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941.
Nitric oxide (NO) is a powerful vasodilator and an inhibitor of platelet aggregation in vitro. While the ability of NO to modulate vascular tone in vivo has been proven, only a few studies have assessed its platelet inhibitory activity in vivo. We have employed two complementary animal models of pulmonary platelet thromboembolism to assess the antithrombotic activity of endogenous NO in vivo. The inhibition of nitric oxide synthase (NOS) by L-NAME significantly potentiated while the administration of the NOS substrate L-arginine significantly reduced the accumulation of 111In-labelled platelets in the pulmonary vasculature of rabbits induced by intravenous collagen plus epinephrine. L-NAME or L-arginine did not, however, modify 111In-labelled erythrocyte distribution in lungs and phenylephrine had no effect on platelet accumulation following collagen + adrenaline, suggesting that the effects of L-NAME were not due to vasoconstriction but rather to a direct modification of platelet function. In mice, L-NAME significantly reduced the dose of collagen + adrenaline required to induce thromboembolic mortality, increased the fall in circulating platelets and increased the % of pulmonary vessels occluded by platelet thrombi. The effects of L-NAME were reversed by L-arginine but not by a dose of nicardipine exerting maximal vasodilatation. Phenylephrine did not potentiate collagen + adrenaline-induced mortality. In the pulmonary vasculature in vivo, endogenous NO inhibits collagen + adrenaline-induced aggregation and enhances platelet disaggregation. This natural modulator function of NO is exerted via a direct effect on platelets and not as a result of haemodynamic changes. 相似文献
942.
C. Andree C. P. Page J. Slama G. B. Stark E. Eriksson 《European journal of plastic surgery》1999,22(7):322-325
A step toward an improved understanding of the complex mechanisms of growth factor interactions may lie in the detection of
endogenous growth factors during normal wound healing. The findings of this study on standardized full thickness wounds in
swine, provide direct evidence that growth factors were present in the wound fluid in the picogram range (highest concentrations
ranging from 1273 pg/ml for transforming growth factor-beta (TGFβ) to 85.6 pg/ml for platelet-derived growth factor-AB (PDGF-AB
) during healing. The presence of transplanted autologous keratinocyte suspensions and cultured epithelial sheet graft had
no significant effect upon the observed growth factor levels, although transplanted keratinocyte cell suspensions (KCS) and
cultured epidermal autografts (CEA) did accelerate healing in comparison to control wounds in our model (KCS treated wounds
healed in 13.2±0.9 days, CEA in 13.7 days±0.8 and control wounds in 14.7 days±0.3). The variable occurrence of growth factors
during normal wound healing may suggest possible mechanisms of growth factor interaction which could have an impact on the
future design of their therapeutic use.
Received: 28 September 1998 / Accepted: 16 November 1998 相似文献
943.
Ruben Pérez Julio S. Rufas José A. Suja Jesús Page Francisco Panzera 《Chromosome research》2000,8(1):17-25
The meiotic behaviour of the X chromosome and one autosomal pair of the heteropteran Triatoma infestans was analysed by means of C-banding plus DAPI staining. At first metaphase, the X univalent is oriented with its long axis parallel to the equatorial plate, which suggests a holocentric interaction with the spindle fibres. After this initial orientation, kinetic activity is restricted to one of both chromatid ends. The election of the active chromatid end is random and it is independent of the end selected in the sister chromatid. At second metaphase, the X and Y chromatids associate side by side forming a pseudobivalent. After that, the kinetic activity is again restricted to either of both chromosomal ends in a random fashion. At first metaphase, the fourth autosomal bivalent shows two alternative random orientations depending on the chromosome end showing kinetic activity (DAPI positive or opposite). At second metaphase, half bivalents are oriented with their long axis parallel to the equatorial plate. Three different segregation patterns are observed. The kinetic activity can be localised: (i) in the end with the DAPI signal (46.9%), (ii) in the opposite end (44.6%) or (iii) in one DAPI-positive end in one chromatid and in the opposite end in the other one (8.5%). The existence of the last pattern indicates that the same end can show kinetic activity during both meiotic divisions. Our results provide new information on the comparative meiotic behaviour of autosomes and sex chromosomes in holocentric systems. 相似文献
944.
945.
Proteomics is a new enabling technology that is being integrated into the drug discovery process. This will facilitate the systematic analysis of proteins across any biological system or disease, forwarding new targets and information on mode of action, toxicology and surrogate markers. Proteomics is highly complementary to genomic approaches in the drug discovery process and, for the first time, offers scientists the ability to integrate information from the genome, expressed mRNAs, their respective proteins and subcellular localization. It is expected that this will lead to important new insights into disease mechanisms and improved drug discovery strategies to produce novel therapeutics. 相似文献
946.
947.
S Patel PR Turner C Stubberfield E Barry CR Rohlff A Stamps E McKenzie K Young K Tyson J Terrett G Box S Eccles MJ Page 《International journal of cancer. Journal international du cancer》2002,98(6):957-957
The original article to which this Erratum refers was published in International Journal of Cancer; 2002; 97(4) 416–422. 相似文献
948.
A.M. Gilroy D.C. Hermey L.M. DiBenedetto S.C. Marks D.W. Page Q.F. Lei 《Clinical anatomy (New York, N.Y.)》1997,10(5):328-332
The obturator artery and vein are usually described as branches or tributaries of the internal iliac vessels although variations with connections to the external iliac or inferior epigastric vessels have been reported. Because these anomalous vessels are at risk in groin or pelvic surgeries that require dissection or suturing along the pelvic rim, we measured the frequency of these variations in 105 pelvic walls (45 in the United States and 60 in China). Our data show that 70–82% of pelvic halves and 83–90% of whole pelves had an artery, vein, or both in the variant position. Arteries were most often found in the normal position only but normal and anomalous veins were most frequently found together. These data show that it is far more common to find a vessel coursing over the pelvic rim at this site than not and have implications for both pelvic surgeons and anatomists. Clin. Anat. 10:328–332, 1997. © 1997 Wiley-Liss, Inc. 相似文献
949.
Delia Baldassarri Scott E. Page 《Proceedings of the National Academy of Sciences of the United States of America》2021,118(50)
We provide commentaries on the papers included in the Dynamics of Political Polarization Special Feature. Baldassarri reads the contribution of the papers in light of the theoretical distinction between ideological partisanship, which is generally rooted in sociodemographic and political cleavages, and affective partisanship, which is, instead, mostly fueled by emotional attachment and repulsion, rather than ideology and material interests. The latter, she argues, is likely to lead to a runaway process and threaten the pluralistic bases of contemporary democracy. Page sees the contribution of the many distinct models in the ensemble as potentially contributing more than the parts. Individual papers identify distinct causes of polarization as well as potential solutions. Viewed collectively, the papers suggest that the multiple causes of polarization may self-reinforce, which suggests that successful interventions would require a variety of efforts. Understanding how to construct such interventions may require larger models with greater realism. 相似文献
950.