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Biomedical subjects

R Tanaka

Publications and source records attributed to R Tanaka.

At least 397 records · Page 22Linked to original sources
PubMed1994

Phosphocholine-bonded galactosylceramides having a tri-unsaturated long-chain base from the clam worm, Marphysa sanguinea.

Seven glycosphingolipids were obtained in the pure state from the clam worm, Marphysa sanguinea, by preparative HPLC with a reversed-phase column in a recycling mode. Their structures were elucidated based on detailed analyses of 1H- and 13C-NMR spectra of the intact compounds. The position and the geometry of double bonds in the long-chain base (LCB) were determined by the two-dimensional NMR (COSY, NOESY, and HMBC) analyses. All compounds are phosphocholine-bonded monogalactosylceramides and two of them have tri-unsaturated long-chain bases.

Animals↗
PubMed1994

Induction of antibody responses that neutralize human T-cell leukemia virus type I infection in vitro and in vivo by peptide immunization.

In order to define neutralization regions on the envelope antigen of human T-cell leukemia virus type I (HTLV-I), we have generated a number of new anti-envelope gp46 monoclonal antibodies from rats and mice. Epitopes recognized by new monoclonal antibodies which could neutralize HTLV-I in syncytium and transformation inhibition assays were localized to sequences in gp46 from amino acids 186 to 193, 190 to 195, 191 to 195, 191 to 196, and 194 to 199. Ovalbumin-conjugated synthetic gp46 peptides containing these neutralization epitopes, pep190-199 (a synthetic gp46 peptide containing amino acids 190 to 199) and pep180-204, but not pep185-194 or pep194-203, could give rise to HTLV-I-neutralizing antibody responses in rabbits. These immune or nonimmune rabbits were then challenged with HTLV-I by intravenous inoculation with 5 x 10(7) live HTLV-I-producing ILT-8M2 cells. By a PCR assay, it was revealed that HTLV-I provirus was detected in peripheral blood lymphocytes from nonimmune and pep288-312-immunized rabbits, whereas the provirus was not detected in peripheral blood lymphocytes from pep190-199- and pep180-204-immunized rabbits over an extended period. These results suggest that the induction of anti-gp46 neutralizing antibody responses by immunization with synthetic peptides has the potential to protect animals against HTLV-I infection in vivo.

Amino Acid Sequence↗
PubMed1994

Draining vein pressure increases and hemorrhage in patients with arteriovenous malformation.

BACKGROUND: Recent radiological studies have shown that arteriovenous malformations with impaired venous drainage may be susceptible to hemorrhage. To evaluate this hypothesis using a hemodynamic approach, we measured intravascular pressure during surgery in three patients with arteriovenous malformation. SUMMARY OF REPORT: In three patients we measured intravascular pressures in the draining venous system and the feeding arteries simultaneously before removal of arteriovenous malformations with marked segmental stenotic or occlusive draining veins and evidence of hemorrhage. The draining vein pressures at prestenotic (or preocclusive) sites in the three patients were 38, 25, and 40 mm Hg, respectively, all significantly above the normal cortical venous pressure, whereas pressure measurements in poststenotic sites and the sagittal sinus pressure in the venous drainage system approached normal values. The feeding artery pressures in the patients were lower than normal cortical artery pressure because of the arteriovenous shunt. CONCLUSIONS: Intraoperative vascular pressure measurements support the hypothesis that arteriovenous malformations with impaired venous drainage may be associated with a local increase in venous pressure and thus may be susceptible to hemorrhage.

Adolescent↗
PubMed1994

Serial changes in hemostasis after intracranial surgery.

We performed hemostatic studies on eight patients undergoing clipping of unruptured cerebral aneurysms to assess the influence of intracranial surgery itself on hemostasis. Blood samples were collected from each patient 10 times: before and after the induction of anesthesia and 6, 12, and 24 hours and 2, 3, 5, and 7 days immediately after surgery. The changes and our interpretation of them include the following: 1) the elevation of thrombin antithrombin III complex levels (activation of blood coagulation) was transient and monophasic; 2) the elevation of plasmin alpha 2-antiplasmin complex and D-dimer levels (activation of fibrinolysis) was biphasic, despite the monophasic elevation of tissue plasminogen activator or plasminogen activator inhibitor-1 levels; 3) the elevation of beta-thromboglobulin and platelet-factor-4 levels (activation of platelet) was also biphasic; 4) fibrinogen level and alpha 2-antiplasmin activity increased in the acute phase of the postoperative course (acute phase reaction); 5) the changes in hematocrit appeared to parallel those in various other parameters, especially platelet count, antithrombin III, and plasminogen levels for 1 or 2 days after surgery; 6) fibronectin appeared to be consumed in the acute phase of postoperative course; and 7) general anesthesia did not significantly affect hemostasis. These serial changes seem to be related to the activation of hemostatic systems after intracranial surgery and the subsequent acute phase reaction.

Acute-Phase Reaction↗
PubMed1994

Liver dysfunction in spontaneous intracerebral hemorrhage.

The purpose of this study was to investigate the relationship between mild degrees of liver dysfunction and spontaneous intracerebral hemorrhage (ICH) from the hemostatic standpoint. A detailed study of hemostatic systems was made in 462 patients with ICH. To compare ICH with the other cerebrovascular diseases, data from 120 patients with subarachnoid hemorrhage and 114 others with cerebral infarction were reviewed. At admission, the medical histories of the patients, including information about previous alcohol consumption, was taken, and blood samples were collected to perform the following studies: platelet count, fibrinogen level, prothrombin time, activated partial thromboplastin time, antithrombin III, plasminogen and alpha 2-antiplasmin activity, platelet aggregability, and liver function tests. The incidence of liver dysfunction and alcohol consumption in patients with ICH was significantly (P < 0.05) higher than in patients with subarachnoid hemorrhage and in those with cerebral infarction. Hematoma volume, mortality rate, and past alcohol consumption in patients with ICH significantly increased with worsening severity of liver dysfunction. Although almost all hemostatic parameters became worse with increasing severity of liver dysfunction, they changed within the normal limits. Platelet aggregability and alpha 2-antiplasmin activity in patients with liver dysfunction were remarkably deteriorated beyond normal limits. In conclusion, liver dysfunction associated with alcohol consumption appears to be an important factor in the deterioration of the clinical status of patients with ICH and may be one of the causative factors in the development of ICH. Although mildly impaired hemostatic systems may be partially responsible for these adverse effects of liver dysfunction on ICH, it seems probable that nonhemostatic mechanisms are attributed to the effects.

Adult↗
PubMed1994

Immunohistochemical analysis of tumor-infiltrating lymphocytes and adhesion molecules (ICAM-1, NCAM) in human gliomas.

The presence of tumor-infiltrating lymphocytes (TILs) and the expression of adhesion molecules were examined in 12 glioma tissues. Most TILs were T lymphocytes, and both cytotoxic/suppressor and helper/inducer. T lymphocyte phenotypes were found. Neural cell adhesion molecule was intensely expressed in 11 gliomas, and intercellular adhesion molecule-1 (ICAM-1) in seven. Many TILs were found only in gliomas expressing ICAM-1, but there was no relationship with clinical course in the patients.

Adult↗
PubMed1994

Ruptured distal anterior inferior cerebellar artery aneurysm--case report.

A 62-year-old female presented with a distal anterior inferior cerebellar artery (AICA) aneurysm showing severe involvement of the facial and acoustic nerves manifesting as progressive left hearing disturbance and left facial nerve paresis. She was admitted to our hospital 2 months after the onset. A saccular aneurysm arising from the meatal loop of AICA was found between the facial and acoustic nerves which were damaged directly by the aneurysm. Magnetic resonance imaging demonstrated a vascular anomaly, differentiating this disorder from cerebellopontine angle tumor, and evidence of an old subarachnoid clot. These characteristics were extremely helpful for the differential diagnosis. Neck clipping and aneurysmectomy were performed to achieve decompression of the cranial nerves. One year and 2 months later full function of the facial nerve returned but the hearing disturbance persisted.

Aneurysm, Ruptured↗
PubMed1994

Effect of hypoxia on proliferation of microvascular endothelial cells derived from Mongolian gerbil brain.

This study investigated the effect of hypoxia on the proliferation of microvascular endothelial cells in the brain. Endothelial cells derived from microvessels of Mongolian gerbil brain and control cells (3T3) were incubated for 7 days under various hypoxic and normoxic conditions at 37 degrees C. The proliferation of endothelial cells was inhibited by severe hypoxia, but stimulated by moderate hypoxia. No significant effect of hypoxia on the proliferation of control cells was observed. Endothelial cell-conditioned medium cultured under moderate hypoxia did not affect the growth of endothelial cells. The stimulatory effect of moderate hypoxia on the proliferation of cultured endothelial cells is due to an inherent property of brain endothelial cells.

Animals↗
PubMed1994

Hematoma enlargement in spontaneous intracerebral hemorrhage.

In order to evaluate the incidence and risk factors of hematoma enlargement in spontaneous intracerebral hemorrhage (ICH), 419 cases of ICH were reviewed. The first computerized tomography (CT) scan was performed within 24 hours of onset and the second within 24 hours of admission; a blood sample was taken for laboratory examination within 1 hour of admission. In 60 patients (14.3%) the second CT scan showed an enlarged hematoma. The incidence of enlargement significantly decreased with time (p < 0.05) and significantly increased with the severity of liver dysfunction and the volume of the hematoma on the first CT scan. Patients with an irregularly shaped hematoma had a higher risk of hematoma growth than those with a round hematoma. In addition, patients with hematoma enlargement were more likely to have coagulation abnormalities (low platelet counts and low levels of fibrinogen, alpha 2-antiplasmin activity and platelet aggregation). Moreover, hematoma growth was associated with a poor clinical outcome. It is concluded that patients admitted to a hospital within 6 hours of onset of ICH, especially those admitted within 2 hours, and patients with liver dysfunction or irregularly shaped large hematomas should be closely observed for at least 6 hours after onset in preparation for emergency surgery, since the risk of hematoma growth in these circumstances is high.

Adult↗
PubMed1994

Primary malignant lymphoma of the brain: demonstration of the p53 gene mutations by PCR-SSCP analysis and immunohistochemistry.

Using PCR-SSCP and immunohistochemical analyses, mutations of the p53 tumor suppressor gene were examined in 5 cases of primary malignant lymphoma of the brain (diffuse large cell type). By PCR-SSCP and nucleotide analyses, p53 gene mutations were seen in 2 of the 5 cases. The mutation in one case was a missense G: C-T:A transversion at codon 176 (TGC-TTC; Cys-Phe) which was located in the highly conserved domains and adjoined a previously proposed hot spot codon (codon 175) in various tumors. p53 immunoreactivity was also shown in this case. The mutation in another case was a nonsense G:C-A:T transition at codon 52 (TGG-TGA; Trp-stop codon) leading to a truncated p53 peptide. Thus, these mutations may have actually given rise to serious structural and functional alterations of the p53 protein. These findings suggested that the p53 gene mutation was related with oncogenesis in the primary malignant lymphoma of the brain.

Adult↗
PubMed1994

[Standardization of regional cerebral count corrected by equilibrium blood count with 99mTc-HMPAO brain SPECT].

To standardize the regional cerebral count with 99mTc-HMPAO, equilibrium blood count of which trapping mechanism is the same as the brain was used in seven patients with cerebrovascular disease. We injected 99mTc-HMPAO 740 MBq in 10-15 sec and got sequential arterial sampling in patients who were undertaken with PET. Four hours later 99mTc-HMPAO brain SPECT was taken and a venous sampling was drawn for determining the equilibrium blood count. Correlation between the area of arterial time activity curve and equilibrium venous blood count was 0.93. After 44 regions (36 in cortical area, 8 in deep area) with 99mTc-HMPAO brain SPECT were placed, SPECT counts were corrected by standardization of equilibrium venous blood count. The correlation between rCBF determined from C15O2 PET and corrected SPECT counts was 0.80 and 0.67, cortical area and deep area, respectively. We concluded that 99mTc-HMPAO brain SPECT count can be corrected by equilibrium blood count to standardize the regional cerebral counts.

Aged↗
PubMed1994

[Venous angioma coexisting with other types of cerebrovascular malformations].

The authors report 3 cases in which, in addition to venous angioma, other types of vascular malformations coexisted. They discussed the pathological significance of this coexistence, and the treatment to be given in these conditions. Case 1: A 38-year-old man was admitted to the hospital because of progressive headaches of 3 days' duration. X-ray CT revealed a large hematoma in the left cerebellar hemisphere. Vertebral angiogram showed a caput medusae in the venous phase, which is a typical picture of venous angioma. The hematoma was surgically removed and careful inspection of the cavity wall was made. A thick vein and many thin walled dilated venules draining to the vein were observed in the cavity wall. These abnormal vessels were completely removed. Because of reaccumulation of the hematoma and massive edema of the hemisphere, reoperation was performed. On removing a part of the cerebellar hemisphere, a small mass of vascular network was found and removed together with the hematoma. Histologically, the first specimen was a typical venous angioma, and the second one was a arteriovenous malformation. Case 2: A girl 9 years of age was admitted because of headache and left sided ataxia. CT and MRI revealed a multi staged hematoma in the left cerebellar hemisphere. Vertebral angiography, however, failed to demonstrate any kind of vascular malformations. The hematoma was removed with its wall. The histological appearance was compatible with venous angioma. 4 years later she bled again, and reoperation was performed. Histological examination this time revealed a cavernous angioma.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

[Imaging and clinical significance of hepatic portal venous gas seen in adult patients].

In 10 adult patients with hepatic portal venous gas (HPVG), the clinical significance of HPVG and the efficacy of X-ray computed tomography (CT) were evaluated. HPVG was associated with ischemic bowel disease (n = 3), trauma (n = 4), liver abscess (n = 1), sepsis (n = 1), and unknown etiology (n = 1). The diagnostic ability of CT for the detection of HPVG was far superior to that of plain abdominal radiograph. Of 9 patients who underwent CT, HPVG located in the left hepatic lobe in all patients, and also in right hepatic lobe in 7 patients. Gas could be recognized in the left lobe and the anterior segment of the right lobe more clearly than in the posterior segment of the right lobe because of its larger amount of intravenous collection. The mortality rate of our cases was 100%. Gas was demonstrated simultaneously in the portal vein radicles and hepatic veins on CT in 4 patients with no clinical evidence of sepsis, which suggested the possibility of intraparenchymal shift of gas from the portal vein into the hepatic vein. In a single case with sepsis, gas was noted in various vessels, including arteries, in addition to the portal venous system. The authors conclude that HPVG is still a grave sign in Japan and prompt appropriate treatment is required. CT may be of great value in the early detection of HPVG and may indicate its etiology.

Abdominal Injuries↗
PubMed1994

Heparin administration and monitoring for neuroangiography.

PURPOSE: To establish the optimal protocol of heparin administration during interventional neuroradiology. METHODS: We assessed 100 cases of neuroangiography, including endovascular surgery, and measured activated coagulation time before and 5 minutes after heparin administration, and before and 5 minutes after protamine neutralization. In some cases actual heparin concentration was assayed using a chromogenic substrate technique. RESULTS: The actual plasma heparin concentration significantly correlated with the dose of heparin administered intravenously (r = .98; P < .0001) and changes in activated coagulation time (r = .85; P < .0001). The change in activated coagulation time significantly correlated with the dose of heparin injected intravenously (r = .54, P < .0001). The ratio of change in activated coagulation time significantly correlated with time elapsed after heparin administration (r = -.70, P < .0001). CONCLUSIONS: The activated coagulation time is useful in monitoring administration and neutralization of heparin during neuroangiography, and a bolus injection of 60 U/kg heparin should be adequate to carry out neuroangiography for 75 minutes safely, even for endovascular surgery.

Cerebral Angiography↗
PubMed1994

An unruptured arteriovenous malformation with edema.

We report a case of unruptured arteriovenous malformation in which an extensive zone of increased signal intensity in the brain parenchyma adjacent to the nidus is demonstrated on T2-weighted MR. This area of perilesional hyperintense signal exerts a compressive effect, suggesting that it represents perilesional edema.

Brain Edema↗
PubMed1994

The effects of complete versus incomplete mitral valve repair in experimental mitral regurgitation.

Severe mitral regurgitation (regurgitant fraction 0.75 +/- 0.02) was created in eight dogs by our closed-chest chordal rupture technique. After 3 months of chronic mitral regurgitation all indices of contractile function were depressed. Mitral valve repair was then attempted. Postoperative regurgitant fraction was reduced compared with the preoperative value in all eight dogs. Concomitantly, forward cardiac output increased in all dogs and pulmonary capillary wedge pressure fell in all dogs. However, in some dogs, significant regurgitation persisted despite repair. Postoperative regurgitant fraction ranged from 0% to 60%. Postoperative residual regurgitant fraction was related significantly to postoperative cardiac output (r = 0.99), pulmonary capillary wedge pressure (r = 0.77), ejection fraction (r = 0.75), and two indices of contractile function--the mass-corrected end-systolic stress volume relationship (r = 0.87) and end-systolic stiffness (r = 0.93). In general, these parameters returned to their normal values before mitral regurgitation when postoperative regurgitant fraction was less than 30%. Myocytes isolated from the ventricles at the end of study also demonstrated normal contractile function when regurgitant fraction was less than 30%.

Animals↗