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71.
72.
Barbara Matheson Herman E Kwansa Enrico Bucci Annette Rebel Raymond C Koehler 《Journal of applied physiology》2002,93(4):1479-1486
The clinical utility of cross-linked tetrameric hemoglobin solutions is limited by peripheral vasoconstriction thought to be due to scavenging of nitric oxide. In addition, transfusion of crude preparations of hemoglobin polymers can cause arterial hypertension. We tested the hypothesis that eliminating low-molecular-weight components from the polymer solution would prevent extravasation and its associated pressor response. A zero-link polymer of bovine hemoglobin was developed without chemical linkers left between the tetramers. Transfusion of unprocessed preparations of these polymers in rats resulted in appearance of the polymer in the renal hilar lymph. However, eliminating the low-molecular-weight components with a 300-kDa diafiltration resulted in an average hydrodynamic radius of 250 A and in undetectable levels of polymer in hilar lymph. Exchange transfusion in anesthetized rats and cats and in awake cats produced no increase in arterial pressure. In anesthetized cats, exchange transfusion with an albumin solution reduced hematocrit from 30 to 18%, increased cerebral blood flow, and dilated pial arterioles. In contrast, reducing hematocrit by transfusing the diafiltered polymer did not increase cerebral blood flow as pial arterioles constricted. These results are consistent with the hypothesis that the increase in arterial pressure associated with cell-free hemoglobin transfusion depends on hemoglobin extravasation. Constriction observed in the cerebrovascular bed with a nonextravasating hemoglobin polymer at low hematocrit is presumably a regulatory response to prevent overoxygenation at low blood viscosity. 相似文献
73.
G N Roviello M Moccia R Sapio M Valente E M Bucci M Castiglione C Pedone G Perretta E Benedetti D Musumeci 《Journal of peptide science》2006,12(12):829-835
In the present work, we report the synthesis and the characterization of a new chiral nucleoaminoacid, in which a diaminobutyric moiety is connected to the DNA nucleobase by an amidic bond, and its oligomerization to give the corresponding nucleo-gamma-peptide. The ability of this synthetic polymer to bind complementary DNA was studied in order to explore its possible use in antigene/antisense or diagnostic applications. Our interest in the presented DNA analogue was also supported by the importance of gamma-aminoacid-containing compounds in natural products of biological activity and by the known stability of gamma-peptides to enzymatic degradation. Furthermore, our work could contribute to the study of the role of nucleopeptides as prebiotic material in a PNA world that could successively lead to the actual DNA/RNA/protein world, as recently assumed. 相似文献
74.
Amiloride does not alter NaCl avoidance in Fischer-344 rats 总被引:2,自引:2,他引:0
Fischer-344 (F-344) rats differ from other common rat strains in that they
fail to show any preference for NaCl at any concentration in two- bottle
preference tests. Because 100 microM amiloride partially blocks the
NaCl-evoked chorda tympani (CT) response in electrophysiological studies,
we tested NaCl preference (0.068-0.273 M) in F-344 rats with and without
100 microM amiloride solution as the solvent. A third group was tested with
unadulterated NaCl solutions following CT transection. Amiloride had no
significant effect on the NaCl preference-aversion function, whereas CT
transection significantly reduced NaCl avoidance. These results suggest
that the amiloride-sensitive component of the NaCl response is not
necessary for F-344 rats to display avoidance of NaCl, but the entire CT
input is.
相似文献
75.
76.
77.
The highly repetitive Rana/Pol III family consists of short, tandemly arrayed sequences, scattered throughout the genomes of Palearctic green water frogs. The repeat unit is about 250 bp in length and is a composite element: it contains a SINE-like retroposon with a tRNA structure, flanked by two short direct repeats, and the occurrence of two internal repeats gives evidence that an additional transposition event may have inserted a segment within the already transposed element. Rana/Pol III family is present in the genomes of Rana lessonae, R. ridibunda, and their hybrid form R. esculenta, as well as in R. shqiperica. R. epeirotica, R. cretensis, and the Italian taxon. These sequences are also present in the Iberian R. perezi, although less abundant, but appear to be lacking in the north African species R. saharica. The distribution of Rana/Pol III in the genomes of Palearctic green frogs is in agreement with the phyletic history based on genetic data. The evolutionary pattern proposed for the genus Rana enables us to suppose that the hybridogenetic mechanism is one of the factors accounting for the possible horizontal transfer of Rana/Pol III elements from the central-north Europe species to R. perezi. 相似文献
78.
William T. Garside J. Ricardo Loret de Mola Jennifer A. Bucci Richard W. Tureck Susan Heyner 《Molecular reproduction and development》1997,47(1):99-104
Zona pellucida thickness was measured daily in zygotes and cleavage stage embryos. Measurements were performed on a Nikon inverted microscope equipped with Hoffman modulation optics, using an ocular micrometer. Zona thickness of each zygote/embryo was measured four times, the zygote/embryo was then “rolled over,” and four more measurements were repeated for a total of eight. The zygotes/embryos were photographed daily and the measurements repeated on the prints. Subsequently, the mean zona thickness for each stage was calculated. A total of 81 patients (mean age 33.8 ± 4.2) participated in the study. A total of 427 embryos were evaluated. Categorical data differences between groups were evaluated by ANOVA and multiple linear regression. For nominal data, the Kruskal-Wallis test was applied; when P < 0.05 the differences were considered to be significant. We found that the average zona thickness on day 1 of in vitro culture was 17.7 ± 0.14 μm; 16.3 ± 0.14 μm on day 2 and 14.9 ± 0.14 μm on day 3 (P < .0001). When the zona thickness was analyzed in relation to the number of blastomeres on day 3 of culture, there was a highly significant correlation with blastomere number (P < .0001). Similarly, there was a highly significant correlation with embryo grade (P < .005) and fragmentation (P < .001). The data were also analyzed for embryos transferred that resulted in a successful pregnancy, revealing that embryos in a pregnancy cycle had significantly thinner zonae pellucidae (P < .0001), when compared to embryos that were not transferred or from nonconceptual cycles. The average zona thickness also decreased with age, and was most apparent after 35 years. Changes in zona thickness correlated with the number of blastomeres, grade, fragmentation, age and were more evident in embryos transferred from cycles resulting in successful pregnancies. Therefore, zona pellucida measurements should be included in the overall assessment of embryo quality, since this information may be useful in the selection of optimal embryos for transfer. Mol. Reprod. Dev. 47:99–104, 1997. © 1997 Wiley-Liss, Inc. 相似文献
79.
Ie-Bin Lian Yi-Hsien Lin Ying-Chao Lin Hsin-Chou Yang Chee-Jang Chang Cathy SJ Fann 《BMC bioinformatics》2008,9(1):246
Background
Association testing is a powerful tool for identifying disease susceptibility genes underlying complex diseases. Technological advances have yielded a dramatic increase in the density of available genetic markers, necessitating an increase in the number of association tests required for the analysis of disease susceptibility genes. As such, multiple-tests corrections have become a critical issue. However the conventional statistical corrections on locus-specific multiple tests usually result in lower power as the number of markers increases. Alternatively, we propose here the application of the longest significant run (LSR) method to estimate a region-specific p-value to provide an index for the most likely candidate region. 相似文献80.
Hsin-Chou Yang Mei-Chu Huang Ling-Hui Li Chien-Hsing Lin Alice LT Yu Mitchell B Diccianni Jer-Yuarn Wu Yuan-Tsong Chen Cathy SJ Fann 《BMC bioinformatics》2008,9(1):196