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Biomedical subjects

Y Honma

Publications and source records attributed to Y Honma.

At least 307 records · Page 17Linked to original sources
PubMed1984

Acute intracranial hypertension and brain-stem blood flow. An experimental study.

This study has been carried out to evaluate the effect of supratentorial mass lesions on the local cerebral blood flow (CBF) of the brain stem. Local CBF of the thalamus, inferior colliculus, and medulla oblongata, and supra- and infratentorial pressure were serially measured in 52 cats with intracranial hypertension produced by supratentorial balloon expansion. The mean control local CBF's in the thalamus, inferior colliculus, and medulla oblongata were 37.5, 42.1, and 30.7 ml/100 gm/min, respectively. At 20 to 30 mm Hg of supratentorial pressure, the local CBF of the thalamus started to decrease, and at 20 mm Hg of infratentorial pressure, the local CBF of the inferior colliculus began to decrease. Finally, at 40 to 60 mm Hg of infratentorial pressure, the local CBF of the medulla oblongata was affected. At the beginning of uncal herniation, indicated by anisocoria, the mean local CBF of the inferior colliculus abruptly decreased from 33.7 to 19.6 ml/100 gm/min in 16 cats. The Cushing response was evoked at a mean supratentorial pressure of 93.4 mm Hg and infratentorial pressure of 49.9 mm Hg in 16 cats. When the systemic arterial pressure was increased to the highest level in 13 cats, the mean local CBF of the medulla oblongata did not show significant change (a decrease from 22.8 to 20.9 ml/100 gm/min). The results suggest that at the beginning of uncal herniation, the local CBF of the upper brain stem markedly decreased. During the Cushing response, the local CBF of the medulla oblongata did not change significantly.

Acute Disease↗
PubMed1984

[The role of brain-stem vasomotor centers on the neurogenic control of the neurogenic control of cerebrovascular tonus. Part 1: In special reference to cerebral blood volume and intracranial pressure].

An increase in cerebral blood volume (CBV) due to a decrease in cerebrovascular tonus has been though to be a major factor in the cause of acute brain swelling. It has been reported that the dorsomedial nucleus of the hypothalamus (DM), one of the brain-stem vasomotor centers, regulates cerebrovascular tonus. The DM and other vasomotor centers, such as the midbrain reticular formation (MBRF) and the reticular formation of the medulla oblongata (MORF), are connected through a series of nerve fibers. This experiment was designed to clarify the neurogenic control of the DM, MBRF, and MORF on cerebrovascular tonus. Using fifty-six cats, unilateral and bilateral DM(A 1.2, L2.0, H-10.0), MBRF (A4.0, L4.0, H0), and MORF (P10.0, L2.5, H-9.0) were coagulated stereotaxically with the condition of 15-10 mA for 1 minute. The lesions in the DM and MBRF were enlarged by increasing the current intensity of electrical coagulation. The effects of the increase on a number of simultaneously coagulated lesions were examined. Changes in systemic blood pressure (BP), intracranial pressure (ICP), and CBV were continuously recorded. Temporary increases in ICP (mean increase 16 mmHg, n = 14) and CBV were observed after unilateral coagulation of the DM. These increases were associated with transient systemic hypotension. The changes lasted only for approximately 5 minutes. The changes that occurred in ICP and CBV as a result of unilateral coagulation in the MBRF were almost the same as those that occurred after coagulation of the DM. In the latter case, the duration of the change was approximately 6 minutes with a mean increase of 12 mmHg (n=12).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1984

Differentiation in vitro of human myelogenous leukemia cells from patients in relapse.

Leukemia cells from patients with acute myeloid leukemia in relapse were treated with various inducers of differentiation of human myeloid leukemia cell lines. Leukemia cells in primary culture from most, but not all, patients underwent morphological, cytochemical and biochemical changes after treatment with inducers of differentiation such as 12-O-tetradecanoylphorbol-13-acetate (TPA), retinoic acid, actinomycin D, aclarubicin, and alkyl lysophospholipid. The most effective inducer varied from specimen to specimen. Leukemia cells from patients in relapse were compared with those from untreated patients. The responsiveness to TPA of leukemia cells from patients in relapse was similar to that of leukemia cells from untreated patients. However, retinoic acid or actinomycin D resistance was more frequently observed in leukemia cells from patients in relapse than in those from patients before initial therapy. This is the first report to indicate that leukemic cells from relapsed patients who are resistant to cytotoxic chemotherapeutic drugs can be induced to differentiate into mature cells by appropriate inducers. However, the responsiveness to inducers of leukemia cells from patients in relapse is not the same as that of leukemia cells before therapy.

Adolescent↗
PubMed1983

Antileukemic effect of alkyl phospholipids. I. Inhibition of proliferation and induction of differentiation of cultured myeloid leukemia cells by alkyl ethyleneglycophospholipids.

Various alkyl ethyleneglycophospholipids, i.e., alkyl phospholipids, with ethyleneglycol or its congener in place of glycerol as a molecular backcone, were synthesized and their effects on cell proliferation and differentiation of cultured human (HL-60) and mosue (Ml) myeloid leukemia cells were studied. On incubation with alkyl ethyleneglycophospholipids, proliferation of both cell lines was inhibited and the cells were induced to differentiate into morphologically and functionally mature granulocytes and macrophages. Among the compounds tested, dodecyl ethyleneglycophospholipid with a pyridinioethyl group was the most effective in induction of differentiation of both cell lines.

Cell Differentiation↗
PubMed1983

Antileukemic effect of alkyl phospholipids. II. Prolongation of survival times of leukemic mice by alkyl ethyleneglycophospholipids.

Alkyl ethyleneglycophospholipids induced differentiation in vitro of mouse myeloid leukemia M1 cells into mature granulocytes and macrophages. The compounds also prolonged the survival of syngeneic SL mice inoculated with M1 cells. Although in mice with florid leukemia these compounds alone scarcely affected survival, administration of dodecyl ethyleneglycophospholipid with pyridinioethyl as a polar group plus actinomycin D significantly prolonged survival.

Animals↗
PubMed1983

Stimulation of cell proliferation by tumor-promoting phorbol esters and inhibition by some inhibitors of tumor promotion in suspension cultures of a human lymphoblastoid cell line.

A human lymphoblastoid cell line, SCC-1, was established from the bone marrow of a patient with acute nonlymphocytic leukemia. 12-O-Tetradecanoylphorbol-13-acetate (TPA) enhanced cell proliferation of SCC-1 cells in suspension culture. A positive correlation was found between the tumor-promoting activities of several plant diterpenes and their enhancing effects on the growth of SCC-1 cells. Various compounds that inhibit tumor promotion were tested for their capacity to inhibit cell proliferation at a physiological concentration. These compounds were not cytotoxic but cytostatic even at high concentration.

B-Lymphocytes↗
PubMed1983

Increased agglutinability of bladder epithelial cells by concanavalin A in rats fed several biphenyl derivatives.

Biphenyl and its derivatives, 2-aminobiphenyl, 2-nitrobiphenyl, 4-aminobiphenyl, 4-nitrobiphenyl, p-phenylphenol, o-phenylphenol (OPP), and o-phenylphenol sodium salt tetrahydrate (OPP-Na) were examined for their bladder carcinogenicity in rats by a short-term assay for agglutinability of bladder epithelial cells with concanavalin A. Increased agglutinability was observed after 1-week treatment with 2.0% and 1.0% OPP, 2.0% and 1.0% OPP-Na, 0.5 and 0.1% 4-aminobiphenyl, and 0.5% 4-nitrobiphenyl in the diet, suggesting carcinogenicity of these compounds in the bladder. Such an increase in agglutinability was not observed in rats fed diets containing biphenyl, 2-aminobiphenyl, 2-nitrobiphenyl or p-phenylphenol at 2.0%. With OPP-Na, an in vivo carcinogenesis experiment was performed. Bladder carcinomas developed in 14 of 36 male Fisher rats fed a 2% OPP-Na diet for 50 weeks.

Agglutination Tests↗
PubMed1983

Cooperative effect of 1 alpha,25-dihydroxyvitamin D3 and dexamethasone in inducing differentiation of mouse myeloid leukemia cells.

Murine myeloid leukemia cells (MI) are induced to differentiate into macrophages by the metabolically active form of vitamin D3,1 alpha,25-dihydroxyvitamin D3[1 alpha,25(OH)2D3] (E. Abe et al., (1981) Proc. Natl. Acad. Sci. USA 78, 4990-4994). At 0.12-120 nM, 1 alpha,25(OH)2D3 suppressed cell growth in a dose-dependent manner and markedly induced phagocytic activity, lysozyme activity, and C3-receptor formation. The potency of 1 alpha,25(OH)2D3, at 0.12-120 nM, in inducing differentiation was nearly equivalent to that of 10-10,000 nM of dexamethasone, one of the most potent stimulators of Ml cells. Simultaneous treatment with low physiological plasma concentrations of 1 alpha,25(OH)2D3 (0.12 nM) and dexamethasone (10 nM) induced differentiation of Ml cells equivalent to the responses obtained only by using much higher concentrations of the respective steroids when used separately. In addition, two variant clones of Ml cells resistant to either 1 alpha,25(OH)2D3 or dexamethasone were isolated. One was resistant to 120 nM of 1 alpha,25(OH)2D3 but sensitive to 10-1000 nM of dexamethasone. The other was resistant to 1000 nM of dexamethasone but sensitive to 12 nM of 1 alpha,25(OH)2D3. This suggests that the mechanism of action of 1 alpha,25(OH)2D3 in inducing differentiation of Ml cells is different at least in part from that of dexamethasone, and that combination therapy by both steroids may be useful in reducing leukemogenicity of Ml cells in vivo.

Animals↗
PubMed1983

Effects of inducers of erythroid differentiation of human leukemia K562 cells on vincristine-resistant K562/VCR cells.

K562/VCR cells, which are resistant to the cytotoxicity of vincristine, were isolated from human erythroleukemia K562 cells. Various compounds that induce erythroid differentiation of K562 cells were tested on K562/VCR cells. Differentiation of K562/VCR cells was not induced by actinomycin D or adriamycin alone, but the resistance of these cells to the inducers was overcome by verapamil. In contrast, mitomycin C, butyric acid and hemin induced differentiation of K562/VCR cells as effectively as that of K562 cells. These results suggest that therapy by induction of differentiation of leukemic cells is effective for leukemic cells that have acquired resistance to therapeutic drugs.

Animals↗
PubMed1983

Acidic isoferritins do not suppress differentiation of mouse myeloid leukemic M1 cells.

The differentiation of mouse myeloid leukemia line cells (M1) into macrophages or granulocytes has been reported. Resistant M1 cells which did not differentiate even with a high concentration of inducer of differentiation were isolated from M1 cells. The conditioned medium of the resistant M1 cells (RCM) inhibited the induction of differentiation of M1 cells and the formation of macrophage and granulocyte colonies of normal mouse bone marrow cells. Acidic isoferritins known as negative regulators of normal bone marrow cells (CFU-GM) failed to inhibit the induction of differentiation and growth of M1 cells. The RCM treated with anti-acidic isoferritin serum could inhibit the induction of differentiation of M1 cells as did the untreated RCM. The activities, in RCM, inhibiting growth and differentiation of the normal bone marrow cells were partly neutralized by treatment with the antiserum but most of the activities remained. These results suggest that growth and differentiation of the mouse myeloid leukemia M1 cells are not regulated by acidic isoferritins and other inhibitory activities affecting normal bone marrow colony formation, in addition to acidic isoferritins, are released from M1 cells.

Animals↗
PubMed1983

Induction of differentiation of human acute non-lymphocytic leukemia cells in primary culture by inducers of differentiation of human myeloid leukemia cell line HL-60.

Leukemia cells from patients with acute non-lymphocytic leukemia were treated with various inducers of differentiation of the human promyelocytic leukemia cell line HL-60. All cells in 14 specimens tested underwent morphological, functional and histochemical changes after treatment with some inducers of differentiation of HL-60 cells, but the most effective inducer varied for different specimens. These results suggest that treatment with some inducers should be effective for inducing most acute myeloid leukemia cells to differentiate into morphologically and functionally mature granulocytes and macrophages.

Adult↗
PubMed1983

Agglutination assay of bladder cells by Concanavalin A proved the high susceptibility of analbuminemic rats to bladder carcinogens.

The susceptibility of analbuminemic rats, a mutant strain of Sprague-Dawley rats, to bladder carcinogens was examined by testing the agglutinability of isolated bladder epithelial cells by Concanavalin A (Con A). One-week treatment with 0.001% N-butyl-N-(4-hydroxybutyl)nitrosamine (BHBN) in the drinking water or 0.01% N-(4-(5-nitro-2-furyl)-2-thiazolyl)-formamide (FANFT), 0.01% and 0.1% 4-aminobiphenyl, 0.1% 4-nitrobiphenyl, 0.1% benzidine, 0.1% 2-napthylamine or 5% sodium saccharin in the diet clearly induced high agglutinability of bladder cells of male analbuminemic rats but not Sprague-Dawley rats. These results suggest that male analbuminemic rats are very susceptible to bladder carcinogens in general and therefore will be very useful in screening tests for bladder carcinogens.

2-Naphthylamine↗
PubMed1983

Antiallergic agents. 2. N-(1H-tetrazol-5-yl)-6-phenyl-2-pyridinecarboxamides.

A new series of N-(1H-tetrazol-5-yl)-6-phenyl-2-pyridinecarboxamides was prepared to determine the effects of substituents on the benzene and pyridine rings on antiallergic activity in the rat passive cutaneous anaphylaxis (PCA) assay after oral administration. One member of this series, N-(1H-tetrazol-5-yl)-4-methyl-6-[4-(methylamino)-phenyl]-2- pyridinecarboxamide (231), has an ED50 value of 0.8 mg/kg po and is 85 times more potent than disodium cromoglycate (DSCG) on intravenous administration. Further evaluation of 231 as a clinically useful antiallergic agent is in progress.

Animals↗
PubMed1983

1 alpha,25-Dihydroxyvitamin D3 and 1 alpha-hydroxyvitamin D3 prolong survival time of mice inoculated with myeloid leukemia cells.

Syngeneic SL mice inoculated with murine myeloid leukemia cells (M1) all died of leukemia within 30 days. Treatment three times a week with 12.5-50 pmol per mouse of either 1 alpha,25-dihydroxyvitamin D3 [1 alpha,25(OH)2D3], the active form of vitamin D3, or its synthetic analog, 1 alpha-hydroxyvitamin D3 [1 alpha(OH)D3], considerably prolonged the survival time of mice inoculated with M1 cells. 1 alpha(OH)D3 was more effective than 1 alpha,25(OH)2D3 in increasing the survival time of the mice. 1 alpha(OH)D3 also increased the survival time of nude mice inoculated with M1 cells. The 1 alpha(OH)[3H]D3 administered intraperitoneally to tumor-bearing mice was converted very rapidly to 1 alpha,25(OH)2-[3H]D3. The chronic administration of 25 pmol of 1 alpha(OH)D3 to tumor-bearing mice for 30 days caused no appreciable hypercalcemia. These results indicate clearly that 1 alpha,25(OH)2D3 is effective not only in inducing differentiation of M1 cells in vitro, as previously reported [Abe, E., Miyaura, C., Sakagami, H., Takeda, M., Konno, K., Yamazaki, T., Yoshiki, S. & Suda, T. (1981) Proc. Natl. Acad. Sci. USA 78, 4990-4994], but also in prolonging the survival time of mice inoculated with M1 cells.

Animals↗