1141174724Complement activation induces dysregulation of angiogenic factors and causes fetal loss

Complement is an important effector in pregnancy loss in the antiphospholipid syndrome. We now test the hypothesis that complement activation is a necessary intermediary event in the pathogenesis of recurrent spontaneous miscarriage in DBA/2-mated female CBA/J mice (CBAxDBA), a well-studied model of autoantibody-independent pregnancy failure. Blockade of C3 activation with Crry-Ig completely rescued pregnancies in CBAxDBA mice (Crry-Ig vs untreated 8.5 ± 6.3% fetal resorptions vs 28.0 ± 7.2%, P <  0.01). Inhibition of C5 cleavage with anti-C5 mAb and blockade of C5a receptors with a peptide antagonist also prevented pregnancy loss (8.6 ± 4.4% and 8.0 ± 5.9% resorptions, respectively, P <  0.01 versus control). Inhibition of the alternative pathway resulted in pregnancy outcomes similar to controls (8.4 ± 6.6% versus 9.2 ± 3.2% resorptions). In CBAxDBA matings, we observed elevated plasma levels of soluble VEGF receptor-1 (sVEGFR-1; a potent anti-angiogenic molecule), increased placental inflammatory infiltrates and defective development of placenta. Our complement inhibitory strategies blocked the increase in sVEGFR-1, prevented functional deficiency of VEGF and rescued pregnancies. We confirmed the importance of complement as a proximal effector in in vitro studies; monocytes stimulated with C5a released sVEGFR-1 which sequesters VEGF required for normal placental development. Our data indicate that complement activation leads to recruitment of inflammatory cells and production of inhibitors of angiogenesis (sVEGFR-1) which cause placental dysfunction and fetal injury. These studies identify key innate immune effectors that mediate poor pregnancy outcomes and provide novel and important targets for prevention of recurrent pregnancy loss in patients.     

Effect on platelet properties of exposure to temperatures below 20 degrees C for short periods during storage at 20 to 24 degrees C

Background : When platelet concentrates (PCs) are shipped over long distances, it is not always possible to ensure that their temperature is maintained at 20 to 24°C. In addition, PCs are not agitated as during routine storage. Study Design and Methods : Studies have been conducted to evaluate how exposure to temperatures below 20°C in the absence of agitation influences properties of platelets. In initial studies, exposure to 4°C for 3 or 5 hours or to 12°C for 5 or 17 hours on Day 2 of a 5- to 6-day storage period was associated with a loss of discoid shape. This was reflected by slightly lower but statistically different morphology scores after storage compared to those observed with control platelets that were stored only at 20 to 24°C. In addition, a qualitative difference in morphology was noted in controls and PCs held at 16°C for 17 hours. In more detailed studies, both the in vivo viability and in vitro properties of platelets exposed between Day 1 and Day 2 to either 12°C or 16°C for 17 hours were evaluated. The protocol involved a paired study design (n = 4 for each exposure temperature) with the simultaneous storage of two identical PCs, one exposed to 12 or 16°C and the other one maintained at 20 to 24°C throughout the 5-day storage. Results : Exposure to 12°C significantly reduced (p < 0.05 by paired t test) the in vivo recovery to 37.6 ± 13.8 percent (mean ± 1 SD) from 47.8 ± 11.5 percent and the survival time to 2.0 ± 0.3 days from 6.5 ± 1.4 days. On exposure to 16°C, the differences in viability from those of control units were much less but still significant. The in vivo recovery was 42.7 ± 3.8 percent compared to 49.2 ± 3.0 percent and the survival time was 3.5 ± 1.2 days compared to 6.6 ± 0.3 days. The loss of in vivo viability of the test platelets was associated with a loss of discoid shape, as reflected by morphology scores, extent of shape change, and mean platelet volume. In addition, platelet metabolism also appeared to be affected, as suggested by increased lactate production. All of the in vitro properties except for total ATP and residual glucose that were statistically different from those of controls on exposure to 12°C were also significantly different on exposure to 16°C. Conclusion : These findings demonstrate that platelets undergo substantial changes in in vivo viability and in vitro properties when they are exposed to temperatures below 20°C for short periods.     

A blinded clinical comparison of MR imaging and CT in neuroradiology

The sensitivity and specificity of magnetic resonance (MR) imaging and computed tomography (CT) were compared in blinded readings of images of a consecutive series of patients with subsequently proved diagnoses. Overall, MR imaging was less sensitive than CT because of its lower sensitivity in detecting benign tumors. With a similar experimental protocol, the effects of technical refinements or contrast media on the sensitivity of MR imaging can be determined.     

Percutaneous transluminal dilatation of the iliac artery: long-term results

One hundred fifty-four patients with stenosis of the iliac artery underwent percutaneous transluminal angioplasty (PTA). These patients were followed for 1-7 years. The long-term results of the PTAs were analyzed by computer, and life tables were generated for dilatations of the iliac arteries with unimpaired flow and for those with an obstruction in the outflow tract. The accumulative 7-year patency rate was 90%, which agrees with other reports. This study demonstrates that the long-term results of PTA of iliac arterial stenoses are competitive with reconstructive vascular surgery. PTA should be the treatment of choice in patients with iliac arterial stenoses.     

Effect of response to backtest and housing condition on cell-mediated and humoral immunity in adult pigs

Several recent studies in juvenile pigs demonstrated a relationship between the degree of resistance displayed early in life in a so-called "backtest" and parameters of cell-mediated and humoral immunity. Some of the immune characteristics were reported to depend on the interaction between backtest classification and housing system. In the present study, the effects of backtest classification and housing condition on immune reactivity in adult gilts were examined. At 10 and 17 days of age, female piglets were subjected to the backtest. In this test, each piglet is restrained on its back for 1 min and the number of escape attempts is scored. Pigs classified as high resisting (HR) or low resisting (LR) were selected and housed in groups of six gilts. At 7 months of age, half of the gilts were housed in individual stalls. At 12 months of age, gilts were challenged by immunization with DNP-KLH. Control gilts were treated similarly with a placebo. Blood samples were drawn prior to immunization (Day 0) and weekly thereafter until Day 28. No significant effects of backtest type on cellular and humoral responses against KLH were found. Furthermore, being housed in stalls as compared to groups had no consequences for the immune response and did not induce differences between HR and LR gilts. Differences in behavior and physiology found previously between HR and LR gilts, particularly in gilts in stall housing, may thus be of relatively little importance for immune-related health.     

Histamine dilutions modulate basophil activation

Background:In order to demonstrate that high dilutions of histamine are able to inhibit basophil activation in a reproducible fashion, several techniques were used in different research laboratories.Objective:The aim of the study was to investigate the action of histamine dilutions on basophil activation.Methods:Basophil activation was assessed by alcian blue staining, measurement of histamine release and CD63 expression. Study 1 used a blinded multi-centre approach in 4 centres. Study 2, related to the confirmation of the multi-centre study by flow cytometry, was performed independently in 3 laboratories. Study 3 examined the histamine release (one laboratory) and the activity of H₂ receptor antagonists and structural analogues (two laboratories).Results:High dilutions of histamine (10^–30–10^–38 M) influence the activation of human basophils measured by alcian blue staining. The degree of inhibition depends on the initial level of anti-IgE induced stimulation, with the greatest inhibitory effects seen at lower levels of stimulation. This multicentre study was confirmed in the three laboratories by using flow cytometry and in one laboratory by histamine release. Inhibition of CD63 expression by histamine high dilutions was reversed by cimetidine (effect observed in two laboratories) and not by ranitidine (one laboratory). Histidine tested in parallel with histamine showed no activity on this model.Conclusions:In 3 different types of experiment, it has been shown that high dilutions of histamine may indeed exert an effect on basophil activity. This activity observed by staining basophils with alcian blue was confirmed by flow cytometry. Inhibition by histamine was reversed by anti-H2 and was not observed with histidine these results being in favour of the specificity of this effect We are however unable to explain our findings and are reporting them to encourage others to investigate this phenomenon.Received 11 December 2002; returned for revision 29 January 2003; accepted by A. Falus 12 November 2003     

Regional distribution of α- and γ-type endorphins in rat brain

The regional distribution of Met-enkephalin, beta-endorphin and alpha- and gamma-type endorphins in rat brain was investigated. To that end, brains were dissected into anatomically defined areas. Acetic acid tissue extracts were fractionated using an HPLC system suitable for separation of endorphins and peptide concentrations were subsequently measured by specific radioimmunoassay systems. The distribution of Met-enkephalin and beta-endorphin through the brain was fairly uneven and in accordance with results obtained by others. The peptides alpha-endorphin, gamma-endorphin, des-Tyr-alpha-endorphin (DT alpha E) and des-Tyr-gamma-endorphin (DT gamma E) were detectable in almost all brain areas. Their distribution, however, appeared to be uneven. Hypothalamus and septum showed the highest levels of alpha- and gamma-type endorphins. These regions also contained high amounts of beta-endorphin, underscoring a precursor function of this peptide in the formation of alpha- and gamma-type fragments. In general, levels of alpha-endorphin were higher than those of des-Try-alpha-endorphin, whereas the opposite was found for gamma- and des-Tyr-gamma-endorphin.     

Multiple sclerosis: specificity of MR for diagnosis

The specificity of magnetic resonance (MR) imaging in the diagnosis of multiple sclerosis (MS) has not been measured systematically. Conventional MR head images with sagittal localizer and axial multiple-echo sequences with long repetition times were obtained in 92 patients with clinically verified MS (Schumacher criteria), 100 healthy volunteers, 60 subjects with hypertension, and eight patients with dementia. Two readers, without the aid of any clinical or demographic information, classified each of the 260 studies as MS or not MS. The readers classified the studies again after being supplied with the subjects' ages and sex. True-negative and true-positive diagnoses of MS were tabulated. The specificity of the MR diagnosis of MS (true-negative results in proportion to all non-MS studies) was 95%-99% with all the control groups included. There is a small risk of misinterpreting incidental periventricular white matter foci as plaques of MS in MR studies.     

Binding of angiotensins to rat brain tissue: Structure activity relationship

The binding of ³H-angiotensin II to a synaptosome-enriched fraction of the subcortical part of rat brain was studied. In this fraction specific high-affinity binding sites for angiotensin II were demonstrated. The binding sites were saturated at a ligand concentration of 2×10⁻⁹ M. Scatchard analysis revealed a single class of binding sites with an apparent maximal binding capacity of 14 fmoles/mg of protein and an equilibrium dissociation constant, K_d, of 0.9 × 10⁻⁹ M. The specific binding at the K_d concentration amounted to 59% of the total binding and was reversible. The association and dissociation rate constants (k₁ and k₋₁) were 0.0212 nM⁻¹ min⁻¹ and 0.0196 min⁻¹, respectively. Binding was dependent on both incubation time and tissue concentration in the incubation mixture. Angiotensins with biological activity in the brain, i.e., angiotensins I, II, III, and the fragments (3–8) and (4–8) competed with ³H-angiotensin II for the binding sites with IC₅₀'s of 9×10⁻⁸ M, 2×10⁻⁹ M, 4× 10⁻⁹ M, 4× 10⁻⁷ M and 4×10⁻⁶, respectively. In the presence of 1 mM of the converting enzyme inhibitor SQ 14,225 the IC₅₀ for angiotensin I was 2 × 10⁻⁷ M. Competition by the biologically active fragment angiotensin (5–8) could not be demonstrated. The latter peptide, however, was highly metabolized during the incubation under the assay conditions used. The binding potency of the various angiotensins paralleled their dipsogenic and presser potency. The present data indicate the possible physiological involvement of these binding sites as specific receptors in the actions of angiotensins in the brain.