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Biomedical subjects

Y Kuroda

Publications and source records attributed to Y Kuroda.

At least 667 records · Page 37Linked to original sources

Pain-related somatosensory evoked potentials following CO2 laser stimulation in peripheral neuropathies.

Pain-related somatosensory evoked potentials (pain SEPs) following CO2 laser stimulation were examined in 30 patients with peripheral neuropathies, and the results were compared with clinical sensory findings. Pain SEP findings showed a significant correlation with the clinical impairment of pain sensation, but not with the impairment of deep sensations. In contrast, conventional electrically-stimulated SEPs (electric SEPs) showed a significant correlation with deep sensations, but not with the impairment of pain sensation. Examinations of both pain SEPs and electric SEPs, therefore, are considered to be very useful to evaluate physiological functions of sensory nerves in patients with peripheral neuropathies.

Adult↗

Systemic interferon-alpha in the treatment of HTLV-I-associated myelopathy.

Treatment with interferon-alpha (IFN-alpha) was undertaken in 16 patients with human T-lymphotropic virus type I-associated myelopathy (HAM). All patients had progressive spastic paraparesis before treatment. Twelve patients were enrolled in an open therapeutic trial with a dose of 3.0 x 10(6) IU/day of IFN-alpha and 4 in a randomized, double-blind, multidose (3.0 x 10(6), 1.0 x 10(6) or 0.3 x 10(6) IU/day) trial. IFN-alpha was injected intramuscularly for 28 days. Eight of 12 patients enrolled in an open trial and 2 patients receiving a dose of 3.0 x 10(6) IU/day of IFN-alpha in a randomized trial showed clinical improvements during and after the treatment. The results showed that, although not for all patients, systemic IFN-alpha with a dose of 3.0 x 10(6) IU/day is effective in the treatment of HAM.

Adult↗

Magnetic resonance imaging of the brain structures in the posterior fossa in retarded autistic children.

Midsagittal magnetic resonance images of the brains of retarded autistic children were compared to those of non-autistic mental retardation patients and controls. We found that the whole brain stem and particularly two of its components (the midbrain and medulla oblongata) were significantly smaller in retarded autistic children and mental retardation cases than in control children. The pons area was significantly smaller in mental retardation cases as compared to control children but did not differ between autistic and control children. Moreover, there was no difference in the brain stem between retarded autistic children and mental retardation cases. We also noted no difference in the cerebellar vermis area among retarded autistic children, mental retardation cases and control children. The ratio of the midbrain to posterior fossa area was significantly smaller only in autistic patients. Although the significance of these results is unknown, further examination of autistic children with a normal IQ is necessary.

Autistic Disorder↗

The posttranslational processing of ras p21 is critical for its stimulation of yeast adenylate cyclase.

Mammalian ras genes substitute for the yeast RAS gene, and their products activate adenylate cyclase in yeast cells, although the direct target protein of mammalian ras p21s remains to be identified. ras p21s undergo posttranslational processing, including prenylation, proteolysis, methylation, and palmitoylation, at their C-terminal regions. We have previously reported that the posttranslational processing of Ki-ras p21 is essential for its interaction with one of its GDP/GTP exchange proteins named smg GDS. In this investigation, we have studied whether the posttranslational processing of Ki- and Ha-ras p21s is critical for their stimulation of yeast adenylate cyclase in a cell-free system. We show that the posttranslationally fully processed Ki- and Ha-ras p21s activate yeast adenylate cyclase far more effectively than do the unprocessed proteins. The previous and present results suggest that the posttranslational processing of ras p21s is important for their interaction not only with smg GDS but also with the target protein.

Adenylyl Cyclases↗

Suprahepatic vena cava anastomosis of the donor liver to the recipient retrohepatic vena cava in canine liver transplantation.

A revised method of the upper caval anastomosis in canine orthotopic liver transplantation is described. It uses the recipient retrohepatic inferior vena cava below the suprahepatic veins for vascular suturing. Ten consecutive operations were performed to assess the feasibility of this method, with special reference to the outflow obstruction at the level of the suprahepatic inferior vena cava. Seven of 10 dogs survived more than 6 days. The cause of death was not related to the outflow obstruction in any instance. Regardless of the duration of survival, free hepatic vein pressures as well as portal vein pressures of all dogs remained in the physiological range even after the skin closures. Based on these observations, we conclude that this approach is safe and reproducible in experimental transplantation of the canine liver.

Anastomosis, Surgical↗

Circadian rhythm in patients with hydranencephaly.

Circadian rhythm and sleep were studied in three hydranencephalic infants who were diagnosed on the basis of computed tomographic and/or magnetic resonance imaging scans and electrophysiologic findings. In all three cases, although the active sleep cycle was preserved, quiet sleep decreased and indeterminate sleep increased. The sleep-circadian rhythm was disturbed in all three cases. The hormone secretion rhythm was studied in two cases (cases 1 and 3). In both cases, cortisol secretion showed two or three peaks during the day. In one case (case 3), growth hormone secretion did not show sleep enhancement. Prolactin secretion showed an increase during sleep in both cases. The circadian rhythm of body temperature appeared at 6 months of age and disappeared after 1 year of age in case 1. Case 2 did not show a circadian rhythm of body temperature, but case 3 did at 2 years 6 months of age. However, it was thought that the circadian rhythm of body temperature in case 3 was a false one due to severe opisthotonus. Thus, it is suggested that the development of the circadian rhythm may require the rostral brain structure more than the midbrain and that there may be multiple oscillators in humans.

Brain Stem↗

Accelerated aging of the brain in Werner's syndrome.

We report the electrophysiologic examination of a 55-year-old woman with Werner's syndrome. Needle EMG and peripheral conduction studies were normal. In contrast, EEG was moderately abnormal, the N20 and P25 potentials of SEPs were delayed and enlarged, and the event-related potential, P300, was delayed. These characteristic findings indicated accelerated aging of the brain, as in the other organs, in Werner's syndrome.

Brain↗

Failure of cerebral blood flow-metabolism coupling after acute subdural hematoma in the rat.

We have used a recently introduced cerebral blood flow tracer, technetium-99-DL-hexamethylpropylene amine oxime, to map regional cerebral blood flow simultaneously with measurements of glucose metabolism ([14C]-2-deoxyglucose technique) using autoradiography. The technique was used to compare the acute effects of middle cerebral artery occlusion with the more complex events that occur after induction of an acute subdural hematoma (SDH) in the rat. Previous studies with this SDH model have shown that an infarction is induced in the cortex under the hematoma. In both models, the core of the infarct zone was associated with a reduction in both flow and metabolism to less than 15% of control values. In both models, the infarct core was surrounded by a band of tissue in which glucose metabolism increases by 60 to 70% and blood flow is reduced by the same amount. Global blood flow after the SDH was reduced by 14%, but remained unchanged after middle cerebral artery occlusion. In the hippocampus, a massive increase in metabolism (up to 157%) after SDH was accompanied by a paradoxical decrease in blood flow (32%). This discrepancy between blood flow and metabolism indicates loss of flow-metabolism coupling and provides a mechanism for infarct recruitment and delayed hippocampal damage after SDH.

Acute Disease↗

Interactions between local anesthetic dibucaine and pig erythrocyte membranes as studied by proton and phosphorus-31 nuclear magnetic resonance spectroscopy.

The interactions between amine local anesthetic dibucaine and pig erythrocyte membranes have been studied by proton and phosphorus-31 nuclear magnetic resonance (1H- and 31P-NMR) spectroscopy. It was found that dibucaine, bound to the membranes, increases the mobility of the hydrophobic acyl chains of the phospholipids, but that it decreases the mobility and/or changes the structure of the polar headgroups. The interactions with peripheral membrane proteins, i.e., spectrin and actin, were found to be weak. These observations indicate that the dibucaine locates across the polar and hydrophobic areas of the lipid phase of the membranes by both electrostatic and hydrophobic interactions. It is assumed that the changes in the mobility and/or the conformation of the phospholipids residing around the Na channel protein are essential in causing anesthesia.

Animals↗

Clinical significance of late potentials in patients after intracardiac operation for congenital heart disease.

The aim of this study was to evaluate the late potentials (LPs) in postoperative patients with congenital heart disease (CHD) and to study the association with the clinical characteristics in the postoperative patients with LPs. Signal averaged electrocardiogram (SA-ECG) was recorded in 119 postoperative patients aged 4 to 23 years and compared with those in age matched 49 healthy volunteers with and without right bundle branch block. Based on control data, criterias of LP were defined and altered in the presence of bundle branch block. Abnormal SA-ECGs were not detected in the patients with non-cyanotic CHD. However, abnormal and borderline SA-ECGs were recognized in 5 (12%) of 42 patients after intracardiac operation for tetralogy of Fallot and 3 (30%) of 9 patients after Rastelli's operation. The patients with abnormal and borderline SA-ECGs were significantly older at the time of operation, and had more frequent ventricular arrhythmias (7/8: 3/111, p less than 0.01) and depression of the ST-T segment on ECG (7/8: 11/111, p less than 0.01), compared with the normal SA-ECG group. Abnormal SA-ECGs including those of borderline patients were 50% sensitive and 96% specific for documented ventricular arrhythmias. However, there was no association between abnormalities of SA-ECGs and cardiomegaly on chest X-ray or left ventricular ejection fraction on echocardiogram. These results indicate that prolonged exposure to hypoxia may be the main cause of the primary role in the development of LPs. And late surgical intervention may result in histological background for the development of LPs.

Action Potentials↗

Fatal abdominal thorotrast granuloma.

We report a case of fatal abdominal thorotrast granuloma seen in a 65-year-old man who had undergone a femoral angiography of thorotrast with some accidental extravasation 49 years previously. As the thorotrast granuloma gradually increased in size, it caused ureteral obstruction, venous thrombosis, and perforation of the urinary bladder and rectum. Symptomatic abdominal thorotrast granuloma is quite rare and this is the first reported case of the granuloma associated with perforation through the urinary bladder and rectum.

Abdominal Neoplasms↗

Transient glucose hypermetabolism after acute subdural hematoma in the rat.

Ischemic brain damage occurs in most patients with acute subdural hematoma, yet many aspects of the distribution and extent of this damage remain unexplained. Previous studies in rat model, which produces a region of infarction under the hematoma, have implicated an "excitotoxic" mechanism, suggesting that high concentrations of excitatory amino acids may exacerbate ischemic damage. A study is described in which local glucose utilization is measured 2 or 4 hours after induction of acute subdural hematoma in the rat. These changes are compared to those produced by introducing the same volume of inert silicone gel into the subdural space. Massive increases (up to 142%) in glucose utilization occurred throughout both hippocampi and in a variable zone around the ischemic core, but these had normalized by 4 hours after blood injection. Hippocampal hypermetabolism was not seen after introduction of the silicone mass, suggesting that diffusible substances from the clotted blood may be responsible for these changes. This transient hypermetabolism accords with an excitotoxic process, which may amplify brain damage after acute subdural hematoma.

Acute Disease↗

[Clinical study on cefprozil fine granules].

Cefprozil (CFPZ, BMY-28100), a new non-ester cephem, was administered to 15 pediatric patients with infectious diseases. The patients included 6 boys and 9 girls from 10 months to 11 years old and they were given oral doses of 18.5-41.7 mg/kg/day for 3 to 8 days. Clinical efficacies were excellent in 3 cases and good in 12 cases, hence the total efficacy rate was 100%. Eosinophilia occurred in 1 case as side effect of the drug, but no other side effects were not found during or after the treatment.

Administration, Oral↗

Local cerebral blood flow mapping before and after removal of acute subdural hematoma in the rat.

The cause of hemispheric swelling and high intracranial pressure after acute subdural hematoma is unknown, yet this is a major cause of death related to this condition. To investigate whether vascular engorgement is the cause of this form of hemisphere swelling, we have autoradiographically mapped regional cerebral blood flow before and after removal of acute subdural hematoma in a rat model. Hyperemia was patchy and infrequent. The major cause of the significant hemisphere swelling seen after hematoma removal was enlargement of the zone of focal tissue ischemia and edema under the hematoma.

Acute Disease↗

[Synaptic plasticity and gene products].

Synaptic plasticity is thought to be the basic mechanism underlying learning and memory. The cellular mechanisms underlying synaptic plasticity have been extensively investigated in invertebrates and in vertebrates. What is the nature of synaptic plasticity? Can genes and gene products regulate plasticity? If so, how? The behavioral sensitization of the gill-and-siphon-withdrawal reflex of Aplysia is a simple model of plasticity in invertebrates, and can be examined in dissociated cell culture. Using a model of plasticity in cell culture, the molecular cascades of both short-term and long-term sensitization have been investigated, and characterized. Both gene transcription and protein synthesis were shown to contribute to the long-term sensitization. Long-term potentiation (LTP) is a well-characterized model for synaptic plasticity in vertebrates. Many possible cascades have been proposed, but it has not yet been settled whether an increase of transmitter release from presynaptic terminal, an increase of synaptic current, is responsible for the maintenance of LTP. Inhibition of protein synthesis resulted in a failure to maintain LTP over 3-4 hours. Thus, new protein synthesis may be needed for the maintenance of LTP. Induction of so-called immediate early genes that are induced immediately upon depolarization or neurotransmitter stimulation of the neuron has been studied as a possible mechanism underlying LTP. However, there is no good evidence yet implicating gene regulation to be involved in plasticity in vertebrates.

Action Potentials↗

[A case of foreign body granuloma due to aspiration of a twig of Cryptomeria].

A 65-year-old man was admitted to Oita Medical School Hospital with complaints of hemoptysis and left anterior chest pain. Chest X-ray film showed a nodular shadow, about 1 cm in diameter, in the left S8 area. A specimen obtained by transbronchial biopsy showed no malignant findings. However, left lower lobectomy was performed because of the possibility of malignancy. The resected specimen contained a twig of cryptomeria within dark-red lung tissue. Histologically, the foreign body granuloma was surrounding a vegetable fiber. We had no information of an episode of pruning a cryptomeria and aspiration of a twig before the operation. Cryptomeria is an extremely rare bronchopulmonary foreign body, and the present case suggests that bronchopulmonary foreign body granuloma is an important disease in the differential diagnosis of pulmonary nodules.

Aged↗