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1.
In order to further reveal the differences of association between body mass index (BMI) and cancer incidence across populations, genders, and menopausal status, we performed comprehensive meta-analysis with eligible citations. The risk ratio (RR) of incidence at 10 different cancer sites (per 5 kg/m2 increase in BMI) were quantified separately by employing generalized least-squares to estimate trends, and combined by meta-analyses. We observed significantly stronger association between increased BMI and breast cancer incidence in the Asia⿿Pacific group (RR 1.18:1.11⿿1.26) than in European⿿Australian (1.05:1.00⿿1.09) and North-American group (1.06:1.03⿿1.08) (meta-regression p < 0.05). No association between increased BMI and pancreatic cancer incidence (0.94:0.71⿿1.24) was shown in the Asia⿿Pacific group (meta-regression p < 0.05), whereas positive associations were found in other two groups. A significantly higher RR in men was found for colorectal cancer in comparison with women (meta-regression p < 0.05). Compared with postmenopausal women, premenopausal women displayed significantly higher RR for ovarian cancer (pre- vs. post- = 1.10 vs. 1.01, meta-regression p < 0.05), but lower RR for breast cancer (pre- vs. post- = 0.99 vs. 1.11, meta-regression p < 0.0001). Our results indicate that overweight or obesity is a strong risk factor of cancer incidence at several cancer sites. Genders, populations, and menopausal status are important factors effecting the association between obesity and cancer incidence for certain cancer types.  相似文献   

2.
Buffer zones along rivers and streams can provide water quality services by filtering nutrients, sediment and other contaminants from the surface. Redundancy analysis was used to determine the influence of the landscape pattern at the entire catchment scale and at multiple buffer zone scales (100 m, 300 m, 500 m, 1000 m and 1500 m) on the water quality in a highly urbanised watershed. Change-point analysis was further applied to estimate the specific locations along a gradient of landscape metric that result in a sudden change in the water quality variable. The landscape characteristics for 100 m buffer zones appeared to have a slightly greater influence on the water quality than the entire catchment. The patch density of urban land and the large patch index of water were recognised as the dominant variables influencing the water quality for a 100 m buffer zone. The result of change-point analysis indicated key interval values of the two landscape metrics within the 100 m buffer zone. When the patch density of urban land was >30–40 n/100 ha and the largest patch index of water was >2.5–3.5%, the watershed water quality appeared to be better protected.  相似文献   

3.
Conservation decisions are well supported by predictive spatial models that indicate the relative ecological condition of a given place. The intent of this 90 m pixel landscape condition model is to use nationally available spatial data from the USA, Mexico, and Canada to express assumptions regarding the relative ecological effects of land uses on terrestrial natural communities and species. This approach emphasizes and updateable and transparent design which takes advantage of empirical biodiversity data from the USA to both calibrate and validate the model. Map layers depicting infrastructure, land use, and modified vegetation were each scored for site impact and distance decay, and then combined into one map surface. Field observations from Natural Heritage Programs, each scored for relative ecological condition (in categories A = excellent to D = poor), were used to calibrate distance decay parameters. Some 90,000 observations for at-risk species, invasive plant species, and natural communities were used for model validation. Statistically significant distinctions in ecological condition among validation samples were predicted by the resultant spatial model. Variation in landscape condition was then summarized by regional U.S. Landscape Conservation Cooperatives (LCCs) in terms of areas approximating A–D condition. Montane and desert LCCs scored on average much higher in area approximating “A” and “B” landscape condition, while LCCs with more substantial agricultural and urban footprints scored overwhelmingly within the “D” range of condition. Similar analyses illustrated range-wide scoring of landscape condition for major vegetation types across temperate North America.  相似文献   

4.
BackgroundCervical cancer screening, regardless of HPV vaccination, is a cornerstone of cancer prevention. This study evaluated associations between prior HPV vaccine doses and initiation and continued participation of screening by age at vaccination.MethodsUsing electronic medical records for a safety net healthcare system (Truman Medical Center), women aged 14⿿26 y vaccinated (n = 1123) between 07/01/2006 and 10/1/2009 were randomly selected and matched on birth year and health campus to unvaccinated (n = 1123) women. Frequency of screening was determined through 07/01/2013. Hazard ratios (HR) for screening were estimated using Cox proportional hazards regression.ResultsScreening rates were higher after vaccination: unvaccinated (53%), first (62%), second (59%) or third (61%) doses. Women who initiated screening were less likely to complete the vaccine series, regardless of age. Women receiving one dose were more likely than unvaccinated women to initiate screening (HR = 2.98 95% Confidence Interval (CI):2.45⿿3.61) and were more likely to screen than those receiving two (1 vs. 2, HR = 2.94 95% CI:2.09⿿4.14) or three doses (1 vs. 3, HR = 3.15 95% CI:2.21⿿4.48). Compared to unvaccinated women, women <21 y who completed 3-doses were 1.8-times more likely to screen at ⿥21 y, whereas vaccinated women ⿥21 y were more likely to screen regardless of number of doses (p < 0.0001).ConclusionsWomen who were vaccinated were more likely to screen than unvaccinated women; screening rate was highest after and occurred closest to the first vaccine dose. Research evaluating the efficacy of a one-dose vaccine is warranted and may provide both higher vaccination and screening rates.  相似文献   

5.
Gastroesophageal reflux disease (GERD) causes local chronic inflammation that increases risks of Barrett⿿s esophagus (BE) and esophageal adenocarcinoma (EA), yet symptomatic GERD is absent in approximately half of all such patients. Obesity exacerbates GERD and is also a component of metabolic syndrome (MetS). We evaluated the hypothesis that MetS is a GERD-independent mechanism by which obesity is associated with increased risks of BE and EA using data from the UK Clinical Practice Research Datalink. BE cases (n = 10,215) and EA cases (n = 592) were each individually matched to five population controls based on age, sex, and general practice. MetS was defined as occurrence of at least three of the following: obesity, type 2 diabetes, hypertension, and high cholesterol. Odds ratios (OR) and 95% confidence intervals (CI) were estimated using conditional logistic regression. MetS was marginally associated with BE (OR = 1.12, 95%CI 1.00⿿1.25). Similar effects were found for the individual component factors of obesity, hypertension, and high cholesterol. History of GERD modified the association (P-effect modification <1E⿿5), with the MetS-BE association confined to patients without a history of GERD (OR = 1.33, 95%CI 1.12⿿1.58). No association between MetS and risk of EA was detected in the main or stratified analyses. In this large population-based case-control study, individuals with MetS had a marginally increased risk of BE in the absence of GERD. The systemic inflammatory state (MetS) may represent a reflux-independent inflammatory pathway that increases the risk of BE. MetS did not increase risk of EA in this study population.  相似文献   

6.
Despite the fact that many ecological landscape indicators have been applied so far, it is challenging to develop an indicator(s) which is easy and cheap to assess while at the same time reflecting the complexity of an ecosystem. The author aimed at the development of such an indicator: the Indicator of Ecological Landscape Quality (IELQ) which ranged from 0 to 2. This is based on the use of surrogate measures of assessing ecological quality (EQ) and a GIS approach. The employed measures include: landscape diversity, the degree of ecological significance of land cover forms, and the character of linear landscape structures. To verify the validity of the adopted measures, the indicator was calculated for areas under different conservation statuses and adjoining non-protected areas located in eastern Poland, 20 sites in total. The results showed that differences in mean IELQ values between areas under different protection regimes are significant (Tukey: p < 0.01). The highest mean values were obtained for nature reserves (0.86), and the lowest for non-protected areas (0.27). Explanatory factors for EQ included the proportion of natural and anthropogenic land cover forms, and the number of land cover forms. Surprisingly, the correlation between the latter factor and IELQ is negative (−0.704), indicating that the lower the landscape diversity, the higher the ecological values. From the protected area management point of view, the developed indicator proved its usefulness in terms of an assessment of ecological values and indicated changes in values over time.  相似文献   

7.
Several biodiversity features can be linked to landscape heterogeneity, that, in turn, can be informative for management and conservation purposes. Usually, the more the landscape is complex the more the biodiversity increases. Biodiversity indicators can be a useful tool to assess biodiversity status, in function of landscape heterogeneity. In this study, we developed a biodiversity indicator, based on Shannon diversity index and built from distribution maps of protected species. With such an approach, we seek to evaluate the feasibility of using a combination of target species as a surrogate for assessing the status of the whole bird community. Our approach was spread over multiple spatial scales, to determine which was the most informative. We selected four species protected by European regulation and generated a presence-absence map from species distribution modelling. We, therefore, used the FRAGSTATS biodiversity metric to calculate Shannon index for the overlapped presence-absence maps, at two spatial scales (500 m and 1000 m). Then, the relationships with the whole community was assessed through generalised least square models, at the spatial scale of 4 ha, 9 ha and 25 ha. Results showed that the higher rate of variability of community was explained by the biodiversity indicator at 1000 m scale. Indeed, the more informative spatial scale for the whole bird community was 9 ha. In addition, a pattern emerged about the relationships between biodiversity indicator and community richness, that is worth of further research. Our study demonstrates that the usefulness of surrogate species for biodiversity and community assessment can become clear only at a certain spatial scales. Indeed, they can be highly predictive of the whole community, and highly informative for conservation planning. Moreover, their use can optimize biodiversity monitoring and conservation, focusing on a small number of noteworthy species.  相似文献   

8.
《Small Ruminant Research》2009,84(1-3):29-33
The objective of this study was to evaluate the LH and ovulatory response of dominant and subordinate dairy does following the introduction of males. A behavioral study was carried out to determine the individual success index (SI) of 35 anestrous does according to their ability to dominate other females. The 8 highest-ranking (highest SI) and the 8 lowest-ranking does (lowest SI) in terms of dominance were separated from the rest of the herd and placed together in the same pen, where a male was later introduced. Blood samples for plasma LH determinations were obtained from the 16 females at 30 min intervals from 0 to 6, 12 to 18 and 33 to 39 h after the introduction of the male, using an intravenous catheter. After day 8, plasma progesterone was also measured daily in order to determine the occurrence of ovulation. None of the does showed LH pulses during the sampling period prior to the introduction of the male. The dominant does showed significantly (p < 0.05) more LH pulses (2.0 ± 0.18 ng/ml vs. 1.2 ± 0.25 ng/ml) and a higher mean plasma LH concentration (0.25 ± 0.03 ng/ml vs. 0.14 ± 0.03 ng/ml) than the subordinate goats during the first 6 h of exposure to the male. There were no differences in LH pulsatility or concentrations at other times. The frequency of goats that ovulated tended to be greater in high-ranked than low-ranked does (87% vs. 37%). It could be concluded that the immediate LH response to the presence of the male (number of LH pulses) is higher in the dominant, compared to the subordinate goats, and this is associated with a higher number of dominant goats ovulating in response to the male effect.  相似文献   

9.
Landscape connectivity analysis is a major tool in supporting biodiversity conservation. Several methodologies have been developed to tackle it by following two main paths. The first path exploits graph approaches and models focal nodes’ connections on a resistance/conductance matrix depending on focal species’ movement potential. The second path considers geometrical pattern analyses based on the calculation of structural landscape metrics. These approaches separately investigate functional and structural features of the landscape, and may come short of a total definition if used separately. Here we propose a new scalable, modular, participative and open-source procedure based on Fuzzy logic to combine the functional and structural aspects of connectivity. We applied this method on the highly fragmented landscape of the Po Plain, focusing on its rare and endangered plain springs named fontanili. We identified an expert panel and involved it in the assignation of permeability values of land use classes with respect to the capacity of movement of animal species typical of fontanili. We concurrently performed a quantitative evaluation of the landscape fragmentation with a moving window. We found that the functional and structural evaluations were poorly correlated in the area under study (Pearson's r = −0.35, p < 0.001). We thus integrated these two non-overlapping analyses of the landscape by Fuzzy logic using thresholds and combination weights obtained from questionnaires proposed to the expert panel. The resulting index, termed Fuzzy Functionality Index (FFI), improved the level of information associated with landscape classification. By merging functional and structural aspects of the landscape, the FFI allowed us to discriminate different functional values of equally permeable parcels and vice versa. We demonstrate that FFI may act as a conductance measure in a circuit theory approach, highlighting ecological corridors between focal points of species’ distribution. We present FFI as an effective predictive index to inspect complex and non-linear landscape dynamics.  相似文献   

10.
Land use and cover changes have been identified as a major factor contributing to shape landscape structure and biodiversity patterns, particulary in areas with a long history of human occupation and habitat fragmentation, such as the Mediterranean landscapes. However, the existing studies on landscape change indicators for Mediterranean areas have mostly focused in Europe, while for other Mediterranean zones, and especially for South America, there is a serious lack of knowledge concerning the impact of landscape dynamics on ecological processes. Further research on this topic is urgently needed, given the high biodiversity levels and the rapidly increasing rates of human modification in the Mediterranean landscapes of South America. For this purpose, we investigated the dynamics of a landscape in the semiarid region of the Mediterranean zone of Chile, and measured the effect of those dynamics on functional connectivity, during a period of about four decades (1975–2011). Landscape connectivity indicators were extracted from a series of Landsat images. The Equivalent Connnected Area index (ECA) was used as indicator of connectivity trends, and was evaluated for three representative distances of seed dispersal in the study area (150 m, 500 m and 1000 m). In addition, the patches that most contribute to maintain the present connectivity, and their roles as connectivity providers, were identified through a set of commensurable indicators: betweenness centrality and the fractions (intra, flux connector) of the Integral Index of Connectivity. We found that these indicators were useful to detect and summarize a number of previously unreported trends in these Mediterranean landscapes. First, population growth and economic development were compatible with an increase in functional connectivity for forest habitats, mainly because the abandonment of marginal agricultural lands and their subsequent conversion to espinals (Acacia caven) triggered vegetation succession towards secondary forests. Second, increased forest connectivity was not associated to a decrease in the characteristic heterogeneity of Mediterranean landscapes. Third, many patches of espinal, despite being commonly regarded as of poor conservation value, were crucial to promote connectivity by acting as stepping stones among other patches with higher habitat quality. The approach here presented provides a combined assessment of landscape structure, function and change that should be valuable and applicable to deliver operational indicators in dynamic landscapes in South America and other Mediterranean regions.  相似文献   

11.
A bioassay-guided fractionation of Salvia lachnostachys Benth leaf extract led to the isolation of three known diterpenes, namely fruticuline A (1), fruticuline B (2) and 7,20-dihydrofruticuline A (3), together with two new compounds, 4 and 5. The structures were mainly elucidated by 1D and 2D NMR spectroscopy and HRESIMS. The cytotoxic activity of the crude ethanol extract, the semi-purified fractions (A-E) and compounds 1, 2 and 4 were evaluated against seven human cancer cell lines and the normal cell line HaCat. The ethanol extract showed activity against all tested cell lines (GI50 25.0⿿44.0 μg/mL). Among the fractions, the greatest activity was exhibited by fraction A (eluted with hexane), which inhibited the growth of all tested cell lines with GI50 of 3.9⿿19.5 μg/mL. Compounds 1 and 4 were the most active, inhibiting the growth of U251, MCF-7, NCI-ADR/RES, 786.0, NCI-H460, PC-3, OVCAR-03 and HaCat cell lines with GI50 < 10 μM. Compound 2 showed moderate activity against MCF-7, NCI-H460, OVCAR-03, K562 and HaCat, with GI50 varying 19.9⿿29.3 μM.  相似文献   

12.
Understanding the factors driving the variation in urban green space and plant communities in heterogeneous urban landscapes is crucial for maintaining biodiversity and important ecosystem services. In this study, we used a combination of field surveys, remote sensing, census data and spatial analysis to investigate the interrelationships among geographical and social-economic variables across 328 different urban structural units (USUs) and how they may influence the distributions of urban forest cover, plant diversity and abundance, within the central urban area of Beijing, China. We found that the urban green space coverage varied substantially across different types of USUs, with higher in agricultural lands (N = 15), parks (N = 46) and lowest in utility zones (N = 36). The amount of urban green space within USUs declines exponentially with the distance to urban center. Our study suggested that geographical, social and economic factors were closely related with each other in urban ecological systems, and have important impacts on urban forest coverage and abundance. The percentage of forest as well as high and low density urban areas were mainly responsible for variations in the data across all USUs and all land use/land cover types, and thus are important constituents and ecological indicators for understanding and modeling urban environment. Herb richness is more strongly correlated with tree and shrub density than with tree and shrub richness (r = −0.472, p < 0.05). However, other geographic and socioeconomic factors showed no significant relationships with urban plant diversity or abundance.  相似文献   

13.
Two new alkaloids, poggeicridone (1) and 2-methoxy-7,8- dehydroruteacarpine (6), together with nine known compounds, were isolated from the dichloromethane (DCM) extract of the bark of Zanthoxylum poggei (Engl.) P. G. Waterman. The structures of all compounds were determined by comprehensive spectroscopic analyses (1D and 2D NMR and EI- and ESI⿿MS). Compounds 5-9 exhibited strong suppressive effects on the phagocytosis response upon activation with serum opsonized zymosan in the in vitro oxidative burst studies using whole blood. The IC50 values were in the range of 12.0⿿25.9 μM. These compounds displayed a moderate level of cytotoxic activity against the human Caucasian prostate adenocarcinoma cell line PC-3, with IC50 values of 15.8 and 22.1 μM (the IC50 value of the positive control standard doxorubicin was IC50 0.9 μM). All isolated compounds were also tested against plant pathogenic bacteria, fungi and oomycetes using the paper disk agar diffusion assay, resulting in no significant activities (MICs > 1 mg/mL).  相似文献   

14.
In most proestrous hamsters, novel wheel exposure phase advances activity rhythms and blocks the preovulatory LH surge, which occurs 2 h earlier the next day. Because wheel immobilization does not prevent these effects we hypothesized that arousal alone blocks and phase advances the LH surge. Ovariectomized (ovx) hamsters received a jugular vein cannula and estradiol benzoate (EB) or vehicle was injected sc. The next day (Day 1), at zeitgeber time (ZT) 4–5 (ZT 12 = lights off), after obtaining a blood sample, each hamster was exposed to constant darkness (DD), and either remained in her home cage or was transferred to a new cage and exposed to a running wheel or a 2-hour arousal paradigm. Blood samples were obtained in dim red light and activity was recorded hourly until ~ ZT 10–11 on Days 1 and 2. For the next 1–2 weeks, activity was monitored in DD. Plasma LH and corticosterone were assessed by RIA. Novel wheel exposure or arousal at ZT 4 greatly attenuated the Day 1 LH surge in ovx + EB hamsters, and phase advanced the Day 2 LH surge by about 2 h. In proestrous hamsters, novel wheel exposure led to a prolonged (> 2 h) increase in corticosterone levels only when LH surges were blocked. Phase advances in activity rhythms were enhanced by estradiol and arousal. The results suggest that estradiol modulates the effectiveness of non-photic stimuli. The role of the increased activity of the hypothalamic–pituitary–adrenal axis associated with novel wheel-induced attenuation of LH surges in ovx + EB hamsters remains to be determined.  相似文献   

15.
Assessing the spatial variability of ecosystem structure and functioning is an important step towards developing monitoring systems to detect changes in ecosystem attributes that could be linked to desertification processes in drylands. Methods based on ground-collected soil and plant indicators are being increasingly used for this aim, but they have limitations regarding the extent of the area that can be measured using them. Approaches based on remote sensing data can successfully assess large areas, but it is largely unknown how the different indices that can be derived from such data relate to ground-based indicators of ecosystem health. We tested whether we can predict ecosystem structure and functioning, as measured with a field methodology based on indicators of ecosystem functioning (the landscape function analysis, LFA), over a large area using spectral vegetation indices (VIs), and evaluated which VIs are the best predictors of these ecosystem attributes. For doing this, we assessed the relationship between vegetation attributes (cover and species richness), LFA indices (stability, infiltration and nutrient cycling) and nine VIs obtained from satellite images of the MODIS sensor in 194 sites located across the Patagonian steppe. We found that NDVI was the VI best predictor of ecosystem attributes. This VI showed a significant positive linear relationship with both vegetation basal cover (R2 = 0.39) and plant species richness (R2 = 0.31). NDVI was also significantly and linearly related to the infiltration and nutrient cycling indices (R2 = 0.36 and 0.49, respectively), but the relationship with the stability index was weak (R2 = 0.13). Our results indicate that VIs obtained from MODIS, and NDVI in particular, are a suitable tool for estimate the spatial variability of functional and structural ecosystem attributes in the Patagonian steppe at the regional scale.  相似文献   

16.
Indicators of landscape condition should be selected based on their sensitivity to environmental changes and their capacity to provide early warning detection of those changes. We assessed the performance of a suite of spatial-pattern metrics selected to quantify the condition of the ridge-slough landscape in the Everglades (South Florida, USA). Spatial pattern metrics (n = 14) that describe landscape composition, geometry and hydrologic connectivity were enumerated from vegetation maps of twenty-five 2 × 2 km primary sampling units (PSUs) that span a gradient of hydrologic and ecological condition across the greater Everglades ecosystem. Metrics were assessed in comparison with field measurements from each PSU of landscape condition obtained from regional surveys of soil elevation, which have previously been shown to capture dramatic differences between conserved and degraded locations. Elevation-based measures of landscape condition included soil elevation bi-modality (BISE), a binary measure of landscape condition, and also the standard deviation of soil elevation (SDSE), a continuous measure of condition. Metric performance was assessed based on the strength (sensitivity) and shape (leading vs. lagging) of the relationship between spatial pattern metrics and these elevation-based measures. We observed significant logistic regression slopes with BISE for only 4 metrics (slough width, ridge density, directional connectivity index – DCI, and least flow cost – LFC). More significant relationships (n = 8 metrics) were observed with SDSE, with the strongest associations for slough density, mean ridge width, and the average length of straight flow, as well as for a suite of hydrologic connectivity metrics (DCI, LFC and landscape discharge competence – LDC). Leading vs. lagging performance, inferred from the curvature of the association obtained from the exponent of fitted power functions, suggest that only DCI was a leading metric of the loss of soil elevation variation; most metrics were indeterminate, though some were clearly lagging. Our findings support the contention that soil elevation changes from altered peat accretion dynamics precede changes in landscape pattern, and offer insights that will enable efficient monitoring of the ridge-slough landscape as part of the ongoing Everglades restoration effort.  相似文献   

17.
A new phytoplankton-based index was designed to respond to the Water Framework Directive (WFD) requirements concerning the assessment of lake ecological status. The “Indice Phytoplancton Lacustre” (IPLAC) is a multimetric index, taking into account biomass, abundance and species composition of communities. The first metric is based on the total phytoplankton biomass (MBA), the second on the abundance and taxonomic composition (MCS) of 165 indicator taxa. The IPLAC was developed on 2 independent databases, one for the calibration and the second for the validation of the metrics. The calibration dataset was composed of 255 “lake-years” from 214 distinct lakes sampled between 2005 and 2012. The validation dataset included 173 lake-years in order to confirm the response of the index to the trophic gradient and anthropogenic pressure.The results show that the IPLAC correctly highlights chemical pressure (eutrophication). Especially high Pearson correlations are shown with total phosphorus (r = −0.71, p-value <0.001), chlorophyll-a (r = −0.83, p-value <0.001) and water transparency (r = 0.73, p-value <0.001) which are the main proxies for the trophic level. Corine land cover was used as an indication of the anthropogenic pressure and good correlations are also found with the watershed land use, negatively correlated with agricultural area (r = −0.60, p-value <0.001), population density (r = −0.36, p-value <0.001) and positively with forest area (r = 0.57, p-value <0.001).The index is WFD-compliant and is dedicated to natural lakes and artificial water bodies in metropolitan France, and will be routinely used by the French Ministry of the Environment to assess lake ecological status through the phytoplankton community. However, the results must be carefully interpreted in two cases: reservoirs with large water level fluctuations, and samples that include less than 5 indicator species.  相似文献   

18.
Loss of luteal progesterone secretion at the end of the ovine estrous cycle is via uterine PGF2α secretion. However, uterine PGF2α secretion is not decreased during early pregnancy in ewes. Instead, the embryo imparts a resistance to PGF2α. Prostaglandins E (PGE; PGE1 + PGE2) are increased in endometrium and uterine venous blood during early pregnancy in ewes to prevent luteolysis. Chronic intrauterine infusion of PGE1 or PGE2 prevents spontaneous or IUD, estradiol-17β, or PGF2α-induced premature luteolysis in nonbred ewes. The objective was to determine whether chronic intrauterine infusion of PGE1 or PGE2 affected mRNA for LH receptors, occupied and unoccupied receptors for LH in luteal and caruncular endometrium, and luteal function. Ewes received Vehicle, PGE1, or PGE2 every 4 h from days 10 to 16 of the estrous cycle via a cathether installed in the uterine lumen ipsilateral to the luteal-containing ovary.Jugular venous blood was collected daily for analysis of progesterone and uterine venous blood was collected on day-16 for analysis of PGF2α and PGE. Corpora lutea and caruncular endometrium were collected from day-10 preluteolytic control ewes and day-16 ewes treated with Vehicle, PGE1 or PGE2 for analysis of the mRNA for LH receptors and occupied and unoccupied receptors for LH. Luteal weights on day-16 in ewes treated with PGE1 or PGE2 and day-10 control ewes were similar (P  0.05), but were greater (P  0.05) than in day-16 Vehicle-treated ewes. Progesterone profiles on days 10–16 differed (P  0.05) among treatment groups: PGE1 > PGE2 > Vehicle-treated ewes. Concentrations of PGF2α and PGE in uterine venous plasma on day-16 were similar (P  0.05) in the three treatment groups. Luteal mRNA for LH receptors and unoccupied and occupied LH receptors were similar (P  0.05) in day-10 control ewes and day-16 ewes treated with PGE2 and were lower (P  0.05) in day-16 Vehicle-treated ewes. PGE2 prevented loss (P  0.05) of day-16 luteal mRNA for LH receptors and occupied and unoccupied LH receptors. Luteal and caruncular tissue mRNA for LH receptors and occupied and unoccupied LH receptors were greater (P  0.05) on day-16 of PGE1-treated ewes than any treatment group. mRNA for LH receptors and occupied and unoccupied receptors for LH in caruncules were greater (P  0.05) in day-16 Vehicle or PGE2-treated ewes than in day-10 control ewes. It is concluded that PGE1 and PGE2 share some common mechanisms to prevent luteolysis; however, only PGE1 increased luteal and endometrial mRNA for LH receptors and occupied and unoccupied LH receptors. PGE2 prevents a decrease in luteal mRNA for LH receptors and occupied and unoccupied receptors for LH without altering endometrial mRNA for LH receptors or occupied and unoccupied receptors for LH.  相似文献   

19.
The aim of this paper is to assess of the stability and repeatability of the biological soil-quality (BSQ) index over time and at short/long distances in agricultural soils of the Po Valley, Northern Italy, to support its correct use in soil-quality monitoring and is based on soil microarthropods representative of the structure, function and composition of ecological systems, but avoiding classification at the species level. Microarthropods are separated from the soil and weighted using the biological form approach to evaluate their level of adaptation to the soil environment. The field test was organized to assess time and scale effects in a landscape within the coordinates 45°00′ to 45°16′N and 9°50′ to 10°15′E for an estimated area of 200 km2. The BSQ had, in different soils cropped with corn and fertilized with sewage sludge, an average value of 76.4 ± 23.5; it appears to be reproducible both over short distances as well as over short periods of time, but no significant differences (p > 0.05) between years nor between farms were observed. In the landscape conditions tested, it appears reproducible and stable at a field and basin scale, though very sensitive to seasonal climatic variations. From a practical point of view, the information reported in this paper contributes to the standardization of the application of BSQ and provides reference values for this index in soils of the Northern Italy cropped with corn.  相似文献   

20.
《Small Ruminant Research》2007,70(1-3):124-128
This study was aimed at comparing the temporal relationship between estrus, the LH peak and ovulation following estrous synchronization in goats using medroxiprogesterone acetate (MGA) or fluorogestone acetate (FGA). Twenty-four cyclic goats were randomly assigned to two treatments: MGA group (n = 12) that individually received a daily oral dose of 0.22 mg MGA for 12 days, and a FGA group (n = 12) treated for 12 days with intravaginal sponges containing 45 mg FGA. The goats from both groups were treated with a prostaglandin analogue (75 μg Cloprostenol i.m.) during the last day of their progesterone treatment. Estrous detection was carried out every 4 h after the end of the treatment, and blood samples for the determination of the serum LH concentrations collected at 2 h intervals for 24 h from the onset of estrus. Ovulation was detected with the aid of transrectal ultrasonography, performed every 4 h starting 15 h after the onset of estrus. All goats showed estrus. In the MGA group the onset of estrus occurred later and was more variable in relation to the end of treatment (86.7 ± 3.9 h), compared to the FGA group (44.4 ± 1.5 h; P < 0.01). The interval between the LH peak and ovulation was significantly (P < 0.05) longer in the MGA group (26.2 ± 1.1 h) than the FGA group (22.4 ± 0.8 h). There were no differences regarding the intervals from the onset of estrus to the LH peak (14.9 ± 1.8 and 15.3 ± 0.9 h) and to ovulation (40.1 ± 2.3 and 37.6 ± 0.5 h) for the MGA and FGA groups, respectively. The amplitude of the LH peak was not different between groups. It could be concluded that the timing of the LH peak and ovulation is not related to the end of treatment, but with the time of onset of estrus. The longer and more variable interval for estrous demonstration following MGA treatment, represents a serious limitation for its use in synchronization programs in goats, where mating is to be performed on a fixed-time basis.  相似文献   

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