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1.
Julian I. Schroeder 《The Journal of membrane biology》1989,107(3):229-235
Summary A quantitative analysis of the time and voltage dependence of outward-rectifying K+ currents (
) in guard cells fromVicia faba is described using the whole-cell patch-clamp technique. After step depolarizations from –75 mV to potentials positive to –40 mV, time-dependent outward currents were produced, which have recently been identified as K+ channel currents. This K+ current was characterized according to its time dependence and its steady-state activation.
could be described in terms of a Hodgkin-Huxley type conductance. Activation of the current in time was sigmoid and was well fitted by raising the activation variable to the second power. Deactivating tail currents were single exponentials, which suggests that only one conductance underlies this slow outward K+ current. Rates of channel closing were strongly dependent on the membrane potential, while rates of channel opening showed only limited voltage dependence leading to a highly asymmetric voltage dependence for channel closing and opening. The presented analysis provides a quantitative basis for the understanding of
channel gating and
channel functions in plant cells. 相似文献
2.
Linkage relationships of 19 enzyme loci have been examined. The chromosomal locations of eight of these loci are formally reported for the first time in this paper. These localizations should assist in the construction of additional useful chromosome marker stocks, especially since several of these enzyme loci lie in regions that were previously poorly mapped. Six loci are on the long arm of chromosome 1. The arrangement is (centromere)—Mdh4-mmm-Pgm1-Adh1-Phi-Gdh1, with about 46% recombination between Mdh4 and Gdh1.—Linkage studies with a2 and pr have resulted in the localization of four enzyme genes to chromosome 5 with arrangement Pgm2-Mdh5-Got3-a2-(centromere)-pr-Got2. Pgm2 lies approximately 35 map units distal to a2 in a previously unmapped region of the short arm of 5, beyond ameiotic.—Approximately 23% recombination was observed between Mdh4 and Pgm1 on chromosome 1, while 17% recombination occurred between Mdh5 and Pgm2 on chromosome 5. Similarly, linkages between Idh1 and Mdh1, about 22 map units apart on chromosome 8, and between Mdh2 and Idh2, less than 5 map units apart on chromosome 6, were observed. Thus, segments of chromosomes 1 and 5 and segments of 6 and 8 may represent duplications on nonhomologous chromosomes. 相似文献
3.
Anne-Spence M. Falk Catherine T. Neiswanger Katherine Leigh Field L. Marazita Mary L. Allen F. H. Siervogel Roger M. Roche Alex F. Crandall Barbara F. Sparkes Robert S. 《Human genetics》1984,67(2):183-186
Summary Two data sets are analyzed for linkage between the PTC and Kell blood group loci. The original report of close linkage for these loci was that of Conneally et al. (1976), where the maximum likelihood estimate of was 0.05. These two new data sets give a combined maximum likelihood estimate of
m=f
=0.28. Estimating the recombination frequency for the sexes separately gave
m
=0.29,
f
=0.23. The combined maximum likelihood estimate over all published data sets including this report is
m=f
=0.14,
max=8.94. There is statistically significant evidence of heterogeneity among the published studies. 相似文献
4.
Gregory K. Snyder Wesley W. Weathers 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》1977,117(3):291-301
Summary Resting rates of O2 consumption
against
, exercise endurance times and
during recovery from vigorous exercise were measured inSceloporus occidentalis captured near sea level and inS. graciosus captured above 2850 m. Oxygen consumption against
was also measured inS. occidentalis captured above 2850 m. When
was recorded continuously, as ambient
was slowly reduced from 155 Torr, it became directly dependent upon ambient
between 110 and 120 Torr. The critical
for the high altitude lizards was lower than that for the lowland lizards, which enabled the former to maintain relatively higher
's when ambient
was reduced below 120 Torr. The high altitude lizards also had significantly greater endurance when stimulated to exercise at 1600 m (
130 Torr). Both the higher
under hypoxia and the greater endurance roughly parallel a significantly greater maximum
in the high altitude lizards. At a simulated altitude of 3600 m (
100 Torr), maximum
and rate of recovery of the O2 debt calculated from post active
were significantly reduced in the lowland but not the high altitude lizards. The effects of simulated altitude conditions on the lowland but not the mountaine animals indicate adaptations to altitude in these sceloporine lizards. We did not find any consistent relationship between organ/body weight ratios or hematocrit and our measures of
endurance or the altitude at which the lizards were captured. 相似文献
5.
Multipoint linkage analysis of the short arm of the human X chromosome in families with X-linked muscular dystrophy 总被引:5,自引:0,他引:5
D. E. Wilcox N. A. Affara J. R. W. Yates M. A. Ferguson-Smith P. L. Pearson 《Human genetics》1985,70(4):365-375
Summary Sixteen three generation families from the West of Scotland with Duchenne muscular dystrophy (DMD) or Becker muscular dystrophy (BMD) have been studied using the Xg blood group and seven cloned DNA sequences which recognise DNA polymorphisms on the short arm of the X chromosome (Xp). Linkage has been established between DMD and probe 754 with a maximum lod score () of 4.47 at a recombination fraction (
) of 0.04. DMD has also been linked to probe 99-6 (=3.75,
=0.03). Combining the data in this study with that of previously published work has established linkage between DMD and L1.28 (=4.42,
=0.17) and altered the linkage estimate between BMD and L1.28 (=3.50,
=0.22).An approximate order for the loci has been deduced by the study of recombinant chromosomes in phase known families informative for three or more loci. The proposed order is centromere-L1.28-754-DMD/BMD-99-6-D2-782-Xg. These results conclusively map both DMD and BMD to the central region of Xp and add weight to the original suggestion that they may be allelic. 相似文献
6.
Summary The genetic behaviour of a human serum -lipoprotein factor, called Ag(a1), was studied by agar micro-diffusion technique, utilizing an antibody detected in the serum from a transfused thalassemia patient. It behaves as an inherited, dominant, autosomal character, with complete penetrance at birth. It is controlled by a gene
and is closely linked to the Ag
x
and Ag
y
genes.The existence of a gene Ag
b
, allelic to
, is postulated but the Ag(b) antigen has not so far been detected by specific antisera.The frequency of the
gene in a Milan population was found to be 0,43, and in a Berne population was 0,46. The frequencies of the four possible gene combinations in the sample group from Milan were: Ag
yb
=0,53;
=0,22;
=0,21; Ag
xb
=0,04.The observed frequencies of the factor Ag(a1) were 0,676 and 0,713, respectively among the Milan and Berne populations. 相似文献
7.
8.
Ekkehard Liefke Dieter Kaiser Ulfert Onken 《Applied microbiology and biotechnology》1990,32(6):674-679
Summary Influence of pressure (P) and oxygen partial pressure (
) on cultivation of various Streptomyces spp. and Micromonospora purpurea was examined in pressurized air-lift and stirred tank fermenters. The maximum
was 2100 mbar. Growth and product formation of all cultures tested were markedly influenced by
higher than 1000 mbar. There is evidence that wild strains are more oxygen tolerant than production strains. At a certain
the metabolic activities of all cultures were inhibited. However, results obtained with S. aureofaciens and S. rimosus indicated an increase in specific product formation rate at elevated pressure. With increase in oxygen tension incorporation of oxygen into tetracycline molecules was enhanced. Since elevated oxygen tension can either show inhibiting effects or may be used for regulation of product formation and selectivity, the influence of
should be determined in an appropriate experimental set-up for each process.Offprint requests to: U. Onken 相似文献
9.
An analytical model is developed to describe the performance of a packed-bed immobilized enzyme reactor in which parallel processes take place. In particular, two-substrate reaction, inhibition of the enzyme by one of the reaction products, and binding of one substrate and/or one product to an added ligand are taken into account. In addition, substrates and product diffusion into the porous catalyst are also considered. Using this model, numerical simulations were performed. The results point to the fact that, when all the above processes occur concomitantly, a variety of performance characteristics can be obtained, depending on the particular values of the related parameters. Moreover, under certain conditions, the reactor performance can be improved by controlled addition of ligand.List of Symbols
A
total concentration of ligand
-
C
1,i
concentration of Substrate-1 in the pores of stage i
-
C
2,i
concentration of Substrate-2 in its free form in the pores of stage i
-
2,i
concentration of the Substrate-2-Ligand Complex in the pores of stage i
-
total concentration of Substrate-2 in the pores of stage i
-
i
concentration of the Product-Ligand Complex in the pores of stage i
-
concentration of the free Product in the pores of stage i
-
total concentration of the Product in the pores of stage i
-
internal (pore) diffusion coefficient for the Substrate-Ligand Complex
-
D
1
internal (pore) diffusion coefficient of Substrate-1
-
D
2
internal (pore) diffusion coefficient of Substrate-2
-
effective (pore) diffusion coefficient for Substrate-2
-
internal (pore) diffusion coefficient for the Product
-
internal (pore) diffusion coefficient for the Product-Ligand Complex
-
effective (pore) diffusion coefficient for the Product
-
K
thermodynamic equilibrium constant for binding Substrate-2 to Ligand
-
K
m,1,K
m,2
Michaelis constants for Substrates-1 and 2, respectively
-
effective Michaelis constant for Substrate-2
-
K
p
thermodynamic equilibrium constant for binding the reaction Product to Ligand
-
effective equilibrium constant for binding Substrate-2 to Ligand
-
effective equilibrium constant for binding the reaction Product to Ligand.
-
K
b
inhibition constant
-
K
q
inhibition constant
-
effective inhibition constant
-
effective inhibition constant
-
k
a, k
d
association and dissociation rate constants for Substrate-2 — Ligand complex
-
association and dissociation constants for Product —Ligand complex
-
n
total number of elementary stages in the reactor
-
Q
volumetric flow rate throughout the reactor
-
R
j,i
reaction rate of Substrate-j in stage i, in terms of volumetric units
-
S
1,0
concentration of Substrate-1 in the reactor feed
-
total concentration of Substrate-2 in the reactor feed
-
S
1,i–1,S
1,i
concentration of Substrate-1 in the bulk phase leaving stages i–1 and i, respectively
-
S
2,i
concentration of Substrate-2 in its free form, in the bulk phase leaving stage i
-
2,i–1,
2,i
concentration of Substrate-2 in the bulk phase leaving stage i–1 and i, respectively
-
total concentration of Substrate-2 in the bulk phase leaving stages i–1 and i, respectively
-
i
concentration of the Product-Ligand Complex in the bulk phase of stage i
-
concentration of free Product in the bulk phase of stage i
-
total concentration of Product in the bulk phase of stage i
-
V
total volume of the reactor
-
V
m
maximal reaction rate in terms of volumetric units
-
y
axial coordinate of the pores
-
y
0
depth of the pores
Greek Symbols
1
dimensionless parameter
-
dimensionless parameter
-
dimensionless parameter
-
1
dimensionless parameter
-
dimensionless parameter
-
1,i
dimensionless concentration of Substrate-1 in pores of stage i
-
dimensionless total concentration of Substrate-2 (in both free and bound form) in pores of stage i
-
dimensionless total concentration of the reaction product in the pores of stage i
-
1
dimensionless parameter
-
dimensionless parameter
-
dimensionless parameter
-
dimensionless parameter
-
dimensionless parameter
-
dimensionless position along the pore
-
volumetric packing density of catalytic particles (dimensionless)
-
porosity of the catalytic particles (dimensionless)
-
1,i
dimensionless concentration of Substrate-1 in the bulk phase of stage i
-
dimensionless total concentration of Substrate-2 (in both free and bound form) in the bulk phase of stage i 相似文献
10.
Lawrence A. Baker Dr. Wesley W. Weathers Fred N. White 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》1972,80(3):312-323
Summary The influence of local temperature changes within the posterior portion of the body on dorsal aorta blood flow (
), femoral arterial pressure (P
a
), peripheral resistance (R), skin blood flow (
) and skeletal muscle blood flow (
) was examined in unanesthetized lizards (Iguana iguana andTubinambis nigropunctatus). In response to local heating of the hind legs and tail
and
increased,P
a
was generally unchanged,R decreased and
decreased or was unchanged (Fig. 2). It is suggested that the acquisition of heat may be favored by diverting the increase in
away from the muscle to the warmer skin. In response to cooling
and
decreased,P
a
was generally unchanged, R increased and
increased or was unchanged. Hence, during cooling the retention of heat may be favored by diverting blood away from the skin to the deeper muscle. The muscle-skin shunt is under sympathetic control since following blockade with phenoxybenzamine HCL (Dibenzyline) muscle blood flow changes in response to temperature were qualitatively similar to those of skin (Fig. 4). These changes in peripheral circulatory patterns are independent of changes in heart rate or deep body temperature.Baker and Weathers were predoctoral and postdoctoral trainees, respectively, under USPHS Grant HE-05696. This study was also supported by NSF Grant GB-8523 and Los Angeles County Heart Association Grant 437IG. 相似文献
11.
Aerobic and anaerobic contribution to Wingate test performance in sprint and middle-distance runners
P. Granier B. Mercier J. Mercier F. Anselme C. Préfaut 《European journal of applied physiology and occupational physiology》1995,70(1):58-65
We investigated the aerobic and anaerobic contributions to performance during the Wingate test in sprint and middle-distance runners and whether they were related to the peak aerobic and anaerobic performances determined by two commonly used tests: the force-velocity test and an incremental aerobic exercise test. A group of 14 male competitive runners participated: 7 sprinters, aged 20.7 (SEM 1.3) years, competing in 50, 100 and 200-m events and 7 middle-distance runners, aged 20.0 (SEM 1.0) years, competing in 800, 1,000 and 1,500 m-events. The oxygen uptake (
) was recorded breath-by-breath during the test (30 s) and during the first 20 s of recovery. Blood samples for venous plasma lactate concentrations were drawn at rest before the start of the test and during the 20-min recovery period. During the Wingate test mean power (
) was determined and three values of mechanical efficiency, one individual and two arbitrary, 16% and 25%, were used to calculate the contributions of work by aerobic (
aer,ind,16%,25%) and anaerobic (
an,ind,16%,25%) processes. Peak anaerobic power (
an,peak) was estimated by the force-velocity test and maximal aerobic energy expenditure (
aer,peak) was determined during an incremental aerobic exercise test. During the Wingate test, the middle-distance runners had a significantly greater
than the sprinters (P < 0.001), who had significantly greater venous plasma lactate concentrations (P < 0.001). Moreover,
aer,ind,16%,25% were also significantly higher (P < 0.05) in the middle-distance runners [
aer,ind 45 (SEM 4) % vs 28 (SEM 2) %;
aer,16% 30 (SEM 3) % vs 19 (SEM 2) %;
aer,25% 46 (SEM 3) % vs 29 (SEM 2)%];
an,ind,16%,25% in the sprint runners (P < 0.05) [
an,ind 72 (SEM 3) % vs 55 (SEM 4) %;
an,16% 81 (SEM 2) % vs 70 (SEM 3) %;
an,25% 71 (SEM 2) % vs 54 (SEM 3) %]. The
aer,ind/
aer,peak and
×
an,ind/
an,peak ratios, however, were not significantly different between the two groups of athletes. These results would indicate that the sprinters and middle-distance runners used preferentially a metabolic system according to their speciality. Nevertheless, under the conditions of its experiment, they seemed to rely on the same percentage of both peak anaerobic and peak aerobic performance for a given exercise task. 相似文献
12.
Stephen C. Wood Kjell Johansen Mogens L. Glass G. M. O. Maloiy 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》1978,127(4):331-336
Summary Oxygen consumption
was measured at rest and during spontaneous activity at body temperatures of 25 and 35°C in 14 fasting Savanna monitor lizards,Varanus exanthematicus ranging in weight from 172 to 7500 g. The allometric relationship between metabolic rate at 25°C and body weight (W) is given by:
(ml O2 STPD·g–1·hr–1)=0.88W
–0.43 (Fig. 2). Although statistical comparisons are equivocal, this intraspecific size dependence exceeds that reported for interspecific comparisons among reptiles and other vertebrate groups (Fig 3). A reproducible diurnal pattern of activity was observed in undisturbed animals with minimum values of
between 2400 and 0800 h (Fig. 1). Spontaneous activity and
generally reached peak values between 1200 and 2000 hrs. The average ratio of active aerobic metabolic rate (AMR) to minimum (standard) aerobic metabolic rate (SMR) was 8.2. This voluntary AMR/SMR inVaranus exceeds the AMR/SMR for most reptiles stimulated to exhaustion. The high aerobic capacity is consistent with other evidence for efficient exchange and transport of respiratory gases inV. exanthematicus; e.g., low or absent intracardiac shunt flow resulting in high arterial saturation and low ventilation
and perfusion
requirements. 相似文献
13.
Effects of ambient temperature and altitude on ventilation and gas exchange in deer mice (Peromyscus maniculatus) 总被引:2,自引:1,他引:1
Mark A. Chappell 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》1985,155(6):751-758
Summary The effects of different ambient temperatures (T
a) on gas exchange and ventilation in deer mice (Peromyscus maniculatus) were determined after acclimation to low and high altitude (340 and 3,800 m).At both low and high altitude, oxygen consumption (
) decreased with increasingT
a atT
a from –10 to 30 °C. The
was 15–20% smaller at high altitude than at low altitude atT
a below 30 °C.Increased
atT
a below thermoneutrality was supported by increased minute volume (
) at both low and high altitude. At mostT
a, the change in
was primarily a function of changing respiration frequency (f); relatively little change occurred in tidal volume (V
T) or oxygen extraction efficiency (O2EE). AtT
a=0 °C and below at high altitude,
was constant due to decliningV
T and O2EE increased in order to maintain high
.At high altitude,
(BTP) was 30–40% higher at a givenT
a than at low altitude, except atT
a below 10 °C. The increased
at high altitude was due primarily to a proportional increase inf, which attained mean values of 450–500 breaths/min atT
a below 0 °C. The
(STP) was equivalent at high and low altitude atT
a of 10 °C and above. At lowerT
a,
(STPD) was larger at low altitude.At both altitudes, respiratory heat loss was a small fraction (<10%) of metabolic heat production, except at highT
a (20–30 °C).Abbreviations
EHL
evaporative heat loss
-
f
respiration frequency
-
HL
a
heat loss from warming tidal air
-
HL
e
evaporative heat loss in tidal air
-
HL
total respiratory heat loss
-
MHP
metabolic heat production
-
O
2
EE
oxygen extraction efficiency
-
RQ
respiratory quotient
-
T
a
ambient temperature
-
T
b
body temperatureT
lc lower critical temperature
-
carbon dioxide production
-
evaporative water loss
-
oxygen consumption
-
minute volume
-
V
T
tidal volume 相似文献
14.
Hisako Sakiyama Noriyuki Inaba Toru Toyoguchi Yasunori Okada Misako Matsumoto Hideshige Moriya Hiroshi Ohtsu 《Cell and tissue research》1994,277(2):239-245
The first component of complement
has been shown to degrade type I and type II collagens (Yamaguchi et al. 1990), the latter of which is a major constituent of the cartilage matrix. In order to understand the physiological roles of
in cartilage resorption, the expression of C1s was examined by immunohistochemistry in the primary ossification center where the matrix is removed and replaced by bone marrow. Hypertrophic chondrocytes, endothelium and hematogenous elements in the capillary buds were intensely stained by a monoclonal antibody against C1s. Matrix metalloproteinase 9 (MMP-9, 92kDa gelatinase/type IV collagenase) was also immunolocalized in hypertrophic chondrocytes, mesenchymal cells in the primitive bone marrow and the cartilage matrix adjacent to the marrow. In addition,
was found to activate the zymogen of MMP-9. These observations suggest that
and MMP-9 coordinately participate in matrix degradation in cartilage.Abbreviations
MMP
Matrix metalloproteinase
-
APMA
4-aminophenylmercuric acetate
-
DFP
diisopropyl fluorophosphate, HE hematoxylin and eosin
-
C1s
inactive C1s
-
activated C1s 相似文献
15.
Jack P. Hayes 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》1989,159(4):453-459
Summary I compared the maximal aerobic metabolic rates (
), field metabolic rates (FMR), aerobic reserves (
-FMR), and basal metabolic rates (BMR) of wild and recently captured deer mice from low (440 m) and high (3800 m) altitudes. To separate the effects of the thermal environment from other altitudinal effects, I examined mice from different altitudes, but similar thermal environments (i.e., summer mice from high altitude and winter mice from low altitude). When the thermal environment was similar,
, FMR, and aerobic reserve of low and high altitude mice did not differ, but BMR was significantly higher at high altitude. Thus, in the absence of thermal differences, altitude had only minor effects on the aerobic metabolism of wild or recently captured deer mice.At low altitude, there was significant seasonal variation in
, FMR, and aerobic reserve, but not BMR. BMR was correlated with
, but not with FMR. The significant positive correlation of BMR with
indicates a cost of high
, because higher BMR increases food requirements and energy use during periods of thermoneutral conditions.Abbreviations
BMR
basal metabolic rate
-
FMR
field metabolic rate
-
partial pressure of oxygen
-
T
a
ambient temperature
-
T
b
body temperature
-
T
e
operative temperature
-
maximal aerobic metabolic rate 相似文献
16.
Gustave Savourey Jacques Bittel 《European journal of applied physiology and occupational physiology》1994,69(3):216-220
The aim of this study was to evaluate the thermoregulatory changes induced by 27-h of sleep deprivation (SD) in men at rest both in a comfortable ambient temperature and in cold air. A group of 12 male subjects were placed in a comfortable ambient temperature (dry bulb temperature,T
db = 25° C, relative humidity, rh = 40%–50% , clothing insulation = 1 clo) for 1 h and then they were submitted to a standard cold air test in a climatic chamber for 2h (T
db=1° C, rh = 40%–50%, wind speed = 0.8 m·s–1, nude), before and after 27 h of sleep deprivation. Thermoregulatory changes (rectal temperature,T
re; mean skin temperature,
sk; metabolic heat production
) were monitored continuously. At comfortable ambient temperature, no significant change was observed after SD forT
re,
sk and
. During the cold test,T
re did not change but
sk and
were higher after SD (P<0.05). Increased
(+ 6%,P < 0.05) was related to earlier and higher shivering, with a possible increase in the sensitivity of the thermoregulatory system as shown by the shorter time to onset of continous shivering (d): 8.66 (SEM 1.33) min versus 28.20 (SEM 1.33) min (P < 0.001) and by a higher
sk observed at d: 27.60 (SEM 1.40)° C versus 21.40 (SEM 0.60)° C (P < 0.001). These results were associated with higher cold sensations and shivering following SD. They also suggested that SD modified thermoregulatory responses at a central level especially in a cold environment. 相似文献
17.
Lars Bo Andersen Jóhanna Haraldsdóttir 《European journal of applied physiology and occupational physiology》1993,67(4):315-320
In a randomly selected sample of 88 men and 115 women, aged 23–27 years from Denmark, maximal oxygen uptake (
O2max), maximal voluntary isometric contraction (MVC) in four muscle groups and physical activity were studied. The
O2max was 48.0 ml · min–1 kg–1 and 39.6 ml · min–1 · kg–1 for the men and the women, respectively. The MVC was 10% lower than in a comparable group of Danes of the same age and height studied 35 years ago. Only in men was sports activity directly related to
O2max (ml · min–1 · kg–1; r=0.31, P<0.01). The MVC of the knee extensors was related to
O2max in the men (r=0.31, P<0.01), but there was no relationship between the other measurements of MVC and
O2max. In the women
O2max (ml · min–1 · kg–1) was only related to body size, i.e. body mass index, percentage body fat and body mass [(r= –0.47, –0.48 (both P<0.001) and –0.34. (P<0.01), respectively)]. There were differences in
O2max in the men, according to education and occupation. Blue collar workers and subjects attending vocational or trade schools in 1983 had lower
O2max and more of them were physically inactive. In the women differences were also found, but there was no clear pattern among the groups. More of the women participated regularly in sports activity, but more of the men were very active compared to the women. 相似文献
18.
K?re B. Hagen Karin Harms-Ringdahl Jostein Hallén 《European journal of applied physiology and occupational physiology》1994,68(6):477-482
Oxygen consumption (
O2), heart rate, ventilation and central rating of perceived exertion (RPE) in repetitive lifting while executing squat and stoop techniques were investigated in ten male forestry workers. In all five mass/frequency combinations studied,
O2 was significantly higher for the squat than for the stoop technique. No differences were found in RPE between the techniques. The
O2 and RPE recordings were also related to those obtained during maximal repetitive lifting (same lifting technique) and maximal treadmill running. The
O2 expressed as a percentage of that obtained during maximal repetitive lifting with the same lifting technique was defined as relative aerobic intensity (%
O2max, lifting). The %
O2max, lifting was not significantly different between the techniques except for the lowest mass lifted (1 kg). This study therefore would support the hypothesis that RPE is more closely related to %
O2max, lifting than to absolute aerobic intensity. Related to maximal treadmill running, it was demonstrated for both lifting techniques that relative RPE (percentage of the RPE during maximal running) was more accurate than relative
O2 (percentage of maximal
O2 during maximal running) for determining the %
O2max, lifting in repetitive lifting. The study showed that the higher
O2 during squat. lifting compared to stoop lifting was caused by the
O2 expended in lifting and lowering the body rather than the
O2 expended lifting and lowering the external mass. It was concluded that the stoop technique was not superior to the squat technique in terms of central RPE. Based on %
O2max, lifting, there may be a rationale for choosing the stoop technique during repetitive lifting with light masses, but not with heavy masses. 相似文献
19.
The effect of short-term fasting and a single meal on protein synthesis and oxygen consumption in cod,Gadus morhua 总被引:2,自引:0,他引:2
A. R. Lyndon D. F. Houlihan S. J. Hall 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》1992,162(3):209-215
Summary Rates of protein synthesis and oxygen consumption (
O2) in cod were compared in both fasted and refed animals. During a 14-day fast both protein synthesis and respiration rates fell to stable values after 6 days. When a meal of whole sandeel at 6% body weight was fed to fish fasted for 6 days, protein synthesis and (
O2) increased to a maximum at between 12 and 18 h after feeding. Peak (
O2) was about twice the pre-feeding values, while whole animal protein synthesis increased four-fold. There were differences between tissues in the timing of maximum protein synthesis; the liver and stomach responded faster than the remainder of the body. Maximum protein synthesis rates in the liver and stomach occurred at 6 h after feeding, at which time their calculated contribution to total (
O2) was 11%. Similar calculations suggested that the integrated increment in whole animal protein synthesis contributed between 23% and 44% of the post-prandial increase in (
O2). It was concluded that protein synthesis is an important contributor to increased (
O2) after feeding in cod.Abbreviations
A
s
absolute rate of protein synthesis
- ASDA
apparent specific dynamic action
- ATP
adenosine triphosphate
-
k
s
fractional rate of protein synthesis
-
k
s/RNA
amount of protein synthesized per unit RNA
- (
O2)
oxygen consumption
- PCA
perchloric acid
- RNA
ribonucleic acid 相似文献
20.
W. Selvamurthy U. S. Ray K. S. Hegde R. P. Sharma 《International journal of biometeorology》1988,32(3):188-193
A study was conducted on 30 healthy soldiers (age: 40–46 years) to assess the effect of selected yogic exercises (asanas) on some physiological responses to cold exposure. They were randomly divided into two groups of 15 each. One group performed regular physical exercises of physical training (PT), while the other group practised yogic exercises. At the end of 6 months of training, both the groups were exposed together to cold stress at 10°C for 2 h, and the following parameters were periodically monitored during cold exposure: heart rate (fH), blood pressure (BP), cardiac output
, oral temperature (Tor), skin temperature (T
sk), respiratory rate (fR), minute ventilation
, oxygen consumption
, and shivering response by integrated electromyogram (EMG). There were progressive increases inBP, fR,
,
, and
and decreases infH,T
or andT
sk during cold exposure in both the groups. However, the decrease inT
or and the increases in
and
were relatively lower (P<0.01) in the yoga group as compared to the PT group. The shivering response appeared much earlier and was more intense in the PT group. These findings suggest that practice of yoga exercises may improve cold tolerance. 相似文献