Intravenous vs. oral rehydration: effects on subsequent exercise-heat stress

Castellani, John W., Carl M. Maresh, Lawrence E. Armstrong,Robert W. Kenefick, Deborah Riebe, Marcos Echegaray, Douglas Casa, andV. Daniel Castracane. Intravenous vs. oral rehydration: effects onsubsequent exercise-heat stress. J. Appl.Physiol. 82(3): 799-806, 1997.This studycompared the influence of intravenous vs. oral rehydration afterexercise-induced dehydration during a subsequent 90-min exercisebout. It was hypothesized that cardiovascular, thermoregulatory, and hormonal variables would be the same between intravenous and oral rehydration because of similar restoration ofplasma volume (PV) and osmolality (Osmo). Eight non-heat-acclimated menreceived three experimental treatments (counterbalanced design) immediately after exercise-induced dehydration (33°C) to 4%body weight loss. Treatments were intravenous 0.45% NaCl (iv; 25 ml/kg), no fluid (NF), and oral saline (Oral; 25 ml/kg).After rehydration and rest (2 h total), subjects walked at 50% maximalO₂ consumption for up to 90 min at36°C. The following observations were made: 1) heart rate was higher(P < 0.05) in Oral vs. ivat minutes 45, 60, and75 of exercise;2) rectal temperature, sweat rate, percent change in PV, and change in plasma Osmo were similar between ivand Oral; 3) change in plasmanorepinephrine decreased less (P < 0.05) in Oral compared with iv at minute45; 4) changes in plasma adrenocorticotropic hormone and cortisol were similar between ivand Oral after exercise was initiated; and5) exercise time was similar betweeniv (77.4 ± 5.4 min) and Oral (84.2 ± 2.3 min). These datasuggest that after exercise-induced dehydration, iv and Oral wereequally effective as rehydration treatments. Thermoregulation, changein adrenocorticotropic hormone, and change in cortisol were notdifferent between iv and Oral after exercise began; this is likely dueto similar percent change in PV and change in Osmo.

     

Noradrenergic and adrenergic systems in the brain of the urodele amphibian,Pleurodeles waltlii,as revealed by immunohistochemical methods

The distribution of noradrenaline and adrenaline in the brain of the urodele amphibian Pleurodeles waltlii has been studied with antibodies raised against noradrenaline and the enzymes dopamine--hydroxylase and phenylethanolamine-N-methyltransferase. Noradrenaline-containing cell bodies were found in the anterior preoptic area, the hypothalamic nucleus of the periventricular organ, the locus coeruleus and in the solitary tract/area postrema complex at the level of the obex. Noradrenergic fibers are widely distributed throughout the brain innervating particularly the ventrolateral forebrain, the medial amygdala, the lateral part of the posterior tubercle, the parabrachial region and the ventrolateral rhombencephalic tegmentum. Putative adrenergic cell bodies were found immediately rostral to the obex, ventral to the solitary tract. Whereas the cell bodies and their dendrites were Golgi-like stained, axons were more difficult to trace. Nevertheless, some weakly immunoreactive fibers could be traced to the basal forebrain. A comparison of these results with data previously obtained in anurans reveals not only several general features, but also some remarkable species differences.Abbreviations Acc Nucleus accumbens - AP area postrema - Apl amygdala, pars lateralis - Apm amygdala, pars medialis - ca commissura anterior - Cb cerebellum - cc central canal - Dp dorsal pallium - epl external plexiform layer - gl glomerular layer of the olfactory bulb - H ganglion habenulae - igl internal granular layer - Ip nucleus interpeduncularis - Lc locus coeruleus - Ll lateral line lobe - Lp lateral pallium - Ls lateral septum - ml mitral cell layer - Mp medial pallium - Ms medial septum - nPT nucleus pretectalis - NPv nucleus of the periventricular organ - nV nervus trigeminus - oc optic chiasm - Poa preoptic area - Ri nucleus reticularis inferior - SC nucleus suprachiasmaticus - sol solitary tract - Str striatum - thd thalamus dorsalis - thv thalamus ventralis - To tectum opticum - TP tuberculum posterius - V ventricle - VH ventral hypothalamic nucleus - III nucleus nervi oculomotorii - IXm nucleus motorius nervi glossopharyngei - Xm nucleus motorius nervi vagi     

Inhibition by Cl− channel blockers of the volume-activated,diffusional mechanism of inositol transport in primary astrocytes in culture

[³H]Inositol accumulated by rat brain cultured astrocytes is released when cells swell by exposure to solutions of decreased osmolarity. Activation of inositol efflux was proportional to reductions in osmolarity from 30%–70%. This volume-activated inositol efflux pathway was increased (27%) in Na⁺-free medium and decreased (22%) in Cl^–-free medium. It was independent of extracellular Ca²⁺ and was reduced (30%) in the presence of the intracellular chelator [1,2-bis(o-aminophenoxy) ethane-N,N,N,N-tetraacetic acid tetra-(acetoxymethyl)-ester] (BAPTA-AM). The inositol efflux pathway was markedly inhibited by Cl^– channel blockers, which at maximal inhibitory concentrations decreased inositol efflux by 70%–83%. The potency range of the drugs was: 5-nitro-2-(3-phenylpropylamino)benzoic acid (NPPB)>1–9, dideoxyforskolin>4,4-diisothiocyanatostilbene-2,2-disulfonic acid (DIDS)>niflumic acid. Inositol efflux was strongly inhibited by the SH blocker N-ethyl maleimide (NEM), which at 100 M abolished inositol release. Inositol efflux can be reversed by increasing its extracellular concentration, suggesting that the efflux is mediated by a diffusional pathway whose direction is given by the concentration gradient. The inhibition of volume-associated fluxes of inositol by Cl^– channel blockers supports the suggestion of an anion channel as the common pathway for inorganic and organic osmolytes in cultured astrocytes.     

Constrained C-terminal hexapeptide neurotensin analogues containing a 3-oxoindolizidine skeleton

Summary In order to enforce different spatial orientations in the C-terminal hexapeptide of neurotensin (NT_8–13) and to gain information about the importance of the 10–11 peptide bond for binding to NT receptors, the Pro¹⁰-Tyr¹¹ fragment has been replaced with (2R,8S,8aR)-, (2S,8S,8aR)-, (2S,8S,8aS)-, (2S,8R,8aS)- and (2R,8R,8aS)-8-amino-2-benzyl-3-oxoindolizidine-2-carboxylic acid. Molecular dynamics calculations and energy minimization studies have shown that, contrarily to the Pro-Tyr moiety, none of these indolizidines display a tendency to adopt type I and III -turns, but those having (8S,8aR) or (8R,8aS) stereochemistry essentially adopt extended conformations and the (8S,8aS) stereoisomer prefers a nonstandard folding. The four diastereomeric NT_8–13 analogues incorporating (8S,8aR) or (8R,8aS) indolizidines displayed binding affinities for the brain NT receptor similar to that of [Ala¹¹]-NT_8–13 and only five- to ninefold lower than that of the corresponding analogue, [Phe¹¹]NT_8–13. Although this slight decrease could be attributed to differences in conformational behavior between these constrained NT_8–13 analogues and [Phe¹¹]NT_8–13 or NT_8–13, it is not clear whether the -turn around Pro¹⁰-AA¹¹ (AA=Phe, Tyr) is conserved upon receptor binding. An excessive restriction in the motions of the aromatic side chain, imposed by the highly steric constraint of the indolizidine moiety, emerges as an alternative explanation. The findings reported here demonstrate the possibility of replacing the Pro¹⁰-Tyr¹¹ dipeptide in NT_8–13 with a non-peptide residue without affecting considerably the affinity for brain NT receptors.     

Solid-state fermentation of sugarcane bagasse with Flammulina velutipes and Trametes versicolor

The mushroom Flammulina velutipes and the white-rot fungus Trametes versicolor were cultivated separately on sugarcane bagasse for 40 days. Trametes versicolor produced laccase and manganese-peroxidase activities, showing a simultaneous degradation of lignin and holocellulose. However, only phenoloxidase activity was found with Flammulina velutipes. A preferential degradation of lignin was detected in F. velutipes, which exhibited a greater reduction in the ratio of weight loss to lignin loss than T. versicolor. A decrease in the syringyl/guaiacyl ratio observed with both fungi indicated the preferential degradation of non-condensed (syringyl-type) lignin units. An increase in the relative abundance of aromatic carboxylic acids suggested that the oxidative transformation of lignin unit side-chains was occurring. This was more noticeable with Flammulina velutipes than with T. versicolor.     

A large transmissible plasmid is required for crystal toxin production in Bacillus thuringiensis variety israelensis

Bacillus thuringiensis var. israelensis (BTI), serotype 14, which produces parasporal crystals toxic to certain dipteran larvae, was analyzed by agarose gel electrophoresis and found to contain a complex plasmid array. Eight plasmids were detected, with approximate sizes of 3.3, 4.2, 4.9, 10.6, 68, 75, 105, and 135 MDa, as well as a plasmidlike linear DNA element of ~10 MDa. Partially cured mutants of BTI implicated the 75-MDa plasmid in crystal production. Fifteen independently isolated acrystalliferous (Cry^?) mutants were found to lack this plasmid. In plasmid transfer experiments, several of the BTI plasmids transferred into a plasmid-free, Cry^? BTI recipient, but only transfer of the 75-MDa plasmid converted the recipient to crystal toxin production. The presence or absence of mosquito-toxic activity in all Cry⁺ and Cry^? variants of BTI was confirmed by bioassay of sporulated cultures against larvae of Aedes aegypti. Southern blot analyses revealed that in one unusual Cry⁺ variant in which no 75-MDa plasmid band was detectable, plasmid sequences were still present, possibly integrated into the chromosome. The 75-MDa plasmid could also apparently recombine with the 68-MDa plasmid, to which it was partially homologous.     

β-Endorphin like immunoreactivity of brain,pituitary gland and plasma of rats submitted to postnatal protein malnutrition: Effect of behavioral training

Wistar-derived rats were raised and maintained either on a normal- (25% casein) or on a low-protein (8% casein) diet until the age of 100 to 114 days. Both diets were isocaloric and contained an adequate supply of salts and vitamins. There were gross differences in body, brain and pituitary weight between the two groups. In addition, the brain and pituitary content of β-endorphin like immunoreactivity was lower in the protein malnourished rats, and three different forms of training (50 tone-footshock shuttle avoidance trials; 50 tones alone (habituation); 50 footshocks alone) caused a depletion of brain β-endorphin like immunoreactivity in the normal, but not in the malnourished rats. Footshock stimulation caused, in addition, a pituitary decrease and a plasma increase of β-endorphin like immunoreactivity, also restricted to the normal diet group. Performance in the habituation and in the shuttle avoidance tasks was similar in the two groups, despite the different responsiveness of their brain and pituitary β-endorphin systems to training and/or stimulation. In view of the possible involvement of these systems in learning suggested by these and by previous data, it seems likely that the neurohumoral regulation of habituation and avoidance learning may be different in rats submitted to protein malnutrition when compared to controls.     

Immunochemical analysis of myosin heavy chains in the developing chicken heart

Monoclonal antibodies (McAb) against myosin from the pectoralis muscle of the adult chicken have been generated and shown to react specifically with the myosin heavy chain (MHC). The reactivities of two such McAbs with myosin from adult chicken atrial and ventricular myocardium were further analysed by immunoautoradiography, radioimmunoassay, and immunofluorescence microscopy. Monoclonal antibody MF 20 was found to bind both atrial and ventricular MHC and stain all striated muscle cells of the adult chicken heart. In contrast, McAb B1 bound specifically to atrial myocytes in immunofluorescence studies, while immunoautoradiography and radioimmunoassay demonstrated the specificity of this antibody for the atrial MHC. Upon reacting these McAbs with myosin isolated from embryonic hearts where definitive atria and ventricles were present, the same specificity of antibody binding was observed. Immunofluorescence studies demonstrated that all striated muscle cells of the embryonic heart contained MHCs recognized by MF 20, while only atrial muscle cells were bound by B1. When extracts of presumptive atrial and ventricular tissue were reacted with MF 20 and B1, significant reactivity of MF 20 was first observed at stage 10 in the presumptive ventricle and thereafter this McAb reacted with all regions of the developing myocardium. Binding of B1 was detected approximately 1 day later at stage 15 and was confined to atrial-forming tissues. These data demonstrate antigenic similarity between adult and embryonic MHC isolated from atrial myocardium and suggest the expression of an atrial-specific MHC early in the regional differentiation of the heart.     

Five new filamentous,glucose-fermenting Candida isolated from decayed wood in the evergreen rainy Valdivian forest of southern Chile

Five novel representatives of the yeast genus Candida isolated from advanced stages of wood degradation from fallen trunks of Eucryphia cordifolia Cav., Laurelia sempervirens Weim., Laurelia philippiana Weim., Nothofagus dombeyii (Mirb.) Blume, and Nothofagus obliqua (Mirb.) Blume, in the evergreen rainy Valdivian forest of southern Chile, are described and illustrated. They clearly differ from all accepted Candida species to warrant their establishment as five new species of yeasts: Candida coipomensis sp. nov., Candida ralunensis sp. nov., Candida laureliae sp. nov., Candida osornensis sp. nov., and Candida llanquihuensis sp. nov.     

Four new species of Apiotrichum isolated from decayed wood in the evergreen rainy Valdivian forest of southern Chile

Four unusual Apiotrichum, isolated from decayed wood of Eucryphia cordifolia Cav., Nothofagus obliqua (Mirb.) Blume, and Laurelia sempervirens Wein., one of which was also isolated from the intestinal tract of Scaptomyza multispinosa Malloch (Diptera), are described and illustrated. These species differ from all the accepted Apiotrichum species (1–3) to warrant their establishment as four new species: Apiotrichum eucryphiae, Apiotrichum osvaldii, Apiotrichum futronensis and Apiotrichum nothofagi.