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1.
A study of 10 infants in severe metabolic acidemia (pH below 7) led to the conclusion that the clinical signs—hyperventilation, coma or lethargy, peripheral vascular collapse, a significantly palpable liver, and abdominal distension—may all be directly related to the metabolic acidemia. In five of 10 infants, an initial erroneous diagnosis of congestive heart failure or pneumonia was made. Dramatic clinical improvement followed correction of the acidemia with rapid intravenous administration of sodium bicarbonate. This rapid administration of sodium bicarbonate was safe, provided hypocalcemia was recognized and treated in its early stages. In severe metabolic acidemia the measurement of blood bicarbonate alone does not reflect adequately the magnitude of the acid-base derangement and repeated measurements of hydrogen ion concentration, Pco2 and bicarbonates are needed to evaluate and treat such infants correctly. 相似文献
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Population genetics and phylogenetics of DNA sequence variation at multiple loci within the Drosophila melanogaster species complex 总被引:14,自引:1,他引:13
Two regions of the genome, a 1-kbp portion of the zeste locus and a 1.1-
kbp portion of the yolk protein 2 locus, were sequenced in six individuals
from each of four species: Drosophila melanogaster, D. simulans, D.
mauritiana, and D. sechellia. The species and strains were the same as
those of a previous study of a 1.9-kbp region of the period locus. No
evidence was found for recent balancing or directional selection or for the
accumulation of selected differences between species. Yolk protein 2 has a
high level of amino acid replacement variation and a low level of
synonymous variation, while zeste has the opposite pattern. This contrast
is consistent with information on gene function and patterns of codon bias.
Polymorphism levels are consistent with a ranking of effective population
sizes, from low to high, in the following order: D. sechellia, D.
melanogaster, D.mauritiana, and D. simulans. The apparent species
relationships are very similar to those suggested by the period locus
study. In particular, D. simulans appears to be a large population that is
still segregating variation that arose before the separation of D.
mauritiana and D. sechellia. It is estimated that the separation of
ancestral D. melanogaster from the other species occurred 2.5-3.4 Mya. The
separations of D. sechellia and D. mauritiana from ancestral D. simulans
appear to have occurred 0.58- 0.86 Mya, with D. mauritiana having diverged
from ancestral D. simulans 0.1 Myr more recently than D. sechellia.
相似文献
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Madin-Darby canine kidney cells deacylate arachidonic acid from cellular phospholipid in response to 12-O-tetradecanoyl-phorbol-13-acetate (TPA) and convert the free arachidonic acid to prostaglandins. We have used this system to characterize the acyl specificity of deacylation. Cells were labeled with either [14C]linoleic, [14C]eicosatrienoic (delta 8,11,14 or delta 5,8,11), or [14C]arachidonic acid and stimulated with 10 nM TPA. We found that TPA stimulated the deacylation of all four acids, primarily from phosphatidylethanolamine and phosphatidylcholine.l Only products from linoleic (presumably through chain elongation and desaturation), eicosatrienoic (delta 8,11,14), and arachidonic acids produced prostaglandins. Those produced from linoleic and eicosatrienoic acid (delta 8,11,14)-labeled cells were determined to be primarily of the 1-series, while arachidonic acid-labeled cells produced prostaglandins of the 2-series. Together these results indicate that the stimulated deacylation of phospholipids is not specific for arachidonic acid and that the membrane acyl composition controls the particular series of prostaglandin which is produced. 相似文献
6.
The arterio--alveolar nitrogen difference (aADN2) has been associated in 27 normal adult subjects aged 20--60 years. As it may be assumed that venous and arterial PN2 are identical, we have used a sample of venous blood. There is a significant positive correlation between aADN2 and age. As the increase of aADN2 with age resembles that found in the literature for AaDO2, we concluded that the latter may be explained by increasing VA/Qc inequality within the lung. 相似文献
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Felix E.G. Beaudry Spencer C.H. Barrett Stephen I. Wright 《Evolution; international journal of organic evolution》2020,74(2):256-269
Empirical evidence from several animal groups suggests sex chromosomes disproportionately contribute to reproductive isolation. This effect may be enhanced when sex chromosomes are associated with turnover of sex determination systems resulting from structural rearrangements to the chromosomes. We investigated these predictions in the dioecious plant Rumex hastatulus, which is composed of populations of two different sex chromosome cytotypes caused by an X-autosome fusion. Using population genomic analyses, we investigated the demographic history of R. hastatulus and explored the contributions of ancestral and neo-sex chromosomes to population genetic divergence. Our study revealed that the cytotypes represent genetically divergent populations with evidence for historical but not contemporary gene flow between them. In agreement with classical predictions, we found that the ancestral X chromosome was disproportionately divergent compared with the rest of the genome. Excess differentiation was also observed on the Y chromosome, even when we used measures of differentiation that control for differences in effective population size. Our estimates of the timing of the origin of neo-sex chromosomes in R. hastatulus are coincident with cessation of gene flow, suggesting that the chromosomal fusion event that gave rise to the origin of the XYY cytotype may have also contributed to reproductive isolation. 相似文献