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It is well known that the number of follicles in the mammalian ovary decreases with age. In light of previous data from this laboratory showing age-related alterations in the secretion and production of follicle-stimulating hormone (FSH) in rats by 5-6 months of age, one objective of the present study was to determine if alterations in FSH secretion were accompanied by changes in the number of antral follicles. A second objective of this study was to determine whether or not interruption of cyclic activity by continuous progesterone (P) treatment could decelerate age-associated changes in FSH secretion possibly by retarding the depletion of follicles through ovulation. For this study, one group of 4-day cycling, 7-week-old rats received one empty Silastic implant while another group received 3-40 mm implants containing 30 mm crystalline P. Implants were replaced every 2 weeks until the animals were 5 months old. Progesterone-implanted rats were acyclic during treatment exhibiting predominantly leukocytic vaginal smears. Regular 4-day cycles resumed when P implants were withdrawn (rats approximately 5-6-months-old). A group of 2-3-month-old untreated rats were used for comparison. As expected from our previous results, serum FSH levels at 1600 h on estrus were significantly higher in 5-6-month-old rats receiving empty capsules than in younger rats. Serum FSH concentrations measured in P-treated rats at this time also were significantly higher than levels of this gonadotropin measured in younger rats. Ovaries of older control and P-treated rats contained significantly fewer medium and large antral follicles (greater than 250 microns) than the ovaries of younger rats despite the curtailment of estrous cyclicity and ovulation by continuous P treatment. Interestingly, P treatment prevented the age-associated decrease in thymus weight. Taken together, the present observations suggest that a decrease in the number of growing follicles may be a factor contributing to early age-related alterations in FSH secretion. Furthermore, the prevention (at least temporarily) of age-related thymic involution by P treatment may be indicative of an interrelationship between thymic and reproductive aging. 相似文献
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S E Evans J S Crawford I D Stevens G M Durbin H Daya 《British journal of obstetrics and gynaecology》1986,93(4):329-333
Two types of fluid regimen were provided for patients having labour induced under epidural analgesia. Reasons for the infusion were to pre-load the circulation before the epidural, and subsequently to sustain maternal hydration. Both fluids were isotonic, one was predominantly saline based (Hartmann's solution) and the other contained both saline and dextrose. Blood glucose and serum sodium, lactate and beta-hydroxybutyrate were measured before the start of induction, at delivery and in the cord sample. Blood glucose and serum sodium were measured in the babies at 12 and 24 h of age. The dextrose-saline fluid caused small but significant changes in blood glucose and serum sodium which did not exceed the normal reference limits for either. The use of Hartmann's solution was associated with considerable rises in maternal serum beta-hydroxybutyrate at delivery. Neither fluid had any significant effect on the blood glucose or serum sodium in infants at 12 and 24 h of age. 相似文献
34.
Immunoglobulins from amyotrophic lateral sclerosis patients enhance spontaneous transmitter release from motor-nerve terminals. 总被引:5,自引:2,他引:3 下载免费PDF全文
O D Uchitel S H Appel F Crawford L Sczcupak 《Proceedings of the National Academy of Sciences of the United States of America》1988,85(19):7371-7374
Amyotrophic lateral sclerosis (ALS) is an incapacitating neuromuscular disease of unknown etiology. Although laboratory evidence is lacking, circumstantial evidence supports the importance of immune factors in the pathogenesis of ALS. In the present study immunoglobulins from 4 of 8 ALS patients induced a significant increase in spontaneous quantal transmitter release as monitored by miniature end-plate potential (MEPP) frequency in mouse phrenic nerve-diaphragm preparations at 23 degrees C, whereas immunoglobulins from normal individuals and from patients with other neuromuscular diseases had no effect. At 32 degrees C neither normal nor disease control immunoglobulins influenced MEPP frequency, but 8 of 11 ALS immunoglobulin samples produced a significant increase in spontaneous quantal transmitter release. The enhancing effect could be prevented by 10 mM Mg2+. No effects were noted on MEPP amplitude and muscle resting potential. These findings suggest that the presynaptic terminal of the motor neuron may be an early target and that immunological factors may play an important role in the disease process. 相似文献
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Marshall Alison L. Bauman Adrian E. Owen Neville Booth Michael L. Crawford David Marcus Bess H. 《Annals of behavioral medicine》2003,25(3):194-202
Background: Intervention trials with self-selected participants have shown that mailed stage-targeted print materials can increase participation
in physical activity in the short term. We examined the effects of a mailed stage-targeted print intervention designed to
promote physical activity, in a random sample of adults living in a regional city.Method: Participants (n = 462, 40–60 years of age) were randomly allocated to an intervention in - 227) or control group (n - 235).
Measures included validated 2-week physical activity recall and stage of motivational readiness for physical activity. The
intervention consisted of a single mailing of a letter and full-color stage-targeted booklets (specific to precontemplation,
contemplation, preparation, and action/maintenance) 1 week postbaseline. Follow-up interviews were conducted at 2 and 6 months
postbaseline.Results: After 2 months, participants in the intervention group were significantly More likely to meet the current American College
of Sports Medicine/Centers for Disease Control and Prevention recommendation for sufficient physical activity than those in
the control group (adjusted odds ratio [OR] - 2.40; 95% confidence interval [CI] = 1.44–3.99). After 6 months, intervention
participants who reported receiving and reading the intervention materials were significantly more likely to be meeting the
sufficient physical activity criterion compared with the control group (adjusted OR = 2.03; 95% Cl = 1.16–3.56).Conclusions: The stage-targeted print intervention was effective in promoting short-term increases in physical activity and was most
effective for participants who recognized and used the materials. This low-cost, generalizable intervention has demonstrated
potential as a practical population-based physical activity promotion strategy. Further research is required before widespread
dissemination would be justified, as additional strategies may be required to ensure sustained change.
This project was supported by a National Heart Foundation of Australia Research Project Grant. David Crawford was supported
by a Nutrition Research fellowship from the National Heart Foundation. 相似文献
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