium was high in the case of liver edema and was suggested to be an indicator. Cadmium in urine was assumed to originate from the liver in the case of high accumulation of the metal.

Animals↗
PubMedDate not supplied

Accumulation and chemical forms of cadmium and its effect on essential metals in rat spleen and pancreas.

Cadmium was injected sc into female Wistar rats at a dose of 3.0 mg Cd/kg body weight, 4 times a week for 1, 2, 3, 4, 5, and 6 wk. Concentrations of cadmium in the spleen and pancreas were determined, together with essential metals, by inductively coupled plasma-atomic emission spectrometry. Cadmium in both tissues increased even after maximum concentration was attained in the liver. Contents of zinc, calcium, and magnesium in the spleen increased with splenomegaly, while content of iron decreased. Concentrations of calcium, magnesium, and iron decreased in the pancreas, while concentration of zinc showed a transitory increase. Cadmium in the spleen and pancreas supernatants was mostly bound to metallothionein, and metallothionein in the pancreas was highly susceptible to oxidation reaction. The spleen and pancreas were histologically less affected by cadmium loading compared to the liver and kidney, and the pancreas showed only slight alterations after injections for 5 and 6 wk.

Animals↗
PubMedDate not supplied

In vitro pesticide degradation in turfgrass soil incubated under open and sealed conditions.

Degradation of selected pesticides was conducted in a turfgrass soil from a golf course under open (i.e., allowing gas exchange with atmosphere) and sealed systems. The time required for 50% of the initial dose of fenitrothion (O,O-dimethyl O-4-nitro-m-tolyl phosphorothioate), diazinon (O,O-dimethyl O-2-isopropyl-6-methylpyrimidin4-yl phosphorothioate), iprodione [3-(3,5-dichlorophenyl)-N-isopropyl-2,4-dioxo-imidazolidine-1-carboxamide], mecoprop [(RS)-2-(4-chloro-otolyloxy)propionic acid], and asulam (4-aminophenylsulfonyl-carbamate) to dissipate (half-life, t 1/2) was less than 2 wk under both conditions. The t 1/2 values of dithiopyr (S,S'-dimethyl 2-difluoromethyl-4-isobutyl-6-trifluoro-methylpyridine-3,5-dicarbothioate) were 324 and 185 d under the open and sealed conditions, respectively. The t 1/2 values of isoprothiolane (di-isopropyl 1,3-dithiolan-2-ylidene-malonate), flutolanil (alpha,alpha,alpha-trifluoro-3'-isopropoxy-o-toluanilide), and benefin (N-butyl-N-ethyl-alpha,alpha,alpha-trifluoro-2,6-dinitro-p-toluidine) under the open conditions were 154, 336, and 47 d, respectively. The t 1/2 values of these pesticides increased slightly under the sealed conditions. The t 1/2 values of terbutol (2,6-di-tert-butyl-4-methylphenyl N-methycarbamate) and one of the major degradation products, N-demethyl-terbutol (2,6-di-tert-butyl-4-methylphenyl carbamate), were 182 and 291 d under the open conditions and increased by six- and threefold under the sealed conditions, respectively. The degradation system under the sealed conditions could characterize the persistence of terbutol and N-demethyl-terbutol, which were the most persistent in the field.

Biodegradation, Environmental↗