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Biomedical subjects

H Shibuya

Publications and source records attributed to H Shibuya.

At least 307 records · Page 17Linked to original sources
PubMed1990

Sphingolipids and glycerolipids. I. Chemical structures and ionophoretic activities of soya-cerebrosides I and II from soybean.

Two glycosphingolipids named soya-cerebrosides I and II were isolated from soybean, the seeds of Glycine max Merrill (Leguminosae), and their chemical structures have been elucidated on the basis of physicochemical evidence and several chemical degradation reactions. By using a newly constructed liquid membrane-type apparatus (W-08) for measurement of ion-transport and ion-binding activities and by employing a method using human erythrocyte membranes for measurement of ion-permeability, it has been found that soya-cerebroside II exhibits ionophoretic activity for Ca2+ ion.

Cerebrosides↗
PubMed1990

Ultrastructural differentiation in the distal ends of ameloblasts from the presecretory zone to the early secretory zone.

Morphological differentiation of the distal ends of ameloblasts (AMs) from the late presecretory to early secretory zones of the rat upper incisor was studied by electron microscopy. Preameloblasts (PAs) showed a high columnar shape, with the nucleus located in the basal portion. The Golgi apparatus occupied the supranuclear region with type-1 vesicles, and microvilli were present at the distal cell membrane. Coarse-textured material was observed inside the type-1 vesicles and in the lateral intercellular spaces as well as along the distal cell membrane, whereas fine-textured material was found along the distal cell membrane. Near the region of initial enamel formation, large matrix islands were found in the lateral intercellular space. A thin electron-dense layer was observed on the dentin surface. This layer might have occurred as a result of diffusion after degradation of the coarse- or fine-textured material into a finer substance in the extracellular spaces. In the region of initial enamel formation, the distal cell membrane of AMs was flat, but shallow and narrow membrane invaginations were associated with the cell membrane close to the matrix islands. In the region of inner enamel formation, a cone-shaped Tomes' process was formed between large matrix islands which had developed in the intercellular spaces between the lateral portions of the distal ends of AMs. It was considered that the membrane invaginations which had existed at the distal end of PAs moved lower toward the distal terminal bar, thereafter becoming microvilli.

Ameloblasts↗
PubMed1990

Prognostic factors in head and neck non-Hodgkin's lymphoma with special reference to serum lactic dehydrogenase and serum copper.

An analysis of prognostic variables was performed in a retrospective study of 121 patients with Ann Arbor stage I-II head and neck non-Hodgkin's lymphoma admitted from 1973 to 1988. The overall actuarial 5-year survival rate was 58.8% and the minimum follow-up 15 months. Nine clinical and laboratory parameters were studied, including serum lactic dehydrogenase (LDH) and serum copper (SCL), and subjected to univariate and multivariate analyses. In univariate analysis, histology and LDH were found to be significant prognostic variables. Evaluation by Cox's multivariate proportional hazard model revealed histology, SCL and sex to be of prognostic significance.

Adolescent↗
PubMed1990

[Radiotherapy of local regional recurrences of a mastectomized breast carcinoma and its results].

Local-regional recurrences of a breast carcinoma after the mastectomy have been studied. A complete response rate of 89% was noted and this rate was found to decrease with an increase in the size of the mass. The most favorable local control rate was noted in carcinomas of the solitary nodular type where as the worst control late was seen in those with a lymph node metastasis. The 5-year survival rate in all cases was found to be 28.0%, and best in the solitary nodular type carcinomas and worst in carcinomas of the invasive type. Chestwall recurrences associated a local lymph node metastases were found to have a poorer prognosis compared to those without a lymph node metastasis.

Adult↗
PubMed1989

Identification of multiple cis-elements and trans-acting factors involved in the induced expression of human IL-2 gene.

Regulated expression of interleukin-2 (IL-2) gene constitutes an essential part in the clonal proliferation of activated T lymphocytes (T-cells). In order to gain insight on the mechanism(s) of the IL-2 gene induction, deletions were introduced in the human IL-2 gene 5'-flanking region and the mitogen inducibility of each deletion mutant was examined in cultured T cell lines. At least four functional regions were identified, they contain potential binding sites for several transcription factors including one NF-kappa B and two octamer binding factor sites. Whereas each of the functional regions (or elements) is required for the maximal induction of the IL-2 gene by mitogen, one such region was found to be dispensable for activation by the HTLV-1-encoded trans-activator, tax-1. Furthermore, the potent immunosuppressive agent, cyclosporin A was found to inhibit the gene induction by mitogen, but not by tax-1.

Cell Line↗
PubMed1989

Involvement of a common transcription factor in the regulated expression of IL-2 and IL-2 receptor genes.

Interleukin-2 (IL-2) plays an essential role in the clonal expansion of antigen-activated T lymphocytes (T cells). In fact, the expression of both IL-2 and IL-2 receptor (IL-2R, p55, CD25) genes is transiently induced upon T cell activation through the interaction of antigen/major histocompatibility complex (MHC) and T cell receptor complex. To elucidate the mechanism(s) of the induced gene expression for IL-2 and IL-2R, we have investigated for the presence of potential transcription factors that specifically interact with regulatory cis-elements. Here, we demonstrate that one such factor mediates the induced expression of both genes. Interestingly, the recognition sequences by this factor are significantly diverse in these two genes and are related to those of immunoglobulin (Ig) kappa chain and MHC class I genes. We provide evidence that this factor indeed binds to the IL-2, IL-2R, and Ig sequence elements with different affinities, thereby affecting the magnitude of gene expression. Interestingly, this factor also binds to other cytokine genes, such as interleukin-6 (IL-6), interferon-gamma (IFN-gamma), and HIV-1 and HTLV-1 LTR sequences.

Base Sequence↗
PubMed1989

Ionophoretic activities of oligopeptide lactones and resin-glycosides in human erythrocytes.

Oligopeptide lactones (theonellapeptolides) isolated from the Okinawan marine sponge Theonella swinhoei and resin-glycosides (merremosides) from the tuber of an Indonesian medicinal plant Merremia mammosa were examined regarding their activities in transporting Na+, K+, and Ca++ ions into human erythrocytes. Each of these lactones, which had been shown, using a supported liquid membrane, to have an ionophoretic effect on the alkali metal ions, transported the ions to a different extent. The ion transporting activities of these compounds were completely lost when the macrocyclic lactone structures were cleaved by sodium methylate. Resin-glycosides with an additional branched glycosyl residue showed much greater ion transporting activities than those without it.

Erythrocytes↗
PubMed1989

Discriminant analysis on the treatment results of interstitial radium tongue implants.

Discriminant analysis was carried out for 48 tongue cancer patients who were treated with radium single-plane implantation. The 48 patients were grouped into 32 successfully cured without complications, five successfully cured with complications, six successfully cured but requiring additional boost therapy and five with local recurrence. To evaluate the relation between the dose distribution and the local treatment results, the analysis was based on a volume-dose relationship. The functions introduced by this discriminant analysis were linear, and the parameters used were modal dose, average dose and shape factors of histograms. Each group of treatment results had a correction rate of greater than 80%, except for the successfully cured group with ulcers. The discriminant functions were useful as an index to obtain a final clinical treatment result at the early time of implantation, and these functions could be used as a criterion for the optimal treatment of tongue carcinoma. We were also able to recognize the limitation of the actual arrangement of sources in the single-plane implant.

Brachytherapy↗
PubMed1989

[Carcinoma of the uterine cervix treated with TAO low-dose rate intracavitary radiation].

Seventy-four patients with carcinoma of uterine cervix were treated radically with TAO low-dose rate afterloading system during 1972 to 1986. Relapse-free rates were 88.9% in stage I, 77.9% in stage II and 48.3% in stage III, and 5-year cause-specific survival rates were 88.9% in stage I, 77.2% in stage II, and 50.5% in stage III respectively. Late complication in recto-sigmoid region was noticed about 10%, but most of them in minor degree. The results remain satisfactory when compared with other published results.

Adult↗
PubMed1989

[The current treatment of maxillary carcinoma].

Several characteristics of maxillary sinus and oral maxillary squamous cell carcinoma have been discussed, After trimodal combination therapy have been introduced to both cancers, improved local control have been obtained. In addition to elevation of survival rate, neck metastases and double cancers have become the problems to be solved.

Adult↗
PubMed1988

Analysis of the angiographic findings in cases of childhood moyamoya disease.

Cerebral angiograms of 34 patients with childhood moyamoya disease have been analysed, this analysis having revealed the following findings. The blood flow to abnormal net-like vessels (ANV) in the base of the brain is mainly supplied from the internal carotid artery (ICA) in the early stage of this disease. In a later stage, however, the blood supply is mainly from the posterior cerebral artery (PCA). Though, no remarkable change was found in the volumes of ANV from the early to later stages of the disease, the leptomeningeal collaterals, the most prominent anastomoses in moyamoya disease, had a tendency to decrease during the later stage with the development of PCA stenosis. Eighteen occlusive PCA lesions were found in the proximal portion of the PCA in eight cases (44%), and in the distal in nine cases (50%). The incidence of aneurysm (1.5%) and intracranial bleeding was low as compared to cases of adult moyamoya disease.

Adolescent↗
PubMed1988

Visual selection from multielement displays: measuring and modeling effects of exposure duration.

In a partial-report experiment, subjects reported the digits from a circular array of digits and letters terminated by a pattern mask. Individual frequency distributions of the number of correctly reported digits were analyzed as functions of number of digits (2, 4, or 6) and number of letters (0, 2, 4, 6, or 8) at nine exposure durations ranging from 10 to 200 ms. The distributions (hundreds of data points per subject) were accurately predicted by a four-parameter fixed-capacity independent race model that assumes exponentially distributed processing times, limitations in both processing capacity and storage capacity, and time-invariant selectivity. Estimated from the data, processing capacity C was 45 items/s, selectivity alpha (ratio between the amount of processing capacity devoted to a distractor and the amount devoted to a target) was 0.48, short-term storage capacity K was 3.5 items, and the longest ineffective exposure duration t0 was 18 ms.

Adult↗
PubMed1988

Neurotransmitters, receptors and neuropeptides in post-mortem brains of chronic schizophrenic patients.

In the analysis of post-mortem brains of 14 chronic schizophrenic patients and 10 controls, biochemical evidence of a hyperdopaminergic state was found in the basal ganglia of schizophrenics; tyrosine hydroxylase activity was increased with a concomitant increase of homovanillic acid. Unusually high tyrosine hydroxylase activity was noted in 2 schizophrenic cases. The Bmax value of 3H-spiperone binding for schizophrenics was higher than the controls. We also found increased specific binding of 3H-kainic acid to the prefrontal cortex in schizophrenics. A negative correlation existed between 3H-kainic acid binding in the medial frontal cortex, and glutamic acid content in various brain areas. Increased immunoreactivity of substance P was found in more than ten brain areas. Methionine-enkephalin was also increased in three areas of the prefrontal cortex of schizophrenics. These results suggest that the hyperdopaminergic state co-existed with glutamatergic hypofunction and increased neuropeptides in various brain areas of chronic schizophrenic patients.

Adult↗
PubMed1988

Radiation injury in a patient with unusually high sensitivity to radiation.

Radiation therapy is usually given with the assumption that interindividual variations in radiosensitivity are small, except for some patients with hereditary diseases associated with increased sensitivity. Recently, we observed radiation induced pericarditis in a breast carcinoma patient, in whom clinical signs, blood counts and chromosome analysis after in vitro irradiation of blood suggested a state of unusually high radiosensitivity. No evidence of constitutional chromosome abnormality was found in karyotypic analysis with the G-banding technique.

Breast Neoplasms↗
PubMed1988

Fatal Yersinia enterocolitica septicemia complicated by unique hemosiderosis. A case report.

A fatal case of Yersinia enterocolitica septicemia which was complicated by unique hemosiderosis is reported. On admission, the patient had diabetes and showed unusual hyperferritinemia. Postmortem examination revealed that the liver was studied with abscesses, and Yersinia antigen was expressed in foamy macrophages within these abscesses. Moreover, the cadaver showed generalized hemosiderin deposition, which was mainly observed in the liver and, to lesser degrees, in the pancreas, spleen, lymph nodes, brain, thyroid and kidneys. Since there was no apparent cause of the hyperferritinemia and generalized hemosiderosis, consideration was given to possible primary hemochromatosis. However, no liver or pancreatic fibrosis was demonstrated. Kupffer cells were also loaded with hemosiderin, and therefore it was considered that these cells had lost their ability to phagocytize the microorganism adequately, leading to major liver involvement. Interestingly, hemosiderin deposits in the kidneys were mostly present in glomerular epithelial cells. To our knowledge, this unique presentation has not been previously described in humans.

Adult↗