Interaction between prostacyclin and colchicine on the gastric mucosa of rat in different experimental ulcer models

The effect of prostacyclin and colchicine on the fundic gastric mucosa of adult female Wistar rats was investigated in stress (immobilization) and indomethacin induced ulcer models. Under prostacyclin treatment the ulcer index decreased significantly in both ulcer models. This effect was inhibited by colchicine. The nuclear volume of fundic epithelial cells increased significantly after application of either type of ulcerogenic stimulus. Prostacyclin did not influence the nuclear volume changes in stress ulcer, while it prevented this phenomenon in indomethacin-induced ulceration. Following colchicine treatment the nuclear volume decreased in both ulcer models. After combined prostacyclin and colchicine treatment the nuclear shrinkage remained unaltered in stress ulcer, while in indomethacin ulcer the nuclear volume decreasing effect of the separately administered drugs disappeared after combined treatment. The latter phenomenon was interpreted as an antagonistic interaction between prostacyclin and colchicine.     

Modification of 144Ce tissue deposition by mixed ligand complex treatment in mice

The individual effect of desferrioxamine-B (DFOA), Na3Ca-diethylene-triaminepentaacetic acid (DTPA), DL-penicillamine (PA) and Na-salicylate (SA) has been examined as well as the effect of mixed-ligand treatment on the retention and elimination of 144Ce in mice. It was found that 144Ce could easily be mobilized by a single dose of DTPA. Mixed-ligand (MLCs) treatment did not change the deposition characteristics and translocation kinetics of 144Ce.     

Effects of arginine-vasopressin and ACTH 4-10 on acquisition of active avoidance response in rats with alcohol pretreatment in prenatal and adult age

Alcohol administration in drinking water to mother rats during gestation resulted in a permanent learning deficit of the offspring when behavioural reactions were tested in active avoidance conditioned reflex situation in adult age. A similar deficit of learning capacity was observed in adult rats following alcohol administration for two weeks; the acquisition of active avoidance response was tested later. Administration of arginine-vasopressin and ACTH 4-10 during behavioural test led to a significant improvement of learning ability of the animals pretreated with alcohol. The observations indicate that the ethanol-induced deficit of learning capacity involves peptidergic mechanisms and the behavioural manifestations following chronic alcohol treatment are not irreversible processes.     

Effects of L-carnitine in acute myocardial ischaemia

Data in the literature suggest that exogenous L-carnitine improves the metabolic function of ischaemic heart cells: it enhances the transport of long-chain fatty acids into the mitochondria, stimulates the slowed beta-oxidation, and moderates the accumulation of amphiphilic acyl esters. A study has therefore been made of the cardiac effects of L-carnitine in dog experiments (n = 8). The left anterior descending coronary artery (LAD) was isolated in anaesthetized, thoracotomized animals in situ. After a control occlusion and equilibration period, the LAD was again ligated at the time of L-carnitine infusion (100 mg/kg iv. during 10 min). The agent diminished the maximal conduction delay and the degree of epicardial ST-segment elevation in the ischaemic myocardial region, and the free fatty acid concentration of the arterial blood, but it did not influence the frequency of ventricular extrasystoles. The anti-ischaemic effect of L-carnitine was manifest only during the infusion, and its discontinuation was immediately followed by an enhanced ST-segment elevation. In the dose applied, the substance did not affect the heart rate, systemic mean arterial pressure, left ventricular end-diastolic pressure (LVEDP), or left ventricular contractility (LV dP/dtmax). In the canine myocardial infarction model employed it was observed that the duration of the anti-ischaemic effect of L-carnitine (100 mg/kg iv.) is very short, and it has no significant antiarrhythmic action.     

Further data on the origin of gonadotropin releasing hormone in the median eminence of the rat hypothalamus

Gonadotropin releasing hormone (GnRH) content of the two halves of the median eminence of the rat hypothalamus was determined by radioimmunoassay three weeks after three different unilateral knife cuts around the preoptic area. A unilateral cut in front or above the area caused a more than 25% decrease in the GnRH content of the two halves of the median eminence. A cut lateral to the preoptic region had only a slight effect similar to that observed after sham operations. The data suggest that probably more than 50% of the rat median eminence GnRH derives from outside the preoptic-suprachiasmatic region. The GnRH fibres projecting to the median eminence but arising from outside the preoptic region, probably mainly from GnRH perikarya in the limbs of the diagonal band of Broca and septum, enter this area partly from rostral and partly from above, but not from lateral direction. partly from rostral and partly from above, but not from lateral direction. Several of these fibres probably cross before terminating in the median eminence.     

Production of specific antibodies against protein A fusion proteins.

The gene for Staphylococcal protein A was fused to the coding sequence of bacterial beta-galactosidase, alkaline phosphatase and human insulin-like growth factor I (IGF-I). The fusion proteins, expressed in bacteria, were purified by affinity chromatography on IgG-Sepharose and antibodies were raised in rabbits. All three fusion proteins elicited specific antibodies against both the inserted protein sequences and the protein A moiety. In the case of IGF-I, the protein A moiety in the fusion protein may act as an adjuvant since native IGF-I alone is a poor immunogen. The results suggest that the protein A fusion system can be used for efficient antibody production against peptides or proteins expressed from cloned or synthetic genes. To facilitate such gene fusions a set of optimized vectors have been constructed.     

Inhibition of sodium for sodium exchange by phlorizin in frog sartorius muscle

The effects of phlorizin (2 X 10(-3) mol X l-1) on the Na transport of frog (Rana esculenta) sartorius muscle were investigated in glucose-free medium. Phlorizin decreased the rate coefficient of 24Na efflux by about 40%. The degree of inhibition was comparable to that caused by ouabain (10(-4) mol X l-1). Phlorizin could evoke a further reduction in the 24Na efflux also in the presence of ouabain. The intracellular Na content of the phlorizin-treated muscles remained unchanged, in contrast to a 60% increase induced by ouabain. 42K uptake was not affected by phlorizin. Data indicate that the ouabain-sensitive Na-K pump was not involved in the action of phlorizin. At the same time, phlorizin failed to alter the residual 24Na efflux measured in Li-Ringer solution containing ouabain. When Na: Na exchange was restored by replacing Na into the washout solution in the presence of ouabain, the increase of 24Na efflux was significantly diminished by phlorizin. Phlorizin reduced the 24Na uptake into a compartment with a half time of 6 min by about 40% without affecting the intracellular compartment. The results suggest that phlorizin inhibits the ouabain-insensitive Na: Na exchange in a superficial Na compartment.     

Urinary catecholamine responses to basic types of physical activity

Urinary adrenaline, noradrenaline, heart rate, and subjective ratings were obtained from 9 healthy males during six different physical activities, ranging in intensity from lying down to running. Heart rate, subjective ratings and noradrenaline excretion reflected the work load in the different conditions. Adrenaline, on the other hand, failed to show this relationship. There was no significant increase in adrenaline excretion even at the highest work load (corresponding to a heart rate of 160 bpm). It was concluded that urinary adrenaline may safely be used as an indicator of mental factors even in situations with different levels of physical activity.