Effects of vagal neuromodulation and vagotomy on control of food intake and body weight in rats.

Food induced neurohumoral signals are conduced to data processing brain centers mainly as vagal afferent discharge resulting in food intake regulation. The aim of this study was to evaluate effects of vagal nerve neuromodulation in control of food intake with fed-pattern microchip (MC) pacing. Experiments were performed on 60 rats divided on 5 groups: I group 0,05Hz left vagal pacing, II - pacing of both vagal nerves with MC 0,05Hz, III- left vagal MC 0,1Hz pacing, IV - pacing of both vagal nerves with MC 0,1 Hz was performed. In group V left vagal pacing was combined with right side abdominal vagotomy. Body weight and total food intake decreased by 12% and 14% (I), 26% and 30%(II), 8% and 21%(III), 14% and 30%(IV), 38% and 41%(IV), respectively (p<0.05). Effects of both vagal nerves stimulation on final body weight and food intake was significantly more effective than only single nerve MC pacing however most effective was stimulation with 0,1Hz combined with right vagotomy. We conclude that vagal stimulation reduce food intake and body weight by increasing vagal afferent signals. Our results suggest that information in vagal afferents can be modulated resulting in changes of feeding behaviour and body weight.     

Inhibition by trifluoperazine of ATP synthesis and hydrolysis by particulate and soluble mitochondrial F1: Competition with H2PO 4 −

The effect of trifluoperazine (TFP) on the ATPase activity of soluble and paniculate F₁ATPase and on ATP synthesis driven by succinate oxidation in submitochondrial particles from bovine heart was studied at pH 7.4 and 8.8. At the two pH. TFP inhibited ATP hydrolysis. Inorganic phosphate protected against the inhibiting action of TFP. The results on the effect of various concentrations of phosphate in the reversal of the action of TFP on hydrolysis at pH 7.4 and 8.8 showed that H₂PO ₄ ^– is the species that competes with TFP. The effect of TFP on oxidative phosphorylation was studied at concentrations that do not produce uncoupling or affect the aerobic oxidation of succinate (<15M). TFP inhibited oxidative phosphorylation to a higher extent at pH 8.8 than at pH 7.4; this was through a diminution in theV _max, and an increase in theK _m for phosphate. Data on phosphate uptake during oxidative phosphorylation at several pH showed that H₂PO ₄ ^– is the true substrate for oxidative phosphorylation. Thus, in both synthesis and hydrolysis of ATP, TFP and H₂PO ₄ ^– interact with a common site. However, there is a difference in the sensitivity to TFP of ATP synthesis and hydrolysis; this is more noticeable at pH 8.8, i.e. ATPase activity of soluble F₁ remains at about 40% of the activity of the control in a concentration range of TFP of 40–100M, whereas in oxidative phosphorylation 14M TFP produces a 60% inhibition of phosphate uptake.     

Synthesis of some racemicγ-fluoro-α-amino acids

Summary Versatile three-step procedures for syntheses of seven racemi-fluoro-a-amino acids are described. Alkylation oftert-butyl N-(diphenylmethylene) glycinate with 1-bromo-2-fluoroalkanes gave N-protected aminoacid esters both in anhydrous medium using lithium-diisopropylamide as base at low temperature or in a two phase system of 50% aqueous sodium hydroxide and methylene chloride with triethylbenzylammonium chloride as the phase transfer catalyst at room temperature. Subsequent two-step deprotection with citric acid and hydrochloric acid gave the title compounds in 13–33% overall yields.Dedicated to Professor Dr.mult., Dr.h.c. Alois Haas on the occasion of his 65th birthday     

Insoluble glycogen, a metabolizable internal adsorbent, decreases the lethality of endotoxin shock in rats

Insoluble glycogen is an enzymatically modified form of naturally occurring soluble glycogen with a great adsorbing capacity. It can be metabolized by phagocytes to glucose. In this study we used insoluble glycogen intravenously in the experimental endotoxin shock of rats. Wistar male rats were sensitized to endotoxin by Pb acetate. The survival of rats were compared in groups of animals endotoxin shock treated and non-treated with insoluble glycogen. Furthermore, we have determined in vitro the binding capacity of insoluble glycogen for endotoxin, tumour necrosis factor alpha, interleukin-1 and secretable phospholipase A2. Use of 10 mg/kg dose of insoluble glycogen could completely prevent the lethality of shock induced by LD50 quantity of endotoxin in rats. All animals treated survived. Insoluble glycogen is a form of 'metabolizable internal adsorbents'. It can potentially be used for treatment of septic shock.     

Prevalence and upper limit of cardiac hypertrophy in professional cyclists

The term athlete's heart refers to an increased left ventricular mass. Few studies have assessed the prevalence and normal upper limit of cardiac hypertrophy in highly trained cyclists and this was the aim of this study. A group of 40 professional road cyclists [mean age 26 (SD 3) years] who had participated in European competitions for 3–10 years, were evaluated at the beginning of the 1992–93 season. Evaluation included a clinical history and physical examination, one and two-dimensional echocardiography, 12-lead resting electrocardiogram and a graded exercise test. Determination of the left ventricular mass index (LVMI) was performed using Devereux's formula with correction for the body surface area. Systolic and diastolic blood pressure were measured at rest and at peak exercise. Of the group 23 cyclists (58%) presented a LVMI greater than 130 g · m^–2, 21 cyclists presented a diastolic ventricular thickness equal to or greater than 13 mm, with a superior limit of 19 mm; 3 cyclists presented asymmetrical septum hypertrophy; and the relationship between posterior wall and left ventricular diastolic radius was equal to or greater than 0.45 in 14 cases (35%). Electrocardiographic abnormalities of ST-T segment were seen in only 1 subject. No correlation was found between the degree of ventricular hypertrophy and arterial blood pressure. We concluded that these professional cyclists showed a high prevalence of cardiac hypertrophy (58%). The distribution of this hypertrophy was concentric in 20/33 and asymmetric in 3/23 of the subjects with left ventricular hypertrophy. The electrocardiograms were normal in 98% of the subjects.     

Induction of autonomous endosperm in Lupinus luteus,Helleborus niger and Melandrium album by in vitro culture of unpollinated ovaries

Autonomous division of the endosperm was induced by in vitro culture of unpollinated ovaries or placenta-attached ovules in Helleborus niger, Lupinus luteus and Melandrium album. The induction frequencies for the three species were 50%, 10–20% and 0.1%, respectively. The endosperms contained up to 20 free nuclei; only a few ovules with 80–420 endosperm nuclei were found. Induction of autonomous division of the endosperm, which is unusual in amphimictic plants, was observed in three new species. No embryos appeared in the ovules. This suggests a developmental independence of the endosperm from the embryo in the culture of unpollinated ovaries or ovules.     

Influence of prostaglandins on electrolyte metabolism of human trabecular bone in vitro

A procedure was developed to investigate the electrolyte metabolism of human trabecular bone and its regulation in vitro, in particular the influence of prostaglandins. Trabecular bone was prepared from femoral heads of patients who had undergone hip replacement surgery for coxarthrosis. 500 mg samples were incubated in modified EAGLE's minimal essential medium. Net electrolyte movements between bone and incubation medium were measured. During 6 hours of incubation PGE2 caused an increase in the release of calcium and magnesium from bone into incubation medium as compared to controls. The effect of PGE2 was dose-dependent and comparable to that of human parathyroid hormone 1-34 (hPTH 1-34) whereas hPTH 3-34 had no effect. Human calcitonin (hCT) caused a decrease in the release of calcium and magnesium. PGE2 was found to be the most potent prostaglandin. PGE1 and PGF2 alpha had about 50% and PGF1 alpha about 40% of the potency of PGE2. PGA1 and PGA2 had no effect. The effect of PGE2 could be completely inhibited by hCT and was not further enhanced by hPTH 1-34. Magnesium movement was affected in the same way as calcium movement, while phosphate movement and release of alkaline phosphatase and hydroxyproline from bone into incubation medium were not affected by prostaglandins.     

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.     

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.