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Biomedical subjects

T Yuge

Publications and source records attributed to T Yuge.

At least 37 records · Page 2Linked to original sources

[Formation of calcium phosphate crystals in pseudophysiological solution by SiC Whisker reinforced glass ceramics. Effect of Phosvitin on nucleation].

The effect of the phosphorylated protein, phosvitin, on the formation of the calcium phosphate crystal was examined in metastable calcium phosphate solution. Addition of glass ceramics caused consumption of hydrochloric acid, as a result of the dissolution of metal oxides. The activities of dissolution and nucleation were both high in the case of CPS-SiC. Phosvitin affected only the nucleation process, not the dissolution process. The decrease of phosvitin concentration after the addition of materials demonstrated adsorption of phosvitin by the material surface. The thermodynamic stability of solution after several days maintained equilibrium against tricalcium phosphate (TCP) and especially against octacalcium phosphate (OCP). From these results, it is concluded that glass ceramic implants have potential to stimulate hydroxyapatite formation, even in the presence of matrix substances.

Calcium Phosphates↗

[Spinal injury in children].

We reported five cases of children with spinal injuries. Spinal injuries are rare in children, and most common from the occiput to C3 in children younger than 8 years. In our cases, two younger children had upper cervical lesions and two older children had lower lesions. These differences result from anatomical characteristics, such as special histological architecture of the growth zones in younger children. One patient had a delayed onset paraplegia without radiographic abnormality. This phenomenon seems to be one of the characteristics of the spinal injuries in children. Because of this, all children with head or neck injuries should be fully investigated. A nine-month-old child who suffered from a fracture of the odontoid process with atlantoaxial dislocation was treated by immobilization only, and the result was good. Generally, fracture of the odontoid process in young children can be treated by proper immobilization. One patient with fracture dislocation of the cervical spine died as a result of cord injury. So immediate surgical decompression is mandatory for patients with evidence of cord compression.

Adolescent↗

Spontaneous regression of primary malignant intracranial lymphoma.

A rare case of intracranial multiple tumor, which disappeared spontaneously on serial cranial computed tomography (CT) scans, is described. The initial CT scan showed multiple, well-enhanced lesions in the right frontal and parietal lobes. The lesions disappeared spontaneously without any treatment during the 2 following months of observation. One month later, however, a newly formed tumor was found on serial CT-scanning. Surgical intervention confirmed the histologic diagnosis of a non-Hodgkin's, large, and diffuse-type malignant lymphoma. The possible mechanism of temporal disappearance of tumors on CT scanning is discussed.

Brain↗

[Treatment of acute subdural hematoma with low GCS score].

In order to clarify the present problems in the treatment of acute subdural hematoma with low GCS score (5 or less), we studied the difference of the outcomes from two different surgical treatments for these patients. The present series included 30 patients who had GCS scores of 3, 4 or 5, and they were divided into two groups: 16 in DH group who had decompressive hemicraniectomy and 14 in HITT group who had hematoma irrigation with trephination therapy. The mean age of the patients was 47 years. They all had an intensive medical management including barbiturate therapy under intracranial pressure (ICP) monitoring after the operation. Time course of ICP after operation was classified as controlled, high but reduced and uncontrollable, based on the ICP level of 30 mmHg. The outcomes of the patients were determined by use of Glasgow outcome scale and classified into good, poor and dead. In these patients, the outcome was good in 13.3%, poor in 23.3% and dead in 63.4%. There was no survived case in those with GCS score of 3. The mortality rate in older patients over 60 years was high as 81.8%. ICP was well controlled in 2 patients (12.4%) in DH group. But there is no such case in HITT group. Uncontrollable ICP was more frequently seen in HITT group than in DH group. The patients showed different outcomes in the two types of treatment. Good outcome was found in 18.7% and the mortality rate was 56.3% in DH group. On the other hand, only one patient (7.1%) showed good outcome and the mortality rate of 71.4% in HITT group.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Disease↗

Massive traumatic haematoma of the corpus callosum.

Five unusual cases with massive haematoma of the corpus callosum caused by blunt head trauma are presented. Aside from the callosal haematomas, intraventricular and subarachnoid haemorrhages or small haemorrhagic foci in the basal ganglia or thalamus were common concomitant lesions on the computerized tomographic (CT) scan. The sites of the impacts were the frontal and occipital areas which were close to the midline and above the level of the corpus callosum. Severe and diffuse brain dysfunction was suggested by the severity of the Glasgow coma score (GCS) and the abnormality on multimodality evoked potentials. An intensive medical treatment such as barbiturate could be promising since a direct surgical approach was dubious because of additional damage to the severely injured brain.

Adult↗

[Efficacy and limitation of postoperative barbiturate therapy in severe head injury].

Efficacy and limitation of barbiturate therapy employed as postoperative treatment for acute traumatic intracranial hematomas were studied in 20 patients. The clinical cases in this series included 15 males and 5 females with mean age of 41.8 years who all were operated on for intracranial hematomas within 3 days after injury. Glasgow Coma Scale (GCS) score was less than 7 in all instances and intracranial pressure (ICP) as well as arterial pressure was monitored postoperatively with Gaeltec and Gould transducers. Barbiturate therapy (5 mg/kg of thiopental as an initial dose and loading dose of 2-3 mg/kg/hour) was given when ICP rose above 20 mmHg and maintained for 3 days after operation. The outcome of the patients was assessed by Glasgow Outcome Scale 3 months after injury. The response of barbiturate on ICP and the changes of cerebral perfusion pressure (CPP) during the therapy in relation to the outcome were studied. Final outcome of the patients revealed 5 of good (good recovery and moderate disability), 3 of poor (severe disability and vegetative state) outcomes and 60% of mortality rate. Eleven out of 20 patients responded to barbiturate therapy and 0-20 mmHg of ICP reduction (mean reduction of 10 mmHg) was obtained in these cases. Among these cases, 2 out of 3 dead patients were older than 60 years. There were no responses of barbiturate in 7 patients to whom the therapy was started when ICP rose above 40 mmHg. No response of the therapy on ICP was also observed in the patients with GCS score of 3.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

[Noninvasive evaluation of hemispheric cerebral circulation and brain function in acute intracranial hypertension].

Disturbance of the hemispheric cerebral circulation and brain dysfunction in acute intracranial hypertension were evaluated noninvasively by ultrasonic Doppler technique and multimodality evoked potentials consisting of auditory evoked brain-stem response (ABR), cortical somatosensory evoked potential (SEP) and visual evoked potential (VEP) in 36 patients with severe head injury and cerebrovascular disease. Glasgow coma scale score was less than 8 in all cases and the age ranged from 17 to 75 years (mean of 46 years). Intracranial pressure (ICP) was measured from the extradural space using Gaeltec transducer and systemic blood pressure was simultaneously recorded. Common carotid blood flow velocity (CBFV) was recorded on both sides and mean velocity (M), diastolic mean velocity (Md) and mean blood flow were calculated. The abnormalities on MEPs were graded into 4 categories. M and Md values on CBFV were significantly (p less than 0.05 and p less than 0.01) lowered on affected side (main lesion side) even when ICP was staying less than 20 mmHg comparing with control value obtained from the normal subjects (M: 19.48 +/- 3.52, Md: 15.98 +/- 2.01 cm/sec). With the increase of ICP more than 21 mmHg, CBFV on the contralateral side was also decreased and M as well as Md values were maintained at the lowered level during 21 to 60 mmHg of ICP. A significant rapid decrease of CBFV was observed at extreme intracranial hypertension more than 61 mmHg. Lowered CBFV was also noted when cerebral perfusion pressure was reduced less than 50 mmHg.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

[Significance of multimodality evoked potentials (MEPs) in severe head injuries].

Clinical significance of multimodality evoked potentials (MEPs) consisting of auditory evoked brainstem response (ABR), cortical somatosensory evoked potential (SEP) and visual evoked potential (VEP) was studied in 14 cases with severe head injuries. The cases in this series associated with cerebral contusion and/or intracranial mass lesions such as acute subdural, intracerebral and acute epidural hematomas and Glasgow Coma Scale (GCS) score was less than 8 in all instances. MEPs were recorded for 14 days after injury and evaluated by MEP grade modified from Greenberg, et al. Intracranial pressure (ICP) was monitored from the extradural space on main lesion side in all cases for 3 to 5 days. Transtentorial herniation on CT scan was also graded according to the status of subarachnoid cisterns around the tentorium. The outcome was assessed by Glasgow Outcome Scale at 3 months after injury and was classified into good, poor and dead. MEPs on admission showed mild to severe abnormalities determined by single or all modalities in all cases and they were fairly well correlated with GCS score on admission and initial ICP. In the cases with good outcome, initial MEPs showed mild to moderate abnormalities determined by single modality and improved within 3 days after injury. They returned to normal or remained at mild abnormality at 7 days. But abnormality on initial MEPs was more severe in the cases with poor outcome and they were deteriorated within 3 to 7 days when elevation of ICP above 25 mmHg was observed. MEPs remained at moderate abnormality even at 14 days after injury in these cases.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

Pharmacokinetic studies of mabuterol, a new selective beta 2-stimulant. I: Studies on the absorption, distribution and excretion in rats.

Pharmacokinetic studies on absorption, distribution, excretion and placental transfer of the beta-sympathomimetic 14C-labelled dl - 1 - (4 - amino - 3 - chloro - 5 - trifluoromethyl-phenyl)-2-tert.-butylamino-ethanol hydrochloride (mabuterol) have been carried out in rats. Mabuterol was easily absorbed from the whole length of the small intestine in a study in situ with the gastro-intestinal ligated loop technique. The blood and tissue levels of radioactivity reached the maximum within 1 h after oral administration. Concerning tissue distribution (excluding the digestive tract) after oral administration, the radioactivity in the liver, lung, kidney and several secretory organs was considerably higher than that in the blood. The levels of radioactivity in these tissues continued at almost the same levels for 2-6 h after oral administration, resulting from a slow gastric emptying of the radioactivity. The whole-body autoradiograms obtained after intravenous administration revealed the secretion of the radioactivity into the stomach. The radioactive concentration in the CNS was much lower than that in the principal organs with either route of administration. About 60% and 26% were excreted into urine and feces, respectively, within 24 h after oral administration. Although about 22% was excreted into bile within 24 h after intravenous administration, no other evidence of enterohepatic circulation was observed. The multiple oral administration of 14C-mabuterol indicated no, appreciable accumulation in the tissues of rats. A placental transfer in the pregnant rats in the last stage of gestation was not significant.

Adrenergic beta-Agonists↗

Pharmacokinetic studies of mabuterol, a new selective beta 2-stimulant. II: Urinary metabolites of mabuterol in rats and their pharmacological effects.

A selective beta 2-stimulating bronchodilator, dl-1- (4-amino-3-chloro-5-trifluoromethyl-phenyl)-2-tert.-butyl-amino-ethanol hydrochloride (mabuterol), is mainly metabolized by oxidative deamination pathway. Unchanged mabuterol and the following 6 types of metabolites, M-1 (hydroxylation of tert.-butyl group), M-2 (glycol), M-3 (mandelic acid), M-4 (aldehyde), M-5 (benzoic acid) and M-6 (hippuric acid) were identified by thin-layer chromatography and mass spectroscopy. Pharmacologically, only M-1 had effects on the airway resistance, blood pressure and heart rate, and the isolated organs. But its selective beta 2-stimulating effect was 2-10 times lower than that of mabuterol. M-1 antagonized the positive inotropic action induced by isoprenaline (isoproterenol). Other metabolites showed no appreciable activity.

Adrenergic beta-Agonists↗