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Biomedical subjects

Y Okuda

Publications and source records attributed to Y Okuda.

At least 253 records · Page 14Linked to original sources
PubMed1994

[Percutaneous radiofrequency coagulation therapy for liver tumor: experimental study].

We invented a newly devised local thermal therapy using radiofrequency energy for treating liver tumors. This method was investigated for evaluating its safety and effectiveness. In vitro study, the maximum size of coagulated albumen was 5.5 to 6.2mm in diameter, and 9.8 to 11.3mm in length. In vivo study using rabbit's liver, the range of coagulated tissue by radiofrequency energy was localized around the tip of the needle. Percutaneous radiofrequency coagulation therapy will be the effective therapy for liver tumor regardless of tumor vascularity.

Animals↗
PubMed1994

[A case of Shy-Drager syndrome complicated with syndrome of inappropriate secretion of antidiuretic hormone (SIADH) and incomplete paralysis of bilateral vocal cords].

A 67-year-old man with SIADH complicated by slowly progressing autonomic failure was described. The patient noticed constipation at the age of 57. In the following years, he suffered from urinary incontinence, depletion of sweating, impotence, sleeplessness with snore, and dizziness while walking. Physical examination revealed a masked oily face with slight cerebellar disturbance. Abnormality of autonomic function tests was recognized and he was diagnosed as Shy-Drager syndrome with gradually progressing, diffuse autonomic failure accompanied by slight cerebellar ataxia and Parkinsonism. Both serum sodium level and plasma osmotic pressure were reduced, whereas daily sodium excretion was more than 100mEq and urinary osmolality was about 500mOsm/kgH2O. His renal function was intact, and the adrenocortical and thyroid hormone levels were normal, then criteria of SIADH was fulfilled. SIADH was thought to have occurred on the basis of Shy-Drager syndrome. Water load test showed failure of adequate water diuresis, but intravenous phenytoin administration following the water load test ameliorated the diuresis to normal. The relationship between plasma osmolality and the ADH response indicates that ADH was adequately secreted in response to the increase in plasma osmolality but not suppressed in response to the decrease in plasma osmolality below 280mOsm/kgH2O. These results suggest that ADH synthesis in the hypothalamus and its secretion from the pituitary gland were both intact. The response of ADH secretion to the orthostatic hypotension induced by head-up tilt was quite blunted, being compatible with Shy-Drager Syndrome. Sleep disturbance was studied by polysomnography and laryngoscopy, and was revealed to be based upon severe sleep apnea due to incomplete paralysis of the bilateral vocal cords. Sleep apnea due to vocal cord paralysis is sometimes found to be complicated in patients with multiple system atrophy (MSA) including Shy-Drager syndrome, and is known as Gerhardt syndrome. This is the first report on a case of Shy-Drager syndrome complicated with SIADH and bilateral vocal cord paralysis. In this case, SIADH is caused by impaired afferent pathways from baroreceptors to the hypothalamus, which transfer inhibitory stimuli on ADH secretion. It is suggested that Shy-Drager syndrome should be considered one of the causes of SIADH.

Aged↗
PubMed1994

Eicosapentaenoic acid enhances intracellular free calcium in cultured human endothelial cells.

Eicosapentaenoic acid (EPA) caused elevations of intracellular free Ca2+ concentration ([Ca2+]i) measured by fura-2 fluorescence in cultured human endothelial cells. The EPA-induced increase in [Ca2+]i could still be observed when either cyclooxygenase or lipoxygenase inhibitors were added. These results suggest that EPA itself rather than its metabolites has direct effects on intracellular Ca2+ mobilization, causing the elevation of [Ca2+]i.

Calcium↗
PubMed1994

Eicosapentaenoic acid enhances myo-inositol uptake in cultured human aortic smooth muscle cells.

The effects of elevated glucose and Eicosapentaenoic acid (EPA, 20:5) on myoinositol uptake in human aortic smooth muscle cells (HASMC) were evaluated. Myo-inositol incorporation into HASMC was dependent on an active transport system via Na(+)-K+ ATPase activity based on the results with Na+ deprivation and Ouabain (5 mM). Although glucose (27.5, 55 mM) inhibited 2-[3H] myo-inositol uptake, the addition of EPA (3 x 10(-4) M) prevented glucose-mediated inhibition. In addition, EPA potentiated Na(+)-K+ ATPase activity of HASMC. Since EPA decrease glucose-mediated inhibition of myo-inositol uptake, this agent might ameliorate aortic smooth muscle cell function associated with diabetes.

Adult↗
PubMed1994

Familial positive ulnar variance with secondary radioulnar joint arthritis and extensor tendon ruptures.

A familial pattern of extensor tendon ruptures due to distal radioulnar osteoarthritis with underlying positive ulnar variance is described. Spontaneous ruptures occurred in four members of the family (one woman and three men) in middle age. Laboratory data did not indicate any sign of rheumatoid arthritis. All cases revealed significant positive ulnar variance and distal radioulnar osteoarthritis. Younger members of the family demonstrated positive ulnar variance although without osteoarthritic changes. The tendon ruptures presumably resulted from a hereditary disorder in conjunction with degenerative changes brought about by age.

Adolescent↗
PubMed1994

Müllerian duct cyst with 46, XYq-.

We report a case of a müllerian duct cyst associated with a 46, XYq- chromosome anomaly. Müllerian duct cyst is a consequence of the abnormal regression of paramesonephric derivative. In the past many different manifestations have been associated with the 46, XYq-, anomaly. We discuss the possibility that a müllerian duct cyst may be one clinical manifestation of 46, XYq-.

Adult↗
PubMed1994

Effect of growth hormone on hepatic glucose and insulin metabolism after oral glucose in conscious dogs.

This study examined the effect of growth hormone (GH) on hepatic glucose metabolism and on the fractional extraction of insulin and glucagon after oral glucose administration. GH treatment [canine GH (0.75 mg/day for 7 days)] significantly increased basal portal vein and hepatic artery flow (P < 0.01 compared with pre-GH treatment). After GH treatment and after oral glucose, glucose levels significantly exceeded those before GH at 100 and 120 min in arterial and portal vein plasma and 120 min in the hepatic vein. The net hepatic uptake of glucose was similar before and after GH treatment. The increment of net nonhepatic splanchnic insulin balance above basal was 131 +/- 31 mU.kg-1.3 h-1 before and 272 +/- 46 mU.kg-1.3 h-1 after GH treatment (P < 0.05). An increase in fractional hepatic extraction of insulin occurred before GH treatment and was significantly greater at 60 min. In summary, despite the increased insulin content after GH administration, there was no change in hepatic uptake of glucose, indicating that the liver was also the site of insulin resistance.

Administration, Oral↗
PubMed1994

Effects of a daily feeding-restriction on the reproductive and development toxicity parameters in female rats.

On the assumption of that the oral administration of an acid-unstable test compound into the empty stomach could enhance the systemic exposure to the test compound, the non-pregnant and pregnant rats had free access to the diet only for five hours per day. Female rats under the restricted feeding for a period of 21 days took diet at two thirds of the daily food-intake by the control animals, and lost their weight more than 10%. The vaginal smear test in these animals revealed a prolonged estrous cycle and diestrous period over four days. On the other hand, the restricted feeding from Day 0 to Day 17 of gestation suppressed the weight gain of pregnant animals but did not cause any significant influence upon the litter data, incidence of external anomalies or fetal skeletal development. The restricted feeding from Day 0 of gestation to Day 7 of lactation seriously disturbed the nursing behavior and the growth of offspring. These results suggested that the dosing method under the above-mentioned restricted feeding might be applicable to the teratology study but could not be applied to the fertility study nor to the peri- and post-natal study.

Abnormalities, Drug-Induced↗
PubMed1994

Syndrome of inappropriate secretion of antidiuretic hormone (SIADH) and Gerhardt syndrome associated with Shy-Drager syndrome.

This is the first report on a case of syndrome of inappropriate secretion of antidiuretic hormone (SIADH) associated with Gerhardt syndrome (paralysis of bilateral vocal cords). A 67-year-old Japanese man suffering from progressive autonomic failure was diagnosed as having Shy-Drager syndrome (SDS) with hyponatremia due to SIADH and severe sleep apnea caused by a bilateral recurrent nerve palsy. Water load test showed alteration in diuresis which was corrected by phenytoin. Arginine vasopressin secretion was not suppressed by plasma osmolality below 280 mOsm/kgH2O. Impairment of the afferent pathways of baroreceptors, or impairment of the osmoreceptors could be speculated as the etiological factor of the SIADH observed in this case.

Aged↗
PubMed1994

Müllerian duct cyst with 46, XYq-.

We report a case of a müllerian duct cyst associated with a 46, XYq- chromosome anomaly. Müllerian duct cyst is a consequence of the abnormal regression of paramesonephric derivative. In the past many different manifestations have been associated with the 46, XYq-, anomaly. We discuss the possibility that a müllerian duct cyst may be one clinical manifestation of 46, XYq-.

Adult↗
PubMed1994

Gallbladder cancer with double pancreatic ducts--a case report.

Various forms of anomalous pancreatic ducts may be encountered. We treated a patient with very rare courses of pancreatic ducts associated with gallbladder cancer. The patient, a 65-year-old female, attended our hospital with epigastric pain and general malaise. Abdominal sonography and a CT scan led to the diagnosis of gallbladder cancer. Endoscopic retrograde cholangiopancreatography revealed two main pancreatic ducts that followed a parallel course and joined the end of the common bile duct to form a common duct. The common duct opened at the ampulla of Vater. Thus, duplicated ducts of Wirsung served as the main pancreatic ducts, with no duct of Santorini. The embryonal mechanism and the clinical significance of double pancreatic ducts remains unknown, and our case is very rare.

Adenocarcinoma↗
PubMed1994

[Amyloidosis in rheumatoid arthritis--clinical study of 124 histologically proven cases].

The diagnosis of secondary amyloidosis due to rheumatoid arthritis (RA) was confirmed by positive tissue staining using Congo-red and antiserum to amyloid A protein. Biopsied specimens were obtained mainly from gastro-intestinal tracts; small salivary glands of the lips as well as abdominal adipose tissues were also studied in a small number. The results were as follows: 1. Gastro-intestinal fiberscopies and biopsies were performed on 789 RA patients for the purpose of routine screening and follow-up for amyloidosis. Seventy-seven cases (10.5%) turned out positive for amyloid. Among the biopsied specimens taken from three different sites, the proportion of amyloid-positivity was 68.9% for gastric antrum, 76.5% for duodenal cap and 88.6% for the second portion of the duodenum, suggesting the higher sensitivity and efficacy of duodenal biopsy in studying secondary amyloidosis in RA. 2. 124 patients of RA complicated with secondary amyloidosis were studied clinically with special reference to its clinical characteristics and prognosis. (1) The mean duration of RA at diagnosis of amyloidosis was 15.4 years and all patients but two were in stage III or IV (Steinbrocker). (2) Gastro-intestinal symptoms were present in 58.1% of the cases, abnormal renal signs in 58.9%, cardiac symptoms in 39.5%, respectively. All of these findings had a significant association with poorer prognosis in secondary amyloidosis due to RA. (3) The 4-year survival rate of all the cases was 57.8%, while the 3-year survival rate for the group without symptoms and signs about amyloidosis was 100%. (4) The causes of death in 36 cases were renal failure (14 cases), infection (13 cases), cerebral bleeding (2 cases), myocardial infarction (1 case), pulmonary infarction (1 case), suicide (1 case) and unknown (4 cases). Patients with intractable diarrhea were mostly susceptible to the ensuing fatal bacterial infection.

Adult↗
PubMed1994

[Influence of stellate ganglion block on bilateral cervicobrachial arterial and venous blood flow].

This study was designed to investigate the influence of stellate ganglion block (SGB) on cervicobrachial arterial and venous blood flow in 12 mongrel dogs. Following general anesthesia, the animals were mechanically ventilated to maintain a constant PaCO2 (35-40 mmHg). After thoracotomy, each dog was given SGB with 0.5% mepivacaine 1.0 ml. In six dogs we measured bilateral common carotid arterial blood flows (CCAF) and external jugular venous blood flows (EJVF), and in other six dogs we measured bilateral brachial arterial blood flows (BAF) and brachial venous blood flows (BVF) before and after SGB by using an ultrasonic transit time flowmeter. CCAF and EJVF in the blocked side and contra-lateral EJVF increased significantly but contra-lateral CCAF decreased significantly after SGB. BAF and BVF in the blocked side increased significantly and contra-lateral BAF and BVF decreased significantly after SGB. The results suggest that increased arterial blood flow in the blocked side after SGB is due to vasodilatation by sympathetic block and that contra-lateral arterial blood flow decreases by the ensuing lending-borrowing phenomenon. Increased venous blood flow in the blocked side after SGB is probably due to vasodilatation by sympathetic block and passive increase of blood flow from increased arterial blood flow. Contra-lateral increased EJVF may also be due to passive increase from arterial blood flow of the blocked side.

Animals↗
PubMed1994

Intraarterial occlusion by radiofrequency.

Arterial occlusion using radiofrequency energy was performed. The length of the noninsulated part of the guidewire was 10 mm and the duration of radiofrequency supply was 20 s. Animal experiments were carried out in 17 canine arteries; 4 out of 6 arteries less than 2.3 mm in diameter were completely occluded during the 20 s radiofrequency supply. A clinical application was also successfully performed without any complications. Arterial occlusion with radiofrequency can be applied to vessels less than about 2 mm in diameter.

Animals↗
PubMed1994

[Structural analysis of the chromatin loop in human chromosome by immunoelectron microscopy].

Synchronized human lymphocytes were exposed to 5-bromo-2'-deoxyuridine (BrdU) for incorporation in the late S-phase. The substituted chromosome bands were detected immunohistochemically by monoclonal anti-BrdU antibodies with the protein A-gold complex. The bands composed of many chromatin loop clusters were examined by electron microscopy without trypsin treatment. These banding patterns corresponded to the G-band by immunostaining. Chromatin loops were stretched around the chromosome, revealing the structure of coiled chromosome with trypsin treatment. The stretched loops were observed in the whole S-phase without treatment of trypsin but were not seen in the late S-phase. Variations in the degree of stretching were correlated with the duration of the BrdU treatment and the period of trypsin treatment. These results indicate that the trypsin treatment is essential to chromatin loops for their stretching in late S-phase and that the chromosome band is composed of numerous chromatin loops.

Antibodies, Monoclonal↗
PubMed1994

Diffusional anisotropy of the human brain assessed with diffusion-weighted MR: relation with normal brain development and aging.

PURPOSE: To analyze diffusional anisotropy in frontal and occipital white matter of human brain quantitatively as a function of age by using diffusion-weighted MR imaging. METHODS: Ten neonates (< 1 month), 13 infants (1-10 months), 9 children (1-11 years), and 16 adults (20-79 years) were examined. After taking axial spin-echo images of the brain, diffusion-sensitive gradients were added parallel or perpendicular to the orientation of nerve fibers. The apparent diffusion coefficient parallel to the nerve fibers (0) and that perpendicular to the fibers (90) were computed. The anisotropic ratio (90/0) was calculated as a function of age. RESULTS: Anisotropic ratios of frontal white matter were significantly larger in neonates as compared with infants, children, or adults. The ratios showed rapid decrease until 6 months and thereafter were identical in all subjects. In the occipital lobe, the ratios were also greater in neonates, but the differences from other age groups were not so prominent as in the frontal lobe. Comparing anisotropic ratios between frontal and occipital lobes, a significant difference was observed only in neonates. CONCLUSIONS: Diffusion-weighted images demonstrated that the myelination process starts earlier in the occipital lobe than in the frontal lobe. The changes of diffusional anisotropy in white matter are completed within 6 months after birth. Diffusion-weighted imaging provides earlier detection of brain myelination compared with the conventional T1- and T2-weighted images.

Adolescent↗
PubMed1993

Effect of antrectomy and drug-induced achlorhydria on urinary excretion of N-terminal big gastrin immunoreactivity in rats.

Immunoreactivities of urinary N-terminal big gastrin and serum C-terminal gastrin were determined in intact and antrectomized rats by radioimmunoassay using two antisera specific for N- and C-termini of big gastrin, respectively. Gel filtration of urine extract from intact rat showed a single giant peak of N-terminal big gastrin immunoreactivity eluted in a later position than 1-17 gastrin-34, indicating that N-terminal peptides smaller than 1-17 gastrin-34 are excreted in urine. Serum C-terminal gastrin concentration in antrectomized rats was about one sixth that in intact rats. Urinary excretion of N-terminal big gastrin in antrectomized rats was about one sixth that in intact rats. 2 week treatment with E3810, a proton pump inhibitor, (40 mg/kg/day, s.c.) induced urinary excretion of N-terminal big gastrin in parallel with a marked increase in serum C-terminal gastrin concentration in intact rats. Antrectomy completely prevented both the increase in urinary excretion of N-terminal big gastrin and the elevation of serum C-terminal gastrin induced by administration of E3810. There was an excellent correlation between serum concentration of C-terminal gastrin and urinary excretion of N-terminal big gastrin. These results suggest that urinary N-terminal big gastrin, which mostly originates from the gastric antrum, is a useful indicator of gastrin secretion in the rat.

2-Pyridinylmethylsulfinylbenzimidazoles↗