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951.
952.
Thomas Bruun Rasmussen Jannik Fonager Charlotte Svrke Jrgensen Ria Lassaunire Anne Sofie Hammer Michelle Lauge Quaade Anette Boklund Louise Lohse Bertel Strandbygaard Morten Rasmussen Thomas Yssing Michaelsen Sten Mortensen Anders Fomsgaard Graham J. Belsham Anette Btner 《PLoS pathogens》2021,17(11)
Mink, on a farm with about 15,000 animals, became infected with SARS-CoV-2. Over 75% of tested animals were positive for SARS-CoV-2 RNA in throat swabs and 100% of tested animals were seropositive. The virus responsible had a deletion of nucleotides encoding residues H69 and V70 within the spike protein gene as well as the A22920T mutation, resulting in the Y453F substitution within this protein, seen previously in mink. The infected mink recovered and after free-testing of 300 mink (a level giving 93% confidence of detecting a 1% prevalence), the animals remained seropositive. During further follow-up studies, after a period of more than 2 months without any virus detection, over 75% of tested animals again scored positive for SARS-CoV-2 RNA. Whole genome sequencing showed that the viruses circulating during this re-infection were most closely related to those identified in the first outbreak on this farm but additional sequence changes had occurred. Animals had much higher levels of anti-SARS-CoV-2 antibodies in serum samples after the second round of infection than at free-testing or during recovery from initial infection, consistent with a boosted immune response. Thus, it was concluded that following recovery from an initial infection, seropositive mink were readily re-infected by SARS-CoV-2. 相似文献
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Gregory B Hammer Susan T Verghese David R Drover Myron Yaster Joseph R Tobin 《BMC anesthesiology》2008,8(1):1-9
Background
Intermittent measurement of cardiac output may be performed using a lithium dilution technique (LiDCO). This can then be used to calibrate a pulse power algorithm of the arterial waveform which provides a continuous estimate of this variable. The purpose of this study was to examine the duration of accuracy of the pulse power algorithm in critically ill patients with respect to time when compared to measurements of cardiac output by an independent technique.Methods
Pulse power analysis was performed on critically ill patients using a proprietary commercial monitor (PulseCO). All measurements were made using an in-dwelling radial artery line and according to manufacturers instructions. Intermittent measurements of cardiac output were made with LiDCO in order to validate the pulse power measurements. These were made at baseline and then following 1, 2, 4 and 8 hours. The LiDCO measurement was considered the reference for comparison in this study. The two methods of measuring cardiac output were then compared by linear regression and a Bland Altman analysis. An error rate for the limits of agreement (LOA) between the two techniques of less than 30% was defined as being acceptable for this study.Results
14 critically ill medical and surgical patients were enrolled over a three month period. At baseline patients showed a wide range of cardiac output (median 7.5 L/min, IQR 5.1 -9.0 L/min). The bias and limits of agreement between the two techniques was deemed acceptable for the first four hours of the study with percentage errors being 29%, 22%, and 285 respectively. The percentage error at eight hours following calibration increased to 36%. The ability of the PulseCo to detect changes in cardiac output was assessed with a similar analysis. The PulseCO tracked the changes in cardiac output with adequate accuracy for the first four hours with percentage errors being 20%, 24% and 25%. However at eight hours the error had increased to 43%.Conclusion
The agreement between lithium dilution cardiac output and the pulse power algorithm in the PulseCO monitor remains acceptable for up to four hours in critically ill patients. 相似文献956.
Comparisons of levels of variability on the autosomes and X chromosome can be used to test hypotheses about factors influencing patterns of genomic variation. While a tremendous amount of nucleotide sequence data from across the genome is now available for multiple human populations, there has been no systematic effort to examine relative levels of neutral polymorphism on the X chromosome versus autosomes. We analyzed ~210 kb of DNA sequencing data representing 40 independent noncoding regions on the autosomes and X chromosome from each of 90 humans from six geographically diverse populations. We correct for differences in mutation rates between males and females by considering the ratio of within-human diversity to human-orangutan divergence. We find that relative levels of genetic variation are higher than expected on the X chromosome in all six human populations. We test a number of alternative hypotheses to explain the excess polymorphism on the X chromosome, including models of background selection, changes in population size, and sex-specific migration in a structured population. While each of these processes may have a small effect on the relative ratio of X-linked to autosomal diversity, our results point to a systematic difference between the sexes in the variance in reproductive success; namely, the widespread effects of polygyny in human populations. We conclude that factors leading to a lower male versus female effective population size must be considered as important demographic variables in efforts to construct models of human demographic history and for understanding the forces shaping patterns of human genomic variability. 相似文献
957.
Shlush LI Behar DM Yudkovsky G Templeton A Hadid Y Basis F Hammer M Itzkovitz S Skorecki K 《PloS one》2008,3(5):e2105
Background
Phylogenetic mitochondrial DNA haplogroups are highly partitioned across global geographic regions. A unique exception is the X haplogroup, which has a widespread global distribution without major regions of distinct localization.Principal Findings
We have examined mitochondrial DNA sequence variation together with Y-chromosome-based haplogroup structure among the Druze, a religious minority with a unique socio-demographic history residing in the Near East. We observed a striking overall pattern of heterogeneous parental origins, consistent with Druze oral tradition, together with both a high frequency and a high diversity of the mitochondrial DNA (mtDNA) X haplogroup within a confined regional subpopulation. Furthermore demographic modeling indicated low migration rates with nearby populations.Conclusions
These findings were enabled through the use of a paternal kindred based sampling approach, and suggest that the Galilee Druze represent a population isolate, and that the combination of a high frequency and diversity of the mtDNA X haplogroup signifies a phylogenetic refugium, providing a sample snapshot of the genetic landscape of the Near East prior to the modern age. 相似文献958.
Abaunza P. Gordo L. Karlou-Riga C. Murta A. Eltink A.T.G.W. García Santamaría M.T. Zimmermann C. Hammer C. Lucio P. Iversen S.A. Molloy J. Gallo E. 《Reviews in Fish Biology and Fisheries》2003,13(1):27-61
There is a broad knowledge of the growth andreproduction of Trachurus trachurus,although important gaps still exist. Horsemackerel are a long-lived species, reaching upto 40 years of age. They have isometric growth,although the alometric parameter b mayvary throughout the year and in relation tolatitude. Growth to age 3 is rapid compared toslower growth later in life. Phenomena ofdensity dependent growth have been observed inthe northeast Atlantic. Horse mackerel are anasynchronous species. The following stages ofatresia have been validated in horse mackerel:alpha, beta, and delta. The transition infemales from the spawning state to postspawning is very fast. The spawning fraction inhorse mackerel is estimated to be between 8.3%and 20.9%. Horse mackerel have a long spawningseason (up to 8 months), which varies accordingto geography. Length at first maturity isbetween 16 and 25 cm, most commonly around21 cm. Males mature at a slightly smallerlength than females. The age at first maturityfor females has been estimated to range from 2to 4 years, depending on the geography. Batchfecundity has been estimated to range between172–209 oocytes per gram-female-weight. Femalespawning lasts between 65 and 94 days. Anindividual female can release from 5 to 16batches during the spawning period. Theestimated potential annual relative fecundityranges from 1040 to 3280 oocytes pergram-female-weight. 相似文献
959.
A H?llrigl A Hergovich I G?rzer A Bader G Ellersdorfer K Habegger E Hammer S Enzinger Y Capetanaki G Weitzer 《Biochemical and biophysical research communications》2001,289(2):329-336
Introduction of nonselectable mutations into the genome of embryonic stem cells by homologous recombination allows to investigate the function of genes at the molecular level and has been achieved, however, at very low efficiencies by the Hit and Run, Tag and Exchange, and Double Replacement strategies. Comparing those strategies at a single locus with vectors derived from a single fragment of the desmin gene led to the improvement of two strategies by employing a new selection cassette and modified selection procedures. Modified strategies resulted in the introduction of nonselectable point-mutations in 53% of the Hit and Run derived embryonic stem cell clones and in 0.7% of the Tag and Exchange clones. Efficiency of intrachromosomal recombination at Hit alleles outscored replacement-type recombination at the tagged alleles making the modified Hit and Run strategy the method of choice for the efficient introduction of nonselectable point mutations into the genome of embryonic stem cells. 相似文献
960.
Novel Ring Cleavage Products in the Biotransformation of Biphenyl by the Yeast Trichosporon mucoides 总被引:2,自引:0,他引:2 下载免费PDF全文
Rabea Sietmann Elke Hammer Michael Specht Carl E. Cerniglia Frieder Schauer 《Applied microbiology》2001,67(9):4158-4165
The yeast Trichosporon mucoides, grown on either glucose or phenol, was able to transform biphenyl into a variety of mono-, di-, and trihydroxylated derivatives hydroxylated on one or both aromatic rings. While some of these products accumulated in the supernatant as dead end products, the ortho-substituted dihydroxylated biphenyls were substrates for further oxidation and ring fission. These ring fission products were identified by high-performance liquid chromatography, gas chromatography-mass spectrometry, and nuclear magnetic resonance analyses as phenyl derivatives of hydroxymuconic acids and the corresponding pyrones. Seven novel products out of eight resulted from the oxidation and ring fission of 3,4-dihydroxybiphenyl. Using this compound as a substrate, 2-hydroxy-4-phenylmuconic acid, (5-oxo-3-phenyl-2,5-dihydrofuran-2-yl)acetic acid, and 3-phenyl-2-pyrone-6-carboxylic acid were identified. Ring cleavage of 3,4,4′-trihydroxybiphenyl resulted in the formation of [5-oxo-3-(4′-hydroxyphenyl)-2,5-dihydrofuran-2-yl]acetic acid, 4-(4′-hydroxyphenyl)-2-pyrone-6-carboxylic acid, and 3-(4′-hydroxyphenyl)-2-pyrone-6-carboxylic acid. 2,3,4-Trihydroxybiphenyl was oxidized to 2-hydroxy-5-phenylmuconic acid, and 4-phenyl-2-pyrone-6-carboxylic acid was the transformation product of 3,4,5-trihydroxybiphenyl. All these ring fission products were considerably less toxic than the hydroxylated derivatives. 相似文献