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John W. Castellani Carl M. Maresh Lawrence E. Armstrong Robert W. Kenefick Deborah Riebe Marcos Echegaray Stavros Kavouras V. Daniel Castracane 《European journal of applied physiology and occupational physiology》1998,77(3):242-248
Exercise following exercise-induced dehydration (EID) has been shown to elevate concentrations of plasma norepinephrine (NE)
and hypothalamic-pituitary-adrenal axis hormones. However, it is not known how intravenous (i.v.) rehydration (Rh) with isotonic
(ISO) or hypotonic (HYPO) saline affects these hormone concentrations. It was hypothesized that HYPO, versus ISO, would lead
to lower plasma NE and cortisol concentrations ([CORT]) during subsequent exercise following EID due to a decrease in plasma
sodium concentration [Na+]. Eight non-heat acclimated men completed three experimental treatments (counterbalanced design) immediately following EID
(33°C) to −4% body mass loss. The Rh treatments were i.v. 0.9% NaCl (ISO, 25 ml · kg−1), i.v. 0.45% NaCl (HYPO, 25 ml · kg−1), and no fluid (NF). After Rh and rest (2 h total), the subjects walked at 53–54 percent of maximal O2 uptake for 45 min at 36°C. After Rh, the following observations were made before/during exercise: percentage change in plasma
volume (PV) was lower in NF compared to ISO and HYPO but similar between ISO and HYPO; Δ[Na+] was similar between ISO and NF and higher in ISO compared to HYPO; Δ plasma NE was higher in NF compared to ISO and HYPO,
but similar between ISO and HYPO; Δ plasma [CORT] was higher in NF compared to ISO and HYPO and higher in ISO compared to
HYPO; rectal temperature was higher in NF compared to ISO and HYPO. These data would suggest that sympathetic nervous activity
and [CORT] during exercise, subsequent to EID and Rh, was affected by lower PV (probably through cardiopulmonary baroreflexes)
as well as core temperature. Furthermore, [CORT] was affected by Δ[Na+] after Rh through an unknown mechanism.
Accepted: 16 July 1997 相似文献
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A comparison of glycoproteins of the zona pellucida (ZP) of five different mammalian species (cat, dog, rabbit, pig, and rat) has been made using polyclonal and monoclonal antibodies. In an enzyme-linked immunosorbent assay (ELISA), polyclonal antisera against total rabbit and pig ZP recognize their homologous ZP to the greatest extent but also detect crossreactive antigenic determinants in the ZP of all other species tested. Polyclonal antibodies against each of two purified rabbit ZP glycoproteins or one purified pig ZP glycoprotein also show some recognition of heterologous (pig, cat, and dog) ZP, but not rat ZP. Monoclonal antibodies (McR5-rabbit ZP protein determinant; McPSI-determinant associated with post-translational modifications of pig ZP proteins such as carbohydrates) further demonstrate that specific determinants are shared between some but not all of these mammalian species. For example, both of these antibodies recognize distinct determinants which are most abundant in pig and cat ZP. However, McR5 recognizes a determinant on all species of ZP except the rat, while McPSI does not recognize either the rabbit or rat ZP. Collectively, these studies suggest that the molecules of the pig, dog, and cat ZP are more closely related to each other than to those of the rabbit ZP, while there is little similarity with rat ZP molecules. Immunoblot analysis of ZP glycoproteins separated by two-dimensional polyacrylamide gel electrophoresis was used to identify antigenic relationships among four different species. The polyclonal antisera show that all of the major proteins of pig, rabbit, cat, and dog ZP are antigenically related.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
137.
On the origins of esterases 总被引:8,自引:0,他引:8
Comparisons among the primary sequences of five cloned eukaryotic esterases
reveal two distinct lineages, neither bearing any significant overall
sequence similarity to the functionally related serine protease multigene
family. We have not eliminated the possibility that the esterases may have
residual conformational similarities to the serine proteases. However, our
profile analysis and analyses of the predicted conformations of the
esterases reveal little similarity to the serine proteases. Four of the
esterase proteins share 27%-53% overall sequence similarity and evidence of
a catalytic mechanism involving the same Arg- Asp-Ser or His-Asp-Ser charge
relay. We propose that these four esterases, three of them cholinesterases,
form part of a multigene family essentially separate from the serine
proteases.
相似文献
138.
A unique ovarian follicle cell culture system has been established to analyze the effects of extracellular matrix (ECM) on early granulosa cell differentiation. Primary and early secondary follicles isolated from ovaries of sexually immature rabbits were grown on poly-D-lysine or Englebreth-Holm-Swarm basement membrane biomatrix substrata (EHS) in serum-free, hormonally defined medium. Granulosa cells from these follicles were examined for growth pattern characteristics and for secretory protein synthesis by two-dimensional (2D) PAGE. Whereas some proteins were synthesized by cells on either matrix, the expression of other secreted proteins was markedly affected by the ECM used. Secretion of zona pellucida (ZP) proteins was demonstrated by ELISA assays and immunoblots of one-dimensional (1D) and 2D-PAGE separations of secreted proteins probed with monoclonal and epitope-selected antibodies. Expression of two ZP proteins was altered by ECM: 55-kDa endo-beta-galactosidase (EBGD)-treated ZP glycoprotein (55-kDaEBGD) was secreted by cells grown on either ECM, but a greater amount of 75-kDaEBGD was secreted by cells grown on poly-D-lysine. These studies are the first to show that granulosa cells from early-stage follicles express ZP proteins in vitro in the absence of oocytes, although proper post-translational modification may not occur. They also demonstrate the dramatic effect of ECM on the expression of these and other secretory proteins. 相似文献
139.
HIGH PERFORMANCE TURNING CAPABILITIES DURING FORAGING BY BOTTLENOSE DOLPHINS (TURSIOPS TRUNCATUS) 总被引:1,自引:0,他引:1
Jennifer L. Maresh Frank E. Fish Douglas P. Nowacek Stephanie M. Nowacek Randall S. Wells 《Marine Mammal Science》2004,20(3):498-509
Large predators should have difficulty catching small prey because small animals demonstrate greater maneuverability and agility compared to large animals. The ability of a predator to capture small prey indicates locomotor strategies to compensate for inequities in maneuverability. Bottlenose dolphins ( Tursiops truncatus ) in Sarasota Bay, Florida feed on fish at least one order of magnitude smaller than themselves. To examine the locomotor strategies involved in prey capture, the foraging movements of these dolphins were videotaped from overhead using a remotely-controlled camera suspended from a helium-filled aerostat, which was tethered to an observation vessel. Dolphins were observed to rapidly maneuver during chases of fish in open water or around patches of rooted vegetation. Video analysis of the chase sequences indicated that the dolphins could move the rostrum through small radius turns with a mean value of 0.20 body lengths and with a minimum value of 0.08 body lengths. Mean rate of turn was 561.6°/sec with a maximum rate measured at 1,372.0°/sec. High turning rates with small turning radii were primarily the result of maneuvers in which the dolphin rolled 90° and rapidly flexed its body ventrally. The ability of dolphins to change body orientation in multiple rotational axes provides a mechanism to reduce turning radius and increase turning rate to catch small, elusive prey. 相似文献
140.
Nicholas JG Webster Lui-Guojing Evans Matt Caples Laura Erker Shern L Chew 《BMC molecular biology》2004,5(1):7-15