We have measured Zn/Ca ratios in two taxa of Holocene‐aged benthic foraminifera from throughout the world's oceans. Zn/Ca is controlled by bottom water dissolved Zn concentration and, like Cd/Ca and ...Ba/Ca, by bottom water saturation state with respect to calcite. Measurements on “live‐collected” foraminifera suggest that the saturation effect occurs during growth and is not a postdepositional artifact. Zn/Ca could be a sensitive paleoceanographic tracer because deep water masses have characteristic Zn concentrations that increase about tenfold from the deep North Atlantic to the deep North Pacific. In addition, since Zn/Ca responds to a different range of saturation states than Cd/Ca, the two may be used together to evaluate changes in deep water carbonate ion (CO32−) concentration.
We present a new method for the quantitative reconstruction of upper ocean flows for during times in the past. For the warm (T>5°C) surface ocean, density can be accurately reconstructed from calcite ...precipitated in equilibrium with seawater, as both of these properties increase with decreasing temperature and increasing salinity. Vertical density profiles can be reconstructed from the oxygen isotopic composition of benthic foraminifera. The net volume transport between two vertical density profiles can be calculated using the geostrophic method. Using benthic foraminifera from surface sediment samples from either side of the Florida Straits (Florida Keys and Little Bahama Bank), we reconstruct two vertical density profiles and calculate a volume transport of 32 Sv using this method. This agrees well with estimates from physical oceanographic methods of 30–32 Sv for the mean annual volume transport. We explore the sensitivity of this technique to various changes in the relationship between temperature and salinity as well as salinity and the oxygen isotopic composition of seawater.
The periovulatory increase in ovarian matrix metalloproteinase inhibitor (MMPI) expression is regulated both in vitro and in vivo by LH, but the intermediary steps in this process are uncertain. The ...purpose of this experiment was to determine whether interleukin-1 beta (IL-1 beta), a known modulator of MMPI expression in other systems and one that is induced by LH in the ovary, is capable of regulating granulosa matrix metalloproteinase inhibitor expression and activity. Using an in vitro rat granulosa cell model, these parameters were assessed in response to IL-1 beta or LH administration alone or in combination. Granulosa cells were obtained from 24-day-old immature female rats primed with 20 IU PMSG at 22 days of age. Cells were cultured under serum-free conditions for 24 h at 37 C in the presence of medium (control), LH (100 ng/ml), IL-1 beta (10 ng/ml), or LH plus IL-1 beta. MMPI activity in the conditioned medium was assessed using a colorimetric assay (n = 6), whereas progesterone and estrogen concentrations in the conditioned medium were determined by RIA (n = 6). RNA was isolated from the granulosa cells and assessed for Northern analysis of tissue inhibitor of metalloproteinase-1 (TIMP-1; n = 4), TIMP-2 (n = 3), and TIMP-3 (n = 3) expression. When added to granulosa cells, IL-1 beta and LH each significantly (P < 0.05) increased MMPI activity in granulosa cell-conditioned medium above control values (40.9 +/- 3.0% inhibition for IL-1 beta and 67.1 +/- 5.6% inhibition for LH vs. 31.4 +/- 2.4% inhibition for controls). When added in combination, IL-1 beta had no effect on LH-stimulated inhibitor activity (67.1 +/- 5.6% inhibition vs. 69.9 +/- 5.1% inhibition for LH and LH plus IL-1 beta, respectively). Methylamine hydrochloride treatment revealed that the majority of inhibitor activity in all treatment groups was derived from TIMPs. The patterns of TIMP-1, TIMP-2, and TIMP-3 messenger RNA expression among the treatment groups paralleled the TIMP-derived inhibitor activity, in that both IL-1 beta and LH alone stimulated transcript expression of all three TIMPs. In addition, an increase in progesterone production was associated with IL-1 beta-stimulated (1.22-fold over control values; P = 0.0006) and LH-stimulated (9.6-fold over control values; P = 0.007) MMPI expression and activity. Lastly, IL-1 beta and LH significantly (P < 0.05) decreased estrogen production by approximately 33% compared to that in cultures with LH only. It is concluded from the current study that IL-1 beta is a mediator of MMPI expression as well as granulosa cell steroidogenesis, and that this cytokine has divergent actions in the presence and absence of LH.
Mid‐Pleistocene benthic δ18O and δ13C time series from the North Atlantic site 983 and Ceara Rise site 928 are compared to an array of existing isotopic records spanning the Atlantic basin and the ...geographic extremes of the North Atlantic Deep Water/Southern Ocean Water interface during both glacial and interglacial periods. This comparison allows the persistent millennial‐scale intermediate depth North Atlantic ventilation changes recorded at site 983 to be placed within the context of the longer period water mass reorganizations taking place throughout the mid‐Pleistocene. Our benthic δ13C results suggest that the intermediate depth North Atlantic experienced millennial‐scale changes in ventilation throughout the mid‐Pleistocene climate shift. The times of poorest ventilation (low benthic δ13C) persisted for only a few millennia and were associated with rapid decreases in benthic δ18O, suggesting that ice sheet decay and melt water induced salinity changes were effective at throttling deep water production in the North Atlantic throughout the mid‐Pleistocene. Similar but less pronounced decreases in the δ13C of the middepth waters also punctuated interglacials, suggesting that large ice sheet fluctuations do not explain all of the observed thermohaline circulation mode shifts in the North Atlantic. Meanwhile, on orbital timescales, glacial deep to intermediate water δ13C gradients evolved after ∼0.95 Ma. Taken together, these observations provide a number of new constraints for understanding the timing and evolution of deep water circulation changes across the mid‐Pleistocene.
The Neotoma Paleoecology Database is a community-curated data resource that supports interdisciplinary global change research by enabling broad-scale studies of taxon and community diversity, ...distributions, and dynamics during the large environmental changes of the past. By consolidating many kinds of data into a common repository, Neotoma lowers costs of paleodata management, makes paleoecological data openly available, and offers a high-quality, curated resource. Neotoma’s distributed scientific governance model is flexible and scalable, with many open pathways for participation by new members, data contributors, stewards, and research communities. The Neotoma data model supports, or can be extended to support, any kind of paleoecological or paleoenvironmental data from sedimentary archives. Data additions to Neotoma are growing and now include >3.8 million observations, >17,000 datasets, and >9200 sites. Dataset types currently include fossil pollen, vertebrates, diatoms, ostracodes, macroinvertebrates, plant macrofossils, insects, testate amoebae, geochronological data, and the recently added organic biomarkers, stable isotopes, and specimen-level data. Multiple avenues exist to obtain Neotoma data, including the Explorer map-based interface, an application programming interface, the neotoma R package, and digital object identifiers. As the volume and variety of scientific data grow, community-curated data resources such as Neotoma have become foundational infrastructure for big data science.
Mifepristone and ovarian function Curry, Jr, T E; Nothnick, W B
Clinical obstetrics and gynecology,
1996-June, Letnik:
39, Številka:
2
Journal Article
Recenzirano
In summary, RU 486 has been a powerful instrument in delineating progesterone action on the ovary. However, early experiments using RU 486 must be interpreted with the understanding that systemic ...administration of the antiprogestin may have had extraovarian sites of action, such as at the hypothalamic-pituitary axis or at the adrenal, that in turn led to indirect ovarian responses. Treatment with progesterone, agonist, or antagonist at periods during which the ovary lacks progesterone receptors would further suggest extraovarian sites of action or nongenomic mechanisms of action. Furthermore, the dose of ligand or antagonist administered and the hormonal milieu at the time of administration may dictate the ovarian response (Espey L, personal communication). For example, low doses of exogenous progesterone may elicit a biologic response, whereas high doses are without effect or may inhibit the biologic effect observed at lower doses. Although RU 486 is classically described as an antiprogestin, agonist actions have been observed in addition to its the well documented antiglucocorticoid effects. All of these variables may contribute to the confounding observations of progesterone and RU 486 action on the ovary. Regardless of these caveats, experimental paradigms have demonstrated that RU 486, either indirectly or directly, regulates ovarian folliculogenesis, stimulates and/or inhibits steroidogenesis depending on the species and time of RU 486 administration, inhibits ovulation, and modulates luteal function. These findings supports a progesterone-dependent mechanism in these varied aspects of ovarian function.
The number of deaths from cervical cancer in the United States has decreased substantially since the implementation of widespread cervical cancer screening and has declined from 2.8 to 2.3 deaths per ...100 000 women from 2000 to 2015.
To update the US Preventive Services Task Force (USPSTF) 2012 recommendation on screening for cervical cancer.
The USPSTF reviewed the evidence on screening for cervical cancer, with a focus on clinical trials and cohort studies that evaluated screening with high-risk human papillomavirus (hrHPV) testing alone or hrHPV and cytology together (cotesting) compared with cervical cytology alone. The USPSTF also commissioned a decision analysis model to evaluate the age at which to begin and end screening, the optimal interval for screening, the effectiveness of different screening strategies, and related benefits and harms of different screening strategies.
Screening with cervical cytology alone, primary hrHPV testing alone, or cotesting can detect high-grade precancerous cervical lesions and cervical cancer. Screening women aged 21 to 65 years substantially reduces cervical cancer incidence and mortality. The harms of screening for cervical cancer in women aged 30 to 65 years are moderate. The USPSTF concludes with high certainty that the benefits of screening every 3 years with cytology alone in women aged 21 to 29 years substantially outweigh the harms. The USPSTF concludes with high certainty that the benefits of screening every 3 years with cytology alone, every 5 years with hrHPV testing alone, or every 5 years with both tests (cotesting) in women aged 30 to 65 years outweigh the harms. Screening women older than 65 years who have had adequate prior screening and women younger than 21 years does not provide significant benefit. Screening women who have had a hysterectomy with removal of the cervix for indications other than a high-grade precancerous lesion or cervical cancer provides no benefit. The USPSTF concludes with moderate to high certainty that screening women older than 65 years who have had adequate prior screening and are not otherwise at high risk for cervical cancer, screening women younger than 21 years, and screening women who have had a hysterectomy with removal of the cervix for indications other than a high-grade precancerous lesion or cervical cancer does not result in a positive net benefit.
The USPSTF recommends screening for cervical cancer every 3 years with cervical cytology alone in women aged 21 to 29 years. (A recommendation) The USPSTF recommends screening every 3 years with cervical cytology alone, every 5 years with hrHPV testing alone, or every 5 years with hrHPV testing in combination with cytology (cotesting) in women aged 30 to 65 years. (A recommendation) The USPSTF recommends against screening for cervical cancer in women younger than 21 years. (D recommendation) The USPSTF recommends against screening for cervical cancer in women older than 65 years who have had adequate prior screening and are not otherwise at high risk for cervical cancer. (D recommendation) The USPSTF recommends against screening for cervical cancer in women who have had a hysterectomy with removal of the cervix and do not have a history of a high-grade precancerous lesion or cervical cancer. (D recommendation).
By 2020, approximately 12.3 million individuals in the United States older than 50 years are expected to have osteoporosis. Osteoporotic fractures, particularly hip fractures, are associated with ...limitations in ambulation, chronic pain and disability, loss of independence, and decreased quality of life, and 21% to 30% of patients who experience a hip fracture die within 1 year. The prevalence of primary osteoporosis (ie, osteoporosis without underlying disease) increases with age and differs by race/ethnicity. With the aging of the US population, the potential preventable burden is likely to increase in future years.
To update the 2011 US Preventive Services Task Force (USPSTF) recommendation on screening for osteoporosis.
The USPSTF reviewed the evidence on screening for and treatment of osteoporotic fractures in men and women, as well as risk assessment tools, screening intervals, and efficacy of screening and treatment in subgroups. The screening population was postmenopausal women and older men with no known previous osteoporotic fractures and no known comorbid conditions or medication use associated with secondary osteoporosis.
The USPSTF found convincing evidence that bone measurement tests are accurate for detecting osteoporosis and predicting osteoporotic fractures in women and men. The USPSTF found adequate evidence that clinical risk assessment tools are moderately accurate in identifying risk of osteoporosis and osteoporotic fractures. The USPSTF found convincing evidence that drug therapies reduce subsequent fracture rates in postmenopausal women. The USPSTF found that the evidence is inadequate to assess the effectiveness of drug therapies in reducing subsequent fracture rates in men without previous fractures.
The USPSTF recommends screening for osteoporosis with bone measurement testing to prevent osteoporotic fractures in women 65 years and older. (B recommendation) The USPSTF recommends screening for osteoporosis with bone measurement testing to prevent osteoporotic fractures in postmenopausal women younger than 65 years at increased risk of osteoporosis, as determined by a formal clinical risk assessment tool. (B recommendation) The USPSTF concludes that the current evidence is insufficient to assess the balance of benefits and harms of screening for osteoporosis to prevent osteoporotic fractures in men. (I statement).
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