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Biomedical subjects

H Fukuda

Publications and source records attributed to H Fukuda.

At least 829 records · Page 46Linked to original sources
PubMed1990

Roentgenographic findings in massive rotator cuff tears. A long-term observation.

It is difficult to determine the size and localization of rotator cuff tears preoperatively. But with the special arthrographic technique, a diagnosis with about 80% accuracy was possible in 65 surgically confirmed rotator cuff tears. With this technique, 22 massive cuff tears were found in conservatively treated patients. In these patients, the plain roentgenograms obtained at the initial examination were also analyzed. The roentgenographic findings included narrowing of the acromiohumeral interval and degenerative changes of the humeral head, the tuberosities, the acromion, the acromioclavicular joint, and the glenohumeral joint. Based on these data, five roentgenographic grades of massive cuff tears were identified. Of seven patients with massive tears, which had been treated conservatively and followed for more than eight years, the roentgenographic grades advanced in five. One shoulder progressed to cuff-tear arthropathy. Based on these observations, it is proposed that the following pathogenetic mechanisms are responsible for the progressive roentgenographic changes: (1) arm elevation in activities of daily living, (2) rupture of the long head of biceps tendon, (3) the abnormal fulcrum of the humeral head against the acromion and the coracoacromial ligament, and (4) the weakness of external rotation. A massive cuff tear will progress to cuff-tear arthropathy, with each step of progression accompanied by characteristic roentgenographic changes.

Acromion↗
PubMed1989

Effects of nutrients and insulin on transcriptional and post-transcriptional regulation of glucose-6-phosphate dehydrogenase synthesis in rat liver.

The transcriptional and post-transcriptional regulation of glucose-6-phosphate dehydrogenase induction of rat liver was investigated using a cDNA cloned in our laboratory. By feeding a carbohydrate/protein diet to fasted rats, the mRNA concentration and enzyme induction of glucose-6-phosphate dehydrogenase (EC 1.1.1.49) reached maximal levels about 10-fold those in the fasted rats at 16 h and 72 h, respectively, whereas the transcriptional rate was increased about 3-fold in 6 h. In the protein fed (without carbohydrate) group, both the mRNA concentration and enzyme induction were increased to about 60% of the levels in the carbohydrate/protein fed group and in the group fed on a carbohydrate diet (without protein) to 30-40%. Further, dietary fat significantly reduced the transcriptional rate, mRNA concentration and enzyme induction to less than half, suggesting that dietary fat primarily reduced transcription. Thus, dietary nutrients appear to be involved in the steps preceding the translation. On the other hand, in diabetic rats, the transcriptional rate was significantly decreased as compared to the normal level and restored by insulin-treatment in 4 h. The mRNA concentration was very low in diabetic rats, and was restored to the normal level by insulin treatment in 8 h, and was half restored by fructose feeding. However, the enzyme induction of glucose-6-phosphate dehydrogenase was scarcely restored by fructose, unless accompanied by insulin treatment. Thus, it is suggested that insulin is involved in translation as well as in transcription. Further, the insulin-dependent increase of glucose-6-phosphate dehydrogenase mRNA was blocked by cycloheximide, suggesting that synthesis of a peptide is required.

Animals↗
PubMed1989

Effects of insulin and fructose on transcriptional and post-transcriptional regulation of malic enzyme synthesis in diabetic rat liver.

Insulin action on regulation of hepatic malic enzyme has been investigated in comparison with fructose, using streptozotocin-induced diabetic rats. Insulin-treatment caused a 2.8-fold increase in the transcriptional rate of malic enzyme (EC 1.1.1.40) after 8 h, and a 5-fold increase in the mRNA concentration of the liver. In Northern blot analysis, we demonstrated that after insulin treatment, the nuclear mRNA of malic enzyme tended to increase more rapidly than the total cellular mRNA. Therefore, it is suggested that the nuclear mRNA was primarily increased by insulin. The insulin-dependent increase of malic enzyme mRNA was blocked by cycloheximide, suggesting that synthesis of a peptide is required. On the other hand, by feeding a high-fructose diet to diabetic rats, the malic enzyme mRNA concentration was considerably increased, though with a delayed peaking in comparison with the insulin-treated animals, whereas the transcriptional rate was not significantly increased. Dietary fructose may stabilize the transcripts. Fructose increased the enzyme level far less than the mRNA level. These results suggest that insulin is required in both the translational and transcriptional regulation of malic enzyme.

Animals↗
PubMed1989

An NADH:Fe(III)EDTA oxidoreductase from Cryptococcus albidus: an enzyme involved in ethylene production in vivo?

An ethylene-forming enzyme which forms ethylene from 2-oxo-4-methylthiobutyric acid (KMBA) was purified to an electrophoretically homogeneous state from a cell-free extract of Cryptococcus albidus IFP 0939. The presence of KMBA, NADH, Fe(III) chelated to EDTA and oxygen were essential for the formation of ethylene. When ferric ions, as Fe(III)EDTA, in the reaction mixture were replaced by Fe(II)EDTA under aerobic conditions, the non-enzymatic formation of ethylene was observed. Under anaerobic conditions in the presence of Fe(III)EDTA and NADH, the enzyme reduced 2 mol of Fe(III) with 1 mol of NADH to give 2 mol of Fe(II) and 1 mol NAD+, indicating that the ethylene-forming enzyme is an NADH-Fe(III)EDTA oxidoreductase. The role of NADH:Fe(III)EDTA oxidoreductase activity in the formation in vivo ethylene from KMBA is discussed.

Butyrates↗
PubMed1989

Calcium-dependent dynamic changes in the subcellular distribution of calmodulin in frog spinal cells.

Calcium-dependent changes in the subcellular distribution of calmodulin (CaM) were investigated using isolated intraarterially perfused frog spinal cords. Perfusion with quin2-tetraacetoxymethyl ester (Q2-AM), an intracellular Ca2+-chelator, increased soluble CaM, measured by radioimmunoassay (RIA), with a concomitant decrease in particulate CaM. By contrast, in synaptosomes, Q2-AM increased soluble CaM and total CaM but not particulate CaM. These results suggest that intracellular Ca2+ controls the binding of CaM to membranes in spinal cells.

Aminoquinolines↗
PubMed1989

The oxygen dependence of the energy state of cardiac tissue: 31P-NMR and optical measurement of myoglobin in perfused rat heart.

The relationship between the energy state and intracellular oxygen concentration was established with cardiac tissue, where the former could be monitored by 31P-NMR and the latter by optical method for myoglobin absorption. The ratio of creatinephosphate to inorganic phosphate, PCr/Pi, started to fall at higher intracellular oxygen concentration than oxygen consumption (10IM). The pH shift measured by frequency shift of Pi paralleled the increase of lactate-release, of which half maximum was approximately 3IM. The critical oxygen concentrations differed nearly 5-fold when determined by energy state and oxygen consumption.

Adenine Nucleotides↗
PubMed1989

Detection of benzodiazepine receptor occupancy in the human brain by positron emission tomography.

Benzodiazepine receptor occupancy in the brain following oral administration of clonazepam (CZP) with a dose of 30 micrograms/kg in six healthy young men and a further dose of 50 micrograms/kg in one of the subjects was estimated by carbon-11 labeled Ro15-1788 and positron emission tomography (PET). The effects of CZP on the latency of auditory event-related potentials (P300) were also studied. Overall brain 11C uptake was depressed and the % inhibition of 11C uptake in the gray matter of the brain at 30 min after [11C]Ro15-1788 injection was 15.3-23.5% (mean, n = 6) following 30 micrograms/kg CZP when compared with that in the control experiment without any previous treatment. The 11C uptake in the cerebral cortex in the subject who received both doses decreased in a dose-related manner after 30 micrograms/kg and 50 micrograms/kg CZP. The P300 latency was prolonged significantly by 30 micrograms/kg CZP [31.6 +/- 16.3 ms (mean +/- SD, n = 6), P less than 0.05]. The P300 latency in the same subject was prolonged in a dose-related manner by 30 micrograms/kg and 50 micrograms/kg CZP. The technique using [11C]Ro15-1788 and PET permits comparison of the pharmacological effects with the percentage of receptor sites which benzodiazepines occupy in the human brain. P300 also seems to be useful to investigate the pharmacological effects of benzodiazepines.

Adult↗
PubMed1989

The anterolateral thigh flap; variations in its vascular pedicle.

The anterolateral thigh flap is based on the septocutaneous perforators of the lateral circumflex femoral artery. Little has been written about anomalies of its vascular pedicle. We report two variants of the pedicle vessel in eight patients in whom this flap was used, and absence of the perforators in five other cases in whom it was attempted. The anterolateral thigh flap has the advantages of thin and pliable skin, long and large pedicle, inconspicuous donor scar and the technical possibility of combination with fascia, sensory nerve and iliac bone. If the perforators are absent, a tensor fasciae latae musculocutaneous flap or anteromedial thigh flap is available with only minor changes of the flap outline.

Adolescent↗
PubMed1989

Technique for superimposing a color slide onto a facial cast to sculpt a facial prosthesis.

A precise and uncomplicated technique for superimposing a color slide onto a facial cast for sculpting a facial prosthesis of the periorbital region is described. This technique allows making a facial impression with the eye closed. The superimposed slide in full-face and profile views provide a natural appearance to the facial cast. Properly selected dental and photographic materials are essential to the success of this imaginative procedure.

Humans↗
PubMed1989

Modulatory roles of GABAergic mechanisms in post-rotatory nystagmus in the rabbit.

1. To determine how the GABAergic mechanism operates in the generation of post-rotatory nystagmus, an experiment was performed with GABAergic drugs in rabbits. 2. Subconvulsive doses of picrotoxin (0.3-0.6 mg/kg, i.v.) and bicuculline (0.1 mg/kg, i.v.) decreased the number of post-rotatory nystagmus beats, whereas strychnine sulphate, at a subconvulsive dose (0.1 mg/kg i.v.), increased it. 3. Diazepam (1 mg/kg, i.v.) remarkably increased the number of post-rotatory nystagmus beats. Pretreatment with picrotoxin (0.45 mg/kg, i.v.), bicuculline (0.1 mg/kg, i.v.) or semicarbazide-HCl (180 mg/kg, i.v.) antagonized the effects of diazepam (1 mg/kg, i.v.). 4. GABAergic mechanisms may play a modulatory role in the production of nystagmus rhythm. Strychnine-sensitive neurons involved in the vestibular mechanism may behave in a different manner from picrotoxin-sensitive neurons.

Animals↗
PubMed1989

Effects of centrally acting muscle relaxants on post-rotatory nystagmus in the rabbit.

1. The effects of some centrally acting muscle relaxants on the post-rotatory nystagmus induced by rotatory stimulation were investigated in the rabbit, to examine the action of the drugs on vestibular function. 2. Tolperisone-HCl (5-10 mg/kg, i.v.) and baclofen (1-3 mg/kg, i.v.) decreased the number of post-rotatory nystagmus beats dose-dependently, whereas mephenesin (40-80 mg/kg, i.v.) and diazepam (0.5-1.0 mg/kg, i.v.) prolonged it dose-dependently. 3. The inhibitory effects of tolperisone-HCl and baclofen may provide some suggestions as to the mechanisms and sites of actions of centrally acting muscle relaxants, while the significance of the prolonging action of mephenesin remains unclear. 4. The prolonging action of diazepam is discussed with reference to GABAergic mechanisms.

Animals↗
PubMed1989

The most desirable conformation of phenylethylamine (PEA) moiety stimulating noradrenergic neurons: effects of PEA, methamphetamine, phenelzine, methylphenidate, nomifensine and mazindol on rat spinal reflexes.

1. The effects of phenylethylamine (PEA) and PEA-related substances on the rat spinal monosynaptic reflex (MSR) were examined. According to the flexibility of the PEA moiety in the molecule, these drugs were classified into three groups, i.e. non-rigid, rigid and semi-rigid groups. 2. PEA, methamphetamine and phenelzine (non-rigid group) showed opposite effects on the MSR, an increase at low doses and a decrease at high doses. The former effect was antagonized by pretreatment with the alpha 1-blocker, prazosin. 3. Nomifensine and mazindol (rigid group), which share the similar spatial relationships between the aromatic moiety and nitrogen, increased the MSR, and this effect was blocked by prazosin. 4. In the semi-rigid group the same result was obtained for methylphenidate but not for 1-methyl-2-benzylpiperidine, which might have difficulty in having the similar conformation of PEA moiety as methylphenidate because of its methyl group. 5. From these results, it appears that the effects of PEA and amphetamines on the MSR are determined by the spatial relationships between the amino group and the aromatic moiety and that the enhancement of the MSR might be induced through alpha 1-adrenergic transmission.

Animals↗
PubMed1989

Macrolide compounds, ivermectin and milbemycin D, stimulate chloride channels sensitive to GABAergic drugs in cultured chick spinal neurons.

1. The effects of ivermectin (IVM) and milbemycin D (MMD) on cultured embryonic spinal neurons were investigated, using the whole-cell recording technique. 2. IVM and MMD caused Cl- current under voltage-clamp conditions. 3. The reversal potential of the MMD-evoked Cl- current was shifted in a positive direction when half of the external Cl- was substituted by isethionate. 4. The MMD-evoked current was inhibited by picrotoxinin and bicuculline, whereas it was enhanced by diazepam. 5. Different characteristics of desensitization were observed between the MMD- (IVM-) and muscimol-induced effects. 6. These results suggest that IVM and MMD directly activate the Cl- channel through their specific sites modulated by GABAergic drugs.

Animals↗
PubMed1989

2-Deoxy-2-[18F]fluoro-D-galactose as an in vivo tracer for imaging galactose metabolism in tumors with positron emission tomography.

The feasibility of 2-deoxy-2-[18F]fluoro-D-galactose ([ 18F]FdGal) for imaging galactose metabolism in tumors with positron emission tomography (PET), was investigated using two hepatomas, Yoshida sarcoma, or glioma in rats, and mouse mammary carcinoma. In hepatoma-bearing rats the highest uptake of [18F]FdGal was observed in the liver followed by the kidney and tumor. The tumor uptake increased with time, and the high uptake ratios of tumor to organ were observed except for the liver and kidney. Tumor uptake was also measured in all tumors. As main metabolites in all tumors, [18F]FdGal 1-phosphate and UDP-[18F]FdGal were found by HPLC. Two hepatomas showed a slightly higher uptake and a larger percentage of UDP derivative than the other three tumors. By autoradiography the brain tumor was visualized clearly. These results indicate that [18F]FdGal has potential as a tracer for imaging galactose metabolism in tumors with PET.

Animals↗
PubMed1989

Coronary flow velocity waveforms in aortic stenosis and the effects of valve replacement.

In 6 patients with pure aortic stenosis, the flow velocity waveforms in the left anterior descending coronary artery were studied using an 80-channel 20-MHz pulsed Doppler velocimeter before and immediately after aortic valve replacement. All patients showed normal coronary arteriograms. The left anterior descending coronary artery flow velocity waveform in aortic stenosis was characterized by a reverse flow in the first half of systole and a slowly increasing diastolic inflow. After aortic valve replacement, the reverse flow in the first half of systole disappeared in all patients, but an end-systolic reverse flow was discerned in 5 of 6 patients. The increasing rate of the diastolic inflow was augmented in all patients. After aortic valve replacement, the time from onset of diastole to the diastolic peak velocity was shortened from 176.8 +/- 28.8 to 90.5 +/- 18.8 ms (p less than 0.01), and the diastolic peak velocity increased from 90.5 +/- 28.0 to 122.5 +/- 17.2 cm/s (p less than 0.05). Blood pressure and heart rate, however, did not change significantly before and after valve replacement. These changes in the left coronary artery velocity waveforms after valve replacement suggest the beneficial effects of removal of aortic stenosis on human coronary artery inflow.

Aortic Valve↗