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At least 631 records · Page 35Linked to original sources
PubMed2006

[Profiles of irregular bleeding induced by low-dose hormone therapy and Chinese formulated herbs products].

OBJECTIVE: To compare profiles and related factors of irregular bleeding induced by different types of low-dose hormone therapy (HT) and a Chinese formulated herbs products. METHODS: Applied with open-labeled, randomized, and clinical trial design, 136 postmenopausal women were assigned into four groups: group A: estradiol valerate (E2 V) 1 mg/d + medroxyprogesterone acetate (MPA) 2 mg/d; group B: conjugated equine estrogen 0.45 mg/d + MPA 2 mg/d; group C: tibolone 1.25 mg/d; group D: a Chinese formulated herbs product (Kuntai) 4# tid. Each subject took element calcium 400 mg/d and vitamin D 200 IU/d concomitantly. Modified Kupperman scores were assessed on baseline and every 3 months thereafter and irregular bleeding was recorded on menopausal diary every day. The duration of this study was 1 year. Results The efficacies were similar in three HT-managed groups, but was better than in group D, although the latter was also effective in alleviating menopausal symptoms. Hazard ratio (HR) of irregular bleeding was 1.00 in group C, 2.43 in group A (95% CI: 1.08-5.46), 3.12 in group B (95% CI: 1.42-6.88), and 0.73 in group D (95% CI: 0.26-2.04). Most cases initially experienced bleeding in the first 3 months but such initiation was a bit later in group C. Endometrium, as detected by B-mode ultrasound, increased approximately 1 mm in HT groups, while it was a bit thicker in group C. Long periods in reproductive age and short time since menopause were high risk factors for irregular bleeding. CONCLUSION: Profiles of irregular bleeding in 3 commonly used types of low-dose HT are different and some factors such as long period in reproductive age and short time since menopause may contribute to bleeding initiation.

Adult↗
PubMed1994

Reproductive isolation and the period gene of Drosophila.

The identification of genes of large effect on ecologically important traits is an important aim of molecular ecology. The period gene of Drosophila is a candidate for a gene with a large influence on premating isolation between Drosophila species, as it determines species specific aspects of courtship behaviour. Strains of D. melanogaster are available which have been genetically transformed with the period gene of either D. melanogaster or D. simulans. Here we show that D. melanogaster females do not discriminate between two such strains. This suggests that period may only make a small contribution to total premating isolation between these species. We discuss the use of genetically transformed strains in assessing the influence of single genes on complex traits.

Animals↗
PubMed2001

Allochronic speciation, secondary contact, and reproductive character displacement in periodical cicadas (Hemiptera: Magicicada spp.): genetic, morphological, and behavioural evidence.

Periodical cicadas have proven useful in testing a variety of ecological and evolutionary hypotheses because of their unusual life history, extraordinary abundance, and wide geographical range. Periodical cicadas provide the best examples of synchronous periodicity and predator satiation in the animal kingdom, and are excellent illustrations of habitat partitioning (by the three morphologically distinct species groups), incipient species (the year classes or broods), and cryptic species (a newly discovered 13-year species, Magicicada neotredecim). They are particularly useful for exploring questions regarding speciation via temporal isolation, or allochronic speciation. Recently, data were presented that provided strong support for an instance of allochronic speciation by life-cycle switching. This speciation event resulted in the formation of a new 13-year species from a 17-year species and led to secondary contact between two formerly separated lineages, one represented by the new 13-year cicadas (and their 17-year ancestors), and the other represented by the pre-existing 13-year cicadas. Allozyme frequency data, mitochondrial DNA (mtDNA), and abdominal colour were shown to be correlated genetic markers supporting the life-cycle switching/allochronic speciation hypothesis. In addition, a striking pattern of reproductive character displacement in male call pitch and female pitch preference between the two 13-year species was discovered. In this paper we report a strong association between calling song pitch and mtDNA haplotype for 101 individuals from a single locality within the M. tredecim/M. neotredecim contact zone and a strong association between abdomen colour and mtDNA haplotype. We conclude by reviewing proposed mechanisms for allochronic speciation and reproductive character displacement.

Animals↗
PubMed1999

[Reproductive performance and milk production of Israeli-Holstein cows with different supplementation during the dry period].

In three field trials comprising 602 Israeli-Holstein dairy cows, the effect of the dry period ration on reproductive performance, culling rate and milk production was investigated. The cows were fed in groups. The basic dry period rations consisted for two herds of medium quality cereal hay and for one herd of corn straw, which were fed ad libitum. In each herd dry cows were assigned to an experimental and control group. Cows of the experimental group were supplemented with 1.5 to 3 kg of lactating cows mixed ration (LMR), whereas in the control group the amount of supplement was increased by the factor two or 3.3. In the experimental group the amount of the supplement was calculated to achieve levels of net energy and of crude protein close to NRC requirements; in the control group the level of net energy and protein was 12 to 18% higher as compared to the experimental group. The amount of LMR supplement in the experimental group of herds A, B, C were 1.5 kg, 1.9 kg, and 3 kg, respectively. In the control groups these amounts were 5 kg, 3.8 kg, and 6 kg, respectively. The groups fed moderate amounts of LMR supplement had a higher conception rate at first insemination, a higher percentage of cows conceiving and fewer cows culled in the consecutive lactation than cows fed increased amounts of LMR supplement. The lactational incidence of reproductive disorders and the milk production were not affected by the differences in feeding during the dry period. Reproductive performance and culling rate appeared to be more favorable for cows fed moderate amounts of supplement during the entire dry period or during the last 3 to 4 weeks of the dry period.

Animal Feed↗
PubMed2000

Temporal and spatial expression of the period gene in the reproductive system of the codling moth.

The authors examined patterns of spatial and temporal expression of Drosophila per gene homologue in the codling moth, Cydia pomonella. Since sperm release in moths is regulated in a circadian manner by an autonomous clock that is independent from the brain, the authors investigated per expression in male reproductive system along with its expression in moth heads. per mRNA is rhythmically expressed with the same phase and amplitude in both tissues under light-dark (LD) conditions. The levels of per mRNA are low during the day, start to increase before lights-off, reach the peak in dark, and decrease after lights-on. In constant darkness (DD), cycling of per mRNA continued in heads with severely blunted amplitude. No cycling of per mRNA was detected in testis in DD. In situ hybridization and immunocytochemistry revealed distinct spatial patterns of per expression in the moth reproductive system. There is no expression of per in cells forming the wall of testes or in sperm bundles. However, per mRNA and protein are rhythmically expressed in the epithelial cells forming the wall of the upper vas deferens (UVD) and in the cells of the terminal epithelium, which are involved in the circadian gating of sperm release. Increase in per mRNA in the UVD coincides with sperm accumulation in this part of the insect reproductive system.

Animals↗
PubMed2006

Expression of amphiregulin during the pre- and post-implantation period in the mouse reproductive tract.

In mammals, embryo implantation is an essential step in reproduction. Implantation is a phenomenon that involves crosstalk between the blastocyst and the maternal endometrium. However, the molecular basis of the connections between the blastocyst and endometrium is not yet fully understood. Amphiregulin is a member of the epidermal growth factor family and is known to be expressed in the luminal epithelium of the mouse uterus on 3.5 days post coitum (dpc). Thus, to clarify the mechanism of amphiregulin at fetomaternal interface, we analyzed the expression pattern of amphiregulin mRNA in the oviducts and uteri of pregnant and psuedopregnant mice by means of real-time PCR. Amphiregulin expression in the pregnant uterus dramatically increased on 2.5 dpc, peaked on 3.5 dpc, and declined by 5.5 dpc. Furthermore, to analyze the effect of the presence of an embryo on amphiregulin expression, we determined the expression pattern of amphiregulin mRNA in the uterus after embryo transfer on 0.5 and 1.5 dpc. A previous study showed that the expression of amphiregulin mRNA depends on the concentration of progesterone. However, our present results indicate that amphiregulin mRNA is upregulated by the presence of fertilized eggs in the lumen of the oviduct on 0.5 dpc.

Amphiregulin↗
PubMed1995

[State of the bone tissue in women of reproductive age at different periods after ovariectomy].

Eighty-eight women subjected to total oophorectomy for benign tumors and tumor-like formations in the uterus and tubes were examined. The mean age of the patients was 33.3 +/- 2.4 years. Bone tissue status was assessed by monophoton absorptiometry and computer-aided tomography. A negligible reduction of mineral density of osseous tissue was observed early after oophorectomy, its annual loss being high. In later periods after surgery, vice versa, a more expressed reduction of bone density and a relatively low rate of its annual reduction were observed. Specific features of the processes of osteoporosis in various periods after surgical removal of the ovaries make substitution hormonal therapy advisable for oophorectomized patients in the early periods after surgery, in order to effectively prevent and treat osteoporosis.

Absorptiometry, Photon↗
PubMed1982

Influences of environment and its modification on dairy animal health and production.

Physiological state of dairy animals is a predisposing factor in environmental influences on animal health. Critical phases of life cycle include neonatal period, postpubertal reproduction, and lactation. Primary effect of environment in neonatal period is increased disease incidence associated with reduced immunoglobulin content in plasma of calves. Cold stress has little effect on reproduction; in contrast, heat stress reduces libido, fertility, and embryonic survival in cattle. Heat stress in late gestation reduces fetal growth and alters endocrine status of the dam. Carryover effects of heat stress during late gestation on postpartum lactation and reproduction also are detectable. Heat stress of lactating cattle results in dramatic reductions in roughage intake and rumination. Decreases in roughage intake contribute to decreased volatile fatty acid production and may contribute to alteration in ratio of acetate/propionate. Rumen pH also declines during thermal stress. Electrolyte concentrations, in particular sodium and potassium, also are reduced in rumen fluid of heat stressed cattle. The decrease in sodium and potassium are related to increases in loss of urinary sodium and loss of skin potassium as well as decline in plasma aldosterone and increase in plasma prolactin. Reduction in thyroxine, growth hormone, and glucocorticoid concentrations in chronically heat stressed cattle appear to be related to decreases in basal metabolism.

Adaptation, Physiological↗
PubMed2005

Is leptin the link between fat and bone mass?

Leptin is a cytokine-like hormone which is considered the link between fat and bone; it is produced by adipocytes and osteoblasts, regulates food intake via specific receptors located in the central nervous system (CNS) and bone mass through alternate pathways: one involving a direct stimulatory effect on bone formation; and another indirect effect through the CNS that suppresses bone formation. Leptin exerts a direct stimulatory effect on osteoblast differentiation and on bone growth if directly administered, while it exerts an inhibitory effect on bone formation if administered in the CNS. It is therefore unclear whether leptin should be considered an antiosteogenic factor or an anabolic agent for bone formation: in all probability, leptin has a broader role in human physiology and in particular its action has evolved in order to synchronize periods of bone growth, mineral accretion and fertility with periods of food availability, while it restricts growth and reproduction during periods of nutritional stress.

Adipocytes↗
PubMed1989

Effect of pinealectomy, eye enucleation, and melatonin treatment on ovarian activity and vitellogenin levels in the catfish exposed to short photoperiod or long photoperiod.

To investigate the relative importance of pineal, and eyes, and melatonin treatment on ovarian activity, catfish. Heteropneustes fossilis subjected to pinealectomy, eye enucleation, or both were exposed to short (LD 9:15) or long (LD 14:10) photoperiod during the different stages of the annual reproductive cycle. During the preparatory period, pinealectomy accelerated ovarian recrudescence under long photoperiod, but no effects of pinealectomy were observed under short photoperiod. Pineal has no influence on ovarian activity during the prespawning and spawning periods of the reproductive cycle. In the late postspawning period, ovarian recrudescence is accelerated after pinealectomy in catfish maintained under short photoperiod (LD 9:15 at 25 degrees C). But under long photoperiod (LD 14:10 at 25 degrees C), pinealectomy delayed ovarian recrudescence. An investigation into the role of the eyes revealed that eye enucleation nullifies the inhibitory effects of LD 9:15 and represses the stimulatory effects of LD 14:10. Combined surgery inhibited ovarian development under both the regimes. It is significant that pinealectomy and/or blinding neither counteracted nor delayed the postspawning ovarian regression. The findings suggest that the role of the pineal in catfish reproduction is variable and depends upon the photoperiod to which they are exposed as well as on the time of the year and the stage of the reproductive cycle. It is concluded that extraretinal and extrapineal photoreceptors also are involved in influencing seasonal reproduction. Further, no effects of melatonin treatment on ovarian activity or on vitellogenin levels during the preparatory or prespawning periods were observed, indicating that the pineal effects on gonadal activity in catfish may not be mediated through the secretion of melatonin.

Animals↗