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971.
Three experiments were performed to study the influence of challenging incentives on feedback-assisted heart rate reduction for coronary-prone (Type A) and non-coronary-prone (Type B) males. In the first experiment, when subjects were given a competitive instructional set, Type As were significantly more successful relative to Type Bs in reducing their heart rate; with a noncompetitive set, Type Bs were significantly more successful than were Type As. In the second experiment, when told that heart rate reduction was a scarce ability, Type As reduced heart rate significantly better than did Type Bs; when told that heart rate reduction was a common ability, Type Bs achieved significantly greater heart rate reduction than did Type As. In the third experiment, when heart rate reduction was described as being instrumental to time-urgency (i.e., getting more done in less time), Type As reduced heart rate significantly bettern than did Type Bs; when heart rate reduction was described as being instrumental to relaxation, Type Bs were significantly better able to reduce heart rate. In all three studies, the incentives had no effect on heart rate when feedback was not provided. The results are discussed as support for the notion that Type A behavioral pattern characteristics can be exploited to reduce Type A symptoms. Implications for how coronary-prone individuals may be challenged to modify symptoms within the clinical setting are discussed. 相似文献
972.
973.
Previous studies by us and others established that cell-cell adhesion is mediated by specific carbohydrate-to-carbohydrate
interaction (CCI). Those previous studies were based on various biochemical and biophysical approaches, including the use
of labeled glycosyl epitopes with fluorescent tag. However, these methods ideally require that the glycosyl epitope must be
fixed to a solid phase molecule, preferably with multivalency. The purpose of the present study is to establish a CCI process
using specific glycosyl residues conjugated to biotinylated diaminopyridine (BAP), and to observe: (i) clear occurrence of
homotypic CCI between “Os Fr.B” having 5–6 GlcNAc termini, vs. absence of such homotypic CCI between “Os Fr.1” having 2 GlcNAc termini; (ii) occurrence of heterotypic CCI between GM3
ganglioside and Os Fr.B, vs. absence of such heterotypic CCI between GM3 and Os Fr.1. Interaction between Os Fr.B-BAP conjugate and Os Fr.B-ceramide
mimetic (Os Fr.B-mCer) was demonstrated based on two experiments: (i) dose-dependent binding of Os Fr.B-BAP conjugate to polystyrene
plates coated with Os Fr.B-mCer was observed in the presence of bivalent cation, a prerequisite for all CCI processes, and
such binding was abolished by EDTA; (ii) binding between equal nanomolar Os Fr.B-BAP and Os Fr.B-mCer was inhibited by mM
concentration Os Fr.B without conjugate, in dose-dependent manner. Thus, cell adhesion processes based on homotypic CCI between
N-linked glycans having multiple GlcNAc termini, and heterotypic CCI between GM3 and such glycans, were clearly observed using
BAP conjugates of glycosyl epitopes. 相似文献
974.
L Levine M N Sawka B E Joyce B S Cadarette K B Pandolf 《European journal of applied physiology and occupational physiology》1984,53(1):12-16
Comparisons of physiological responses to 0, 0.5, 1, and 2 mg atropine (IM) were made in seven males (X +/- SD: age, 24 +/- 3 years; ht, 174 +/- 12 cm; wt, 76 +/- 3 kg) while they exercised (approximately 390 W) in a hot-dry (40 degrees C, 20% rh) environment. Responses to 4 mg, as well as repeatability of responses to 2 mg, were studied in two and six of these subjects, respectively. On 8 test days an intramuscular injection of atropine or saline control was administered 20 min before subjects walked on a treadmill for two 50-min bouts. Heart rate (HR) during exercise did not change in the control trial but by min 50 increased during all atropine trials (P less than 0.01). Rectal temperature (Tre) increased (P less than 0.01) in all trials by min 50 and continued increasing (P less than 0.01) in the 2-mg trial during the second exercise bout. For the two subjects tested with all dosages (0.5 - 4 mg atropine), the change in HR and Tre between the atropine and control trials at 50 min of exercise was regressed against the various atropine dosages. The relationship (r = 0.92) for HR was curvilinear while the relationship (r = 0.99) for Tre was linear. Mean weighted skin temperature (Tsk) was relatively constant during exercise and was warmer (P less than 0.05) with increasing atropine dosage. In a repeat 2 mg trial, HR was 6 bt . min-1 lower (P less than 0.05) on the second exposure but Tre was the same (P greater than 0.05) on both days. For subjects walking in the heat, three new observations were: 1) 0.5 mg of atropine resulted in increased HR and Tsk compared to control values; 2) HR was elevated but the magnitude of change decreased with increasing dosage, while the elevation in Tre was consistent with increasing dosage; and 3) rectal temperatures (in trials with and without atropine) were unaffected by previous days of atropine administration. 相似文献
975.
Background
Many molecules are flexible and undergo significant shape deformation as part of their function, and yet most existing molecular shape comparison (MSC) methods treat them as rigid bodies, which may lead to incorrect shape recognition. 相似文献976.
N Bonaventure B Jardon 《Comptes rendus de l'Académie des sciences. Série III, Sciences de la vie》1992,315(6):241-246
The systemic administration of atropine, a muscarinic cholinergic antagonist, was found to suppress the Nasal-Temporal (N-T) component of the frog monocular optokinetic nystagmus (OKN), which had appeared following a prior injection of bicuculline and which does not exist in the normal animal. On the contrary, the administration of a nicotinic cholinergic antagonist (D-TC, alpha-BGT, Hexamethonium) following that of bicuculline has prolonged the duration of the induced N-T component. Thus, ACh was shown to attenuate or to reinforce the GABAergic inhibition of the N-T component through muscarinic receptors or nicotinic receptors respectively. These data point to the existence of strong interactions between these two neurotransmission systems involved in frog monocular OKN. 相似文献
977.
Selective proteolysis of ovine lutropin or its beta subunit by endoproteinase Arg-C. Properties of the Arg beta 43 cleaved hormone 总被引:2,自引:0,他引:2
Ovine lutropin (oLH) and its beta subunit (oLH beta) were nicked by short-term incubations with endoproteinase Arg-C. Isolated oLH beta was rapidly nicked and converted from an Mr 18,000 band on sodium dodecyl sulfate-polyacrylamide gels to an Mr 13,000 band. Partial nicking of only the beta subunit in intact oLH was also observed as indicated by the appearance of small amounts of the Mr 13,000 band detected in Arg-C-treated oLH samples. The alpha subunit was protected by association with the beta subunit, but free alpha subunit was rapidly degraded. Sequence analysis of nicked oLH beta indicated that one of the peptide bonds on either side of Arg43 was cleaved by the protease, with a slight preference for the amino side of this residue. Nicked oLH beta was reassociated with oLH alpha, and the resulting dimer was separated from unrecombined subunits. The biologic activity of nicked oLH beta + oLH alpha in an LH radioligand assay was only 2% that of intact oLH. 相似文献
978.
The ability of a purified rat liver microsomal uridine-5'-diphosphoglucuronosyltransferase to catalyze the glucuronidation of stereoisomeric trans- and cis-9, 10-dihydroxy-9, 10-dihydrophenanthrenes and 4, 5-dihydroxy-4,5-dihydrobenzo[alpha]pyrenes is examined. The enzyme shows the ability to discriminate kinetically between the antipodes of trans-9, 10-dihydroxy-9, 10-dihydrophenanthrene with turnover numbers of 0.070 and 1.4 s-1 and kc/Kmapp values of 4.4 X 10(3) and 1.1 X 10(3) M-1 s-1 for the 9R, 10R and 9S, 10S stereoisomers. Glucuronidation of the nondissymmetric cis-9, 10-dihydroxy-9, 10-dihydrophenanthrene proceeds with a turnover number of 0.037 s-1 and kc/Kmapp of 18 X 10(3) M-1 s-1 to give a 60/40 mixture of the two possible diastereomeric products. Three of the four stereoisomers of 4,5-dihydroxy-4,5-dihydrobenzo[alpha] pyrene are regioselectively glucuronidated by the enzyme with a high degree of kinetic discrimination. Turnover numbers for the 4S,5S, 4R,5R, and 4S,5R stereoisomers are 4.1, 0.37, and 0.23 s-1 with kc/Kmapp values of 23.8 X 10(3), 0.23 X 10(3), and 3.15 X 10(3) M-1 s-1, respectively. The 4R,5S cis isomer is not a substrate. Enzyme-catalyzed reactions of the 4S,5S and 4S,5R isomers give exclusively (greater than or equal to 95%) the 4-glucuronide with the 4R,5R isomer giving the 5-glucuronide. The kinetic and regiochemical results indicate that the enzyme recognizes hydroxyl groups on the beta-face or bottom face of the 4,5-dihydroxy-4,5-dihydrobenzo[alpha]pyrenes.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
979.
Marion S. Ecob Gillian S. Butler-Browne Robert G. Whalen 《Differentiation; research in biological diversity》1984,25(1-3):84-87
Abstract. Organotypic nerve-muscle cultures were prepared from foetal mouse spinal cord and adult mouse muscle fibres. In this system, the adult fibres degenerate and new myotubes form. The regenerated muscle fibres become innervated, develop cross-striations, and survive for several months. We have investigated the isozymes of myosin present in these muscle fibres using histochemistry and immunocytochemistry with antibodies to rat embryonic, neonatal, and adult fast myosins. We demonstrate that some of the regenerated fibres contain adult fast but not embryonic or neonatal myosin. This is the first demonstration of the production of adult myosin heavy chain in tissue culture. This system therefore offers the possibility for further study of the development of adult myosin isoforms in vitro. 相似文献
980.
Gillian D Alton David L Pearl Ken G Bateman W Bruce McNab Olaf Berke 《BMC veterinary research》2010,6(1):42