Search PubMed⌕ Search

Biomedical subjects

Y Sakurai

Publications and source records attributed to Y Sakurai.

At least 469 records · Page 26Linked to original sources
PubMed1987

Subarachnoid hemorrhage of unknown cause.

After the institution of computed tomography (CT), 814 cases of spontaneous subarachnoid hemorrhage (SAH) were treated during a period of 6 years and 9 months (April 1978 through December 1984). In 9 (22.0%) of 41 patients whose cause of SAH was not determined by the first four-vessel study (cerebral panangiography), ruptured aneurysms were found by repeated four-vessel study. Thus, of 814 cases, only 32 (3.9%) were diagnosed as cases of unknown etiology at discharge. The 32 cases were monitored by follow-up examination for 5 to 67 months (median, 27.1 months) after onset. No recurrence of SAH was reported, and all patients were rehabilitated except 2 who suffered terminal carcinoma. A third follow-up four-vessel study was performed 8 to 44 months (median, 22.0 months) after the second study in 14 of the 16 patients with SAH initially demonstrated by CT. In 1 of these cases, an aneurysm found 9 months after the initial SAH was treated surgically. Ultimately, 31 cases (3.8%) were diagnosed as cases of SAH of unknown cause. This incidence is low when compared with those in previous reports. Because of the strict examination schedule including repeated angiography, the incidence is lower and the prognosis is relatively favorable.

Cerebral Angiography↗
PubMed1987

[A case of hepatocellular carcinoma associated with multiple pulmonary tumor thrombi and rupture of its right adrenal metastasis].

A 54-year-old man, who had the history of a blood transfusion 29 years ago, was admitted to our hospital because of dyspnea and abdominal fullness. Physical examination revealed jaundice and massive ascites and laboratory data suggested liver cirrhosis. The high level of AFP and a CT scan indicated the association of hepatocellular carcinoma and its metastasis to the right adrenal gland. On the 21st hospital day, he suddenly complained of severe pain in the right upper quadrant and the right flank, and fell into hemorrhagic shock. Blood transfusion was given, but he died on the 24th hospital day. Autopsy revealed liver cirrhosis, accompanied by hepatocellular carcinoma with the metastasis to the right adrenal gland and multiple pulmonary tumor thrombi. Massive hemorrhaging due to rupture of the right adrenal metastasis was seen in the retroperitoneal space.

Adrenal Gland Neoplasms↗
PubMed1987

[Two cases of intracranial fibromuscular dysplasia whose repeated angiography disclosed progression of the lesion].

Fibromuscular dysplasia (FMD) is well known owing to the characteristic angiographical finding of a "string of beads" appearance, but intracranial involvement with this disease is extremely rare. Moreover, to our knowledge, only seven cases that had repeated angiograms disclosed progression of FMD lesion in the literature. Such cases of intracranial FMD which showed progression in the follow-up angiography are reported. Case 1: A 8-year-old boy was referred to our hospital because of aphasia and right hemiplegia following right hemiconvulsion. Left carotid angiography on the 7th day from the onset revealed a "string of beads" appearance involving the left middle cerebral artery from M1 to M2 portion. He was treated with low molecular dextran, urokinase and steroid. After these drugs were administered, his speech was normalized. A repeat left angiogram performed two months later disclosed definite increase in the degree of stenosis associated with FMD. Perivascular sympathectomy around common and internal carotid artery and superior cervical ganglionectomy on the left side carried out on the 70th day from the onset. Postoperative left carotid angiogram showed improvement of the stenosis markedly, and the motor disturbance was improved gradually. Case 2: A 34-year-old woman presented with head dullness and disorientation suddenly. Left carotid angiogram on the third day from the onset showed a "string of beads" appearance from C1 to M1 portion. Follow-up angiography three days later revealed some progression of the stenosis. Furthermore a repeat left angiogram disclosed occlusion of left internal carotid artery at the C2 portion. Left STA-MCA bypass surgery was performed on the 61st day from the onset.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1987

[Cerebral blood flow in moyamoya disease].

Regional cerebral blood flow in forty cases of moyamoya disease was investigated by intravenous 133Xe injection method. Twenty-one cases were children and other nineteen were adults. No or only slight neurological deficit were found at the CBF studies. CBF was calculated by initial slope index. For investigation of the relation between hemispheric blood flow and age, the regression curve was calculated and that with highest correlation was chosen. In normal group, the relationship between hemispheric CBF and age was correlated to following equation: y = 146.5-58.4 log x (r = -0.903). In contrast, in moyamoya disease, it was correlated to following equation: log y = 2.04-0.23 log x (r = -0.730). It can be said that CBF of the whole brain in moyamoya disease is below normal. The distribution of the rCBF was characteristic in moyamoya disease. There are low CBF values in the frontal and temporal lobes and relatively high values in the occipital lobes as compared with normal CBF distribution. These results are thought to indicate the importance of blood circulation to the brain from the vertebro-basilar arterial system. Moreover a comparison of these CBF results with the six stages of basal moyamoya seen angiographically was investigated in child cases. As the stage of moyamoya disease progressed, the hemispheric CBF decreased gradually and the distribution of blood flow gradually changed from a predominance of flow to the frontal lobes to a predominance of flow to the occipital lobes.

Adolescent↗
PubMed1987

[Regional cerebral blood flow in children--normal value and regional distribution of cerebral blood flow in childhood].

The changes in CBF and rCBF through the entire age range include the rapid period in childhood was reported. Sixteen children between the ages of 1 and 15 and 14 adults were studied. These 30 subjects were either volunteers of out-patients without CT and EEG abnormalities. rCBF was measured by the 133Xe intravenous injection method using Varmet rCBF analyzer. Ther relationship between age and CBF, the correlation coefficient was calculated based on the regression equations and the regression curve with the highest correlation was chosen. For the analysis of rCBF, he mean rCBF values (ISI) of 3 channels corresponding to the frontal, temporal, parietal and occipital lobes were expressed as a percentage of the hemispheric CBF. The hemispheric blood flow (ISI and CBF gray) of children less than 5 years of age was approximately twice that found in adults. This value decreased rapidly with age and in the 10-15 years the blood flow was approximately 1.3-fold that of adults. Thereafter, there was a slow decrease and a negative correlation with age was found. The decrease showed the correlation on the following equations; y = 146.5 - 58.5 log x. (r = -0.903) for ISI and log y = 2.26 - 0.29 log x. (r = -0.881) for CBF gray, which was statistically significant. In contrast, the CBF white showed a slightly higher value in the 1-2 years old children, but thereafter the CBF did not show a notable decreases with age. Through the entire age range, a best fit for the Fw values was found with : y = 18.3 + 37.5/x. (r = 0.798), which was also statistically significant.

Adolescent↗
PubMed1986

Alpha 1 type IV collagen gene evolved differently from fibrillar collagen genes.

Type IV collagen is a major structural component in basement membranes. It is considerably different from the fibrillar collagens, types I-III. For example, unlike fibrillar collagens, the triple helical domain of type IV collagen is frequently interrupted by nonhelical regions. In this report, we demonstrate several overlapping genomic clones which cover most of the mouse alpha 1(IV) chain. Electron microscopic analysis of R-loops revealed that there were at least 28 exons within 35 kilobases of the gene segment. The sizes of six exons were determined by DNA sequence analysis to be 81, 178, 134, 73, 129, and 213 base pairs. These sizes do not appear to be related to the 54-base pair coding unit which is characteristic of fibrillar collagen exons, suggesting that the alpha 1 type IV collagen gene evolved differently from the fibrillar collagen genes.

Actin Cytoskeleton↗
PubMed1986

Adhesion behavior of rat lymphocyte subpopulations (B cell and T cell) on the surface of polystyrene/polypeptide graft copolymer.

Polyvinyl/polypeptide graft copolymers having microdomain structure on their surfaces were newly synthesized for the development of a specific cell separator, and the adhesion behavior of rat lymphnode lymphocytes with these materials was examined by column method. Morphologic change of lymphocytes adherent to the graft copolymers was found to be less than that of cells adherent to corresponding homopolymers, i.e., polystyrene and poly (gamma-benzyl L-glutamate). Separation of lymphocyte subpopulations (B cell and T cell) was examined in the absence of serum proteins. The adhesion selectivity for B cell was found to depend on the microdomain structure, since the highest value, 2,2, was observed for the graft copolymer with the polypeptide content of 50 wt%. Synthetic polypeptide derivatives may be promising materials which substitute for a conventional system with nylon fiber and fetal calf serum.

Animals↗
PubMed1986

Adhesion behavior of rat lymphocytes to poly(ether)-poly(amino acid) block and graft copolymers.

Block and graft copolymers consisting of poly(ether) and poly(amino acid) were synthesized, and adhesion behavior of rat lymphocytes to the surface of the film made from these copolymers was analyzed by the microsphere column method. Poly(ethylene glycol) (PEG) and poly(benzyl L-glutamate) (PBLG) were used as poly(ether) and poly(amino acid), respectively. Adhesion behavior of lymphocytes was found to depend on the content and chain length of the components in these copolymers.

Animals↗
PubMed1986

Hydrophilic-hydrophobic microdomain surfaces having an ability to suppress platelet aggregation and their in vitro antithrombogenicity.

Block copolymers were synthesized by a coupling reaction of hydrophilic chains of poly(2-hydroxyethyl methacrylate) (PHEMA) with hydrophobic chains of polystyrene (PSt), or poly(dimethyl siloxane) (PDMS). Microstructures of films of the block copolymers exhibited a hydrophilic-hydrophobic microphase separated structure. For evaluation of in vivo antithrombogenicity, small diameter tubes (1.5 mm I.D. and 20 cm length) coated by the copolymers on their internal surfaces were implanted in rabbits as arteriovenous shunts. Occlusion times of the tubes, measured by formation of thrombus, were three days for PHEMA, two days for PSt, and three days for PDMS. The block copolymers showed excellent antithrombogenic properties: occlusion times were 20 days for HEMA-St block copolymer and 12 days for HEMA-DMS block copolymers. In vitro examination of polymer-platelet interaction in terms of platelet adhesion and aggregation, which are important initial processes of blood coagulation, demonstrated suppressed adhesion and aggregation on microdomain surfaces constructed of hydrophilic and hydrophobic block copolymers. From both in vivo and in vitro examination, it was concluded that HEMA-St and HEMA-DMS block copolymers showed promising antithrombogenic activities by suppressing activation and aggregation of platelets.

Animals↗
PubMed1986

Effect of microstructure of poly(propylene-oxide)-segmented polyamides on platelet adhesion.

The relationship between microstructure and platelet adhesivity of six types of poly(propylene oxide) (PPO)-segmented polyamides based on the polyamide segments nylon 210, 310, 410, 510, 610, and 710 were investigated. These multiblock PPO-segmented copolymers were prepared by interfacial polycondensation. Physical characterization of these copolymers was by means of thermal analysis, transmission electron microscope, wide-angle X-ray diffraction (WAXD), and small-angle X-ray scattering (SAXS). The WAXD and SAXS measurements showed that the copolymers had microstructures containing crystalline and amorphous phases and that these microstructures, represented by means of crystallite thickness and long period, varied with incorporation of PPO segments. Blood compatibility of these copolymers was evaluated by estimating the amount of adhering platelets on the copolymer surfaces. The amount of adhering platelets was minimum for the surfaces of the copolymers having a crystallite thickness of 6.0-6.5 nm and a long period of 12-13 nm. This result suggests that the particular size and distribution of the crystalline and amorphous phases in the copolymer could be determining factors for suppressing platelet adhesion on the copolymer surface, and that the control of these factors could lead to ideal antithrombogenic polymers.

Animals↗
PubMed1986

Suppression of platelet activity on microdomain surfaces of 2-hydroxyethyl methacrylate-polyether block copolymers.

Block copolymers constructed from chains of poly(2-hydroxyethyl methacrylate) (PHEMA) and either poly-ethyleneoxide (PEO) or poly-propyleneoxide (PPO) were synthesized. These block copolymers exhibited microdomain structure. Platelet adhesion on their surfaces was investigated by a column elution method to examine the effect of microdomain structure. The number of platelets adhered from whole blood was smaller for the block copolymer systems than for the homopolymers. Minimum points of platelet adhesion appeared at approximately 0.38 mol fraction of HEMA in the HEMA-PO system. Both block copolymer surfaces showed microdomains of alternate lamellar structure. Furthermore, the percent of platelets released from the column after incubation was investigated using PRP. In the case of homopolymers, released platelet percentages decreased with an increase of incubation time. Released platelet percentages from the block copolymers, however, were nearly constant with changing incubation time. These results show that HEMA-EO and HEMA-PO block copolymers had the ability to suppress both reversible and irreversible adhesion of platelets to their respective microdomain surfaces.

Animals↗
PubMed1986

Multiple unit activity of prefrontal cortex and dorsomedial thalamus during delayed go/no-go alternation in the rat.

While the rat was performing a go/no-go alternation task with a 10-s delay period, neuronal activity was recorded from electrodes chronically implanted in the prefrontal cortex (PFC) and the dorsomedial thalamus (DMT). In both PFC and DMT, neuronal activity during the delay period prior to a 'go' response was different from that prior to a 'no-go' response. The results suggest that during the delay period the PFC and DMT maintain a memory for the generation of the response. Furthermore, it was found that DMT neuronal activity in the delay period was different between correct and error trials. Therefore, the DMT may be primarily important in performing the alternation behavior.

Animals↗
PubMed1986

Agents for the treatment of brain edema. 2. [(2,3,9,9a-Tetrahydro-3-oxo-9a-substituted-1H-fluoren-7-yl)oxy]+ ++alkanoi c acids and some of their analogues.

Our initial paper discussed brain edema resulting from traumatic head injury and the need for specific and effective agents to treat the disorder and disclosed a novel approach for the discovery of a drug of this kind. The current study describes the synthesis of a series of [(2,3,9,9a-tetrahydro-3-oxo-9a-substituted-1H-fluoren-7-yl)oxy]alk anoic acids and their analogues. These compounds were evaluated in an in vitro cerebrocortical tissue slice assay for their relative potencies in inhibiting K+ + HCO3- induced swelling. Structural modification at a number of sites in the "lead" compound revealed that significant biological activity was inherent only within a very narrow range of structural types. The observation that nearly all the biological activity resided in one of the two enantiomers demonstrated the marked stereospecificity of the most active compounds. One of the most potent compounds, (R)-(+)-[(5,6-dichloro-2,3,9,9a-tetrahydro-3-oxo-9a-propyl-1H-fluoren -7-yl) oxy]acetic acid ((+)-5c), exhibited a dose-response relationship in the in vivo acceleration/deceleration brain edema assay, and the data from the two highest doses were statistically significant. Electron microscopic examination demonstrated that the perivascular astroglial swelling that arises from this procedure is abolished in the animals treated with (+)-5c. This compound is currently being evaluated for its clinical efficacy and safety in the treatment of traumatic head injury.

Animals↗
PubMed1986

Cyclosporin A-induced suppression of ongoing IgE antibody formation in the mouse.

Persistent anti-ovalbumin (OA) IgE antibody formation in the mouse was suppressed by oral administration of cyclosporin A (Cy A). Spontaneous anti-OA IgE antibody formation in vitro was also suppressed by Cy A added to the culture. Anti-OA IgG antibody responses in vivo and in vitro were less affected by Cy A. Cy A-induced immunosuppression was T cell-dependent since removal of T cells from the immune spleen cell suspension abolished the Cy A-induced suppression of antibody formation. Supplementing normal spleen T cells resulted in recovery of Cy A-induced suppression of spontaneous antibody formation in vitro. Cy A-induced suppressor T cells carried both Lyt 1 and Lyt 2 surface markers.

Animals↗
PubMed1986

A case of moyamoya disease accompanied by an arteriovenous malformation.

It is well known that moyamoya disease sometimes is accompanied by cerebral aneurysm; however, no case of moyamoya disease with arteriovenous malformation has previously been published. We report such a case. A 33-year-old man suffered from transient left motor weakness and visual disturbance. Plain computed tomography (CT) showed a low density area in the left parietooccipital cortex. Enhanced CT revealed a ribbon-shaped enhanced area in the right temporooccipital cortex and a spotty enhanced area in the right frontal subcortex. Cerebral angiography revealed moyamoya disease. On the basis of Suzuki's angiographic classification, the patient was diagnosed as Stage III. Right carotid angiography revealed an arteriovenous malformation fed by basal moyamoya vessels and draining to the vein of Trolard and the sylvian vein of the right frontal lobe. This arteriovenous malformation consisted of feeders, the nidus, and drainers. Trolard's vein, which was one of the draining veins of the arteriovenous malformation, flowed to the moyamoya vessels of the right parietal vault.

Adult↗