A comparative dynamic study of the effectiveness of gastric cytoprotection by vitamin A, De-Nol, sucralfate and ulcer healing by pirenzepine in patients with chronic gastric ulcer (a multiclinical and randomized study)

The gastric cytoprotective effects of vitamin A, De-Nol and sucralfate were compared with the effectiveness of pirenzepine in healing ulcer in patients with chronic gastric ulcer. A total of 100 patients was randomized into different groups: the patients were treated with antacids, vitamin A (3 X 50.000 IU), De-Nol liquid (4 X 5 ml), sucralfate (4 X 1 g) or pirenzepine (3 X 50 mg). The treatment was continued for 4 weeks. At the beginning, 2 and 4 weeks after starting treatment the patients were subjected to endoscopy and the size of the ulcer was measured planimetrically. The ulcer-healing effect of De-Nol liquid was significantly better than that of the antacids (p less than 0.01). Ulcer size was reduced significantly in all groups (p less than 0.01), however, at the end of the study the gastric ulcers were smallest in the De-Nol treated group (p less than 0.001). The dynamics of ulcer healing in the second week was most favourable in the patients receiving vitamin A (p less than 0.01). The present data point to the cytoprotective effects of De-Nol liquid, vitamin A and sucralfate and to their ability of healing chronic gastric ulcers.     

The interrelationships between the development of ethanol-, HCl, NaOH and NaCl-induced gastric mucosal damage and the gastric mucosal superoxide dismutase activity in the rats

Gastric mucosal damage was produced by intragastric administration of 96% ethanol, 0.6 M HCl, 0.2 M NaOH or 25% NaCl. The animals were killed 1 hr later, when the number and severity of gastric lesions (ulcers) was recorded. At the time of the sacrifice of the animals gastric mucosal superoxide dismutase (SOD) activity was measured. It was found that (1) the gastric mucosal damage could be induced by the administration of any of the necrotizing agents in all animals, (2) superoxide dismutase (SOD) activity increased significantly in the damaged gastric mucosa following 96% ethanol, while its activity decreased significantly during the development of gastric mucosal damage produced by the intragastric administration of 0.6 M HCl, 0.2 M NaOH or 25% NaCl. It has been concluded that: (1) the enzyme systems necessary to generate the superoxide free radical anions can be stimulated by ethanol, and they can be inhibited by the application of 0.6 M HCl, 0.2 M NaOH and 25% NaCl: (2) the observed stimulation or inhibition of the enzyme systems to generate the superoxide free radical anions may be of pathological significance in the development of gastric mucosal damage produced by the intragastric administration of 96% ethanol, 0.6 M HCl, 0.2 M. NaOH or 25% NaCl.     

Hormonal imprinting in cell culture II. Evidence of hormonal imprinting and thyrotropin (TSH) -gonadotropin (FSH) overlap in a Chinese hamster ovary (CHO) cell line

Reexposure of cultures of the Chinese hamster ovarian cell line CHO K1 to FITC-labeled hormone 48 h after the first 24-h exposure to FSH or TSH showed that hormonal imprinting, accounting for a greater binding capacity on reexposure, also took place in in vitro conditions. TSH amplified the receptors of FSH to a greater degree than FSH itself, although the reverse effect failed to happen. TSH was able to bind the ovarian cells at first exposure, and to amplify the receptors for itself and--remarkably--to a considerably greater degree for FSH, exactly as observed earlier in in vivo systems.     

Evidence for the development of tolerance to PGF2 alpha on the ethanol-induced gastric mucosal damage

PGF2 alpha, 100 micrograms/kg intraperitoneally, applied 30 min before 1.0 ml intragastric ethanol (96%) exerts cytoprotective effect on the gastric mucosal membrane. After a week long pretreatment of the animals with 0.25; 0.5 and 1.0 mg/day PGF2 alpha resulted in a diminishing cytoprotective effect. The gastric tissue cAMP level raised simultaneously and after the PGF2 alpha pretreatment with the taming cytoprotection the cAMP level diminished parallel in a dose dependent manner. It is assumed that after PGF2 alpha pretreatment the density of the cellular PGF2 alpha receptors decreases, according to the observed phenomenon.     

Study of the imprinting and overlap of insulin and concanavalin-A at the receptor level in a protozoan (Tetrahymena) model system

In a protozoan (Tetrahymena) model system, insulin treatment produced a long-term imprinting which upon re-exposure to the hormone resulted in an enhanced binding of the hormone. Insulin pretreatment produced similar effect with regard to the binding of concanavalin-A. Concanavalin-A could only induce a short-term imprinting for itself and was not capable at all of inducing imprinting for insulin. Based on the results of this study it appears that the binding of the sugar component of the receptor, which can be achieved also by lectin, is not sufficient to induce imprinting but the whole (hormone) molecule is needed.     

Preventive effect of PGI2, 7-oxo-PGI2 and 17-aza-PGF2 alpha derivate on the development of indomethacin-induced intestinal mucosal damage in rats

Intestinal mucosal damage was produced in rats by the s.c. administration of indomethacin (10 mg/kg). The number and severity of the small intestinal mucosal lesions was recorded. Different doses of prostacyclin (PGI2), 7-oxo-PGI2 and 17-aza-PGF2 alpha (0.25-0.5-1.00 mg/kg) were given i.p. at the time of administration of indomethacin. The effects of these compounds were studied on the number and severity of the small intestinal mucosal lesions. It was shown that (1) all tested compounds inhibited the number and severity of the intestinal mucosal lesions, however, to different extent; (2) the inhibition of the development of small intestinal mucosal damage displayed a dose-response relationship; (3) 17-aza-PGF2 alpha was found to have the most potent effect on the development of the intestinal lesions as well as on the development of gastric mucosal damage produced by ethanol.     

Modification of acetylcholine sensitivity of neuronal membrane by presynaptic stimulation

The action of electrical stimulation of one of the pallial nerves on the sensitivity of the bursting RPa1 neuron of Helix pomatia to acetylcholine (ACh) was investigated. The depolarizing effect of ACh was significantly decreased by presynaptic stimulation. Stimulation leads also to an attenuation of the ACh-induced increase in membrane conductivity. The effect of stimulation on the ACh evoked response of the membrane was reversibly blocked by cold and was completely eliminated after long term incubation of the neuron under "in vitro" conditions.     

Direct gene transfer to plants

Evidence for direct, gene-mediated stable genetic transformation of plant cells of Nicotiana tabacum is presented. A selectable hybrid gene comprising the protein coding region of the Tn5 aminoglycoside phosphotransferase type II gene under control of cauliflower mosaic virus gene VI expression signals was introduced into plant protoplasts as part of an Escherichia coli plasmid. The gene was stably integrated into plant genomic DNA and constitutively expressed in selected, drug resistant, protoplast-derived cell clones. The mode of integration of the foreign gene into the plant genome resembled that observed for DNA transfection of mammalian cells. Plants regenerated from transformed cell lines were phenotypically normal and fertile, and they maintained and expressed the foreign gene throughout the development of vegetative and generative organs. Microspores, grown in anther culture, developed into resistant and sensitive haploid plantlets. Genetic crossing analysis of one of the transformed plants revealed the presence of one dominant trait for kanamycin resistance segregating in a Mendelian fashion in the F₁ generation.     

Fluctuation of free IAA under inductive and non-inductive photoperiods in Chenopodium rubrum

Fluctuation in levels of endogenous free IAA has been followed in the SD plant Chenopodium rubrum under photoperiodic conditions inductive or not inductive of flowering. Endogenous IAA was measured fluorimetrically as -pyrone. The level of IAA shows little fluctuation under continuous illumination. An endogenous rhythm of IAA fluctuation was found in plants transferred from light to continuous darkness, with a natural period of 30 hrs. The troughs of minimum IAA level within the endogenous rhythm coincided with the peaks in the endogenous rhythm of flowering response, which possessed the same period length. The concentration of IAA in the shoot always decreased at the end of cycles of dark period that induce flowering. The results are discussed in relation to the role of IAA in flowering of SD plants.