Search PubMed⌕ Search

Biomedical subjects

S Ueda

Publications and source records attributed to S Ueda.

At least 415 records · Page 23Linked to original sources
PubMed1995

Disappearance of arachnoid cysts after head injury.

The mechanism of the disappearance of arachnoid cysts is not fully understood. This article discusses the spontaneous disappearance of these cysts after head injury. Five patients underwent computed tomography and were diagnosed as having a subdural hematoma or effusion associated with arachnoid cysts. In four of the five patients, the cyst decreased in size or disappeared. These cases suggest a possible mechanism by which this type of cyst associated with subdural hematoma or effusion might disappear. For the arachnoid cyst to disappear, the rupture of the cyst wall appears to be essential, and after rupture, subdural effusion must develop around the cyst. As this effusion is absorbed, the fluid in the cyst drains away, after which the cyst becomes smaller and gradually disappears. This hypothesis supports the possibility of a "natural cure" for arachnoid cysts without surgical intervention.

Adolescent↗
PubMed1995

Hemodynamic evaluation of spinal arteriovenous malformations before and after embolization--preliminary report.

This preliminary study investigated local hemodynamic changes in intramedullary spinal arteriovenous malformation (AVM) before and after embolization. 99mTcO4- was injected into the anterior spinal artery feeding the AVM via a Tracker-10 or MAGIC microcatheter. Time-dependent radioisotope images were sequentially obtained in the anteroposterior plane every 0.2 sec before and just after embolization. Local mean transit time (MTT) was then calculated for both the nidus and draining vein and compared before and after embolization. Prior to embolization, MTTs in the nidus and in the draining vein were 1.84 +/- 0.62 (mean +/- SD) and 2.80 +/- 0.69 sec for the five patients, respectively. MTTs in both the nidus and the draining vein were significantly prolonged after embolization to 3.32 +/- 1.14 and 4.90 +/- 0.93 sec, respectively (p < 0.02 and p < 0.005, respectively). In vivo measurements of local hemodynamic changes in the spinal cord during the treatment of spinal AVMs could be achieved. This method may allow investigation of the hemodynamic mechanisms which induce ischemic symptoms in patients with spinal AVM.

Adult↗
PubMed1995

Delayed activation of altered fusion glycoprotein in a chronic measles virus variant that causes subacute sclerosing panencephalitis.

We compared the intracellular processing of the fusion (F) glycoproteins of an acute measles virus (MV) Nagahata strain and its relative Biken strain that caused subacute sclerosing panencephalitis (SSPE), Nagahata strain synthesizes a precursor F0 which acquires three asparagine (N)-linked oligosaccharide chains sequentially in 1 h. One oligosaccharide chain on the partially glycosylated F0 is less accessible to endo-beta-N-acetylglucosaminidase H (endo-H) but becomes accessible as the protein becomes fully glycosylated, suggesting a protein conformational change. Biken strain SSPE virus synthesizes a similarly glycosylated F0. However, one oligosaccharide chain on the Biken F0 remains less accessible to endo-H even after the protein is fully glycosylated. The Nagahata F0 is cleaved into the F1 and F2 subunits with a half life of 1 h. The Biken F0 is cleaved with a half life of 4 h. We cloned the F genes of Nagahata and Biken strains and showed by transfection that the defect causing delayed cleavage of F0 resides in the Biken F gene. Sequence analysis predicts a mutation in the cleavage recognition sequence, a truncated carboxyl-terminus, and multiple mutations in F1 of the Biken F protein. Expression of chimeric F genes showed the mutated cleavage recognition sequence and the carboxyl-terminal truncation do not delay cleavage of F0. Instead, delayed F0 cleavage is due to multiple mutations in the extracellular domain of F1, and four amino acid substitutions near the transmembrane region impair endo-H access to the oligosaccharide chain. These results provide detailed information on the normal maturation process of the F protein of MV and additional clues to the mechanisms of MV persistence in the CNS.

Animals↗
PubMed1995

Delayed activation of altered fusion glycoprotein in a chronic measles virus variant that causes subacute sclerosing panencephalitis.

We compared the intracellular processing of the fusion (F) glycoproteins of an acute measles virus (MV) Nagahata strain and its relative Biken strain that caused subacute sclerosing panencephalitis (SSPE). Nagahata strain synthesizes a precursor F0 which acquires three asparagine (N)-linked oligosaccharide chains sequentially in 1 h. One oligosaccharide chain on the partially glycosylated F0 is less accessible to endo-beta-N-acetylglucosaminidase H (endo-H) but becomes accessible as the protein becomes fully glycosylated, suggesting a protein conformational change. Biken strain SSPE virus synthesizes a similarly glycosylated F0. However, one oligosaccharide chain on the Biken F0 remains less accessible to endo-H even after the protein is fully glycosylated. The Nagahata F0 is cleaved into the F1 and F2 subunits with a half life of 1 h. The Biken F0 is cleaved with a half life of 4 h. We cloned the F genes of Nagahata and Biken strains and showed by transfection that the defect causing delayed cleavage of F0 resides in the Biken F gene. Sequence analysis predicts a mutation in the cleavage recognition sequence, a truncated carboxyl-terminus, and multiple mutations in F1 of the Biken F protein. Expression of chimeric F genes showed the mutated cleavage recognition sequence and the carboxyl-terminal truncation do not delay cleavage of F0. Instead, delayed F0 cleavage is due to multiple mutations in the extracellular domain of F1, and four amino acid substitutions near the transmembrane region impair endo-H access to the oligosaccharide chain. These results provide detailed information on the normal maturation process of the F protein of MV and additional clues to the mechanisms of MV persistence in the CNS.

Animals↗
PubMed1995

[Effects of prostaglandin E1 (PGE1) on pulmonary hypertension and lung vascular remodeling in a rat monocrotaline model of human pulmonary hypertension].

Prostaglandin E1 (PGE1) has been shown to be a potent pulmonary vasodilator in humans and in many animals. The effects of PGE1 on the development of pulmonary hypertension and on pulmonary vascular remodeling were studied in a rat monocrotaline (MCT) model of human pulmonary hypertension. By 3 weeks after injection, MCT (80 mg/kg S.C.) had resulted in high values of mean pulmonary arterial pressure and of the ratio of right ventricular weight to left ventricle+septum weight (RV/LV+S). PGE1 inhibited the development of pulmonary hypertension (300 micrograms/kg) and right ventricular hypertrophy (300 and 100 micrograms/kg) induced by MCT. Three weeks after the injection, the media walls of pulmonary arteries in lungs from rats given MCT were significantly thicker than those from lungs of control rats. PGE1 (300, 100, and 30 micrograms/kg) resulted in significantly less of this morphologic change, in a dose-dependent manner. These results indicate that PGE1 inhibits the development of pulmonary hypertension associated with lung vascular thickening induced by MCT. PGE1 may be useful for the treatment of pulmonary hypertension in humans.

Alprostadil↗
PubMed1995

[Effect of adhesiveness of white blood cells on pulmonary vascular permeability and resistance].

We studied pulmonary vascular injury evoked by mechanically activated white blood cells (WBCs). In isolated perfused rat lungs, changes in pulmonary vascular resistance were measured, and a gravimetric method was used to measure the pulmonary vascular filtration coefficient, which was taken as an index of pulmonary vascular injury. WBCs were activated by gentle agitation in a glass container for 10 sec. The filtration coefficient was measured under baseline conditions, and then inactive or activated WBCs were added to the perfusate. The perfusion was stopped for 90 minutes and then the lungs were reperfused. The expression of CD18 on the surface of WBCs was measured by flow cytometry. The filtration coefficient and the pulmonary vascular resistance in lungs exposed to activated WBCs were about 2.5 times and 3.3 times higher, respectively, than those in the lungs exposed to inactive WBCs. These results indicate increases in resistance and in pulmonary vascular permeability. The results of flow cytometry indicated that the mechanical agitation increased the expression of CD18 on the surface of WBCs. In conclusion, WBCs in which adhesiveness has been increased can induce pulmonary vascular injury and can increase pulmonary vascular resistance.

Animals↗
PubMed1995

[Evaluation by proton magnetic resonance spectroscopy of carotid-cavernous fistula with cortical venous drainage].

Cases with carotid-cavernous fistula (CCF) associated with cortical venous drainage through the sylvian veins are rather rare. However, such cases involve risk for subarachnoid hemorrhage, subcortical hemorrhage and venous infarction due to venous hypertension in the brain. Even without these symptoms, CCF under these conditions provokes disturbance in cerebral metabolism. We report two cases of CCF associated with cortical venous drainage evaluated by proton magnetic resonance spectroscopy (1H-MRS). Case 1: A 56 year-old female suffered from a right CCF associated with cortical venous drainage through the sylvian veins after trauma. Before embolization with a detachable balloon catheter, the ratios of N-acetyl-aspartate (NAA)/Choline (Cho) and NAA/Creatine (Cr) in 1H-MRS on the right temporo-basal ganglia were lower than those in normal volunteers. After curative balloon embolization of the CCF, serial 1H-MRS still demonstrated laterality (NAA/Cho and NAA/Cr ratios on the right side were lower than those on the left). Six months after embolization, these ratios on the right became closer to those on the left. Case 2: A 48 year-old female suffered from spontaneous CCF associated with cortical venous drainage. Before embolization of the CCF, ratios of NAA/Cho and NAA/Cr on the temporo-basal ganglia of the drainage side (left side) were lower than those on the contralateral side. After partial embolization of the CCF, which caused the angiographical disappearance of the cortical venous drainage, NAA/Cho and NAA/Cr ratios on the affected side increased to almost the same levels as those on the contralateral side. We consider that 1H-MRS is noninvasive and is a useful method to generate data evaluation of affected brain metabolism by venous reflux in cases of CCF associated with cortical venous drainage.

Arteriovenous Fistula↗
PubMed1995

[Immune reactions that mediate tubulointerstitial nephritis].

Experimental autoimmune tubulointerstitial nephritis (TIN) is induced by immunization with TBM antigen and adjuvant in guinea pigs, rats, and mice. In animal models, both anti-TBM autoantibody and TBM-sensitized T cells have important roles in development of TIN. Antibodies deposited on TBM bind with complements, and these complexes induce infiltration of macrophages and leukocytes into interstitium. And, then, lymphocytes infiltrate into the inflammatory lesions. In these lesions, inter-cellular adhesion molecule-1 (ICAM-1) is expressed within peritubular endothelia and tubular epithelia. There are several subpopulations of TBM-specific T cells associated TIN. One is Helper T cells (CD8+), they induce cytotoxic T cells which is CD8 positive and have cytotoxic activity against tubular epithelia. The function of cytotoxic T cells is downregulated by suppressor T cells.

Animals↗
PubMed1995

[Usefulness of coronary angiography in patients undergoing carotid endarterectomy].

We evaluated 37 cases of coronary angiography in patients undergoing carotid endarterectomy (CEA). The severity of coronary stenosis was estimated by Gesini's scoring system. There was no correlation between the severity of carotid stenosis and that of coronary stenosis, but those patients who had a history of coronary artery disease, carotid bruit or intracranial artery stenoses presented significant severe coronary stenosis in most cases. Even in the patients who had no history of coronary artery disease (n = 26), 13 patients (50%) had stenotic lesions shown by coronary angiography. Eight patients required treatment for their coronary stenotic lesions: 5 were treated with percutaneous transluminal coronary angioplasty (PTCA) and 3 with coronary artery bypass grafting. Intraoperative occlusion tests monitored by EEG and SEP showed abnormal findings in 6 CEA operations. One of these patients received PTCA before CEA, and had a good clinical course during and after the CEA procedure. In conclusion, in patients undergoing CEA there is frequently concomitant coronary artery stenosis. We should thus assess the coronary artery lesion more precisely by coronary angiography, and should carry out prophylactic treatment for these lesions.

Aged↗
PubMed1995

[Alexia-agraphia of kanji (Japanese morphogram) after left posterior-inferior temporal lesion].

Several cases of selective alexia with agraphia of kanji have been reported in Japan in this decade. It is well known that the lesion in the posterior inferior temporal lobe of the dominant hemisphere is responsible for this cognitive syndrome. Neuropsychological data in our patient suggest that the postero-inferior region of the temporal lobe of the dominant hemisphere may be the visuo-verbal association area for the analysis of the complex visuo-verbal information. The symptoms caused by the same lesion in western patients might be subangular alexia (alexia without agraphia). Alexia with agraphia of kanji and subangular alexia would appear to be distinct entities, but a dual processing hypothesis of visuo-verbal information and the concept of the visuo-verbal association area might well explain both syndromes.

Agraphia↗
PubMed1995

[Carbon-11 labeled diacylglycerol for signal transduction imaging by positron CT: evaluation of the quality and safety for clinical use].

To elucidate the synaptic transmission in the neural system, we have been developing fundamental studies for intracellular signaling. For clinical application of carbon-11 labeled diacylglycerol (1-[1-11C]butyryl-2-palmitoyl-rac-glycerol: 11C-DAG) using positron emission computed tomography (PET), we evaluated the quality and the safety of 11C-DAG as the solution for injection. As a result, 11C-DAG was synthesized within 50 minutes, including the preparation step for injection. The half life time and energy spectrum of 11C-DAG were the same as the physical character of carbon-11, and other radioisotopes were not detected. In the quality control, 11C-DAG solution was negative in the examination of bacterial contamination and the pyrogen test in three successive synthesis procedures. In the acute toxicity test by administration of 11C-DAG and 100 mumol/kg of non-radioactive DAG to the rat intravenously, the systemic condition of the rat was not changed and no abnormalities were found in any organ 24 hours after administration. These findings indicated the safety of 11C-DAG solution. Clinical application of 11C-DAG using positron emission tomography may be useful to elucidate the dysfunction of intracellular signaling in disorders of higher cortical function such as Alzheimer disease.

Animals↗
PubMed1995

[Hydraulic conductivity of the visceral pleura with hemodynamic lung edema in dogs].

Hydraulic conductivity of the visceral pleura was measured in situ in anesthetized dogs. There were two groups: control (n = 7), and edema (n = 5). The 7th intercostal space of the left thorax was opened. In each group, a hemispherical capsule, filled with physiological salt solution, was attached to the visceral pleura of left lobe by negative pressure made with a vacuum pump. In the edema group, pulmonary venous pressure was increased by ligation of the pulmonary vein. The transpleural fluid flow (V) was measured at different intracapsular pressures (delta P). The hydraulic conductivity was calculated from the relation between the fluid flow rate (v) and the intracapsular pressure, i.e., the slope of the linear regression line. The hydraulic conductivities in the control and edema groups were 1.49 +/- 0.68 and 3.19 +/- 1.13 nL.min-1.cmH2O-1.cm-2, respectively. We conclude that the pleural tissue may play an important role in hydraulic conductivity of the visceral pleura when pulmonary venous pressure is high.

Animals↗
PubMed1995

[Vasoactive intestinal peptide (VIP)-induced pulmonary vasodilation mediated by EDRF/NO in isolated perfused rat lungs].

We studied the effects of Vasoactive Intestinal Peptide (VIP) on the pulmonary circulation in isolated perfused rat lungs. VIP caused pulmonary vasodilation in a dose-dependent manner. This effect was inhibited by pretreatment with L-N omega-nitro-arginine (L-NNA), a competitive inhibitor of endothelium-derived relaxing factor (EDRF/NO), but not by meclofenamate, a cyclooxygenase inhibitor. Addition of L-arginine, a substrate of EDRF/NO, after treatment with L-NNA reversed VIP-induced pulmonary vasodilation. These results indicate that VIP causes pulmonary vasodilation, and they suggest a role for EDRF/NO in VIP-induced pulmonary vasodilation in isolated rat lungs.

Animals↗
PubMed1995

[Surgical treatment of lung cancer over 80 years of age: investigation from post operative complications].

Seventeen patients with lung cancer over 80 years were treated surgically from 1983 through 1993 in our department. Thirteen patients were male and four were female. The histology of the tumor was adenocarcinomas, squamous, large and small cell carcinomas, in 9, 6, 1 and 1 cases, respectively. More than single lobectomy was performed in each patient. Unilateral pulmonary occlusion test was applied in patients whose expected contralateral FEV1.0/BSA was less than 800 ml.m2, or expected residual FEV1.0/BSA was less than 850 ml.m-2. Postoperative cardiovascular complications, such as PAT, PAC, PVC or Af, were seen in 9 patients, respiratory problems, namely, sputa retention, retained secretions or atelectasis, in 7 patients. Blood chemistry and hematology were performed for about three weeks after operations, and found increases in serum transaminases, and leukocytosis. However, there were no operative death. We conclude that some patients over 80 years of age are candidates for surgery after careful cardiopulmonary preoperative evaluation.

Adenocarcinoma↗
PubMed1995

["Disproportionately large, communicating fourth ventricle" due to membranous obstruction of Magendie's foramen].

A case of disproportionately large, communicating fourth ventricle (DLCFV) with the entire ventricular system dilated symmetrically due to membranous obstruction of Magendie's foramen is reported. A 20-year-old female complained of headache and nausea. Slight papilledema was found in both eyes. CT scan and MRI showed that the entire ventricular system was dilated symmetrically, but we could not locate the cause of this disease, for example, tumor, arachnoid cyst, cerebellar malformation and so on. Although cinemode-MRI showed CSF pulsation as if CSF flowed through Magendie's foramen, we were not convinced that CSF flowed through it. We speculated that something obstructed CSF flow at Magendie's or Luschka's foramen, so surgery was performed by suboccipital craniectomy. As expected, a membranous obstruction was found at Magendie's foramen. After excision of the membrane, all symptoms improved. Postoperative cinemode-MRI clearly demonstrated CSF flow through Magendie's foramen. Ventriculoperitoneal shunting is generally effective for DLCFV, but we do not consider it the optimal treatment. The cause of DLCFV must be confirmed by suboccipital craniectomy if evidence of NPH, mass lesion or cerebellar malformation cannot be found anywhere especially around Magendie's foramen.

Adult↗