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1.
ILAN KRAUSE MIRI BLANK BORIS GILBRUT YEHUDA SHOENFELD 《American journal of reproductive immunology (New York, N.Y. : 1989)》1993,29(3):155-161
PURPOSE: To evaluate the effect of aspirin treatment upon fetal loss in mice with experimental antiphospholipid syndrome (APLS). MATERIALS AND METHODS: Experimental APLS was induced in pregnant mice by passive transfer of mouse monoclonal anticardiolipin antibody. The mice were treated with high (100μg/d) or low (10μg/d) does of aspirin, using vitaminC(100μg/d or 10μg/d)as a control. The mice were assessed for the presence of lupus anticoagulants (prolonged aPTT), thrombocytopenia, degree of fetal resorption rate and mean embryo and placental weights. RESULTS: The mice with APLS had a higher fetal resorption rate(45.7± 12.2% vs 2.5 ± 0.4%, P<0.001), reduced placenta mean weight(104 ± 8 mgvs 169 ±7mg, P<0.001), prolonged aPTT (94± 14sec vs 39±4sec, P<0.001), and reduced mean platelet count(597± 186 ± 103/mm3vs 847±51 ± 103/mm3,P<0.001). The groupof mice with APLS, who were treated with low-dose aspirin, had a lower resorption rate (11.1 ±9.3% vs 45.7±12.2%, P<0.001), a higher placenta mean weight (178 ± 8 mg vs 104 ± 8 mg, P<0.001), a higher mean embryo weight (1042 ± 134 mg vs 721±91 mg, P<0.001), and a lower aPTT (58±15 sec vs 94±14 sec, P, <0.001). Micewho were treated with high-dose aspirin also had a lower resorption rate, although not as much as in the low-dose aspirin group (34.2 ± 12.7% vs 45.7 ± 12.2%, P<0.001). CONCLUSION: Aspirin, especially in low dose, has a protective effect against obstetrical complications associated with experimental APLS. 相似文献
2.
Csar O. García A. Kanbour-Shakir Hua Tang Jos F. Molina Luis R. Espinoza Azzudin E. Gharavi 《American journal of reproductive immunology (New York, N.Y. : 1989)》1997,37(1):118-124
PROBLEM: Immunization with β2-glycoprotein I (β2GPI) induces antiphospholipid antibodies (aPL) in normal mice and rabbits. Recently we reported early onset of autoimmunity in MRL/++ mice following immunization with β2GPI. There is a close association between aPL with thrombosis, recurrent fetal loss, and intrauterine growth retardation. In this study we evaluated the effect of β2GPI-induced aPL on pregnancy outcomes in an inbred strain of mice (PL/J). METHOD: Three groups of seven-week-old female PL/J mice (12 per group) were studied. Group A was immunized with β2GPI and group B with ovalbumin; group C was not immunized. After two booster injections, the mice were tested for aPL, anti-DNA by ELISA, and for ANA by indirect immunofluorescence. Platelet count and pregnancy outcomes were studied at the age of 14 weeks. RESULTS: The aPL and anti-DNA levels were higher at 12 and 14 weeks in group A; the optical densities (OD) were 1.72±0.6 and 0.699±0.25 for group A, 0.091 ±0.040 and 0.230±0.47 for group B, and 0.0435±0.003 and 0.119±0.026 for group C (comparing group A with groups B and C combined, P<0.001). ANA titers rose in groups A and B by age, but they were significantly higher at 14 weeks in group A. The mean titers were 1/286, 1/90, and 1/16 for A, B, and C, respectively (P<0.001). The platelet counts were not significantly different among the three groups. The litter size was significantly smaller in group A, as evidenced by the numbers of viable fetuses among the mice that became pregnant in each group: 0.75, 2.45, and 5.5 in groups A, B, and C, respectively. Seven pregnant mice in group A had complete resorption, seven pregnant mice in group B showed focal (partial) resorption areas, and only one mouse in group C had complete resorption of the embryos, as shown by histopathological studies, although the fecundity rate was similar in the three groups. CONCLUSION: Our data suggest a pathogenic role for β2GPI-induced aPL in the development of experimental models of APS in PL/J mice. 相似文献
3.
Antiphospholipid syndrome (APS) is a common autoimmune disease, manifested by vascular thrombosis and fetal loss in the presence
of antiphospholipid antibodies. Orthopedic involvement is a relatively novel and underrecognized feature of APS. In this article
we review the association of primary, secondary, and catastrophic APS with diverse orthopedic conditions, including osteonecrosis
in adult and pediatric patients, bone marrow necrosis, nontraumatic fractures, and some other disorders. 相似文献
4.
Shi Hua Bao Xi Peng Wang Qi De Lin Wen Di Liang Xu Chuan Wei Ding 《American journal of reproductive immunology (New York, N.Y. : 1989)》2008,60(4):372-378
Problem In order to investigate the value of anticardiolipin antibodies (ACA) and anti‐β2‐GPI antibodies detection in screening autoimmune type recurrent spontaneous abortion and its clinic application in antiphospholipid syndrome diagnosis, we adopt repeat combined ACA and anti‐β2‐GPI antibodies detection in this study. Method of study Sera were collected from patients and work‐up was done for detection of ACA and anti‐β2‐GPI antibodies by enzyme‐linked immunosorbent assay (ELISA). The work‐up was done for detection of antibodies once in every 6 weeks for 14 times consecutively. Results The repeated and combined detection of ACA and anti‐β2‐GPI antibodies detection could raise the positivity rate up to 21.8% (P < 0.05) in comparison with positive for ACA alone (14.1%), positive for anti‐β2‐GPI alone (3.1%), and concurrently positive for both ACA and anti‐β2‐GPI antibodies (4.6%). In 91 confirmed positive antiphospholipid antibodies (APA) patients, with more frequent screening for ACA and anti‐β2‐GPI antibodies, more patients with APA were found. The positive rate of five and more screenings was over 81.32%, which was statistically significant (P < 0.05), in comparison with that of four or less screenings (68.13%). Conclusion Our data implied that it would be appropriate to take over five or more screenings of combined ACA and anti‐β2‐GPI antibodies detection in suspect patients to facilitate the positive diagnostic rate for autoimmune type RSA. 相似文献
5.
PENNY CHONG WILLIAM MATZNER WENDELL CHING 《American journal of reproductive immunology (New York, N.Y. : 1989)》1998,40(6):414-417
PROBLEM: Antiphospholipid antibodies (APAs) are important in the etiology of reproductive failure. Studies have shown that binding proteins are necessary for the detection of APAs. One of these, β2-glycoprotein, has been shown to be necessary for detection of anticardiolipin antibodies. It is felt that some APAs may be directed to the binding protein itself, or to a combination of the binding protein and phospholipid. METHOD OF STUDY: In this study, a comparison of APAs vs. anti β2-glycoprotein antibodies was performed on the sera of 123 women younger than 40 years of age with a history of reproductive failure. Antibodies to six phospholipid epitopes, cardiolipin, phosphatidyle-thanolamine, phosphatidylserine, phosphatidylinositol, phosphatidic acid, phosphatidylglycerol, and phosphatidylserine, were measured. RESULTS: Of the 123 women tested, 33 had one or more positive immunoglobulin (Ig)G antibodies to phospholipids, of which 9 were to cardiolipin. However, only 1 of 123 women had IgG antibodies to β2-glycoprotein and she was APA negative. Thirty-eight of 123 women had one or more IgM antibodies to phospholipids, with none directed to cardiolipin IgM. In contrast, only 8 of the 123 women had IgM antibodies to β2-glycoprotein. Five of the eight patients had IgM APA; 4 of 5 had IgM antibodies to PE, 1 to PI. CONCLUSIONS: There is no correlation between β2-glycoprotein antibodies and APA status in this population. To date, our most sensitive test for detecting phospholipid autoimmune-mediated in vitro fertilization failure still appears to be the ELISA assay for APA. 相似文献
6.
Noura Al Jameil Poonam Tyagi Amal Al Shenefy 《International journal of clinical and experimental pathology》2015,8(3):3204-3209
The aim of this research study was to estimate anticardiolipin (IgG & IgM) antibodies (aCL) and lupus anticoagulant (LA) factor in patients of recurrent unexplained pregnancy loss and intrauterine fetal deaths (IUFD). 82 women were selected for this study by virtue of having more than two consecutive unexplained pregnancy losses in their first trimester and were referred by the department of Obstetrics and Gynecology, King Saud Medical City Hospital, Riyadh, KSA. All patients had gone through a standardized investigation sequence. Lupus anticoagulants and Anticardiolipin antibodies (IgM and IgG) were detected in the serum by the enzyme linked immunosorbent assay method. To check the significance of aCL and LA, two-tailed t-test was done. Non parametric data was calculated either by Chi-Square test or Fischer exact test when relevant. Total 82 females grouped as 52 cases of recurrent (≥ 2) mainly first and second trimester miscarriage and 30 cases of recurrent (≥ 2) late intrauterine fetal death. Lupus anticoagulants was observed in twenty one (21) cases (25.6%) while anticardiolipin antibodies IgM and or IgG positive cases were estimated in forty four (44) cases (53.65%). The prevalence of APS in both studied group was thirty five (35) cases (42.68%). Antiphospholipid antibodies are calculated as the most important reason for recurrent abortion. The patients with unexplained recurrent pregnancy loss must be advised to go for a screening test for all this aPL antibodies. 相似文献
7.
Hirsch CS Johnson JL Okwera A Kanost RA Wu M Peters P Muhumuza M Mayanja-Kizza H Mugerwa RD Mugyenyi P Ellner JJ Toossi Z 《Journal of clinical immunology》2005,25(4):353-364
The role of TGF-β TNF-α FasL and Bcl-2 in apoptosis of CD4 T-cells during active TB was studied. Coculture of PBMC from TB patients with neutralizing antibodies to TGF-β or TNF-α decreased spontaneous (P ≤ 0.05) and MTB-induced (P≤ 0.02) T-cell apoptosis by 50–90%, but effects were not additive. Interestingly, only levels of TGF-β in supernatants correlated with rates of spontaneous and MTB-induced apoptosis. FasL surface and mRNA expression were higher in unstimulated and MTB-stimulated PBMC from patients than controls, and neutralization of FasL abrogated apoptosis of T-cells from patients only. Intracellular Bcl-2 protein was lower among unstimulated CD4 T-cells from patients than those from controls (P ≤ 0.02), and MTB stimulation reduced intracellular Bcl-2 content in CD4 T-cells from patients only (P ≤ 0.001). These findings may indicate that, during TB, predisposition of CD4 T-cells to apoptosis may involve both low expression of Bcl-2, and excessive expression of TGF-β TNF-α and FasL. 相似文献
8.
OBJECTIVE: To investigate the close association between different antiphospholipid antibodies (aPL) caused by infection and their appearance together with a prolonged activated partial thromboplastin time (aPTT). METHODS: Sera from 122 children were evaluated in this study. Thirty-seven children with mild to medium prolonged aPTT (>37.2s) and elevated C-reactive protein (CRP) levels during various forms of infections (group 2), 18 children without infections (group 3) but with mild to medium prolonged aPTT and 13 children with infections (group 4) and with elevated CRP-level as well as a control group (group 1) of 54 patients without any infection and normal aPTT and negative CRP levels were investigated with commercially available ELISA tests (AESKU.Diagnostics, Wendelsheim, Germany) for the presence of antibodies directed against cardiolipin (CL), phosphatidylserine (PS) and beta2-glycoprotein I (beta 2GPI). The cutoff for positive results was defined with the healthy, aged matched control group (group 1) using the mean OD values plus 2 standard deviations. The lupus anticoagulant (dilute Russell's Viper Venom time, dRVVT) and coagulation Factor XII were determined with routine tests (Dade Behring). RESULTS: Detection of at least one antibody to phospholipids was possible in 89.2% of group 2. It could be shown that IgM anti-beta 2GPI antibodies were found in 27 (59.5%) of group 2, but only in 1 (5.6%) of group 3 (p=0.024) and only in 4 (7.4%) of the controls (p=0.014). The presence of IgG-anti-beta 2GPI antibodies showed no significant difference in the different groups. Furthermore, children of groups 2, 3 and 4 had statistically significant higher levels of antibodies against PS IgG and PS IgM than controls. Also, antibodies to CL of the IgG-type were more frequently detected in children of group 2 than in controls (p=0.038). Detection of CL-IgM antibodies did not reach a significant level in the comparison of the different groups. CONCLUSION: During commonly acquired infections elevation of aPL of nearly all types seems to be a common process. Mild prolongation of aPTT might reflect this presence of aPL in the course of the infectious disease. Our data suggest that there exists no differences in specificity in comparison to the "pathogenic" aPL but the presence over time might be the trigger for the autoimmune activity to begin. 相似文献
9.
Tojoniaina-Herinjaka Andriamandimbisoa Jean-Emmanuel Kahn Frédéric Bourdain Dominique François Marc Vasse 《Immunobiology》2018,223(12):772-776
Protein Z (PZ) is a vitamin K-dependent protein involved in the down-regulation of coagulation by forming a complex with the protein Z-dependent protease inhibitor. The complex inhibits the activated factor X on phospholipid surface. Presence of anti-PZ (aPZ) antibodies was first described in women with pathological pregnancies but the significance of aPZ antibodies in other pathological situations was poorly studied. In this work we analyzed the frequency of aPZ antibodies in a series of 86 consecutive patients with anticardiolipin (aCL) antibodies and studied the association of aPZ with other antiphospholipid (aPL) antibodies [lupus anticoagulant (LAC) and anti-ß2GP-1 antibodies] and the clinical signification of these aPZ antibodies in term of thrombosis or fetal loss. Anti-PZ antibodies (IgG and IgM) were detected using commercially available ELISA assays. The frequency of aPZ antibodies was 40.7% in the patient group versus 6.8% in a group of 59 healthy volunteers (p?<?0.0001). The frequency of aPZ antibodies significantly increases (p?<?0.05) in patients with a double or triple positivity of aPL antibodies and a higher frequency of aPZ antibodies was observed in patients with LAC (57.7%) than in patients without LAC (25.6%, p?=?0.02). There were no significant differences in aPZ antibodies frequency between patients with and without thrombotic events. Interestingly, among the 8 women with recurrent foetal losses, aPZ antibodies were observed in 7 cases, in agreement with previous observations suggesting that aPZ antibodies may be associated with obstetrical complications. 相似文献
10.
MAYUMI OGASAWARA KOJI AOKI EIJI MATSUURA MITOSHI KUNIMATSU IWAO OHKUBO MONICA GALLI MAKOTO SASAKI YOSHIAKI YAGAMI 《American journal of reproductive immunology (New York, N.Y. : 1989)》1995,34(5):269-273
PROBLEM : Anticardiolipin antibodies (aCL) are commonly associated with recurrent pregnancy loss, though the mechanism is uncertain. Some investigators have indicated that aCL may be directed at a complex made up of cardiolipin and a blood anticoagulant, β2-glycoprotein I (β2GPI). We therefore investigated the effects of β2GPI-dependent aCL IgG enriched fractions, isolated from sera of patients with pregnancy losses, on blood coagulation. METHOD : β2GPI-dependent aCL were prepared from sera of three women with second trimester pregnancy losses, by cardiolipin affinity column chromography, following by anti-β2GPI affinity column chromatography. The effects of β2GPI and β2GPI-dependent aCL on the activation of factor X in vitro were examined. RESULTS : β2GPI inhibited the activation of factor X and β2GPI-dependent aCL blocked this inhibitory effect in a dose dependent manner. CONCLUSION : These results imply the possibility of β2GPI-dependent aCL induce hypercoagulation or thrombus by blocking the inhibitory effect of β2GPI on activation of factor X, which may result in pregnancy loss. 相似文献
11.
Ogasawara M Aoki K Katano K Aoyama T Kajiura S Suzumori K 《American journal of reproductive immunology (New York, N.Y. : 1989)》1999,41(1):86-90
PROBLEM: It is well known that the prevalence of several autoantibodies is higher in patients with recurrent miscarriages than in normal women. However, links between individual autoantibodies are unclear. The present study focuses on the possible association between beta 2-glycoprotein I (beta 2-GPI)-dependent anticardiolipin antibody (aCL), lupus anticoagulant (LA), and antinuclear antibody (ANA) in patients with recurrent miscarriages. METHOD OF STUDY: Three hundred and one patients, with a history of two or more unexplained miscarriages, were studied. The titers of beta 2-GPI-dependent aCL and LA were then compared between single-antibody-positive and three-antibody-positive groups. RESULTS: The prevalences of beta 2-GPI-dependent aCL, LA, and ANA were 3.3, 10.0, and 25.2%, respectively. Four of the 301 patients had all three antibodies. The LA titers in patients with positive values for three antibodies was significantly higher than in cases with only LA. CONCLUSION: beta 2-GPI-dependent aCL, LA, and ANA define three distinct, but partly related populations in patients with recurrent miscarriage. We should test at least two kinds of autoantibodies in recurrent aborters, because it has been found that, e.g., beta 2-GPI-dependent aCL and LA are predictors for miscarriages. 相似文献
12.
N. Del Papa E. Raschi L. Catelli P.L. Meroni M.A. Khamashta K. Ichikawa A. Tincani G. Balestrieri 《American journal of reproductive immunology (New York, N.Y. : 1989)》1997,38(3):212-217
PROBLEM: To investigate the role of the plasma cofactor for antiphospholipid antibodies in antibody binding to endothelial cells. METHOD OF STUDY: a) Evaluation of endothelial cell binding of polyclonal and monoclonal anti-β2 glycoprotein I antibodies; and b) study of the effects of antibody binding: adhesion molecule expression, leukocyte adhesion, and interleukin-1β secretion. RESULTS: Anti-β2 glycoprotein I antibodies bind endothelial cell monolayers in vitro by reacting with the cofactor adhered to the cell membranes. Antibody binding induces an upregulation of adhesion molecules, favours leukocyte adherence, and increases interleukin-1β secretion. Interleukin-1β plays an active role to mediate adhesion molecule expression through an autocrine loop, as shown by the inhibitory effect of interleukin 1 receptor antagonist. CONCLUSIONS: Antiphospholipid antibodies do react with endothelium through the co-factor adhered to their cell membranes and induces a pro-adhesive cell phenotype. 相似文献
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14.
J. ARVIEUX B. ROUSSEL D. PONARD M. G. COLOMB 《Clinical and experimental immunology》1994,95(2):310-315
The IgG subclass and light chain distribution of antiphospholipid antibodies (aPL) occurring in autoimmune patients were determined by means of two radioimmunoassays using either cardiolipinor β2 glycoprotein 1 (β2GP1)-coated microtitre plates and mouse MoAbs. Of 50 sera selected for positivity of anticardiolipin antibodies (ACA) of the IgG isotype, 32 (64%) possessed anti-β2GPl antibodies and their presence was closely associated with clinical features of the antiphospholipid syndrome. Good correlations were found between ACA and anti-β2GP1 antibodies when considering antibody level and patterns of light chain and IgG subclass, suggesting that, overall, the same antibodies were being measured. Light chain analysis showed the polyclonal origin of these antibodies and, in most sera, a trend towards use of λ chain. Among sera positive for anti-β2GP1 antibodies, IgG2 was the major subclass reactive with β2GP1 and cardiolipin (87% and 74β2 of the IgG antibody activity, respectively). In contrast, in the group of 18 sera lacking anti-β2GP1 antibodies, ACA were largely restricted to lgG3, with a lesser contribution by IgGl. A few selected sera from the anti-β2GP1-positive group were shown to contain mixtures of antibodies that required β2GP1 (restricted to IgG2 present in large amounts) and did not require this cofactor (restricted to IgG3 and/or IgG1 present in low amounts) for their reactivity with cardiolipin. There was no contribution of glycosylation to the epitopes recognized by anti-β2GP1 antibodies, even though human anti-carbohydrate antibodies are restricted to the IgG2 subclass. These findings further emphasize the intra- and interindividual heterogeneity of aPL, and should help to discriminate clinically relevant specificies. 相似文献
15.
Magnus Stangenberg Gran Lingman George Roberts Pinar Ozand 《American journal of medical genetics. Part A》1992,44(2):142-144
We report on fetal hydrops presenting at 18 weeks of gestation and diagnosed as β-glucuronidase deficiency. The parents were first cousins and there were 2 previous similar fetal deaths. β-Glucuronidase was absent in cultured fetal fibroblasts and lymphoblasts but was normal in the tested relatives. The activities of other lysosomal enzymes were normal. © 1992 Wiley-Liss, Inc. 相似文献
16.
Liu Li Hao Song Liang Zhong Rong Yang Xiao-Qun Yang Kai-Ling Jiang Bei-Zhong Liu 《International journal of medical sciences》2015,12(10):805-810
Acute promyelocytic leukemia (APL) is a subtype of acute myeloid leukemia (AML). With the application of all-trans retinoic acid (ATRA) and arsenic trioxide (ATO), APL becomes one of best prognosis of leukemia. However, ATRA and ATO are not effective against all APLs. Therefore, a new strategy for APL treatment is necessary. Here, we investigated whether lithium chloride (LiCl), a drug used for the treatment of mental illness, could promote apoptosis in human leukemia NB4 cells. We observed that treatment with LiCl significantly accelerated apoptosis in NB4 cells and led to cell cycle arrest at G2/M phase. Moreover, LiCl significantly increased the level of Ser9-phosphorylated glycogen synthase kinase 3β(p-GSK-3β), and decreased the level of Akt1 protein in a dose-dependent manner. In addition, LiCl inhibition of c-Myc also enhanced cell death with a concomitant increase in β-catnin. Taken together, these findings demonstrated that LiCl promoted apoptosis in NB4 cells through the Akt signaling pathway and that G2/M phase arrest was induced by increase of p-GSK-3β(S9). 相似文献
17.
Stephen J. Simpson Georg A. Hollnder Emiko Mizoguchi Deborah Allen Atul K. Bhan Baoping Wang Cox Terhorst 《European journal of immunology》1997,27(1):17-25
An inflammatory bowel disease (IBD) comparable to human ulcerative colitis is induced upon transfer of T cell-depleted wild-type (F1) bone marrow into syngeneic T cell-deficient (tgε26) mice (F1 → tgε26). Previously we have shown that activated CD4+ T cells predominate in transplanted tgε26 mice, and adoptive transfer experiments verified the potential of these cells to cause disease in immunodeficient recipient mice. Using flow cytometry for the detection of intracellular cytokine expression, we demonstrate in the present study that large numbers of CD4+ and CD8+ TCRαβ+ T cells from the intraepithelial region and lamina propria of the colon of diseased, but not from disease-free mice, produced interferon-γ (IFN-γ) and tumor necrosis factor-α (TNF-α). Large numbers of T cells from peripheral lymphoid tissues of these animals also expressed IFN-α and TNF-α, but few expressed interleukin-4, demonstrating g strong bias towards Th1-type T cell responses in these animals. TCRγδ+ T cells, typically minor constituents of the inflammatory infiltrate of the colon in F1 → tgε26 mice, also expressed IFN-γ at a high frequency upon CD3 stimulation. In light of these findings we examined the potential involvement of TCRγδ+ T cells by testing their ability to induce colitis in tgε26 mice. We report here that tgε26 mice transplanted with T cell-depleted bone marrow from TCRαnull and TCRβnull animals developed IBD. Furthermore, disease in these mice correlated with the development of peripheral and colonic TCRαδ+ T cells capable of IFN-γ production. These results suggest that IFN-γ may be a common mediator of IBD utilized by pathogenic T cells of distinct phenotype. 相似文献
18.
John A. McIntyre Dawn R. Wagenknecht Toshitaka Sugi 《American journal of reproductive immunology (New York, N.Y. : 1989)》1997,37(1):101-110
PROBLEM: Antibodies to phospholipid antigens (aPA) are associated with thrombosis thrombocytopenia and recurrent pregnancy loss. Contemporary data show many aPA target phospholipid-binding plasma proteins and not phospholipids. The purpose of this overview is to describe several phospholipid-binding proteins and provide data to demonstrate how the interaction between phospholipids and phospholipid binding proteins results in expression of neo-autoantigenic epitopes. METHOD: Review of existing data. RESULTS: Illustrations of how certain plasma proteins β2 glycoprotein I, prothrombin, high and low molecular weight kininogens interact with the anionic phospholipids, cardiolipin and phosphatidylserine and the zwitterionic phospholipid, phosphatidylethanolamine are shown and discussed. A model of aPA mediated thrombosis is presented. CONCLUSIONS: Some aPA recognize phospholipids directly, however, the majority and many which correlate with pathology target phospholipid binding proteins. Published data indicate that aPA represent a constellation of antibodies with multiple specificities. Insight into mechanisms responsible for aPA-associated thrombosis should provide a basis for treatment. 相似文献
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20.
Acute blockade of β1-receptors in the asphyxiated sheep fetus. Acta Physiol Scand 130 , 381–385. Received 5 November 1986, accepted 9 February 1987. ISSN 0001–6772. Department of Paediatrics, Landspitalinn, University Hospital, Reykjavik, Iceland and Department of Physiology and Department of Paediatrics I, University of Goteborg, Sweden. The effects of acute β1-blockade on fetal cardiovascular reactions during asphyxia were evaluated in 11 exteriorized sheep fetuses. Gestational age was 110–142 days. Asphyxia was induced either by ventilating the mother with low oxygen gas mixture or by mechanical reduction of placental blood flow. During asphyxia all fetuses reacted to metoprolol injection with a decrease in heart rate, myocardial contractility, cardiac output and arterial blood pressure. Five experiments resulted in irreversible fetal cardiovascular collapse. Isoprenaline was given to the fetuses during hypoxia to test the ability to further increase heart rate and activate myocardial β-adrenoceptors. In those experiments with fetal cardiovascular demise after metoprolol, the isoprenaline injection did not result in a significant tachycardia. The surviving fetuses could increase their heart rate as a sign of a capacity to further increase the sympatho-adrenergic drive. 相似文献