PubMed · 10742921
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J S Fine. 2000. Iron poisoning.. https://doi.org/10.1067/mps.2000.104055
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Calves were vaccinated orally, subcutaneously or intraperitoneally with a smooth, plasmid-cured strain of Salmonella enterica serovar typhimurium, strain 81. Oral vaccination was not effective, as only 1/5 calves survived challenge with virulent S. typhimurium. Strain 81 was attenuated for calves, as only a slight rise in rectal temperatures was detected after vaccination. The organism was excreted by some calves in the faeces, but no signs of diarrhoea were observed after vaccination. After parenteral vaccination, strain 81 was able to reach the intestines, gastric associated lymphoid tissues and other internal lymphoid tissues and remained viable for up to 14 days in the bovine host. After oral challenge with a virulent strain, 9/10 vaccinated calves survived challenge as opposed to 4/10 control calves (p<0.5). Diarrhoea was present in all calves of the control groups, but in only 4/10 of the vaccinated calves. The clinical reactions of the vaccinated calves were milder than in the control calves, as the rises in rectal temperatures were lower, diarrhoea was less severe, and the challenge strain was present in fewer organs from vaccinated calves than control calves. This study showed that parenterally administered Salmonella vaccines can induce both mucosal and systemic immunity, and it is postulated that this capability of strain 81 is related to its colonisation of lymphoid tissues and other systemic and intestinal tissues. This study confirmed that plasmid-cured strains were attenuated in the bovine host and conferred significant protection after parenteral vaccination, but not oral vaccination.
OBJECTIVES: Aim was to compare the effects of estradiol-only therapy with combined estradiol/progestin treatment on the excretion of vasoactive mediators surrogating on possible effects in the vascular system. The progestin used was dienogest, a new C19-progestin with antiandrogenic properties. METHODS: Prospective, randomized trial, 25 healthy postmenopausal women treated for 3 months with estradiol valerate (2 mg/day) and 27 women with estradiol valerate (2 mg/day) continuously combined with dienogest (2 mg/day). Assessment of the following markers or their stable metabolites in nocturnal urine: cGMP, serotonin, prostacyclin and thromboxane, and urodilatin. RESULTS: Estradiol alone increased the excretion of cGMP and serotonin significantly suggesting vasodilating effects. The prostacyclin/thromboxane ratio known to be crucial for the relation of vasorelaxation to vasoconstriction significantly increased. No significant changes were found for urodilatin, which is known to elicit different effects in the cardiovascular and renal system, respectively. Combined estradiol/dienogest therapy also led to significant increases in cGMP and serotonin excretion suggesting that progestin addition for three months does not affect these markers. However, in contrast to estrogen-only treatment, there was no significant increase for the prostacyclin/thromboxane ratio, which can be explained by antagonistic action of the progestin. The excretion of urodilatin was increased significantly, which might be due to counterbalancing progestin effects in the renal vascular system. CONCLUSIONS: The changes in vasoactive markers suggest an estrogen effect that is vasorelaxant. Since there were no significant differences between the two groups, possible vascular effects of the progestin dienogest, for the first time evaluated, might not be of clinical relevance, at least not in women without cardiovascular diseases.
OBJECTIVES: To disclose if oral estradiol (E(2)), alone or in combination with natural progesterone (P) or medroxyprogesterone acetate (MPA), may modify the oxidizability of low density lipoprotein (LDL), and if the effect is achieved at physiological dosages. LDL oxidizability was assessed by the resistance to oxidation by copper and by the particle size profile, since small particles have increased oxidation susceptibility. METHODS: Thirty-three women received two consecutive, two-month length doses of 1 and 2 mg/day of oral E(2). They were then randomly assigned to a fourteen-day treatment of 2 mg/day E(2) plus either 300 mg/day P or 5 mg/day MPA. A parallel group of experiments was performed on a pool of baseline plasma, where hormones were added at the desired concentration. Lipoprotein levels, resistance of LDL to oxidation, and LDL particle diameter, were measured at baseline and after each treatment. RESULTS: Estradiol reduced LDL levels and increased high density lipoprotein (HDL) and triglycerides. P abolished these changes, whereas MPA only reversed the increase of HDL. Estradiol protected LDL from oxidation in a dose-dependent manner, although only at pharmacological concentrations (1 microM or higher). Both P and MPA were inert at either physiological or pharmacological concentrations. The size of the LDL particles remained unaffected except under MPA, in which it was reduced. CONCLUSIONS: Estradiol has a protective effect against LDL oxidation, although only at pharmacological dosages. P and MPA did not limit the E(2) action. The size of the LDL particles remained unaltered after each E(2) dose, but MPA, and not P, was associated with a diminution.