Effect of neurotensin on pancreatic function in man

The effect of neurotensin on submaximally-stimulated hepatobiliary and pancreatic secretion was studied in 6 healthy subjects. An intravenous infusion of neurotensin 1.4 ± 0.3 pmol/kg/min, designed to reproduce plasma neurotensin immunoreactivity levels within the physiological range, produced a significant increase in pancreatic bicarbonate output. Plasma concentrations of pancreatic polypeptide rose by 83 ± 16 pmol/l and were associated with a small reduction in trypsin, but no significant change in bilirubin outputs.     

Effect of Metalaxyl on the incidence and severity of Pearl millet downy mildew disease in Northern Nigeria

Pearl millet downy mildew (DM) incidence, severity and yield losses of two pearl millet varieties (local and improved) due to the disease were determined in the field. Significant differences in the disease incidence and severity were recorded in the plots sown with metalaxyl-treated seeds and those sown with non-treated seeds, indicating the efficacy of the fungicide on the fungus. Yield losses due to non-treatment of seeds with metalaxyl was 40.88 and 45.39% in a local variety and 43.00 and 18.60% in an improved variety in the 2000 and 2001 cropping seasons respectively. Significant differences between plots sown with metalaxyl-treated and those sown with non-treated seeds were obtained for other yield components such as 1000-grains weight, panicle length and weight.     

Effect of temperature on the saccharide composition obtained after alpha-amylolysis of starch

The hydrolysis of starch to low-molecular-weight products (normally characterised by their dextrose equivalent (DE), which is directly related to the number-average molecular mass) was studied at different temperatures. Amylopectin potato starch, lacking amylose, was selected because of its low tendency towards retrogradation at lower temperatures. Bacillus licheniformis alpha-amylase was added to 10% [w/w] gelatinised starch solutions. The hydrolysis experiments were done at 50, 70, and 90 degrees C. Samples were taken at defined DE values and these were analysed with respect to their saccharide composition. At the same DE the oligosaccharide composition depended on the hydrolysis temperature. This implies that at the same net number of bonds hydrolysed by the enzyme, the saccharide composition was different. The hydrolysis temperature also influenced the initial overall molecular-weight distribution. Higher temperatures led to a more homogenous molecular weight distribution. Similar effects were observed for alpha-amylases from other microbial sources such as Bacillus amyloliquefaciens and Bacillus stearothermophilus. Varying the pH (5.1, 6.2, and 7.6) at 70 degrees C did not significantly influence the saccharide composition obtained during B. licheniformis alpha-amylase hydrolysis. The underlying mechanisms for B. licheniformis alpha-amylase were studied using pure linear oligosaccharides, ranging from maltotriose to maltoheptaose as substrates. Activation energies for the hydrolysis of individual oligosaccharides were calculated from Arrhenius plots at 60, 70, 80, and 90 degrees C. Oligosaccharides with a degree of polymerisation exceeding that of the substrate could be detected. The contribution of these oligosaccharides increased as the degree of polymerisation of the substrate decreased and the temperature of hydrolysis increased. The product specificity decreased with increasing temperature of hydrolysis, which led to a more equal distribution between the possible products formed. Calculations with the subsite map as determined for the closely related alpha-amylase from B. amyloliquefaciens reconfirmed this finding of a decreased substrate specificity with increased temperature of hydrolysis. Copyright 1999 John Wiley & Sons, Inc.     

Gender differences in EEG coherence during memorization of dichotically and monaurally presented verbal stimuli

Gender differences in changes of coherence values in the theta and alpha frequency bands during encoding of dichotically and monaurally presented verbal information were studied. Right-handed students (14 male and 14 female subjects) participated in experiments. The EEG was recorded from 16 electrodes placed at homologous sites of the left and the right hemispheres. In male subjects, numerous differences in coherence values between conditions of dichotical and monaural word presentation were found in the theta2- and alpha1-bands, in females, the differences were most pronounced in the theta1- and theta2-frequency bands. Numerous differences in coherence values differentiated between dichotic and left-sided monaural presentations in males and between dichotic and right-sided monaural presentations in females. As compared to dichotic presentation, in condition of the monaural presentation, higher coherence values were observed in men and lower in women. The features of gender differences in frequency-spatial patterns of changes in EEG coherence values under conditions of bilaterally and unilaterally directed attention in male and female groups may testify that female subjects predominantly use right-hemispheric processing strategy, whereas male subjects use, mainly, left-hemispheric strategy for selection and memorization of concrete nouns.     

Differences in latent inhibition between men and women under conditions of nonverbal visually-spaatial masking]

In order to study gender differences in development of the latent inhibition (LI) and the influence of laterality (hemisphere) factor, two groups of subjects were examined. In the preexposure phase, subjects of the control group were presented with a pair of geometric figures, which appeared either in the right or in the left visual hemifield (at random) with the exposure time of 80 ms. A subject had to compare the figures in a pair and to press a button in case of their identity. In the preexposure (experimental) group, the subject solved the same task, but half of them was presented with the same set of stimuli which appeared in the right hemifield, another half of subjects received these stimuli in the left hemifield. Simultaneously with the target stimuli, the opposite hemifield was stimulated with a nonattended symbol "[symbol: see text]". In the test phase, all the subjects (both of the control and experimental groups) had to respond to the symbol "[symbol: see text]" (previously nonattended in the experimental group), which appeared in part of the trials, by pressing the button. Pairs of stimuli which had been target ones in the preexposure phase, became masking stimuli in the test phase. Correct responses were reinforced by presentation of a special sound. The number of trials required for acquisition of the instrumental contingency served as an index of the LI. Analysis of variance showed that significant strong effect of the LI was observed only in men (comparison between the control and preexposure groups), while there was no significant difference between women of the control and preexposure groups. There was no laterality effect. Gender differences and hemispheric asymmetry in the LI organization are discussed.