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  • 1
    ISSN: 1420-908X
    Keywords: Key words: Ephedrine – Stomach – Passive cutaneous anaphylaxis – Adrenergic nerve – Adrenoceptor
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract. Objective and Design: We previously demonstrated that oral l-ephedrine exerts an extremely rapid (within 20 s) inhibition of 48-h passive cutaneous anaphylaxis reaction (PCA) in rats by a possibly unidentified mode of action. In the present experiments, we elucidated the mechanism of the PCA inhibition by l-ephedrine using adrenoceptor agonists and antagonists.¶Materials: Rat antiserum was prepared with dinitrophenylated Ascaris suum extract + Bordetella pertussis.¶Treatment: Passively skin-sensitised Wistar rats were mainly used. l-Ephedrine, and adrenoceptor agonists and antagonists were orally administered immediately before PCA provocation. Catecholamine depleting (6-hydroxydopamine, 6-OH-DA), amine depleting (reserpine) or ganglion blocking (hexamethonium) agent was intraperitoneally or intravenously administered before the provocation.¶Methods: The effects of the drugs on PCA were assessed by inhibition of the dye leakage.¶Results: β-(propranolol) and β 2-(butoxamine) blocking agents reduced the inhibition of PCA by l-ephedrine, while the inhibition was not altered by either an α-blocking agent (phentolamine) or a β 1-(atenolol) selective antagonist. On the other hand, β-(isoproterenol) and β 2-selective (salbutamol) agonists showed extremely rapid inhibition of PCA. However, the β 1-selective agonist (dobutamine) had no effect on the reaction. The pretreatment with hexamethonium, reserpine or 6-OH-DA substantially attenuated the inhibitory effect of l-ephedrine on PCA.¶Conclusions: The results strongly suggest that β 2-adrenoceptors locate in the stomach and that their receptor excitement finally may lead to the inhibition of PCA via the stimulation of the central and peripheral nervous systems.
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  • 2
    ISSN: 1420-908X
    Keywords: Key words: Ephedrine - Ephedra herb - Passive cutaneous anaphylaxis - Mast cell - Histamine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract: Objective and Design: Whether Mao-Bushi-Saishin-To (MBST), one of the formulas of classical Chinese medicine, is effective on 48-h passive cutaneous anaphylaxis (PCA) in rats and which substance in the formula is responsible for its inhibitory action were examined.¶Treatment: In the studies on PCA, MBST (hot water extract of the whole herbal formula), extracts of Ephedra herb (Mao), l-ephedrine and other reference drugs were orally administered immediately or at various times before or 5 min after the antigen challenge. In the experiments on anaphylactic histamine release from rat peritoneal mast cells, l-ephedrine and d-pseudoephedrine were added at 10-4-10-7 g/ml at 30, 10, 3 or 0 min before antigen provocation.¶Results: The time course study indicated that MBST produced a prompt and long lasting inhibition of PCA. Among the constituents of Mao, l-ephedrine exerted this prompt inhibitory activity, but d-pseudoephedrine did not. Neither pseudoephedrine nor l-ephedrine prevented the anaphylactic histamine release from isolated peritoneal mast cells.¶Conclusions: It is strongly emphasised that the rapid suppression of PCA by orally administered l-ephedrine must be exerted by a mechanism distinct from that of suppression produced following gastrointestinal absorption of the drug, because the time required for the inhibition was extraordinarily short. However, direct inhibition of anaphylactic histamine release from isolated mast cells was excluded in this inhibition of PCA.¶
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  • 3
    ISSN: 1420-908X
    Keywords: Key words: Ephedrine - Passive cutaneous anaphylaxis - Mast cell - Vascular permeability - Histamine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract: Objective and Design: We previously reported that oral l-ephedrine showed extraordinarily rapid inhibition of 48-h passive cutaneous anaphylaxis (PCA) in rats. In the present study, in vivo and in vitro experiments were performed to elucidate a possible mechanism for the inhibition.¶Materials: Rat antiserum was prepared with dinitrophenylated Ascaris suum extract + Bordetella pertussis.¶Treatment: Wistar rats were passively skin-sensitised, actively sensitised or non-sensitised. l-Ephedrine immediately before provocations was orally or intravenously administered in in vivo experiments. In in vitro experiments, the drug was added at various time and concentrations before the challenge.¶Methods: The intensity of PCA was assessed by dye leakage method. Histamine and serotonin released in vitro or retained in the skin in vivo by anaphylaxis were assayed fluorometrically.¶Results: Oral l-ephedrine rapidly inhibited the PCA by inhibiting the release of histamine and serotonin from the reaction site, whereas anaphylactic histamine and serotonin releases from skin fragments were not affected by the drug. Furthermore, the orally administered drug influenced neither the histamine- nor serotonin-induced cutaneous vascular permeability.¶Conclusions: These results were strongly indicative that the prompt suppression of the PCA by oral l-ephedrine was not exerted following the drug was absorbed from the gastrointestinal tract. Thus, the result may be from an indirect inhibition of chemical mediator release, possibly through an unidentified stimulation of the nervous system, but not from the inhibition of chemical mediator release by the direct interaction of drug to mast cells and not from the decreased vascular permeability.¶
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  • 4
    ISSN: 1439-0264
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Changes in cell density and size in the ganglion cell layer (GCL) of the retina were studied in chick embryos and post-hatching chicks. The total number of cells in the GCL increased from 3.64 million at embryonic day 8 (E8) to the maximal 7.85 million at E14. After E14, the number of cells decreased to 6.08 million at post-hatching day 1 (P1) and 4.87 million at P8. Cell density in the GCL decreased unevenly according to retinal regions; cell density in the presumptive central area (pCA) of P8-chicks decreased to approximately 45% of that in E8-embryos. Densities of the nasal peripheral retina (NP) and temporal peripheral retina (TP) of P8-chicks decreased to 23 and 18% of E8-embryos, respectively. Differentiation of the central (44 000 cells/mm2 in pCA) – peripheral (28 000 cells/mm2 in TP) gradient in cell density was formed by E8. The presumptive dorsal area (pDA) was shaped by E11, but became obscure with age. Although ganglion cell sizes were basically uniform at E8, differentiation occurred with the appearance of larger ganglion cells after E14. Mean size of retinal ganglion cells increased 2.8-fold in the pCA and 3.8-fold in the TP between E8 and P8, accompanying a similar scale of decreases in cell densities.
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  • 5
    ISSN: 1365-2036
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Background: The relationship between 1/f fluctuation of the heart rate variability and Helicobacter pylori infection was evaluated, in order to clarify whether autonomic nervous dysfunction is a necessary condition for chronic peptic ulcer formation. Methods: The subjects were 11 patients with recurrent chronic peptic ulcer and 20 age-matched normal subjects. Holter ECGs were recorded over 24 h, and the 1/f –x fluctuation of the heart rate was computed. The 1/f –x fluctuation of the heart rate is a novel index of autonomic function that has been shown to reflect a patient's pleasant mood. For 1/f –x fluctuation, the slope of the regression line (–x) was determined and cosine fitting of the absolute slope of the regression line over a 24-h period was performed. Results: For the normal group, the absolute slope of the regression line during daytime and night-time were 0.53 ± 0.16 and 1.05 ± 0.18, respectively. For the peptic ulcer group, the corresponding values during daytime and night-time were 0.94 ± 0.15 and 1.84 ± 0.18, respectively. The mean value of the cosine curve was 0.76 ± 0.23 in the normal group and 1.12 ± 0.25 in the peptic ulcer group. Thus, these values were significantly higher for the latter group than for the former group (P 〈 0.05). No statistically significant difference in H. pylori infection between the two groups was observed. Conclusions: Autonomic nervous dysfunction as well as H. pylori infection appears to be a necessary condition for chronic peptic ulcer formation.
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  • 6
    ISSN: 1435-232X
    Keywords: Key words Thalassemia ; Globin ; Genotype ; Haplotype ; Nepal ; Malaria ; Mitochondrial DNA
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Thalassemia is a prevalent hereditary disorder characterized by impaired synthesis of globin chains. It has been suggested that the high frequency of thalassemia might reflect heterozygote advantage due to reduced susceptibility to malaria. In Nepal, malaria has often occurred in places below the altitude of 1200 m. We carried out a microepidemiological study on thalassemia in two neighboring populations in Nepal, the Danuwar and the Tamang. Settlements of the Danuwar are located below the limit of the malarial zone (1200 m in altitude), whereas those of the Tamang are found in malaria-free uplands. Three heterozygotes for hemoglobin (HbE) were observed in the Danuwars. We detected one type (−α3.7I) of α+-thalassemia that involves a deletion of 3.7 kb, leading to a loss of one of two α-globin genes, in the Danuwars, at a high gene frequency of 63%, while the gene frequency in the Tamangs was only 5%. Analysis of the α-globin gene cluster revealed that four different haplotypes were associated with the type of α+-thalassemia in the Danuwars. Nucleotide sequences of the D-loop region in the mitochondrial DNA of the two populations indicated a similar nucleotide diversity in each population. The fixation index, FST, representing the degree of genetic differentiation estimated from mitochondrial DNA diversities (FST, 0.05), was smaller than that obtained from the gene frequencies of α+-thalassemia (FST, 0.55). If we assume neutral molecular evolution in the D-loop region of mitochondrial DNA, these results suggest that the high frequency of α+-thalassemia may be due to biological adaptation to the malarial environment rather than to events such as a bottleneck.
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