Apomorphine (A po ) a dopaminergic agonist, elicited protracted bouts of pecking when injected intramus cularly into pigeons. Repeated injections of either a small or a large dose of Apo into two separate groups of pigeons led to progressive increments in pecking up to two different asymptotic response levels (dose-related sensitization). A subsequent switch of the Apo doses between the groups yielded two statistically undistinguishable asymptotic response levels. A smaller dose of Apo induced a signifi cantly higher asymptotic response if the pigeons had been pre-treated with a larger dose than if they had not. The results are discussed in relation to a simple classical condi tioning model of sensitization, and are related to behavioural contrast phenomena that occur in conventional conditioning paradigms involving changes of food reward magnitudes.
Glycerol-1,2,3-tris(methylsuccinate) is a novel ester of succinic acid which displays high insulinotropic efficiency either in vitro or in vivo after intravenous administration. In this study, we investigated its effect on insulin secretion after enteral administration in conscious overnight fasted rats. The animals received, by the intragastric route, 3 mi of a mixture of labrasol and polysorbate 80 containing, as required, the ester (230 mM), methanol (691 mM) or unesterified glycerol (230 mM). In all cases, this resulted in comparable increases in both plasma D-glucose and insulin concentrations, peaking 20-30 min after administration of the surfactant blend. These findings argue against any significant stimulation of insulin release by orally administered glycerol-1,2,3- tris(methylsuccinate). Med Sci Res 27:303-303 (C) 1999 Lippincott Williams & Wilkins.
Intravenous leiomyomatosis is a rare benign neoplasm which has malignant potential. We present two cases, aged 39 and 41 years, diagnosed postoperatively on the basis of histopathological evaluation of the specimen. We analysed our findings in light of the current literature. Two and three years follow-up of the cases revealed no recurrence. Med Sci Res 27:719-720 (C) 1999 Lippincott Williams & Wilkins.
Asialoorosomucoid (AOM) was modified by the water soluble carbodiimide N-ethyl-N'-(trimethylpropylammonium) carbodiimide (Me+CDI) at a 1: 1,800 mole ratio to afford an AOM derivative bearing 10 positively charged N-acylurea moieties at aspartate and glutamate residues (Me+CDI urea-AOM). Demonstration of complex formation between the modified glycoprotein and pBR322 plasmid DNA in a gel retardation assay showed all the DNA to be associated with Me+CDI urea-AOM at a glycoprotein: DNA ration of 6:1 (w/w). Only partial dissociation of complexes took place in NaCl solutions up to 0.8 M, revealing a nonelectrostatic component in the binding interaction. Complexes were also shown to be essentially larger than 0.2 mu m in diameter. Me+CDI urea-AOM:pRSVL DNA complexes transfected HepG2 cells in a process which was enhanced by poly-L-lysine(52). Med Sci Res 27:831-833 (C) 1999 Lippincott Williams & Wilkins.
Reproductive ageing in the human female is indicated by a decline in fertility. In addition to the decline in oocyte quality, uterine factors which involve both hormonal and stromal-epithelial interactions have vital importance in reduced implantation with ageing. The decidual cells, which have a major role in implantation, are formed by the differentiation of stromal cells. The aim of this study was to analyse the effect of ageing on the decidualization capacity of stroma cells. For this purpose we cultured isolated stromal cells from young (age: 38-42 years) and old (age: 46-52 years) patients in the presence of progesterone, in which they undergo decidual reaction. Secreted prolactin was measured in the spent medium. The mean prolactin amounts were 0.74 +/- 0.09 ng/mu DNA day and 0.79 +/- 0.03 ng/mu DNA day in young and aged groups respectively. The difference was statistically insignificant. We conclude that other cellular and molecular mechanisms must be considered for the role of the uterine factors. Med Sci Res 27:817-820 (C) 1999 Lippincott Williams & Wilkins.
The aim of this study was to evaluate the diuretic and antidiuretic effects of fruit extracts of unripe Mormodica charantia Linn. and Mormodica dioica Roxb. (Family: Cucurbitaceae), using the hydrated rat assay technique and a randomized Latin square design. The freeze dried extracts suspended in 0.5% polyvinylpyrrolidone in dose of 30-60 mg/kg or hydrochlorothiazide (diuretic, 30 mg/kg) or hydralazine (antidiuretic, 30 mg/kg) were administered orally to male rats and their urine output was monitored over a 5 h period. The urine samples and both fruit extracts were analysed for sodium and potassium content using flame photometry. Both extracts failed to induce significant diuretic and antidiuretic activities. In contract, the reference diuretic and antidiuretic drugs caused a significant increase and reduction respectively in urine output. Urinary sodium excretion also remained unaltered with extract treatments but urinary potassium content increased markedly (M. charantia by 66% and M. dioica by 60%) and significantly. Further, both extracts had a high endogenous potassium content (M. charantia and M. dioica 65 and 85 meq/1 respectively). We conclude that M. charantia and M. dioica fruits may be useful as a cheap food supplement to replenish potassium loss in patients on diuretic therapy. Med Sci Res 27:821-823 (C) 1999 Lippincott Williams & Wilkins.
The beta-anomer of L-glucose pentaacetate, injected intravenously (8.8 nmol/g body wt) into fed anaesthetized rats, caused, over 30 min, a biphasic increase in plasma insulin concentration. This exceeded the increase in control experiments including the administration of the vehicle (ethanol-H2O, 1-3, v-v) used to dissolve the ester. It could not attributed to the modest rise in plasma D-glucose concentration recorded in these experiments. Our findings are compatible with the proposal that selected esters of L-glucose could conceivably be used as insulinotropic tools in the treatment of non-insulin-dependent diabetes mellitus. Med Sci Res 27:467-469 (C) 1999 Lippincott Williams & Wilkins.
Our objective was to study the effect of allopurinol - an inhibitor of xanthine oxidase - in hepatic cell lipid peroxidation caused by oxygen free radicals. We used Wistar rats divided into three groups: (1) non-ischaemic group; (2) rats given ischaemia for 50 min followed by 50 min of hepatic reperfusion; and (3) rats given allopurinol (50 mg/kg: intraperitoneally) 5 h and 1 h before the hepatic ischaemia-reperfusion. We measured hepatic lipid peroxidation by the thiobarbituric acid reactive substances method and the tert-butyl hydroperoxide-initiated chemiluminescence technique. Hepatic lipid peroxidation was significantly higher in the hepatic ischaemia-reperfusion animals (P < 0.05). Furthermore, pre-treatment with allopurinol reduced significantly the concentration of malondialdehyde (a product of lipid peroxidation) (0.165 +/- 0.021 vs 0.285 +/- 0.022 nmol/mg of protein; P < 0.05), and the emission of chemiluminescence (4,097 +/- 678 vs 6,057 +/- 376 counts/s/mg of protein; P < 0.05) in the rats subjected to hepatic ischaemia-reperfusion. Med Sci Res 27:829-830 (C) 1999 Lippincott Williams & Wilkins.
Dopaminergic D-2 antagonists are effective antiagressive agents. This study was designed to examine the effects of SCH 23390 (0.01, 0.03 and 0.05 mg/kg, i.p), a selective dopamine D-1 antagonist, on isolation-induced aggression, using an ethopharmacological procedure. 10 min of diadic interactions were staged between a singly housed and an anosmic mouse in a neutral area. These encounters were video-taped and the accumulated time allocated by subjects to 10 broad behavioural categories was estimated. Besides other behaviours, the aggressive and motor behaviours were evaluated 15 min after injection using an ethologically based analysis. SCH 23390 did not affect significantly offensive behaviours (threat or attack), as compared with the control group. Only the highest dose used (0.05 mg/kg) showed a significant increase in immobility. These results suggest that dopaminergic D-1 receptors are not involved in modulating aggressive behaviour in male mice. Med Sci Res 27:177-179 (C) 1999 Lippincott Williams & Wilkins.
