Biomedical subjects

T Ohmoto

Publications and source records attributed to T Ohmoto.

At least 235 records · Page 13Linked to original sources

PubMed1992

Steroidal saponins from Smilax riparia and S. china.

Two new neotigogenin glycosides were isolated from the rhizomes and roots of Smilax riparia and a new isonarthogenin glycoside from those of S. china. The structures were elucidated by a combination of spectroscopic analysis and hydrolysis followed by spectral and chromatographic analysis. Several known saponins were also isolated and identified. The inhibitory activity of the saponins on cAMP phosphodiesterase was examined.

3',5'-Cyclic-AMP Phosphodiesterases↗

PubMed1992

Steroidal saponins from the rhizomes of Smilax sieboldii.

Six new steroidal saponins were isolated from the rhizomes of Smilax sieboldii. Their structures were determined by spectroscopic analysis and hydrolysis to be 3 beta-hydroxy-(25R)-5 alpha-spirostan-6-one (laxogenin) 3-O-beta-D-glucopyranosyl-(1----4)-O-[alpha-L-arabinopyranosyl-(1- ---6)]-beta-D-glucopyranoside, laxogenin 3-O-alpha-L-arabinopyranosyl-(1----6)-beta-D-glucopyranoside, 3 beta,27-dihydroxy-(25S)-5 alpha-spirostan-6-one 3-O-beta-D-glucopyranosyl-(1----4)-O-[alpha-L-arabinopyranosyl-(1- ---6)]- beta-D-glucopyranoside, 26-O-beta-D-glucopyranosyl-3 beta,22 xi,26-trihydroxy-(25R)-5 alpha-furostan-6-one 3-O-alpha-L-arabinopyranosyl-(1----6)-beta-D-glucopyranoside, 26-O-beta-D-glucopyranosyl-3 beta,22 xi,26-trihydroxy-(25R)-5 alpha-furostan-6- one 3-O-beta-D-glucopyranosyl-(1----4)-O-[alpha-L-arabinopyranosyl-(1- ---6)]- beta-D-glucopyranoside and (25R)-5 alpha-spirostan-3 beta-ol (tigogenin) 3-O-beta-D-glucopyranosyl-(1----4)-O-[alpha-L-arabinopyranosyl- (1----6)]-beta-D-glucopyranoside. The inhibition of cAMP phosphodiesterase by the saponins was evaluated.

3',5'-Cyclic-AMP Phosphodiesterases↗

PubMed1992

Jatropham derivatives and steroidal saponins from the bulbs of Lilium hansonii.

Two new jatropham derivatives and three new steroidal saponins were isolated from the fresh bulbs of Lilium hansonii, along with previously known compounds. The structures of the new compounds were elucidated, on the basis of spectroscopic data and chemical evidence, and by comparing them with those of known compounds, as (-)-5-hydroxy-3-methyl-3-pyrrolin-2-one (jatropham) 5-O-beta-D-glucopyranosyl-(1----3)-beta-D-glucopyranoside, (2S*,4R*)-1-(3-methyl-2-oxo-3-pyrrolinyl)-4-methyl-5-oxo-2-pyrr olidinecarboxyli c acid, 26-O-beta-D-glucopyranosyl-(25R)-5 alpha-furostan-3 beta,22 zeta-diol 3-O-alpha-L-rhamnopyranosyl-(1----2)-O-[beta-D-glucopyranosyl-(1----4)]- beta-D-glucopyranoside, (25R)-5 alpha-spirostan-3 beta,12 alpha-diol 3-O-alpha-L-rhamnopyranosyl-(1----2)-O-[beta-D-glucopyranosyl-(1----4)]- beta-D-glucopyranoside and (25R)-spirost-5-en-3 beta,12 alpha-diol 3-O-alpha-L-rhamnopyranosyl-(1----2)-O-[beta-D-glucopyranosyl-(1----4)]- beta-D-glucopyranoside, respectively. The stereostructure of jatropham dimer, the plain structure of which was presented previously, was confirmed by X-ray crystallographic analysis. The inhibitory activity on cyclic AMP phosphodiesterase of the steroidal saponins was evaluated.

3',5'-Cyclic-AMP Phosphodiesterases↗

PubMed1992

Trigeminal neurinoma presenting with intratumoral hemorrhage: report of two cases.

We report 2 cases of trigeminal neurinoma presenting with spontaneous intratumoral hemorrhage. There are only 2 similar cases reported in the literature. Presenting symptoms were headache, diplopia, disturbed consciousness and trigeminal disturbance with sudden onset. CT scan showed a typical fluid-fluid level within low-density mass in the cerebellopontine angle in one case. On MRI, one case showed a typical fluid-fluid level on T2-weighted image and another one had mixed signal intensities including hyper- and hypointensities on both T1- and T2-weighted images. Histologically, increased vascularity, consisting of dilated and thin-walled vessels presenting telangiectatic or cavernous angiomatous appearances were observed in the specimens in both cases. The size of these tumors was about 3 cm each in diameter. Risk factors for hemorrhage appear to be large tumor size and increased vascularity.

Aged↗

PubMed1992

Neurinomas presenting as spontaneous intratumoral hemorrhage.

Massive intratumoral or subarachnoid hemorrhage from neurinomas is very rare. The authors report on six patients, four men and two women, with neurinomas that presented as spontaneous intratumoral hemorrhage. The average age of the patients was 56.8 years (range, 31-74 years). Neurinomas originated from the acoustic nerve in four patients and from the trigeminal nerve in two. Four cases were accompanied by the sudden occurrence of clinical symptoms such as headache, double vision, and hemisensory or motor disturbance. The maximum diameter of the tumors ranged from 2.8 to 3.8 cm (average, 3.1 cm). Histological examinations showed massive hemorrhage and increased vascularity, with dilated, thin-walled vessels, in all cases. The size of the tumor and the increase in vascularity with dilated, thin-walled vessels within neurinomas are important pathogenetic factors of hemorrhage. When sudden onset of symptoms or rapid worsening of chronic symptoms occurs in neurinomas, intratumoral or subarachnoid hemorrhage should be considered as a possible cause, and magnetic resonance imaging can be an important tool in obtaining correct diagnosis.

Adult↗

PubMed1992

Relations between the averaged 13C nuclear magnetic resonance chemical shift and the carcinogenic activity of polycyclic aromatic hydrocarbons.

13C Nuclear magnetic resonance (13C-NMR) spectra were measured for polycyclic aromatic hydrocarbons (PAH) to examine the correlation between their chemical shift and carcinogenicity. We confirmed our previous proposition that the carcinogenicity of PAH molecules can be predicted from the value of the averaged 13C-NMR chemical shift. It was also found, using the averaged chemical shift as a parameter, that several quantum chemical indices for the intermediate states of the metabolic transformation are correlated with the carcinogenic activity of PAH. This indicates that the averaged chemical shift can be applied to investigate the metabolic transformation of carcinogenicity.

Carcinogens↗

PubMed1992

[The study of Chinese herbal medicinal prescription with enzyme inhibitory activity. VI. The study of makyo-kanseki-to with adenosine 3',5'-cyclic monophosphate phosphodiesterase].

A Chinese herbal medicinal prescription, Makyo-kanseki-to, was studied for the inhibitory activity of adenosine 3',5'-cyclic monophosphate (cAMP) phosphodiesterase. The effect for the inhibitory activity of cAMP phosphodiesterase by combination with constituent crude drugs of the prescription was studied. Gypsum acted as a mitigatory component for Ephedra herb and Glycyrrhiza in cAMP phosphodiesterase inhibition test.

3',5'-Cyclic-AMP Phosphodiesterases↗

PubMed1992

[The study of Chinese herbal medicinal prescription with enzyme inhibitory activity. VII. The study of inchinko-to with adenosine 3',5'-cyclic monophosphate phosphodiesterase].

A Chinese herbal medicinal prescription, Inchinko-to, was studied for the inhibitory activity on adenosine 3',5'-cyclic monophosphate (cAMP) phosphodiesterase (PDE). The inhibitory activity on cAMP PDE of the extract of each constituent from the crude drug and of several compounds isolated from the drug was studied. By changing the combination ratio of two kinds of the crude drugs from 1:1 to 1:5, the inhibitory activity on cAMP PDE was estimated and it was found to be highest at the ratio of 1:3 in Rhubarb and Gardenia fruit, and at 1:4 in Rhubarb and Capillaris buds. These were the same ratio which is now commonly used for Chinese herbal medicinal prescription in Japan. Similar results were obtained in the combination test of the components of the crude drug such as emodin, geniposide, capillarisin and dimethylesculetin. The effects of Inchinko-to and its prescription which lacks one of the constituents of the crude drugs on carbon tetrachloride inducing liver injury in mice were also studied. Among the four prescriptions the antihepatotoxic activities were observed in the prescriptions containing Capillaris buds. Correlation between the administrated content of dimethylesculetin and antihepatotoxic activity was not recognized.

3',5'-Cyclic-AMP Phosphodiesterases↗

PubMed1992

Preliminary results of interstitial 192Ir brachytherapy for malignant gliomas.

Twenty-six patients with recurrent or unremovable malignant gliomas were treated by interstitial brachytherapy with iridium-192 seeds. Stereotactic implantation of the afterloading catheters using the Brown-Roberts-Wells computed tomography (CT)-guided stereotactic system was performed in 24 patients and surgical implantation in two patients with pontine glioma. The response to therapy was measured by serial CT, magnetic resonance imaging, and clinical examination. Tumor regression was seen in 17 patients 1-3 months after implantation. Tumor progression was seen in only three patients. After interstitial brachytherapy, the most commonly observed CT finding was central low density. Median survival time was 18 months after implantation. Autopsies in five patients revealed the delayed effects of radiation injury such as typical vascular changes, microcalcification, and coagulative necrosis in the implant area and tumor recurrence at the periphery. The results suggest that brachytherapy is not curative but prolonged the median survival time by 6 months.

Adult↗

PubMed1992

Metastatic choriocarcinoma with neoplastic aneurysms cured by aneurysm resection and chemotherapy. Case report.

A case of choriocarcinoma with brain and lung metastasis is reported. The patient was admitted for treatment of a cerebral hemorrhage from neoplastic aneurysms and, following removal of the hematoma and resection of the aneurysms, her carcinoma was successfully managed with chemotherapy. She has survived for 6 years after onset without neuroimaging evidence of recurrence. Surgical treatment of metastatic lesions followed by prolonged intensive chemotherapy are indicated for the improved prognosis of choriocarcinoma.

Adult↗

PubMed1992

Direct thrombosis of aneurysms with cellulose acetate polymer. Part I: Results of thrombosis in experimental aneurysms.

The authors have developed a liquid material for thrombosing aneurysms. This material is a mixture of cellulose acetate polymer and bismuth trioxide dissolved in dimethyl sulfoxide. On contact with blood, the dimethyl sulfoxide diffuses and cellulose acetate polymer forms, which balloons when slowly injected into the blood. The polymer solidifies from surface to core in 5 minutes. Cellulose acetate polymer was injected directly into experimental aneurysms created in 10 dogs; it rapidly hardened in the shape of the aneurysms, completely obliterating them but preserving the parent vessels in all cases. No distal migration of the polymer was seen. The good results of this experimental trial led to a clinical study using a cellulose acetate polymer, as described in Part II.

Aneurysm↗

PubMed1992

Direct thrombosis of aneurysms with cellulose acetate polymer. Part II: Preliminary clinical experience.

The authors report the treatment of seven intracranial aneurysms in six patients with direct infusion of cellulose acetate polymer solution, a new liquid thrombotic material. These aneurysms were considered inoperable because of their size or location, or because of the patient's neurological condition. This material avoids the difficulties associated with balloon occlusion, and completely fills even irregularly shaped aneurysms. Cellulose acetate polymer solution hardens in about 5 minutes and remains solid once inside the aneurysm. Because this technique is less invasive than surgery, it can be used for high-risk patients in the acute stage of subarachnoid hemorrhage. Transient motor aphasia occurred in one patient. A small residual neck, which caused rebleeding 3 months after the treatment, remained in another patient. This article describes the new material, the procedure for direct thrombosis, and preliminary clinical results.

Adult↗

PubMed1992

[Brainstem glioma with supratentorial meningeal dissemination--a case report].

We present a very rare case of 7 year-old-girl who had a pontine glioma with supratentorial meningeal involvement. She complained severe headache with meningeal irritation. She showed fluctuating cranial nerve impairment of the both abducens and glosopharyngeal nerves but no signs of weakness or facial paresis. She also reported two episodes of generalized convulsion with unconsciousness during admission. MRI disclosed a hypointensity intrinsic brainstem mass with an enhancing exophytic component in the prepontine cistern and a sharp contrast uptake is disclosed in the left-meninges of the supratentrial structures. An open biopsy was performed and diagnosed as a high grade astrocytoma.

Astrocytoma↗

PubMed1992

[Cool storage of fetal rat brain for neural transplantation].

The availability, storage and transportation of donor tissue are major practical problems associated with the potential use of grafted neural cell replacements in neurodegenerative diseases. The capacity to collect and maintain viable fetal neural tissue would facilitate possible clinical applications, and provide opportunities to study various neural diseases. In the present study, we examined the effect of cool storage on the survivability of intraventricular rat fetal ventral mesencephalic grafts (gestational days 15). In all experiments, fetal ventral mesencephalons were dissected out under a dissecting microscope in calcium-free magnesium-free buffer (CMF: 0.15 M NaCl, 0.008 M Na2HPO4, 0.0027 M KCl, 0.0015 M KHPO4, 0.026 M NaHCO3, with 0.1% glucose, 100 micrograms/ml streptomycin, 2.5 micrograms/ml fungizone). Fetal mesencephalic tissue was grafted into the lateral ventricle following pregraft refrigeration in calcium-free magnesium-free buffer at 4 degrees C. Fetal mesencephalic tissue was hibernated for 5, 12, 16, 20, 24, 28, 32 hours (group A, B, C, D, E, F and G, respectively). As a control group, fetal mesencephalic tissue was grafted into the lateral ventricle immediately after dissection. Grafted fetal mesencephalic tissue which had been hibernated for 16 hours or less survived well. There were no significant decreases in the size of grafts among group A, B, C and the control group. In group A, B, C and the control group, clusters of TH-positive neurons and dense networks of neuritic profiles within the grafts provided a morphological appearance reminiscent of the dendritic bundles that characterize the zone reticulate of the substantia nigra in situ.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1992

[Analysis of tumor-infiltrating lymphocyte in primary malignant lymphoma of the central nervous system using double immunofluorescence staining method].

Three cases of malignant lymphoma were examined immunohistochemically using anti-Leu monoclonal antibodies (MAB) against B lymphocytes, T lymphocytes subsets, NK cells, IL-2 receptor. In all three cases tumor cells were stained with anti-B cell's MABs, that is they were diagnosed as B cell type of malignant lymphoma. Moderate tumor-infiltrating lymphocytes in the parenchyma or around blood vessels were observed, and majority of these cells were T lymphocytes, demonstrating Leu 2a or Leu 3a + 3b positive phenotypes. IL-2 receptor positive cells also found in the parenchyma of these tumors. T lymphocyte subsets, such as Leu 2a positive cells and Leu 3a + 3b positive cells, were analyzed by means of double immunofluorescence staining method using the combination of Leu 2a and Leu15, or Leu 3a + 3b and Leu 8 MABs. This method demonstrated that most of Leu 2a positive cells were negative for Leu 15 and that the majority of Leu 3a + 3b positive cells were negative for Leu 8. These results suggested that tumor-infiltrating lymphocytes in the malignant lymphoma were mainly activated cytotoxic or helper T cells.

Brain Neoplasms↗

PubMed1992

[One-year follow-up study of patients with severe head injury; comparison of outcomes for focal and diffuse brain injuries].

Forty patients with severe head injury were classified on the basis of initial CT findings into 2 groups of focal injury (n = 20, mean age = 55.2 years), and diffuse injury (n = 20, mean age = 45.0 years). Glasgow Outcome Scale (GOS) status at 2 post-injury intervals (at discharge and 1 year after injury) of the 2 groups were compared and prognostic factors examined. At discharge (less than 3 months after injury), there were slight differences between the 2 groups in GOS score distribution, with nearly half of the patients in each group being independent. One year after injury, mean GOS score of the focal injury group was relatively more favorable, with about 60% of patients being independent, while no significant improvement was observed in the diffuse injury group. With the exception of brainstem signs, in both groups, the parameters of type of lesion detected on initial CT, modality of treatment, patient age, and operative timing all proved of little prognostic value. Brainstem injury due to intracranial mass lesions or postoperative brain edema was presumably a critical factor affecting prognosis in the focal injury group, while both primary and secondary brainstem injuries could have been major factors affecting prognosis in the diffuse injury group. In the prognosis of patients with severe head injuries, not only the parameter of initial CT findings but also time course of changes in brainstem signs, serial CT findings, MRI, and electrophysiological analyses such as motor evoked response should be considered.

Age Factors↗

PubMed1991

The effect of a new immunosuppressive agent, FK-506, on xenogeneic neural transplantation in rodents.

This study examines the effect of a novel immunosuppressive agent FK-506 (FK) on the survivability of embryonic (E14) rat ventral mesencephalic tissue after intracerebral grafting to the lateral ventricle of adult mice. The recipient mice were given FK in doses of 10 mg/kg or 1 mg/kg for 2 weeks postgrafting, at which time they were sacrificed and histologically processed except for one group of animals on the high dose (10 mg/kg). In this group most animals died from side effects of the drug during the following days. Only the mice receiving the high dose of FK displayed healthy grafts without signs of rejection.

Animals↗

PubMed1991

The fine structure of the S-100 protein positive cells in the rat pituitary gland: an immunoelectron microscopic study.

We examined the fine structure of rat folliculo-stellate (FS) cells of the anterior pituitary and pituicytes of the neural lobe using immunoelectron microscopy for S-100 protein. The study proves that S-100 protein is solely expressed in the FS cells and pituicytes. However, the ultrastructural differences between these two cell types demonstrated in this study may argue against the hypothesis that the FS cells and the pituicytes have a common origin.

Animals↗