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  • Author or Editor: A. Pusztai x
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An experiment was conducted to study the effect of large-dose (-carotene supplementation on blood retinoid and (-carotene levels as well as on the progesterone secretion of the granulosa cells in Japanese quail. Laying quails were assigned to three dietary groups. The control group (Group C) received the basal diet (laying feed containing 9000 IU vitamin A/kg). In the treated groups (Groups BC1 and BC2) the basal diet was supplemented with 102and 103mg/kg (-carotene (BC), respectively. At the end of the two-week feeding period, 10 birds from each group were euthanised. Blood samples were analysed for retinol, retinyl palmitate and (-carotene concentrations. Granulosa cells were isolated from ovarian follicles (F1and F2), and PMSG-inducedin vitroprogesterone (P4) secretion was measured. Similar retinol concentrations were found in both (-carotene supplemented groups, indicating saturation of the retinol-transporting system. (-carotene supplementation was accompanied by hypercarotenaemia, but did not increase the retinyl palmitate levels in the blood. PMSG-induced P4production of the granulosa cells decreased significantly in Groups BC1 and BC2 in a dose-dependent manner.

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Short-term effects of orally administered plant lectins, with special reference to the Phaseolus vulgaris agglutinin (phytohaemagglutinin, PHA), were studied in growing rats.  The orally administered PHA elicited a dose-dependent accumulation of liquor with elevated pH in the proximal small intestine. Although the concentration of a-amylase activity did not change, total a-amylase activity slightly, but significantly increased in the gut. When a panel of plant lectins with different carbohydrate binding specificities was tested at the dose of 100 mg/kg body weight, most of them stimulated the secretion of liquor, but the total a-amylase activity was increased only by PHA, ConA or WGA.

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A panel of orally administered lectins (100 mg/kg b.w.) of different binding specificities was tested for suppression of voluntary food consumption in prefasted rats. PHA isolectins (Phaseolus vulgaris) and RPA-I (Robinia pseudoacacia) were found to exert a marked and significant effect, but two other gut-binding lectins, i.e. SBA (Glycine max) and WGA (Triticum vulgare) and several non-binding lectins were ineffective. In cannulated rats PHA infused into the duodenum induced food suppression, i.e. binding of the lectin to the mouth or stomach was unnecessary. Suppression of food consumption lasted through the whole nocturnal feeding period, control (BSA) and experimental (PHA) curves of cumulative food consumption showed a V-like divergence. Suppression by PHA or RPA-I showed very similar time courses, but a long-lasting inhibition of gastric emptying was only observed in the RPA-treated animals. Intraperitoneally administered lectins suppressed food consumption much more effectively than the oral ones, whereas Galanthus nivalis agglutinin (GNA) had little or no effect. It is concluded that lectins can be used as effective tools for the modulation of food consumption and gastric emptying in experimental animals.

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Male Wistar rats wearing chronically implanted cortical electrodes were exposed to Mn-containing nanoparticles via the airways for 8 weeks following a 2-week pre-exposure period. The rats’ cortical electrical activity and open field motility was recorded simultaneously, in weekly repetitions. It was supposed that this technique can provide better insight in the development of Mn-induced CNS damage. Decreased motility (less distance covered, longer periods of immobility) and increased total power of cortical electrical activity developed in parallel in the first 4–5 weeks of treatment but showed little change afterwards. Both the behavioral and the electrophysiological effect were in fair correlation with the rats’ internal Mn exposure determined from brain samples. The results confirmed the non-linear dose- and time-dependence of Mn effects suggested by previous studies. Repeated simultaneous behavioral and electrophysiological recording during a longer treatment with neurotoxic metals (or other xenobiotics) seems to be a promising method.

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Authors: K Baintner, P Kiss, A Pikli, W Peumans, Susan Bardocz and A Pusztai

After oral administration several gut-binding lectins induce accumulation of liquor and amylase in the proximal small intestine (2). Orally administered Phaseolus vulgaris phytohaemagglutinin (PHA) was used to study the mediation of these effects in rats. The regulation of amylase secretion clearly differed from that of the liquor. The amylase activity was of pancreatic origin, in agreement with the known cholecystokinin-releasing effect of PHA. It appears that CCK exerts its effect both directly and by facilitating neural stimulatory pathways. Intestinal secretion was identified as the source of the liquor, without a contribution by other secretions. It was mediated by a local cholinergic reflex with the involvement of both muscarinic and nicotinic acetylcholine receptors. It is speculated that the observed enteric reflex may enable the gut to transport secreted antibacterial peptides or secretory antibodies from the crypts to adherent bacteria on adjacent villi.

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Authors: Ibolya Stiller, Rozália Pusztai, Erzsébet Sombor, L. Orosz, A. Pál and B. Taródi

The prevalence, the level and the avidity of human herpesvirus-6 (HHV-6) specific IgG were examined in pregnant women and age-matched female blood donors. The study group consisted of 180 women (age 14-45); 60 women with normal pregnancy, 60 pregnant women with fetuses suspected of having any viral infection and 60 healthy blood donors with no history of pregnancy. Plasma or serum samples were tested for HHV-6 IgG antibodies by an immunofluorescence assay. Ninety-eight percent of blood donors and 97% of 120 pregnant women had IgG antibodies to HHV-6. The rate of seropositivity in women  with normal pregnancies  and women with fetuses suspected to have viral infection was the same. Pregnant women (n=120) had significantly lower antibody titer than blood donors. No significant differences were found in the same respect between the two groups of pregnant women. Low avidity of IgG antibodies to HHV-6 was detected in 5% of pregnant women.

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