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A. T. Fisk M. Holst K. A. Hobson J. Duffe J. Moisey R. J. Norstrom 《Archives of environmental contamination and toxicology》2002,42(1):118-126
To examine the influence of diet and age on organochlorine contaminant (OC) concentrations in two closely related ringed seal
(Phoca hispida) populations enantiomeric fractions (EFs) of chiral contaminants and stable isotopes of nitrogen (δ15N) and carbon (δ13C) were measured along with OCs in ringed seals collected from the east and west side of the Northwater Polynya. Seals from
these two locations were feeding at the same trophic level based on δ15N values in muscle but had slightly different sources of carbon based on δ13C measurements in muscle. After removing the influence of age, sex, and blubber thickness, OC concentrations did not vary
between ringed seals from the east and west side of the polynya. ΣPCB, ΣDDT, and Σchlordane were found to increase with age
for both male and female seals. The inclusion of older (>20 years) female seals, which may have a reduced reproductive effort,
may influence the relationships in females. Stable isotopes failed to describe OC concentrations in ringed seals suggesting
that diet was not a major factor in variation of OC concentrations within this ringed seal population. Cis- and trans-chlordane, oxychlordane, and heptachlor epoxide were all nonracemic in the ringed seal blubber but did not vary with age,
sex, or collection site. α-HCH appeared racemic (enantiomeric fraction = 0.50 ± 0.01) in the seals, although this EF is different
than those previously observed in their prey species, and was found to vary significantly with age. EF values in the ringed
seals varied considerably from other Arctic marine mammals and seabirds, providing addition evidence that the type(s) and
characteristic(s) of the enzymes involved in biotransformation of chiral OCs vary between these organisms.
Received: 11 April 2001/Accepted: 27 June 2001 相似文献
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N M Fisk D Ronderos-Dumit Y Tannirandorn U Nicolini D Talbert C H Rodeck 《British journal of obstetrics and gynaecology》1992,99(1):18-22
OBJECTIVE: To characterize amniotic pressure (AP) in pregnancies with normal amniotic fluid volume. DESIGN: Observational study, mainly cross-sectional. SETTING: Fetal medicine unit within a tertiary referral hospital. SUBJECTS: Patients undergoing transamniotic invasive procedures in whom amniotic fluid volume was subjectively assessed as normal on ultrasound. Those beyond 16 weeks with a deepest vertical pool on ultrasound less than 3.0 or greater than 8.0 cm were excluded. Overall 194 pregnancies were studied on 232 occasions between 7 and 38 weeks gestation. INTERVENTIONS: Manometry readings referenced to the top of the maternal abdomen were obtained via a fluid-filled line from the needle hub and either connected to a pressure transducer (n = 190) or held vertically against a ruler (n = 42). MAIN OUTCOME MEASURES: AP in mm Hg, AP corrected for gestational age (z scores), semi-quantitative ultrasonic indices of amniotic fluid volume, clinical variables. RESULTS: AP in singleton pregnancies increased with advancing gestation (P less than 0.001), and the sigmoid-shaped regression curve plateaued in the mid-trimester. AP z scores were not influenced by volume-related phenomena such as twin gestation, the deepest vertical pool, or amniotic fluid index, nor by maternal age, parity, gravidity, fetal sex, or subsequent spontaneous preterm delivery. CONCLUSIONS: These findings suggest that AP is not principally determined by intrauterine volume. We speculate that AP, which reflects change in uterine tension as a function of radius, may instead be determined by gestation-specific anatomical and hormonal influences on gravid uterine musculature. A reference range for AP has been constructed for use in amnioinfusion and amnioreduction procedures. 相似文献
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M J O Taylor L Y Wee M L Denbow N M Fisk 《Ultrasound in obstetrics & gynecology》2004,24(4):479; author reply 479-479; author reply 481
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AR Jones BSC AJP Sandison FRCS WJ Owen MS FRCS 《International journal of clinical practice》1997,51(5):294-295
Pre-clerking of all patients undergoing elective general surgical operations was introduced at our hospital in an attempt to reduce an unacceptably high operation cancellation rate. A prospective audit has been performed on the effect of this policy on the cancellation rate. Before the introduction of pre-clerking there was a marked seasonal variation in the number of patients who failed to attend for surgery, which could be explained by absence on holiday. This seasonal variation disappeared after the start of pre-clerking clinics, but there has been no reduction in the number of cancellations for medical reasons. 相似文献
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Isolation, regulation, and DNA-binding properties of three Drosophila nuclear hormone receptor superfamily members. 总被引:2,自引:0,他引:2
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G J Fisk C S Thummel 《Proceedings of the National Academy of Sciences of the United States of America》1995,92(23):10604-10608
We have designed a rapid cloning and screening strategy to identify new members of the nuclear hormone receptor superfamily that are expressed during the onset of Drosophila metamorphosis. Using this approach, we isolated three Drosophila genes, designated DHR38, DHR78, and DHR96. All three genes are expressed throughout third-instar larval and prepupal development. DHR38 is the Drosophila homolog of NGFI-B and binds specifically to an NGFI-B response element. DHR78 and DHR96 are orphan receptor genes. DHR78 is induced by 20-hydroxyecdysone (20E) in cultured larval organs, and its encoded protein binds to two AGGTCA half-sites arranged as either direct or palindromic repeats. DHR96 is also 20E-inducible, and its encoded protein binds selectively to the hsp27 20E response element. The 20E receptor can bind to each of the sequences recognized by DHR78 and DHR96, indicating that these proteins may compete with the receptor for binding to a common set of target sequences. 相似文献
10.
Berbaum KS; el-Khoury GY; Franken EA Jr; Kathol M; Montgomery WJ; Hesson W 《Radiology》1988,168(2):507-511
The effect of knowledge of localizing symptoms and signs in the detection of fractures was studied. Forty radiographs of the extremities were examined twice by seven radiologists; the sessions were separated by 4 months. In 26 cases, a subtle fracture was present; 14 cases were normal. In half of the cases at each session, the precise location of pain, tenderness, or swelling was provided. The observer was asked to determine if the case was normal or abnormal (provide the exact location of the fracture) and to indicate the degree of confidence in the diagnosis. Responses were converted to a numeric scale for analysis. Analysis of receiver operator characteristic parameters indicates that clues regarding location of trauma facilitate detection of fractures. The improvement is based largely on an increased true-positive rate without an increased false-positive rate, regardless of the decision criteria of the radiologist (overall willingness to "overread" or "underread"). This has direct clinical applicability and reinforces the plea of radiologists for precise clinical information. 相似文献