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Biomedical subjects

Y Sakamoto

Publications and source records attributed to Y Sakamoto.

At least 541 records · Page 30Linked to original sources
PubMed1988

[Clinical implication of serum antibody to Thomsen-Friedenreich antigen in patients with gynecological malignancies].

Thomsen-Friedenreich antigen (T-antigen) is a carbohydrate antigen that is expressed in a variety of cancer tissues. T-antigen is thought to have an antigenicity because circulating T antibodies can be detected as natural antibodies in humans. In this study, we examined the serum T antibody titers in patients with gynecological cancer using the hemagglutination test, and studied the relationship between the expression of T-antigen in cancer tissues and serum TA-4 levels and serum T antibody titers. Serum T antibody titers in patients with gynecological cancer were lower than those in normal controls, especially in endometrial and ovarian cancer (p less than 0.05) in which T-antigen was strongly expressed. Furthermore, the low antibody titers correlated with the expression of T-antigen in cancer tissues. T antibody titers significantly increased (p less than 0.01) after operation and the inverse relationship was found with the levels of circulating TA-4 in cervical cancer patients. These findings suggests that patients with gynecological cancer immunologically responded to T-antigen and the measurement of circulating T antibodies may be useful as an indicator of the progression of cancer in tissues.

Antibodies↗
PubMed1988

[Basic studies in intra-arterial chemotherapy with degradable starch microspheres (DSM) on human gastric cancer xenografts in nude rats].

Enhancement of the antitumor effect of adriamycin (ADR) was investigated by using degradable starch microspheres (DSM) and pharmacokinetics of ADR in combination with DSM. An intra-arterial chemotherapy model of the nude rats transplanted of human cancer xenografts (H-154 gastric cancer) in the lower limbs was used for this study. Drug was administered through a catheter inserted into the carotid artery with the tip in the common iliac artery. DSM 30 mg/kg, which causes temporary arrest of blood flow in the tumor, had an only weak effect on tumor growth, whereas. DSM 30 mg/kg, mixed with ADR 3 mg/kg solution, was more effective than ADR solution. Furthermore, DSM 30 mg/kg mixed with ADR 3 mg/kg had a greater effect on the tumor growth than DSM 15 mg/kg mixed with ADR 3 mg/kg. In the pharmacological study, increase of the regional uptake of ADR and decrease of systemic distribution of ADR were recognized in some degree. It seems that embolization by DSM, retention of ADR in regional tissues and cytotoxic effect of ADR contributed to such a strong effect of ADR mixed with DSM on tumor growth.

Animals↗
PubMed1987

Thickness of uninvolved fibromuscular stroma and extrauterine spread of carcinoma of the uterine cervix.

The minimum thickness of cervical fibromuscular stroma remaining uninvolved with invasive cervical carcinoma was examined in relation to pelvic node metastases and 5-year cancer death rate, using specimens from Stage IB, IIA, and IIB patients who underwent radical hysterectomy and pelvic lymphadenectomy. The nodal metastasis and 5-year cancer death rates were 7% and 8%, respectively, in patients with the uninvolved fibromuscular stroma thickness above 3 mm, and 37% and 26%, respectively, in patients with the thickness below 3 mm. The thickness of cancer-unaffected cervical fibromuscular stroma seemed to be closely related to and to be a more useful parameter of the biological behavior of invasive cervical carcinoma than the depth of the cancer invasion. A threshold value of the minimum thickness of the tissue as a barrier against extrauterine spread of cervical cancer could not be identified in this study.

Adenocarcinoma↗
PubMed1987

Quantitative estimation of the effects of capsaicin on the mouse primary sensory neurons.

Studies were made on the quantitative effects of capsaicin on the L4 dorsal roots and their ganglia (DRG) in mice. Capsaicin at a dose of 50 mg/kg was injected s.c. 1-3 times into neonatal mice, while other mice received only vehicle as controls. After capsaicin treatment unmyelinated fibers decreased by 41.3-75.3% compared to controls. After 2 or 3 capsaicin injections there was a greater decrease in unmyelinated fibers than after a single treatment. Capsaicin had most effect on Schwann cell subunit size of more than 13 axons. Reduction of myelinated fibers ranged from 6.1 to 11.6% (mean: 7.9) in 4 mice. A beta and A delta fibers of 4-5 microns diameter were significantly reduced, whereas A delta fibers of less than 2.0 microns diameter were slightly increased. Small DRG neurons (50-500 microns 2 area) decreased by 50.6-77.4% (mean: 69.6) compared to controls. In addition, capsaicin caused a decrease of 14.2-51.6% (mean: 35.2, n = 4) in large-sized neurons (500-1950 microns 2 area). Thus, capsaicin widely affects small and certain types of large neurons as well as unmyelinated and certain myelinated fibers.

Animals↗
PubMed1987

Complete amino acid sequence of PO protein in bovine peripheral nerve myelin.

The P0 protein is a major structural glycoprotein of molecular weight 28,000 in peripheral nerve myelin. The complete amino acid sequence of bovine P0 protein was determined. The polypeptide chain consists of 219 amino acid residues and includes a highly hydrophobic domain (residues 125-150) in the middle, which probably represents a transmembrane segment. The amino terminal domain (residues 1-124) is relatively hydrophobic, but contains a negatively charged carbohydrate chain at Asn93. This domain is most likely located on the extracellular side of the membrane and may contribute to formation of the myelin intraperiod line by hydrophobic and electrostatic interactions. On the other hand, the basic carboxyl-terminal domain (residues 151-219) may protrude from the cytoplasmic side of the membrane and is probably involved together with basic proteins in the formation of the major myelin dense line through electrostatic interaction with acidic lipids in the membrane. The few interspecies amino acid variations between the bovine P0 and the rat P0 sequences, deduced from the cDNA (Lemke, G., and Axel, R. (1985) Cell 40, 501-508), indicate that the P0 protein is conserved across species.

Amino Acid Sequence↗
PubMed1987

Effect of capsaicin on neurites of cultured dorsal root ganglia and isolated neurons of chick embryos.

The effects of capsaicin on neurites of cultured chick lumbar dorsal root ganglia and their isolated single neurons were investigated. Capsaicin-treated neurites showed a disappearance of their tips, dumpling-like structures, and retardation as a result of degeneration. However, some of the retarded neurites showed a reextension. By electron microscopy the degeneration appeared similar to that caused by beta,beta'-iminodipropionitrile with respect to segregation of the cytoskeleton. This finding provides support for the idea that capsaicin inhibits axonal transport.

Animals↗
PubMed1987

The mechanism and overcoming of resistance in ACNU-resistant sublines of C6 and 9L rat glioma.

In order to study the mechanism of the resistance to chemotherapeutic agents, especially ACNU [1-(4-amino-2-methyl-5-pyrimidinyl) methyl-3-(2-chloroethyl)-3-nitrosourea hydrochloride), two variant cell lines (C6/ACNU and 9L/ACNU) resistant to ACNU were selected in vivo from rat C6 and 9L glioma, respectively. Uptake and efflux of ACNU in these resistant cells were studied with Ethylene[14C]ACNU. The result indicated that the resistance exhibited by both sublines were due to both the reduced uptake of the drug and the increased efflux. The study of the effects of oxidative phosphorylation inhibitor, DNP (2,4-dinitrophenol), on the uptake and retention of ACNU suggested that there is an active outward transport mechanism for ACNU in both glioma sublines and that enhanced activity of this efflux mechanism renders cells highly resistant to the cytotoxic action of ACNU. In an attempt to clarify the more detailed biochemical mechanisms of this active efflux system, we surveyed various membrane-modifying agents which potentiate the sensitivity of these resistant cells to ACNU. Among a number of membrane-modifying agents, reserpine was found to retain ACNU in the resistant cells and to enhance the action of ACNU on these resistant cell lines. It may be concluded that drugs such as reserpine may overcome a mechanism of ACNU resistance.

Animals↗
PubMed1987

Increased MR signal intensity secondary to chronic cervical cord compression.

Magnetic resonance images of 128 patients with compressive lesions of the cervical spinal canal were reviewed to determine whether a high signal intensity lesion within the spinal cord was present on T2 and proton density weighted spin echo images. Such high signal intensity was observed in 24 cases or 18.8%. The incidence was higher in herniated disk (32.4%), atlanto-axial dislocation (28.6%), and ossification of the posterior longitudinal ligament (22.7%), whereas the abnormality was found sporadically in cervical spondylosis and vertebral body tumors. The high intensity lesion on T2 weighted images was generally observed in patients with constriction or narrowing of the spinal cord. The lesion was not demonstrated on T1 weighted spin echo images. Spinal cord constriction or localized narrowing seemed to be the most important predisposing factor in producing such a high signal intensity. The pathophysiologic basis of such an abnormality was presumed to be myelomalacia or cord gliosis secondary to a long-standing compressive effect of the spinal cord.

Atlanto-Axial Joint↗
PubMed1987

Colposcopic findings of gland openings in cervical carcinoma: their histological backgrounds.

During the past 8 years 1501 colposcopies were performed paying a special attention to cervical glands for diagnosis of cervical intraepithelial neoplasia (CIN) and carcinoma. Normal openings could exclude these diseases at the error rate of only 5.1%, while atypical openings could identify them at the high confidence rate of 96.3%. False positive evaluations were mostly attributable to a marked degree of squamous metaplasia in the glands. The absence of gland openings in the main portion of the lesions amounted to 88.6% in invasive carcinomas but to only 12.4% in CIN. Adenoma malignum was a highly characteristic exception.

Carcinoma in Situ↗
PubMed1987

Shellfish and fish poisoning related to the toxic dinoflagellates.

At least four different species of the toxic dinoflagellates cause shellfish and fish poisoning in the United States: Ptychodiscus brevis, neurotoxic shellfish poisoning; Protogonyaulax catenella and P tamarensis, paralytic shellfish poisoning; and Gambierdiscus toxicus, ciguatera fish poisoning. These three disorders have similar clinical manifestations, primarily neurologic and alimentary. A complete history is essential; confirmation, while dependent on specific laboratory analysis, is usually based on a history of ingestion of fish or shellfish previously associated with these types of poisonings. The principal toxins affect sodium channels; Ptychodiscus brevis toxins and ciguatoxin by stimulating these channels and saxitoxin by blocking them. Since no antidote is known, treatment is symptomatic. Public health measures and public education are necessary to prevent this form of poisoning.

Animals↗
PubMed1987

Cataract survey in the local area using photographic documentation.

An epidemiological survey of cataract was performed in a limited local population. 1,020 individuals over 40 years of age were examined. The crystalline lens findings were documented by both Scheimpflug and retroillumination photography. Cataractous changes were classified into three groups according to early senile changes, incipient cataractous changes and only prominent cataractous changes. Forms of opacification were classified as cortical, subcapsular, nuclear, mixed type and others. The percent prevalence of cataracts including early senile changes was 33.9% in the 40-year-old population, 62.8% in the 50, 76.2% in the 60, 84.0% in the 70 and 100% for those in their 80s. Prominent cataractous opacification was 1.6% in the 40-year-old population, 3.1% for those in their 50s, 19.0% in their 60s, 28.6% in their 70s and 57.1% in their 80s, respectively. Until age 60, the type of opacification was mainly cortical alone; however, after age 70, cortical opacity accompanied by nuclear and/or capsular opacities increased. The pure nuclear type increased in individuals over 70.

Adult↗
PubMed1987

Electrical and mechanical interaction between circular and longitudinal muscle layers of the guinea-pig stomach.

The effects of prostaglandin E1 and F2 alpha on the mechanical and electrical responses of circular strips dissected from various parts of the guinea-pig stomach were examined. Prostaglandin E1 induced the tonic contraction without an inhibition of the phasic contraction in lower parts of stomach. The amplitude of tonic contraction decayed along with greater curvature of the stomach, that is, it was largest in pylorus region and smallest in upper corpus. Furthermore, the tonic contraction increased depending on concentrations of prostaglandin E1. When a longitudinal muscle layer was removed from the circular strips, the tonic contraction disappeared. On the other hand, prostaglandin E1 or F2 alpha consistently induced an increase in the resting tone and the phasic contraction in longitudinal strips of all parts of stomach. Simultaneous recordings of the electrical and mechanical activities showed a correlation between membrane depolarization and tonic contraction induced by prostaglandin E1. Above results were not affected by nerve-blocking agent, atropine or tetrodotoxin. Thus it is suggested that the tonic contraction in circular strips induced by prostaglandin E1 is closely related to the longitudinal tonic contractions.

Animals↗
PubMed1987

The long-lasting contraction induced by transmural stimulation in the longitudinal muscle of the guinea-pig gastric corpus.

The mechanisms involved in the long-lasting contraction induced by transmural stimulation were investigated in the isolated longitudinal muscle of the guinea-pig gastric corpus. Transmural stimulation induced an initial rapid contraction, a subsequent relaxation and a long-lasting contraction which was mimicked closely by the responses to noradrenaline and ATP. The rapid contraction was blocked by tetrodotoxin or by atropine, and the subsequent relaxation was also blocked by tetrodotoxin, but not by atropine. The long-lasting contractions were not inhibited by atropine, phentolamine, and propranolol. However, some of those were partially inhibited by tetrodotoxin and guanethidine, and others were enhanced by tetrodotoxin. The noradrenaline- but not ATP-induced long-lasting contraction was blocked by phentolamine. Furthermore, indomethacin completely abolished the long-lasting contractions induced by transmural stimulation, noradrenaline, and ATP, but did not significantly affect the response to prostaglandin E2. The results indicate that the long-lasting contraction induced by transmural stimulation is mediated through prostaglandins release which may be triggered by neuro-transmitters or by endogenous substances.

Adenosine Triphosphate↗
PubMed1987

Modulation in vitro and in vivo of ACNU resistance in a subline of C6 glioma with reserpine.

Reserpine enhanced in vitro the cytotoxicity of 1-(4-amino-2-methyl-5-pyrimidinyl) methyl-3-(2-chloroethyl)-3-nitrosourea hydrochloride (ACNU) in both the C6 glioma and its ACNU-resistant subline, C6/ACNU. Reserpine also enhanced the chemotherapeutic effect of ACNU in C6/ACNU-bearing (C6/ACNU-meningeal gliomatosis) rats, in which ACNU resistance could be modulated by combined ACNU and reserpine therapy. When 10 microM reserpine was added to ACNU in culture, the concentration of drug required for 50% inhibition of cell growth (IC50) of ACNU for C6/ACNU cells decreased to the level of that for C6 cells. When 20 microM reserpine was added to the culture, intracellular uptake of ACNU in C6/ACNU cells increased further and the efflux of the drug from the cells decreased. In in vivo experiments in rats, combined chemotherapy with ACNU (1 mg/kg) and reserpine (250 micrograms/kg) by intrathecal injection significantly increased the life span of the rats as compared to results with ACNU chemotherapy alone. The enhanced cytotoxicity of ACNU in ACNU-resistant glioma cells in vitro and in vivo may be explained by the increase of intracellular concentration of ACNU resulting from the inhibition of ACNU efflux from the resistant cells by reserpine. It was concluded that ACNU resistance could be modulated in vitro and in vivo by combined therapy with ACNU and reserpine.

Animals↗
PubMed1987

[Treatment of rat glioma with a beta-adrenergic agonist and a phosphodiesterase inhibitor in vivo].

Rat C 6 glioma is known to possess a beta-adrenergic receptor with which intracellular cyclic adenosine monophosphate (cAMP) levels are altered to control cell growth in vitro. In order to study the effect of beta-adrenergic agonist, isoproterenol, in growth-inhibitory action upon C 6 glioma cells, subcutaneous tumor models and meningeal gliomatisis (MG) models as a brain tumor model have been exposed to the treatment of isoproterenol. Growth of subcutaneous tumor was suppressed by the treatment of the drug, and the survival time of MG rats was prolonged by the intrathecal (i. t.) injection of isoproterenol. The addition of papaverine, phosphodiesterase inhibitor, to the treatment schedule augmented the growth-inhibitory effect of isoproterenol. Therefore, it is concluded that the survival time of the brain tumor models could be prolonged through the inhibition of the growth of C 6 glioma cells by such drugs as those which elevate intracellular cAMP levels.

Animals↗
PubMed1987

Involvement of calcium and cyclic AMP in the K+-induced rhythmic contraction of isolated rat vas deferens.

Mechanisms involved in the K+-induced rhythmic contraction were investigated in the isolated rat vas deferens. Isolated vas deferens is mechanically quiescent in normal Krebs-bicarbonate solution, but addition of KCl (10 to 35 mM) to the solution induces a rhythmic contraction. The K+-induced rhythmic contraction was not inhibited by tetrodotoxin, prazosin and indomethacin as well as by in vivo pretreatment with reserpine, but was abolished by verapamil or by Ca++ removal from the solution. TMB-8, a calcium release blocker, blocked the K+-induced rhythmic contraction and, instead, sustained tonic contractions developed. The rhythmic contraction was abolished by isoproterenol or by 3-isobutyl-1-methylxanthine, a phosphodiesterase inhibitor. The action of isoproterenol was inhibited by propranolol and was potentiated by 3-isobutyl-1-methylxanthine. In addition, dibutyryl cyclic AMP, but not dibutyryl C-GMP, blocked the rhythmic contraction. After those drugs affecting intracellular C-AMP levels, addition of excess KCl to the solution induced a sustained contraction, but not the rhythmic contraction. These results suggest that K+-induced rhythmic contractions are myogenic in origin and are caused by Ca++ movements which are controlled by intracellular cyclic AMP levels.

Animals↗