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  • 1
    ISSN: 1432-0851
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In vitro effects of methotrexate (MTX) on interleukin-2(IL-2)-mediated cytotoxicity of peripheral blood mononuclear cells (PBMC) were studied. PBMC were incubated with human recombinant IL-2 (25 U/ml) for 72 h; during the last 24 h, various concentrations (10 pM–1 µM) of MTX were added to the culture. Cytotoxicity against k562 cells was measured by a 4-h51Cr-release assay. The IL-2-mediated cytotoxicity was paradoxically increased at around a concentration (10 nM) MTX. Such a low concentration of MTX showed no anti-proliferative effect on cell growth. This enhancement with 10 nM MTX was shown only in an E-rosette+ (E+) population, but not in E-rosette− (E−). In addition, when E+ cells were treated with an anti-CD16 monoclonal antibody plus complement after incubation with IL-2 and MTX, MTX-induced enhancement was lost, suggesting that an E+CD16+ cell population was mainly involved in this augmentation. Positively sorted E+CD16+ cells showed similar enhancement of cytotoxicity after treatment with IL-2 plus MTX. On the other hand, MTX treatment did not show the phenotypical changes including of the E+CD16+ cells, indicating that this treatment did not affect the differentiation and proliferation of the specific cell subset. Our results indicate that a low dose of MTX could have a role in the regulation of immunological anti-cancer surveillance systems through the natural killer and lymphokine-activated cytotoxic cells.
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  • 2
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: This study focuses on the influences of spreading multiple dipoles in the human head upon surface magnetic fields. A source model of the magnetoencephalogram (MEG) activity is proposed. This source model is expressed by spreading multiple dipoles which have time-varying dipole moments. Using this source model, spatio-temporal patterns of MEGs are simulated. Effects of spreading dipoles on spatio-temporal magnetic fields are investigated. The computer simulations show that the wave forms and amplitude of magnetic fields are affected significantly by the spread of the source and the conduction velocity of traveling dipoles. The latency of the peak magnetic field generated by spreading multiple dipoles varies with the measurements points on the surface of the head.
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  • 3
    ISSN: 1432-1041
    Keywords: alpha-adrenergic blocker ; hypertension ; blood pressure ; pulse rate ; noradrenaline ; plasma renin activity ; plasma aldosterone ; dopamine-beta-hydroxylase ; E-643
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary To determine whether E-643, a new α-blocking agent, would reduce the blood pressure, regardless of the posture, a 1 mg dose was given 3 times daily for 7 consecutive days, to 8 male and 7 female inpatients, aged 37–73 years, with essential hypertension. Blood pressure and pulse rate were measured daily in the supine, sitting and standing positions. Before and after the treatment with E-643, plasma levels of noradrenaline, adrenaline, dopamine-β-hydroxylase, renin and aldosterone were determined, samples being obtained with the subjects recumbent and after standing upright for 60 min. A significant reduction in the systolic and diastolic blood pressures was evident in the supine (172±31/100±12 → 151±28/89±14 mmHg), sitting (158±22/101±11 → 138±28/89±15 mmHg) and standing (153±32/103±21 → 129±31/89±20 mmHg) positions. The reduction in blood pressure remained unchanged throughout the period of administration of E-643. Pulse rate was not affected when the subjects were supine (67±10 → 69±10 beats/min), but was increased in the sitting (68±10 → 73±9 beats/min) and standing (73±10 → 81±11 beats/min) positions. The increased pulse rate tended to decline during continued administration of E-643. Treatment with E-643 produced no significant change in plasma levels of adrenaline, noradrenaline, dopamine-β-hydroxylase, renin and aldosterone. The antihypertensive effect of treatment was more prominent in the patients with higher levels of plasma catecholamines and dopamine-β-hydroxylase, and was less prominent in those with higher plasma renin and aldosterone. Two patients had temporary bouts of dizziness and visual disturbances, but there were no subjective complaints during treatment.
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  • 4
    ISSN: 1432-0738
    Keywords: Key words Butyltin compound ; Hepatotoxicity ; Lipid peroxidation ; Glutathione
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  The in vivo induction of hepatotoxicity, as evaluated by the activity of ornithine carbamyl transferase in serum, was investigated in mice administered orally with the following three butyltin compounds: tributyltin chloride (TBTC), dibutyltin dichloride (DBTC) and monobutyltin trichloride (MBTC). The minimal concentrations of TBTC and DBTC that caused hepatotoxicity at 24 h after oral administration were 180 μmol and 60 μmol/kg, respectively, while MBTC did not induce liver injury even at 7000 μmol/kg. Additionally, when the administered doses were equivalent (180 μmol/kg), a time course (3–96 h) study revealed that the hepatotoxicity of TBTC and DBTC appeared at 24 and 12 h, respectively, but that MBTC showed no hepatotoxicity even at 96 h. The amounts of Sn excreted into urine for 4 days were 1.5 fold greater with TBTC than with DBTC treatment and were lowest in MBTC group. Similarly, the total liver Sn content was 2- to 5-fold greater in the TBTC group than in the DBTC group whereas the liver Sn content in the MBTC treatment showed the lowest value throughout the 3- to 96-h period. Thus, the non-hepatotoxicity of MBTC may be due either to low absorption through the digestive tract of mice or to the low levels of Sn in liver; however, the level of Sn in liver was not associated with the induction of hepatotoxicity by TBTC and DBTC. The analysis of metabolites of TBTC (180 μmol/kg) and DBTC (60 μmol/kg) at equivalent hepatotoxicity showed that the main tin compounds in the liver after the administration of TBTC were dibutyltin and monobutyltin as well as inorganic tin compounds, while most (〉78%) of the total tin compounds in the liver of mice treated with DBTC was in the form of dibutyltin. In addition, the levels of monobutyltin and inorganic tin compounds in the livers of mice treated with TBTC were greater than those with DBTC, but the levels of dibutyltin did not differ significantly between TBTC and DBTC. The levels of lipid peroxidation (LPO) and hepatic glutathione (GSH) content in the liver showed a transitory increase after the administration of MBTC and TBTC, respectively. These results suggest that DBTC is more hepatotoxic than TBTC, and that dibutyltin inside the cells may be the main form of tin which is responsible for induction of hepatotoxicity following in vivo administration of TBTC and DBTC. The generation of free radical species, as evaluated by LPO and GSH levels, may not be associated with the hepatotoxicity caused by butyltin compounds.
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  • 5
    ISSN: 1432-119X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Cyclic 3′, 5′-mononucleotide phosphodiesterase (cyclic nucleotide PDEase) activity was studied histo-and cytochemically in the retinal rod photoreceptor cells of the rat by means of a newly developed technique utilizing the intrinsic 5′ nucleotidase activity instead of an exogenous 5′ nucleotidase source (snake venom). Cyclic GMP and cyclic AMP were used as substrates. When cyclic GMP was used as a substrate, the intense activity of phosphodiesterase (PDEase) was distributed over the entire rod outer segments; reaction product was observed on the plasmalemma and on the disk membranes of the outer segments. A slight reaction was also observed on the plasmalemma of the inner segments. However, no precipitate was found in the perinuclear and synaptic regions of the rod photoreceptors. In contrast, when cyclic AMP was utilized as a substrate, a moderate reaction was seen in the synaptic region of the plexiform layer. The intensity of the reaction in the outer segments was much reduced in comparison to the results with cyclic GMP. The enzyme activity was almost completely inhibited by 2 mM 3-isobutyl-1-methylxanthine (IBMX) or 2 mM theophylline, which were potent inhibitors of PDEase. To confirm the propriety of our new cytochemical method, the localization of 5′ nucleotidase was also studied utilizing 5′ AMP or 5′ GMP as substrates. In contrast to the activity of cyclic nucleotide PDEase, the activity of 5′ nucleotidase was distributed on all membranes of the photoreceptors from the synaptic outer plexiform layer to the tip of outer segments. After inhibition of the intrinsic 5′ nucleotidase activity with the use of 1 mM Ni-ions or 10 mM NaF no demonstration of cyclic nucleotide PDEase activity was possible; the existence of intrinsic 5′ nucleotidase activity is necessary for the release of free phosphateions from 5′ AMP (5′ GMP), which are a prerequisite for the histochemical reaction. For comparison, some sections were incubated with the conventional cyclic nucleotide PDEase incubation medium containing snake venom from Ophiophagus hannah. With this conventional method, morphological preservation was extremely poor, and moreover, the reaction itself was weaker than that with the presently described method.
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  • 6
    ISSN: 1432-119X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Periodical changes in Ca2+-ATPase and Mg2+-ATPase activity were observed cytochemically in the crayfish gastrolith epithelium during the molting cycle in relation to the calcium transport mechanism. The ATPase activity was demonstrated by a new one-step lead citrate method. The reaction products were mainly restricted to the matrix of type II cell mitochondria. The Ca2+-ATPase activity was intensely observed in two calcium moving stages, the small gastrolith period which indicates the beginning of gastrolith formation, and the aftermolt, when the calcified gastrolith has been dissolved in the stomach and then reabsorbed from the stomach epithelium into the newly formed soft exoskeleton through the blood. Although the intensity of reaction products of Mg2+-ATPase varied in each stage, the enzymatic activity was observed throughout all molting stages. Reaction products were observed in all mitochondria, basement membranes, apical cytoplasmic membranes, and in some lysosomes. In conclusion, periodical changes in the two types of ATPase activity were seen in the mitochondria of gastrolith epithelium during the molting cycle, but Ca2+-ATPase activity seemed to be more prominently synchronized to the calcium movement in the gastrolith epithelium than Mg2+-ATPase activity. These results provide the strong evidence that Ca2+-ATPase may act strongly in the calcium transport system of crayfish molting.
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  • 7
    ISSN: 1432-119X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The distribution of ecdysteroid binding sites in the stomach and gastrolith disc tissue of cryafish (Procambarus clarkii) was examined in relation to the molting stage by thaw-mount autoradiography. The radiolabeled hormone analogue ponasterone A (25-deoxy-20-hydroxyecdysone) was used. Ecdysteroid binding sites were demonstrated only in certain molting stages, the small gastrolith period and the aftermolt stage. In gastrolith epithelium, ponasterone A binding sites first appeared in the cytoplasm, and then in the nuclei and cytoplasm. In the stomach epithelium, many nuclear binding sites were detectable during the period of gastrolith secretion. These periodical changes in specific ponasterone A binding when correlated with the molting stages clearly show that ecdysteroids may function as an initiator for gastrolith formation and reabsorption. The findings also suggest that ecdysteroids control calcium transport in the stomach epithelium. The time-related and functional differences of cytoplasmic and nuclear concentration of ecdysteroid receptors indicate the presence of cytoplasmic and nuclear receptors associated with specific actions.
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  • 8
    ISSN: 1432-1203
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary We have performed formal genetic studies on 26 patients (14 males, 12 females) with neurofibromatosis 1 (von Recklinghausen's disease, NF1) in Japan. Family studies of 74 members of 18 kindreds revealed that 50% of the cases were caused by a new mutation; the mutation rate was assumed to be 7.3–10.5 × 10-5. A tendency of paternal age effect, which was not accounted for by the maternal age effect, was observed, but live-birth order had no significant effect. Genetic linkage of neurofibromatosis 1 to the NF1 gene or the genetic marker in the pericentric region of chromosome 17 was established in 3 informative families.
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  • 9
    ISSN: 1432-1203
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary A homozygous gene deletion at the GST1 locus of genomic DNA isolated from peripheral blood was investigated for its relationship with several types of cancer using the polymerase chain reaction (PCR) technique. DNA samples were prepared from blood obtained from 128 healthy blood donors and 150 patients with cancer or chronic hepatitis. PCR primers were prepared based on the human cDNA sequence and the intron/exon sequences of the rat Yb2 gene. The amplified sequence between exons 5 and 6 including intron 5 showed very clearly the presence of absence of the GST1 gene, after electrophoresis in a 2% agarose gel. Segregation of the presence and absence of PCR product from samples of twins and their parents indicated that presence involves homozygous or heterozygous normal GST1 genotypes while absence invovles only homozygous gene deletion. The patients with stomach cancer had a significantly higher frequency of gene deletion than did the healthy controls (P〈 0.005). Thus, GST1 deletion may be a possible genetic marker for early detection of a group at high risk of stomach cancer.
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  • 10
    ISSN: 1432-1041
    Keywords: Calcium channel blocker ; Nilvadipine ; blood pressure ; liver disease ; pharmacokinetics ; pharmacodynamics ; cirrhosis ; hepatitis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Fourteen normotensive patients with liver disease (6 with cirrhosis and 8 with chronic hepatitis) and 7 healthy volunteers were given a single oral dose of nilvadipine 2 mg. In addition, nilvadipine 4 mg was administered orally twice daily for several months to 6 hypertensive patients with mild liver dysfunction and 18 hypertensives with normal liver function. A significant increase in plasma nilvadipine was found in the patients with cirrhosis as compared both to the normal and chronic hepatitis subjects; the time to peak concentration was similar among the three groups. The peak plasma nilvadipine concentration was closely correlated both with the serum albumin level and the retention of indocyanine green. Changes in blood pressure, pulse rate and various vasoactive hormones following a single oral dose of nilvadipine did not differ between the groups. Thus, an increase in plasma nilvadipine relative to the level in normal subjects was demonstrated in patients with cirrhosis following a single oral dose, as well as in patients with slight liver dysfunction following long-term oral administration.
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