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N Shibuya

Publications and source records attributed to N Shibuya.

At least 145 records · Page 8Linked to original sources
PubMed1986

Griffonia simplicifolia I isolectin as a functionally monovalent probe for use in flow cytometry.

The inherent tendency of lectins to agglutinate cells has limited their use as reagents for the detection of carbohydrate groups on cell surfaces by flow cytometry. In the current study, we demonstrate a method for the use of a fluoresceinated tetrameric isolectin (Griffonia simplicifolia I-A3B, FITC-GS I-A3B) as a functionally monovalent, nonagglutinating probe in flow cytometry. This isolectin contains three A subunits and one B subunit. Both types of subunits bind alpha-D-galactopyranosyl (alpha-D-galp-) end groups with similar affinities; however, the A subunits have a 1,000-fold greater affinity for N-Acetyl-D-galactosamine (GalNAc) than does the B subunit. The addition of low (1-2 mM) concentrations of GalNAc to the FITC-GS I-A3B isolectin results in blockage of the three A subunits without significantly affecting the B subunit; this yields a functionally monovalent probe for the detection of cell surface alpha-D-Galp end groups. This approach has been used to examine two types of cells: Ehrlich ascites tumor cells and rat alveolar macrophages, both of which are known to express cell surface alpha-D-Galp end groups. Lectin binding, as determined by number of positive cells and fluorescence intensity, was dependent upon concentration of the lectin and haptenic sugar. Specificity of the staining was demonstrated by the ability of methyl alpha-D-galactopyranoside (Met alpha-D-Galp) to abolish the binding of the lectin to the cells. Elimination of both GalNAc and Met alpha-D-Galp from the staining solution resulted in agglutination of the cells, indicating that the A subunits were active in the absence of GalNAc.

Animals↗
PubMed1986

Hyperpolarization of the membrane potential caused by somatostatin in dissociated human pituitary adenoma cells that secrete growth hormone.

Membrane electrical properties and the response to somatostatin were examined in dissociated human pituitary adenoma cells that secrete growth hormone (GH). Under current clamp condition with a patch electrode, the resting potential was -52.4 +/- 8.0 mV, and spontaneous action potentials were observed in 58% of the cells. Under voltage clamp condition an outward K+ current, a tetrodotoxin-sensitive Na+ current, and a Ca2+ current were observed. Cobalt ions suppressed the Ca2+ current. The threshold of Ca2+ current activation was about -60 mV. Somatostatin elicited a membrane hyperpolarization associated with increased membrane permeability in these cells. The reversal potential of somatostatin-induced hyperpolarization was -78.4 +/- 4.3 mV in 6 mM K+ medium and -97.2 +/- 6.4 mV in 3 mM K+ medium. These reversal potential values and a shift with the external K+ concentration indicated that membrane hyperpolarization was caused by increased permeability to K+. The hyperpolarized membrane potential induced by somatostatin was -63.6 +/- 5.9 mV in the standard medium. This level was subthreshold for Ca2+ and Na+ currents and was sufficient to inhibit spontaneous action potentials. Hormone secretion was significantly suppressed by somatostatin and cobalt ions. Therefore, we suggest that Ca2+ entering the cell through voltage-dependent channels are playing an important role for GH secretion and that somatostatin suppresses GH secretion by blocking Ca2+ currents. Finally, we discuss other possibilities for the inhibitory effect of somatostatin on GH secretion.

Action Potentials↗
PubMed1986

Role of insulin in the increase in serum 1,25-dihydroxyvitamin D concentrations in response to phosphorus deprivation in streptozotocin-induced diabetic rats.

To evaluate the role of insulin in the regulation of circulating 1,25-dihydroxyvitamin D [1,25(OH)2D] levels, serum 1,25(OH)2D concentrations in response to phosphorus (P) deprivation were examined in control, streptozotocin-diabetic and insulin-treated diabetic rats. Dietary P deprivation for 1 week caused a marked increase in serum 1,25(OH)2D level from 75 +/- 4 pg/ml to 274 +/- 16 pg/ml in control rats. In contrast, serum 1,25(OH)2D level was significantly lower in diabetic rats on a normal P diet (20 +/- 2 pg/ml) compared to that in control rats and increased only slightly by P deprivation (33 +/- 4 pg/ml). Treatment of the diabetic rats on normal P diet with insulin caused an increase in serum 1,25(OH)2D concentration to a level (82 +/- 10 pg/ml) similar to that in control rats and restored the increase in serum 1,25(OH)2D concentration in response to P deprivation (315 +/- 38 pg/ml). Although there was a marked decrease in serum phosphate level by P deprivation in all groups of animals, the rise in serum calcium level by P deprivation seen in control rats was abolished in diabetic rats. In addition, while bone mineral contents decreased significantly in response to P deprivation in control rats, no significant changes in either bone calcium or P contents were observed after P deprivation in diabetic rats. Insulin treatment of the diabetic rats recovered the responsiveness to P deprivation in both serum calcium level and bone mineral contents. P deprivation did not affect plasma glucose or serum creatinine level in any group of rats. These results suggest that insulin, either directly or indirectly, is required for the increase in circulating 1,25(OH)2D concentrations in response to P deprivation, and that the rise in serum 1,25(OH)2D level may play a role in the hypercalcemic response to P deprivation.

Animals↗
PubMed1984

Immunity to transplantable nitrosourea-induced neurogenic tumors. III. Systemic adoptive transfer of immunity.

The effect of intravenously injected tumor immune spleen cells on growth of 3 X 10(5) gliosarcoma T9 cells injected intradermally (ID) or intracerebrally (IC) into sublethally irradiated CDF rats was evaluated. Spleen cells from donor rats with sufficient immunity to reject 5 X 10(5) T9 cells inhibited the growth of T9 cells mixed with spleen cells in a ratio of 1:25 and injected ID, but could not act after intravenous transfer. However, donor rats which had rejected increasing T9 challenge doses up to 1 X 10(7) cells produced immune spleen cells which, upon IV transfer, could inhibit growth of ID T9 challenge but not of EB-679, an unrelated glioma, in recipient rats. Rejection of IC T9 challenge was also obtained after IV transfer, in recipients of such "hyperimmune" spleen cells, but was less (60% maximum) than that noted after ID T9 challenge (100% maximum). The removal of B cells from the transferred spleen cells did not affect the results, suggesting that the specific immunity was mediated by T cells. We conclude that the special immunological circumstances of tumors growing in the brain renders them less accessible to rejection by systemically transferred immune cells, but it is nevertheless possible to effect a significant incidence of rejection of syngeneic tumor growth in the brain by the intravenous transfer of hyperimmune spleen cells.

Animals↗
PubMed1983

[Anti-tumor activity of ACNU against malignant glioma--a clinical application of in vitro sensitivity test of chemotherapeutic agent].

In vitro sensitivity test of cultured human malignant glioma cells to ACNU[1-(4-amino-2-methyl-5-pyrimidinyl) methyl-3-(2-chloroethyl)-3-nitrosourea hydrochloride] was performed on Falcon 3064 microtestplate. Early culture cells established from 10 clinical cases were examined by means of this method and the correlation between in vitro response and clinical response of tumor to ACNU was studied. In microtestplate assay, it was defined as ACNU sensitive when the tumor growth showed more than 60% suppression when tumor was cultured in the medium which contained 40 meg/ml of ACNU. Clinical responses were evaluated by means of CT scan, being divided into 4 classes, PR (partial response), CR (complete response), NC (no change) and PD (progressive disease). The former two groups were regarded as responder and the latter two as nonresponder. The correlationship between in vitro response and clinical response was higher in resistant group (100%) than in the sensitive group (60%), so the resistant tumor can be checked with this method. For this reason, the use of this assay may prove helpful in the selection of the chemotherapeutic agents.

Adolescent↗
PubMed1983

[Malignant intracranial lymphoma--clinical and patho-immunological study].

Clinical and patho-immunological study was made on 15 cases of primary intracranial malignant lymphoma. The average age of the patients was 45.2, however older man suffered more than younger one. Male to female ratio was 3:2. The duration between onset to diagnosis was less than 6 months in 13 cases. The common signs and symptoms were hemiparesis (60%) and signs of intracranial hypertension (45%), followed by disturbance of consciousness, visual disturbances, convulsion and signs of inflammation. The location of the lesions was in parietal lobe (44%), temporal lobe (27.8%), cerebellum (22.2%), brain stem and basal ganglia (18%). Multiple lesions were found in 4 cases. CT scan was the most diagnostic method not only to delineate the location of lesions but also to recognize the biological natures of this condition. The radiosensitivity of this tumor was also confirmed by follow-up CT scans during radiotherapy. Most of the lesions were avascular by carotid angiography, but capillary blush at the tumor site was shown in some cases. Laboratory findings revealed that derangement of gamma globulin in the serum and decline of cellular immunity were demonstrated in many cases. Surgical removal followed by whole skull irradiation was made in all cases except one. Remission of neurological signs and symptoms with disappearance of lesions on CT scan was obtained in 7 cases for one to 9 months. All cases except two survival, died during 3 to 28 months (average: 10.1). Survival rate at one year and 2 years was 35.7% and 14.3% respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1982

Sensitivity to 1-(4-amino-2-methyl-5-pyrimidinyl)methyl-3-(2-chloroethyl)-3-nitrosourea hydrochloride (ACNU) of glioma cells in vivo and in vitro.

A new water-soluble nitrosourea (ACNU) was tested for its antitumor activity against four glioma cell lines. Four factors were studied to determine its antitumor activity: inhibition of cell growth, morphologic observation, analysis of DNA histogram with flow microfluorometry, and sensitivity testing with microtest plate. Growth inhibition in response to ACNU was seen in two cell lines (EA285, U251-MG), whereas two cell lines (YE2-02, T98) were resistant to ACNU. The results of the present sensitivity test concur with those of other examinations that this test is useful in selecting a drug and determining the effective dose.

Animals↗
PubMed1982

Brain metastasis of choriocarcinoma.

Twenty-four patients with histologically verified brain metastasis of choriocarcinoma were analyzed regarding autopsy and operative findings, signs and symptoms, diagnosis, method of treatment, and prognosis. The autopsy incidence of brain metastasis was 66.7% in patients with choriocarcinoma, and the predominance of single brain lesions was confirmed. Most of the metastatic lesions were hemorrhagic. The hemorrhages were intratumoral, peritumoral, and/or subarachnoid. These findings were well correlated with the findings on computed tomographic (CT) scans and the acute onset with rapid progression of symptoms. The history of molar pregnancy, measurements of urinary chorionic gonadotropin, and findings on CT scans were diagnostic. Surgical removal of the lesion followed by chemotherapy combined with irradiation is the treatment of choice in patients with progressive neurological deterioration in whom chemotherapy alone is ineffective.

Adult↗