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Biomedical subjects

M Yasui

Publications and source records attributed to M Yasui.

At least 199 records · Page 11Linked to original sources

The termination of retinofugal fibers in the crab-eating monkey (Macaca irus): an autoradiographic study.

In the crab-eating monkey (Macaca irus), the subcortical projection from the retina was studied by means of the autoradiographic method. Retinofugal fibers terminated bilaterally in the suprachiasmatic, pregeniculate, lateral geniculate, olivary, pretectal, lateral terminal and dorsal terminal nuclei and the superior colliculi. In the ipsilateral lateral geniculate nucleus, the retinofugal fibers terminated on laminae 0, 2, 3, and 5; in the contralateral nucleus, they ended in laminae 1, 4, and 6. In the superior colliculi, retinal terminals were aggregated in the stratum griseum superficiale. The ipsilateral suprachiasmatic nucleus showed a heavier labeling than the contralateral nucleus.

Animals↗

Wilson's disease; increased aluminum in liver.

Interaction of trace metal metabolism was studied in a patient with Wilson's dease. Atomic absorption analysis showed markedly increased urinary excretion of copper and aluminum and an increased aluminum content was found in the biopsied liver by neutron activation analysis. These findings suggest a complicated pathogenetic mechanism involving other metals besides copper in the Wilson's disease.

Aluminum↗

Epidermodysplasia verruciformis: viral particles in early malignant lesions.

Two cases of epidermodysplasia verruciformis were studied histologically and electron microscopically. Four lesions examined were histologically benign, and had viral particles morphologically similar to that of common human warts. Two lesions on the forehead and the face were histologically in the stages of malignant transformation, the intraepidermal epithelioma and the early invasive squamous cell carcinoma. Similar viral particles were also observed in the upper layers of these 2 lesions. These results suggest that at least some of the virus-induced lesions of epidermodysplasia verruciformis actually become malignant.

Adult↗

Impaired liver function and long-term prognosis after hepatectomy for hepatocellular carcinoma.

Patients with hepatocellular carcinoma (HCC) show a wide variety of histologic changes in the noncancerous liver parenchyma, and these changes may affect the prognosis. In this study, we grouped patients according to the extent of liver impairment and investigated their long-term prognosis after hepatectomy for HCC. A total of 194 patients were divided into two groups according to their plasma clearance rate of indocyanine green (ICG-K) values: those with values < 0.13 min-1 (group A, n = 97) and those with values of > or = 0.13 min-1 (group B, n = 97). Eighty-nine patients with stage I or II HCC were also divided into two groups: those with values < 0.13 min-1 (group C, n = 52) and those with values of > or = 0.13 min-1 (group D, n = 37). Group B patients tended to survive longer than group A patients during 4 years after hepatectomy, and group D patients survived significantly longer than group C patients (p < 0.01). There was no significant difference in the recurrence-free survival rates between those in groups A and B or groups C and D. Because patients with poor liver function frequently had multiple recurrent lesions and limited therapeutic options, patients with good liver function received more intensive treatment. In conclusion, the extent of liver impairment is one of the factors determining long-term prognosis after hepatectomy for HCC, especially during the early stage of the disease.

Adult↗

Comprehensive MR imaging of acute gynecologic diseases.

Rapid advances in techniques of magnetic resonance (MR) imaging have enabled diagnosis of acute gynecologic conditions, which are characterized by sudden onset of lower abdominal pain, fever, genital bleeding, intraperitoneal bleeding, or symptoms of shock. The chemical-selective fat-suppression technique not only helps establish the characteristics of lesions that contain fat components but also increases the conspicuity of inflammatory lesions. When a T2-weighted image is obtained with a very long effective echo time (>250 msec), even a small amount of ascites can be easily identified and the contrast between urine and complex fluid becomes more conspicuous. T2*-weighted images are useful for identification of hemorrhagic lesions by demonstrating deoxyhemoglobin and hemosiderin. Contrast material-enhanced dynamic subtraction MR imaging performed with a three-dimensional fast field-echo sequence and a rapid bolus injection of gadopentetate dimeglumine allows evaluation of lesion vascularity and the anatomic relationship between pelvic vessels and a lesion and allows identification of the bleeding point by demonstrating extravasation of contrast material. To optimize the MR imaging examination, attention should be given to the parameters of each pulse sequence and proper combination of the sequences.

Diagnosis, Differential↗

Scavenger effect of elastase on calcifications in liver, kidney and central nervous system tissues of rabbits with atherosclerosis induced by cholesterol-rich diet.

The inhibitory effect of elastase on calcification in liver, kidney and the central nervous system (CNS) was studied in rabbits with atherosclerosis induced by a cholesterol-rich diet. A total of 25 male rabbits were divided into six groups. In the first three groups, rabbits received a standard diet, a 1.5% cholesterol-rich diet or a 1.5% cholesterol-rich diet with intraperitoneal elastase (450 IU/kg.day) for 3 months. In the second three groups, rabbits received a standard diet, a 0.67% cholesterol-rich diet or a 0.67% cholesterol-rich diet with intraperitoneal elastase (450 IU/kg.day) for 6 months. Tissue calcium levels were then determined by neutron activation analysis. Tissue lipid levels were also measured. Dietary cholesterol increased serum lipid levels, atherosclerotic lesions and calcium levels in the CNS, but not in the liver or kidney. Calcium levels in the cerebellum and spinal cord of rabbits receiving the 0.67% cholesterol-rich diet plus elastase were significantly lower than those of rabbits receiving the 0.67% cholesterol diet alone. Elastase had a gradual inhibitory effect on the increase in calcium levels in CNS of cholesterol-induced atherosclerotic rabbits, reduced the increase in serum lipids and decreased the incidence of atherosclerotic lesions.

Animals↗

Calcium, phosphorus and aluminium concentrations in the central nervous system, liver and kidney of rabbits with experimental atherosclerosis: preventive effects of vinpocetine on the deposition of these elements.

Calcium, phosphorus and aluminium concentrations in the central nervous system, liver and kidneys were determined in 16 rabbits with atherosclerosis experimentally induced by a cholesterol-rich diet and the protective effect of 3 or 10 mg/kg.day vinpocetine (14-ethoxycarbonyl-(3 alpha,16 alpha-ethyl)-14,15-eburnamenine) given orally on the deposition of these elements was assessed. Rabbits fed a cholesterol-rich diet developed atherosclerosis after 3 months and these rabbits possessed high concentrations of calcium, phosphorus and aluminium in the central nervous system, determined by neutron activation analysis. In atherosclerotic rabbits fed a vinpocetine supplement, there was a decrease in concentrations of these elements in tissues. It is suggested that calcium, phosphorus and aluminium may be implicated in the aetiology of atherosclerosis and that vinpocetine may have a preventive action on the deposition of these elements in central nervous tissue, liver and kidney.

Aluminum↗

Effects of ibudilast on calcium deposition in soft tissues of rabbits with atherosclerosis.

The effects of 2.5 mg/kg.day ibudilast, with or without 300 mg/kg.day nicomol, or 10 mg/kg.day ibudilast on calcium and magnesium concentrations in the central nervous system (CNS), heart, liver, kidney, skeletal muscle, abdominal aorta and bone were determined in rabbits fed a 1% cholesterol-rich diet for 3 months. Serum thromboxane B2 concentrations were reduced in rabbits treated with 10 mg/kg.day ibudilast or with 2.5 mg/kg.day ibudilast plus 300 mg/kg.day nicomol, and atherosclerotic lesions were ameliorated compared with untreated rabbits. Calcium concentrations in the frontal cortex and cerebellum were lower in ibudilast/nicomol-treated rabbits and in those fed a standard diet compared with those receiving a cholesterol-rich diet only. Calcium concentrations in the pons and abdominal aorta were also lower in ibudilast/nicomol-treated rabbits whereas the calcium concentrations in the cerebellum were lower in rabbits treated with either 2.5 or 20 mg/kg.day ibudilast. There were no significant changes in tissue magnesium concentrations after feeding a cholesterol-rich diet, with or without drug treatment. It is concluded that 2.5 mg/kg.day ibudilast plus 300 mg/kg.day nicomol or 10 mg/kg.day ibudilast produced a scavenger effect on calcium deposited in the CNS and abdominal aorta of rabbits fed a cholesterol-rich diet.

Animals↗

Effects of bifemelane on calcium and magnesium deposition in the central nervous system tissues of rats maintained on low-calcium diets.

The effects of bifemelane [4-(o-benzylphenoxy)-N-methylbutylamine hydrochloride] on the deposition of calcium and magnesium in central nervous system (CNS) tissues, heart, liver, kidney, muscle, abdominal aorta and bones were studied in rats maintained on standard and low-calcium diets. Rats were maintained for 90 days on the following diets: standard calcium (12.5 g/kg diet); standard with 100 mg/kg bifemelane; low-calcium (30 mg/kg diet); and low-calcium with bifemelane. The presence of bifemelane did not affect blood chemistry, but the magnesium concentration in the cerebellum was significantly (P less than 0.05) higher in rats receiving standard diet after bifemelane treatment. Magnesium concentrations in the pons, cerebellum, spinal cord, heart, liver and femur of bifemelane-treated rats fed low-calcium diets were significantly (P less than 0.05) higher compared with the corresponding controls, whereas the calcium concentration in the liver was significantly (P less than 0.05) lower. In general, bifemelane tended to decrease calcium deposition in the CNS and soft tissues of rats fed standard or low-calcium diets. Bifemelane may activate cerebral metabolism and maintain magnesium concentrations in the CNS and soft tissues, and be implicated in metal metabolism in rats fed low-calcium diets.

Animals↗

Effects of bifemelane hydrochloride on atherosclerosis in aged rats fed low-calcium diets.

The preventative effects of bifemelane (4-(o-benzylphenoxy)-N-methylbutylamine hydrochloride) on atherosclerosis in aged rats fed low-calcium diets were investigated. Male 18-month-old Wistar rats were maintained for 90 days on the following: (A) standard diet (n = 7), (B) low calcium, low magnesium, high aluminium diet (n = 8), (C) standard diet plus oral intubation with 10 mg bifemelane/kg daily (n = 6), (D) low calcium and magnesium, high aluminium diet plus oral intubation with 10 mg bifemelane/kg daily (n = 6). All groups were give these diets and water ad lib for 90 days, after which blood samples were taken from the abdominal aorta and samples of aorta were examined for atherosclerotic changes. The serum concentrations of the following were determined: calcium, magnesium, zinc, aluminium, inorganic phosphorus, cholesterol, glutamate-oxaloacetate transaminase, glutamate-pyruvate transaminase, lactate dehydrogenase, cholinesterase, creatine phosphokinase, blood urea nitrogen and N-terminal parathyroid hormone. The only significant differences between the groups in serum chemistry were reduced concentrations of cholinesterase and magnesium in groups B and D, increased aluminium in group B, and increased N-terminal parathyroid hormone in groups B and D. In groups C and D the atherosclerosis was much improved compared with that in groups A and B. It appears that bifemelane largely prevents atherosclerosis caused by calcium deposition in the arteries of rats fed low-calcium diets, due to its effect in maintaining magnesium and calcium in bones.

Aluminum↗

Pulmonary infiltrates with eosinophilia due to naproxen.

An increasing number of drugs have been implicated in the etiology of eosinophilic pneumonia characterized by the development of pulmonary infiltrates, and peripheral blood eosinophilia. Naproxen is a commonly used nonsteroidal anti-inflammatory drug which may be added to the growing list of pharmacologic agents associated with infiltrative pulmonary lesions. A case of eosinophilic pneumonia induced by Naproxen is described. The results of TBLB, a lymphocyte stimulation test, and a challenge test supported this diagnosis.

Aged↗

Oddi sphincter and common channel: evaluation with pharmacodynamic MR cholangiopancreatography using fatty meal and secretin stimulation.

PURPOSE: This study was performed to assess the usefulness of pharmacodynamic MR cholangiopancreatography (MRCP) in depicting the segment covered by the Oddi sphincter. MATERIALS AND METHODS: Twelve volunteers were studied by pharmacodynamic MRCP. After stimulation by the oral intake of a fatty meal and an intravenous injection of secretin, a single-shot rapid acquisition relaxation enhancement (RARE) sequence was used to obtain consecutive images of the segment covered by the Oddi sphincter. The contraction range of the Oddi sphincter and the lengths of the common channel were measured on the MR console by comparing the most contracted image of the sphincter with the most relaxed image. RESULTS: Pharmacodynamic MRCP showed periodic contraction of the Oddi sphincter in all cases. The range of sphincteric contraction over the biliary duct was 8-19 mm (11.8+/-3.2 mm, mean +/- standard deviation) and over the pancreatic duct 8-23 mm (10.0+/-1.5 mm). In 11 of the 12 cases, the common channel was depicted and its length ranged from 3-8 mm (5.2+/-1.3 mm). CONCLUSION: Pharmacodynamic MRCP clearly depicted the range of contraction of the Oddi sphincter and the common channel, which are not usually revealed by conventional MRCP.

Adult↗