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1.
Genetic variation at the Major Histocompatibility Complex locus DQ beta was
analyzed in 233 beluga whales (Delphinapterus leucas) from seven
populations: St. Lawrence Estuary, eastern Beaufort Sea, eastern Chukchi
Sea, western Hudson Bay, eastern Hudson Bay, southeastern Baffin Island,
and High Arctic and in 12 narwhals (Monodon monoceros) sympatric with the
High Arctic beluga population. Variation was assessed by amplification of
the exon coding for the peptide binding region via the polymerase chain
reaction, followed by either cloning and DNA sequencing or single-stranded
conformation polymorphism analysis. Five alleles were found across the
beluga populations and one in the narwhal. Pairwise comparisons of these
alleles showed a 5:1 ratio of nonsynonymous to synonymous substitutions per
site leading to eight amino acid differences, five of which were
nonconservative substitutions, centered around positions previously shown
to be important for peptide binding. Although the amount of allelic
variation is low when compared with terrestrial mammals, the nature of the
substitutions in the peptide binding sites indicates an important role for
the DQ beta locus in the cellular immune response of beluga whales.
Comparisons of allele frequencies among populations show the High Arctic
population to be different (P < or = .005) from the other beluga
populations surveyed. In these other populations an allele, Dele-DQ
beta*0101-2, was found in 98% of the animals, while in the High Arctic it
was found in only 52% of the animals. Two other alleles were found at high
frequencies in the High Arctic population, one being very similar to the
single allele found in narwhal.
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2.
Elongation factor-1 alpha occurs as two copies in bees: implications for phylogenetic analysis of EF-1 alpha sequences in insects 总被引:5,自引:1,他引:4
We report the complete sequence of a paralogous copy of elongation factor-1
alpha (EF-1 alpha) in the honeybee, Apis mellifera (Hymenoptera: Apidae).
This copy differs from a previously described copy in the positions of five
introns and in 25% of the nucleotide sites in the coding regions. The
existence of two paralogous copies of EF-1 alpha in Drosophila and Apis
suggests that two copies of EF-1 alpha may be widespread in the
holometabolous insect orders. To distinguish between a single, ancient gene
duplication and parallel, independent fly and bee gene duplications, we
performed a phylogenetic analysis of hexapod EF-1 alpha sequences.
Unweighted parsimony analysis of nucleotide sequences suggests an ancient
gene duplication event, whereas weighted parsimony analysis of nucleotides
and unweighted parsimony analysis of amino acids suggests the contrary:
that EF-1 alpha underwent parallel gene duplications in the Diptera and the
Hymenoptera. The hypothesis of parallel gene duplication is supported both
by congruence among nucleotide and amino acid data sets and by
topology-dependent permutation tail probability (T-PTP) tests. The
resulting tree topologies are also congruent with current views on the
relationships among the holometabolous orders included in this study
(Diptera, Hymenoptera, and Lepidoptera). More sequences, from diverse
orders of holometabolous insects, will be needed to more accurately assess
the historical patterns of gene duplication in EF-1 alpha.
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3.
Meendering JR Torgrimson BN Miller NP Kaplan PF Minson CT 《American journal of physiology. Heart and circulatory physiology》2008,294(4):H1630-H1637
Medroxyprogesterone acetate (MPA) is widely known for its use in combination hormone therapy for postmenopausal women. However, MPA is also commonly used in young women for contraception and treatment of a number of gynecological conditions. Despite its widespread use, the cardiovascular effects of MPA in young women are unclear. Therefore, the purpose of this study was to determine the acute effects of MPA when used in combination with estradiol on markers of cardiovascular risk in young women. We suppressed endogenous estrogens and progesterone in 10 premenopausal women using a gonadotropin-releasing hormone antagonist (GnRHa) for 10 days. On day 4 of GnRHa subjects received 0.1 mg of estradiol (GnRHa+E(2)), and on day 7 5 mg of MPA was added (GnRHa+E(2)+MPA). Endothelium-dependent vasodilation and endothelium-independent vasodilation of the brachial artery, lipids, homocysteine, high-sensitivity C-reactive protein, and endothelin-1 were assessed during treatment with GnRHa, GnRHa+E(2), and GnRHa+E(2)+MPA. Four additional subjects were tested to validate the efficacy of the GnRHa model and confirm the findings. Endothelium-dependent vasodilation was greater during GnRHa+E(2) than during GnRHa or GnRHa+E(2)+MPA (P = 0.006). Endothelin-1 was lower during GnRHa+E(2) than GnRHa alone (P = 0.039). Endothelin-1 increased with the addition of MPA and was not significantly different from GnRHa alone. There were no differences in the other markers of cardiovascular risk between hormone treatment days. These data suggest that acute MPA administration negates the beneficial effects of estradiol on endothelium-dependent vasodilation in young women. In addition, these data suggest that estradiol decreases endothelin-1 concentrations and the addition of MPA may counteract the effect of estradiol on endothelin-1. 相似文献
4.
This study continues analysis from a companion paper on over 350,000 insured Swedish dogs up to 10 years of age contributing
to more than one million dog-years at risk during 1995–2000. The age patterns for total and diagnostic mortality and for general
causes of death (trauma, tumour, locomotor, heart and neurological) are presented for numerous breeds. Survival estimates
at five, eight and 10 years of age are calculated. Survival to 10 years of age was 75% or more in Labrador and golden retrievers,
miniature and toy poodles and miniature dachshunds and lowest in Irish wolfhounds (91% dead by 10 years). Multivariable analysis
was used to estimate the relative risk for general and more specific causes of death between breeds accounting for gender
and age effects, including two-way interactions. Older females had tumour as a designated cause of death more often than males
in most breeds, but not in the Bernese mountain dog. Information presented in this and the companion paper inform our understanding
of the population level burden of disease, and support decision-making at the population and individual level about health
promotion efforts and treatment and prognosis of disease events. 相似文献
5.
6.
Background
Movement of cells, either as amoeboid individuals or in organised groups, is a key feature of organ formation. Both modes of migration occur during Drosophila embryonic gonad development, which therefore provides a paradigm for understanding the contribution of these processes to organ morphogenesis. Gonads of Drosophila are formed from three distinct cell types: primordial germ cells (PGCs), somatic gonadal precursors (SGPs), and in males, male-specific somatic gonadal precursors (msSGPs). These originate in distinct locations and migrate to associate in two intermingled clusters which then compact to form the spherical primitive gonads. PGC movements are well studied, but much less is known of the migratory events and other interactions undergone by their somatic partners. These appear to move in organised groups like, for example, lateral line cells in zebra fish or Drosophila ovarian border cells. 相似文献7.
8.
Meendering JR Torgrimson BN Houghton BL Halliwill JR Minson CT 《American journal of physiology. Heart and circulatory physiology》2005,288(1):H103-H110
Numerous studies have shown that the female sex hormones estrogen and progesterone have multiple effects on the vasculature. Thus our goal was to investigate the effects of estrogen and progesterone on calf venous compliance by looking for cyclic changes during the early follicular, ovulatory, and midluteal phases of the menstrual cycle and during high and low hormone phases of oral contraceptive use. Additionally, we wanted to compare the venous compliance of normally menstruating women, oral contraceptive users, and men. We studied eight normally menstruating women (23 +/- 1 yr of age) during the early follicular, ovulatory, and midluteal phases of the menstrual cycle. Nine triphasic oral contraceptive users (21 +/- 1 yr of age) were studied during weeks of high and low hormone concentrations. Eight men (23 +/- 1 yr of age) were studied twice within 2-4 wk. With the use of venous occlusion plethysmography with mercury in-Silastic strain gauges, lower limb venous compliance was measured by inflating a venous collection cuff that was placed on the thigh to 60 mmHg for 8 min and then reducing the pressure to 0 mmHg at a rate of 1 mmHg/s. Venous compliance was calculated as the derivative of the pressure-volume curves. There were no differences between early follicular, ovulatory, and midluteal phases of the menstrual cycle or between high and low hormone phases of oral contraceptive use (P > 0.05). Male venous compliance was significantly greater than in normally menstruating women (P < 0.001) and oral contraceptive users (P < 0.002). These data support a sex difference but also suggest that venous compliance does not change with menstrual cycle phase or during the course of oral contraceptive use. 相似文献
9.
Background
Calcineurin (CaN) is an important serine-threonine phosphatase (PP2B), which plays a crucial role in calcium-calmodulin mediated signal transduction events. Calcineurin has been implicated in pathogenesis of various diseases cardiac hypertrophy, diabetic neuropathy and Alzheimer's, however its role in neoplasia remains unclear. 相似文献10.
Torgrimson BN Meendering JR Kaplan PF Minson CT 《American journal of physiology. Heart and circulatory physiology》2007,292(6):H2874-H2880
Oral contraceptive pills (OCPs) are a popular contraception method. Currently, lower-dose ethinyl estradiol formulations are most commonly prescribed, although they have been linked to increased arterial vascular risk. The aim of this study was to investigate endothelial function in healthy young women using lower-dose ethinyl estradiol OCPs. We examined flow-mediated, endothelium-dependent and nitroglycerin-mediated, endothelium-independent vasodilation of the brachial artery, comparing two doses of ethinyl estradiol/levonorgestrel OCPs in 15 healthy young women on two study days: once during the active phase and once during the placebo phase of an OCP cycle. Group low dose (LD) (n=7) active pills contained 150 microg levonorgestrel/30 microg ethinyl estradiol versus Group very low dose (VLD) (n=8) with 100 microg levonorgestrel/20 microg ethinyl estradiol. Endothelium-dependent vasodilation was lower during the active phase in Group VLD (5.33 +/- 1.77% vs. 7.23 +/- 2.60%; P=0.024). This phase difference was not observed in Group LD (8.00 +/- 0.970% vs. 7.61 +/- 1.07%; P=0.647). Endothelium-independent vasodilation did not differ between phases in either group. Finally, we measured endothelium-dependent vasodilation in two additional women who received 10 microg of unopposed ethinyl estradiol. Endothelium-dependent vasodilation was increased by unopposed ethinyl estradiol compared with the placebo phase (10.88 +/- 2.34% vs. 6.97 +/- 1.83%). These results suggest that levonorgestrel may antagonize the activity of ethinyl estradiol. Thus both the progestin type and estradiol dose need to be considered when assessing arterial vascular risk of OCP use in women. 相似文献