The role of work period duration as the principal factor influencing carbohydrate metabolism during intermittent exercise has been investigated. Fuel oxidation rates and muscle glycogen and free carnitine content were compared between two protocols of sustained intermittent intense exercise with identical treadmill speed and total work duration. In the first experiment subjects (n=6) completed 40 min of intermittent treadmill running involving a work : recovery cycle of 6 : 9 s or 24 : 36 s on separate days. With 24 : 36 s exercise a higher rate of carbohydrate oxidation approached significance (P=0.057), whilst fat oxidation rate was lower (P ≤ 0.01) and plasma lactate concentration higher (P ≤ 0.01). Muscle glycogen was lower post‐exercise with 24 : 36 s (P ≤ 0.05). Muscle free carnitine decreased (P ≤ 0.05), but there was no difference between protocols. In the second experiment a separate group of subjects (n=5) repeated the intermittent exercise protocols with the addition of a 10‐min bout of intense exercise, followed by 43 ± 5 min passive recovery, prior to sustained (40 min) intermittent exercise. For this experiment the difference in fuel use observed previously between 6 : 9 s and 24 : 36 s was abolished. Carbohydrate and fat oxidation, plasma lactate and muscle glycogen levels were similar in 6 : 9 s and 24 : 36 s. When compared with the first experiment, this result was because of reduced carbohydrate oxidation in 24 : 36 s (P ≤ 0.05). There was no difference, and no change, in muscle free carnitine between protocols. A 10‐min bout of intense exercise, followed by 43 ± 5 min of passive recovery, substantially modifies fuel use during subsequent intermittent intense exercise. 相似文献
A subgenomic (SG) RNA ( approximately 800 nucleotides) is a minor component of barley stripe mosaic virus RNAs. The SG-RNAs isolated from the Type and North Dakota 18 (ND18) strains of BSMV have sequence homology with RNA 2 of the ("pseudo-two component") Type strain, which has two electrophoretic components, but only limited homology is evident with RNA 2 of the ND18 and Norwich strains, which have three electrophoretic components ("three component" strain). Instead, eDNAs from SG-RNA hybridize most efficiently with RNA 3 of the ND18 and Norwich strains. In wheat germ extracts the SG-RNAs direct the synthesis of two polypeptides with apparent molecular weights of 20 to 21 x 10(3). However, these two polypeptides were difficult to detect by polyacrylamide gel electrophoresis of extracts from Type- or ND18-infected barley and so appear not to accumulate during infection. 相似文献
In-vitro fertilization patients (n = 15) at risk of ovarian
hyperstimulation syndrome (OHSS) (oestradiol > or =4500 pg/ml on the day
of human chorionic gonadotrophin administration and 25 or more follicles of
intermediate or large size) underwent aspiration of all follicles and
cryopreservation of all fertilized oocytes at the pronuclear stage.
Patients were monitored for up to 2 weeks post- retrieval. Subsequent
transfer of cryopreserved-thawed embryos was performed in programmed cycles
using exogenous oestrogen and progesterone for endometrial preparation. Two
patients (13%) developed OHSS necessitating hospitalization and vaginal
aspiration of ascitic fluid. Two other patients (13%) developed moderate
OHSS requiring ascitic fluid vaginal aspiration in the office setting, with
dramatic improvement of the condition. Subsequent transfer of
cryopreserved- thawed embryos yielded a clinical pregnancy rate of 58% per
transfer and ongoing or delivery rates of 42 and 67% per transfer and per
patient respectively. By eliminating pregnancy potential with
cryopreservation of all prezygotes and examining the pregnancy potential
with subsequent cryopreserved-thawed transfers, it is concluded that OHSS
is reduced, but not eliminated for patients at risk. Subsequent transfer of
cryopreserved-thawed prezygotes in a programmed cycle with exogenous
steroids yields an excellent pregnancy rate.
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The aim of this study was to compare the efficacy of pure follicle
stimulating hormone (FSH) with that of FSH/human menopausal gonadotrophin
(HMG) combination in downregulated cycles. A total of 357 patients was
evaluated retrospectively. Sixty percent of patients in the FSH group and
55% in the FSH/HMG group were new; the others were repeat patients.
Ovulation was suppressed with leuprolide acetate in all patients, followed
by either FSH (n = 218) or FSH/HMG (n = 119). There was no difference in
patients' age, infertility factors, number of ampoules used, length of
stimulation, oestradiol levels on day of human chorionic gonadotrophin
(HCG) administration, number of oocytes recovered or the number of embryos
transferred. Also, nuclear maturity at aspiration and fertilization rates
were not different between the two groups. FSH stimulation resulted in a
significantly higher percentage of mature oocytes that showed the typical
'mature' morphological characteristics (P < 0.0001). The clinical
pregnancy rates per transfer were 40 and 28% in patients stimulated with
pure FSH and FSH/HMG respectively (P < 0.05). The significantly higher
number of immature oocytes matured in vitro in the FSH/HMG group (P =
0.001) suggests a possible effect on in-vitro maturation, due to
luteinizing hormone present in HMG. The difference in mature oocyte quality
may be an important determinant in the higher pregnancy rates for the FSH-
stimulated patients.
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A systematic comparison of the effect of architectural modifications to the network structure on the internal microstructure of N‐isopropylacrylamide (NIPA) based hydrogels showed that the addition of a second component to the network significantly increased the proportion of macropores in the network. The second components considered were short poly(N‐isopropylacrylamide) (PNIPAM) chains grafted to the network backbone, high‐molecular‐weight polyacrylamide (PAM) chains, or microsphere particles of PNIPAM. Structures are proposed for each of the modified gel networks taking into account the new structural information. Through a combination of the pore size and network structure data reported here, and with the shrinking data obtained previously, shrinking mechanisms are proposed for each of the modified network structures. In all cases, the enhanced shrinking rates were directly caused by the presence of the second component, which acted as nuclei for shrinking (graft‐PNIPAM and PNIPAM microspheres) or as water‐release channels (PAM gel), and indirectly caused by the second components via their affect on the network microstructure.
Proposed structures for the architecturally modified gels based on the pore‐size information. Graft‐PNIPAM gel. The freely mobile graft chains prevent chains from meeting resulting in larger pores. 相似文献
Components of the fibrinolytic enzyme system, FR-antigen and fibrinogen, were measured in 20 healthy volunteers aged 20-40 years and in 61 elderly subjects aged 66-96 years. Plasminogen activator levels did not significantly differ between the 20-40 and 66-75 age groups, but were higher in those over 75. Plasminogen showed no change with age except for a fall in those over 75. Fibrinogen, FR-antigen, alpha(1)-antitrypsin, and alpha(2)-macroglobulin all rose with age, but the mean fibrinogen concentration fell in the very elderly. 相似文献
This study of 75 college student subjects investigated the psychophysiological correlates of electrodermal lability. Resting-stabile and resting-labile subjects were defined as those who were respectively below and above the median of all same-sex subjects in frequency of nonspecific skin conductance responses during rest, whereas stimulus-stabile and stimulus-labile subjects were those respectively below and above the median in trials to habituation of the skin conductance orienting response. These two classification systems were found to be highly correlated with one another, but not entirely equivalent. With both lability measures, labiles had higher resting skin conductance levels than stabiles and also exhibited larger skin conductance orienting responses to both signal and nonsignal tones. Labiles produced orienting responses with shorter latencies, rise times, and half recovery-times. Resting-labiles also differed from resting-stabiles in the components of the triphasic heart rate response to the tones, having larger decelerative responses. The data are consistent with the view that labiles are better able than stabiles to allocate attentional capacity to environmental events and to respond to changing demands in an attentional situation. 相似文献
The cardiovascular response to exercise with several groups of skeletal muscle implies that work with the legs may reduce arm blood flow. This study followed arm blood flow ( arm) and oxygenation on the transition from arm cranking (A) to combined arm and leg exercise (A+L). Seven healthy male subjects performed A at ∼80 % of maximum work rate ( W max) and A at ∼80 % W max combined with L at ∼60 % W max. A transition trial to volitional exhaustion was performed where L was added after 2 min of A. The arm was determined by constant infusion thermodilution in the axillary vein and changes in biceps muscle oxygenation were measured with near-infrared spectroscopy. During A+L arm was lowered by 0.38 ± 0.06 l min−1 (10.4 ± 3.3 %, P < 0.05 ) from 2.96 ± 1.54 l min−1 during A. Total (HbT) and oxygenated haemoglobin (HbO2) concentrations were also lower. During the transition from A to A+L arm decreased by 0.22 ± 0.03 l min−1 (7.9 ± 1.8 %, P < 0.05 ) within 9.6 ± 0.2 s, while HbT and HbO2 decreased similarly within 30 ± 2 s. At the same time mean arterial pressure and arm vascular conductance also decreased. The data demonstrate reduction in blood flow to active skeletal muscle during maximal whole body exercise to a degree that arm oxygen uptake and muscle tissue oxygenation are compromised. 相似文献
Naive T cells after allogeneic hematopoietic cell transplantation are thought to originate from the engrafted hematopoietic cells. In this report, we show that there is a correlation between the number of naive CD4 T cells infused with peripheral blood stem cell grafts and the absolute number of peripheral naive CD4 T cells on day 30 (R = 0.65; P <.001), day 80 (R = 0.63; P <.001), and day 180 (R = 0.66; P <.001) after transplantation. These results suggest that in the first 6 months after transplantation, most naive CD4 T cells are derived from the naive T cells infused with the graft. 相似文献