Search PubMed⌕ Search

Biomedical subjects

H Namba

Publications and source records attributed to H Namba.

At least 199 records · Page 11Linked to original sources
PubMed1989

Changes of local cerebral glucose utilization, DC potential and extracellular potassium concentration in experimental head injury of varying severity.

The negative shift of DC potential was associated with an increase of extracellular potassium and energy metabolism. Therefore this dramatic phenomenon following the trauma to the brain was thought to be identical to spreading depression. 1. Spreading depression was most frequently observed between one and two hours after injury. 2. Spreading depression can be elicited in the deep structures as well as in the cortex. The more severe the injury, the more frequently the negative shifts were observed. The DC index seems to correlate well with the severity of the experimental model. It is concluded that the energy metabolism after the brain contusion was different from structure to structure and was changing continuously in the course of time.

Animals↗
PubMed1989

Hypermetabolic state following experimental head injury.

Local cerebral glucose utilization (LCGU) was studied in 35 conscious rats after a fluid percussion injury (cerebral contusion). The experiments were divided into two parts. (I) Natural course: LCGU was quantitatively measured in 17 rats by the 14C-deoxyglucose autoradiographic method (Sokoloff et al. 1977) at 1, 2, 4 and 24 hours after injury. Sham operation was made in six rats. (II) DC-potential and LCGU: LCGU was studied with DC-potential and EEG monitoring in 12 rats. Results were as follows: (I) i) Glucose uptake was reduced at the center of the contusion in all cases. ii) Two different effects were observed in LCGU change two hours after injury: normal or slight increase in four of six rats (type A) and a remarkable increase in the cortex of the injured hemisphere in two of six rats (type B). iii) The pattern of increase in LCGU (type B) resembles that of cortical spreading depression. (II) i) Negative shift of DC-potential concomitant with EEG suppression in the injured hemisphere was observed frequently one to two hours after injury. ii) The increased LCGU pattern during DC-potential negative shift was identical with that of type B. iii) LCGU pattern without DC-potential change resembles that of type A. We concluded that the hypermetabolism occurring in the damaged cortex was due to a spreading depression. The findings obtained here should yield very important information concerning pathogenesis and treatment of human head injury.

Animals↗
PubMed1989

Post-traumatic intention tremor--clinical features and CT findings.

Eight patients with post-traumatic intention tremor were reported. Intention tremor developed in the young as a late complication of severe head injury (Glasgow Coma Scale was below 8 in all cases) and impaired their functional outcome. This state was treatable with medication or by stereotactic thalamotomy. Neurologically, all the patients lapsed into coma immediately after the injury and many patients manifested clinical signs of a midbrain lesion in the chronic stage. The characteristic CT (computed tomography) findings in the acute stage were a high density area in the midbrain, accompanied by diffuse cerebral swelling or intraventricular hemorrhage, and in the chronic stage, brain atrophy or ventricular enlargement were the most prominent CT findings. These characteristics, indicating diffuse brain damage in addition to midbrain injury, may suggest the presence of shearing injury. The midbrain damage is consistent with the classical hypothesis that the damage to the Dentate-Rubro-thalamic system accounts for the occurrence of intention tremor. Furthermore, the presence of diffuse brain damage suggests that a more widespread brain injury may participate in its development.

Adolescent↗
PubMed1989

Reperfusion through balloon catheter to minimize myocardial infarction during the interval between failed percutaneous transluminal coronary angioplasty and emergency coronary artery bypass grafting.

A 65-year-old man was admitted with chest pain. A diagnosis of spastic angina was made because of symptoms of recurrent anginal attacks associated with ST-segment elevations in the electrocardiogram. A selective coronary arteriogram revealed a 90% diameter narrowing of the proximal left anterior descending coronary artery (LAD). No angiographically visible collaterals from the right coronary artery to the LAD were observed. The ventriculogram showed normal contraction of the left ventricle with an ejection fraction of 65%. Percutaneous transluminal coronary angioplasty (PTCA) failed resulting in total occlusion of the stenosis. Repeat PTCA at a higher pressure and of longer duration failed to redilate the artery. Reperfusion with the blood from the femoral artery through the balloon catheter, which was used for the PTCA, was carried out until coronary artery bypass grafting (CABG). Blood flow rate of perfusion was approximately 25 ml/min. Reperfusion through the balloon catheter reduced chest pain and ST-segment elevations in the electrocardiogram. The patient tolerated the operative procedure well and his post-operative course was uncomplicated. The interval between the acute occlusion and revascularization by CABG was approximately 4 1/4 h. The ventriculogram taken 56 days after the CABG demonstrated normal contraction of the anterior wall of the left ventricle with an ejection fraction of 63%. Abnormal Q waves did not appear in precordial leads of the electrocardiogram after the surgery. The thallium scintigram showed no perfusion defects. In conclusion, this case suggested that autologous blood reperfusion through balloon catheter would be worth attempting in some cases for minimization of myocardial infarction during the interval between failed PTCA and emergency CABG.

Angioplasty, Balloon, Coronary↗
PubMed1989

Insulin-like growth factor-I action on growth hormone secretion and messenger ribonucleic acid levels: interaction with somatostatin.

Insulin-like growth factor I (IGF-I) suppresses GH gene transcription and GH secretion, while somatostatin (SRIF) only suppresses GH secretion. The interaction of these inhibitors of GH was, therefore, tested in primary rat pituitary cells grown in serum-free medium. Maximal inhibition of GH secretion (to 30% of the control value) was achieved by 13 nM IGF-I, while 5 nM SRIF suppressed GH to 36% of control secretion. The respective ED50 values for IGF-I and SRIF inhibition of GH secretion were similar (approximately 2.5 nM). Treatment of cells with the two agents together resulted in a further inhibition of basal GH secretion to 18% of control untreated cells (P less than 0.005). Increasing doses of SRIF (2.5-10 nM) in the presence of IGF-I caused a dose-dependent suppression of GH secretion. PRL levels were not altered by these treatments, indicating a selective effect on GH. GRH-induced GH secretion was further attenuated by combined IGF-I and SRIF treatment compared to the effect of either of these two agents alone. Northern analysis showed that IGF-I suppressed GH mRNA transcripts, while SRIF did not alter GH mRNA levels. The results indicate that physiological concentrations of both IGF-I and SRIF suppress long term basal GH secretion. Only IGF-I alters GH mRNA levels. These two peptides, therefore, appear to attenuate in vitro GH secretion by different mechanisms.

Animals↗
PubMed1989

[Intention tremor after head injury. Clinical features and computed tomographic findings].

Eight cases of intention tremor as a late complication of head injury were investigated. The patients ranged in age from 3 to 24 years. All received severe head injuries and lapsed into coma immediately afterward (Glasgow Coma Scale scores less than or equal to 8). Six patients exhibited decerebration or decortication. Hemiparesis was present in six cases and oculomotor nerve palsy in four. In the chronic stage, all patients displayed some degree of impairment of higher cortical function and five had dysarthria and/or ataxia. Initial computed tomography (CT) scans within 3 hours after the injury were obtained in five cases, of which four showed a hemorrhagic lesion in the midbrain or its surroundings. Other CT findings were diffuse cerebral swelling (four cases), intraventricular hemorrhage (three), and multiple hemorrhagic lesions (two). In the chronic stage, generalized cortical atrophy or ventricular enlargement was noted in five cases. These clinical features and CT findings indicate diffuse brain damage as well as midbrain damage and may reflect shearing injury.

Adolescent↗
PubMed1989

Spreading depression following experimental head injury in the rat.

The direct current (DC) potential and electroencephalographic (EEG) changes were continuously monitored following fluid percussion head injury (brain contusion) in 10 conscious rats. Local cerebral glucose utilization (LCGU) was measured by the autoradiographic [14C]deoxyglucose method. Measurement of LCGU was started at the lowest point of the first or second DC potential negative shift when it occurred, and 2 hours after contusion if no DC potential changes were observed. The DC potential did not change in four rats (Group A), whereas DC potential negative shifts together with marked suppression of EEG activity occurred at 54 +/- 6.9 minutes after injury in six rats (Group B). In Group A, LCGU was decreased nonsignificantly in both the right and left cortices. In Group B, however, LCGU in the lesioned cortex rose to 160-190% of the level observed in the contralateral cortex (p less than 0.05). The autoradiographic pattern in Group B was identical to that seen in spreading depression. These findings can contribute to the effort to better understand the pathophysiology of head injury.

Animals↗
PubMed1989

[Surgical repair and late problem for Ebstein's anomaly--surgical cases with severe tricuspid stenosis or regurgitation].

In this report, we described our surgical experiences of Ebstein's anomaly with severe tricuspid stenosis (TS) or regurgitation (TR). Long-term clinical assessments and late problems of the treatment were also mentioned. From 1953 to 1988, a total of 2850 patients with congenital heart malformation underwent surgery in our hospital. During this period, 32 patients with Ebstein's anomaly were admitted, and surgical treatment was performed in 10 of these patients. Thus, the surgical treatment of Ebstein's anomaly took only 0.35% of total surgeries of congenital heart diseases. According to Takayasu's classification of Ebstein's anomaly, 6 of our these patients were classified into TS, and 4 into TR type. The operative methods were shunt operation in 3 patients, plication in 2 patients and tricuspid valve replacement (TVR) in 5 patients. One patient was died during the operative course of Glenn's procedure. Other 9 patients are alive and the longest follow-up period is 18 years at this moment. In the remaining two patients with shunt operation, Blalock-Taussig's procedure completely diminished their polycythemia. In the cases of TVR, the replaced valve was sutured to the right atrium in 2 patients with TS, true annulus in 2 patients with TR, valve remnant in one patient with TR type. Delayed cardiac tamponade occurred in 2 patients and calcification of Xenograft valve was observed at 8 years after the surgery in one patient with TVR. Although the hemodynamics did not improve immediately just after open heart surgery, cardio-thoracic ratio reduced and clinical symptoms were improved remarkably throughout the long-term follow-up.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

[Emergency operation in impending rupture of aortic arch dissecting aneurysm--a case report of dissecting aortic aneurysm with adhesion to the lung after lobectomy].

Successful surgical treatment of impending rupture of a aortic arch dissecting aneurysm in a 59-year-old man was reported. The aneurysm was tightly adhered to the lung, because he had a previous history of lobectomy. In this case, the permanent aortic bypass with permanent aortic clamp as a means of exclusion procedure of the aortic aneurysm was effective. The postoperative course was uneventful. In the emergency operation for aortic arch aneurysm, operative procedure should be selected by operative findings and risk.

Aortic Dissection↗
PubMed1989

[Changes in local cerebral glucose utilization, DC potential and extracellular potassium in various degree of experimental cerebral contusion].

UNLABELLED: Pathophysiology of the traumatized brain, especially that of cerebral contusion, is very complex and has not been well understood. In recent years, changes in extracellular ion concentration have been known in various pathological conditions such as cerebral concussion, spinal contusion, ischemia, hypoglycemia, epilepsy and spreading depression as one of the triggers to lead to secondary brain damage. To know the metabolic and ionic changes following cerebral contusion, the authors made various degree of cerebral contusion by fluid percussion method, and observed successive changes in EEG, DC potential, extracellular potassium concentration and local cerebral glucose utilization (LCGU). MATERIALS AND METHODS: Using 42 male Wistar rats, mild (0.2 kg/cm2), moderate (0.4 kg/cm2) and severe contusion (0.6 kg/cm2) were made in the left lower parietal region of the rats. EEG, DC potential and extracellular potassium concentration (using potassium sensitive glass microelectrode) were monitored for four to five hours after making the contusions. LCGU (by 14C-2-deoxyglucose method) was studied at the time of the negative shift of DC potential. RESULTS: The negative shift of DC potential with EEG suppression was observed at 30 min. to 3 hours after injury. The severer the injury was, the earlier and the more frequent negative shifts appeared. LCGU showed no significant changes in the mild injury group. In the moderate injury group, frequent negative shifts of DC potential associated with EEG suppression were observed. A 20% increase of glucose utilization in the cortex of the lesion side was observed whereas 50% decreases in the subcortical structures were found. In the severe injury group, EEG was suppressed immediately after contusion and had never recovered. DC potential fluctuated and was unstable. The increase of LCGU was noted not only in the cortex of the lesion side but also in some of the subcortical structures (hippocampus, caudate nucleus, dentate nucleus and thalamus). The extracellular potassium concentration rose to 30 mM, being correlated closely with DC potential. DISCUSSION: Increase of LCGU associated with EEG suppression, negative shift of DC potential and elevation in extracellular potassium concentration was thought to be due to spreading depression. It was postulated that spreading depression following cerebral contusion causes energy failure and can lead to secondary brain damage.

Animals↗
PubMed1989

[A case report of emergency thoracotomy and aortic cross clamp for massive abdominal hemorrhage due to the rupture of a pancreatic pseudocyst].

The authors present a rare case of a 58-year-old female who had cardiac arrest due to massive abdominal hemorrhage because of the rupture of pancreatic pseudocyst during an emergency operation. We succeeded in resuscitation by performing emergency thoracotomy and internal cardiac compression. Thoracic aortic cross clamping was employed to control bleeding, and we could perform the operation. She recovered without any neurological deficits. Thoracic descending aortic cross clamping should be always considered both before and during operation for the control of massive abdominal hemorrhage to avoid circulatory collapse.

Abdomen↗
PubMed1988

Local cerebral glucose utilization in controlled graded levels of hyperglycemia in the conscious rat.

Local cerebral glucose utilization assayed by the [14C]deoxyglucose ([14C]DG) method and calculated by means of its operational equation with values for the rate constants and lumped constant determined in rats under physiological conditions remains relatively stable with variations in arterial plasma glucose concentration within the normoglycemic range. Large changes in arterial plasma glucose level may, however, significantly alter the values of these constants and lead to artifactual results. Values for the lumped constant have been measured and reported for a wide range of arterial plasma glucose concentrations ranging from hypoglycemia to hyperglycemia in the rat (Schuier et al., 1981; Suda et al., 1981; Pettigrew et al., 1983). In the present study we have redetermined the rate constants in rats with arterial plasma glucose levels clamped at approximately 350, 450, and 550 mg/dl (i.e., 19, 25, and 31 mM) by a glucose clamp technique. The rate constants for the transport of DG from plasma to brain, K1*, and its phosphorylation in tissue, k3*, were found to decline with increasing plasma glucose levels, while the rate constant for its transport back from brain to plasma, k*2, remained relatively unchanged from its value in normoglycemia. These rate constants were used together with the previously determined values for the lumped constants to calculate local rates of cerebral glucose utilization in three groups of rats in which arterial plasma glucose levels were clamped at approximately 350, 450, and 550 mg/dl (i.e., 19, 25, and 31 mM). Average glucose utilization in the brain as a whole was unchanged in hyperglycemia from the values calculated in normoglycemic rats with the standard normal set of constants. Changes in the rate of glucose utilization were found, however, in the hypothalamus, globus pallidus, and amygdala during hyperglycemia.

Animals↗
PubMed1988

[Partial oculomotor nerve palsy due to midbrain lesion--case report and discussion on its characteristics].

UNLABELLED: A case of partial oculomotor palsy due to midbrain infarction is reported. CASE PRESENTATION: Fifty-one-year old man noted a sudden onset of double vision. He transiently presented right hemiparesis, right hemihyposthenia and cerebellar ataxia. The main symptom was the left oculomotor palsy selectively involving extraocular muscles (levator and pupil sparing), lasting for more than 6 months. The CT scan showed localized and well demarcated low-density areas at the left tegmentum of midbrain and left anteromedial thalamus, diagnosed as lacunar infarction due to occlusion of paramedian perforators at the basilar bifurcation. This midbrain infarct was supposed to be responsible for the partial oculomotor palsy. Extramedullary compressive and ischemic lesions have been well-known main causes of partial oculomotor palsy. This case, however, has emphasized the importance of recognition of midbrain lesion as a causative location of the partial oculomotor palsy. While the anatomical elucidation of this infrequent palsy is not sufficient, a topography of oculomotor nuclear complex in rhesus monkey proposed by Warwick, is worthwhile to correlate with midbrain oculomotor palsy in human cases. The pupil and levator sparing oculomotor palsy is most frequently caused by the laterally localized lesion at the fascicular portion which extends transversely at the midbrain tegmentum. This is the most likely lesion in this reported case. It is reported, on the other hand, that the levator sparing type oculomotor palsy is caused by a paramedian lesion of rostral midbrain and pupil sparing type by caudal midbrain. These may be explainable by rostro-caudal extension of the nuclear complex.

Cerebral Infarction↗