Donor‐Specific Antibodies Are Produced Locally in Ectopic Lymphoid Structures in Cardiac Allografts

Cardiac allograft vasculopathy (CAV) is a transplant pathology, limiting graft survival after heart transplantation. CAV arteries are surrounded by ectopic lymphoid structures (ELS) containing B cells and plasma cells. The aim of this study was to characterize the antigenic targets of antibodies produced in ELS. Coronary arteries and surrounding epicardial tissue from 56 transplant recipients were collected during autopsy. Immunofluorescence was used to identify antibody‐producing plasma cells. Immunoglobulin levels in tissue lysates were measured by enzyme‐linked immunosorbent assay and analyzed for donor‐specific HLA antibodies by Luminex assay. Cytokine and receptor expression levels were quantified using quantitative polymerase chain reaction. Plasma cells in ELS were polyclonal and produced IgG and/or IgM antibodies. In epicardial tissue, IgG (p < 0.05) and IgM levels were higher in transplant patients with larger ELS than smaller ELS. In 4 of 21 (19%) patients with ELS, donor‐specific HLA type II antibodies were detected locally. Cytokine and receptor expression (CXCR3, interferon γ and TGF‐β) was higher in large ELS in the epicardial tissue than in other vessel wall layers, suggesting active recruitment and proliferation of T and B lymphocytes. ELS exhibited active plasma cells producing locally manufactured antibodies that, in some cases, were directed against the donor HLA, potentially mediating rejection with major consequences for the graft.     

ST-analysis in electronic foetal monitoring is cost-effective from both the maternal and neonatal perspective

Objective: Electronic foetal monitoring (EFM) together with non-invasive ST-analysis (STAN) has been suggested as a superior technique to EFM alone for foetal surveillance to prevent metabolic acidosis. This study aims to compare the cost-effectiveness of these two techniques from both maternal (short term) as neonatal (long term) perspective to guide clinical decision-making.

Methods: We created two models: a maternal model, focused on the difference in mode of delivery as most important outcome, and a neonatal Markov model focused on the differences in metabolic acidosis – and its relationship to cerebral palsy (CP) – as the most relevant outcome to estimate the long-term cost-effectiveness. The cost to prevent one instrumental delivery was estimated in the maternal model. The costs to prevent one metabolic acidosis and the costs per quality adjusted life years were calculated in the neonatal model.

Results: The average costs of STAN are only €34 higher when compared to EFM alone. From maternal perspective the cost of preventing one instrumental delivery was estimated at €2602. From neonatal perspective the cost to prevent one case of metabolic acidosis was €14 509. Over the long term, STAN becomes a dominant (cost saving) strategy if?>1% of the patients exposed to metabolic acidosis acquire CP.

Conclusions: Our study suggests that STAN, when compared to EFM alone, can be a cost-effective strategy from both a maternal and neonatal perspective.     

The potential shortcomings of measuring hyperactivated motility by computer-aided sperm analysis when sperm motion is multiphasic

This paper was written from the standpoint that computer-aidedsperm analysis (CASA) instruments, which capture a 'snapshot'of sperm trajectories in order to generate their data, may providea poor measure of hyperactivated motility in a sperm populationwhere hyperactivation is multiphasic in nature. To illustratethis point, a series of theoretical sperm populations were constructedwhich varied subtly but significantly in the nature of the hyperactivatedbehaviour expressed by spermatozoa. The parameters which weremanipulated were: (I) the number of hyperactivated phases exhibitedwithin a given period of time; (ii) the duration of these phases;and (iii) proportion of spermatozoa within the population whichexhibited hyperactivated phase. Thee populations were then subjectto an analysis in which snapshots of sperm motion were examinedto determine the percentage of hyperactivated spermatozoa forthat population. The results indicated that whilst this snapshotapproach to quantifying hyperactivation could provide a figurefor the percentage of hyperactivated spermatozoa for that population.The results indicated that whilst this snapshot approach toquantifying hyperactivation could provide a figure for the percentageof hyperactivated spermatozoa within the sample window, thisoften inaccurately described the underlying behaviour of thepopulation. Since there is very likely to be a significant amountof biological information contained within the nature of multiphasicbehaviour, this paper has argued that this aspect of snapshotanalysis is one which requires serious consideration by CASAmanufacturers and medical researchers.     

In vivo treatment of rats with unfractionated heparin (UFH) or low molecular weight heparin (LMWH) does not affect experimentally induced colon carcinoma metastasis

Recent randomized trials have suggested that treatment with low molecular weight heparin (LMWH) improves survival of cancer patients with venous thromboembolism, as compared to treatment with unfractionated heparin (UFH). Experimental studies have shown that UFH has activities besides its anticoagulant function which may affect progression of malignancy, including stimulation of new blood vessel formation. In contrast, LMWH has been suggested to inhibit angiogenesis. In the present study, we compared quantitatively the effects of treatment with UFH, LMWH or placebo on the development of experimentally induced colon carcinoma metastases in rat liver and on tumor-associated angiogenesis. It is shown that UFH and LMWH in therapeutic dosages neither affect development of metastases nor tumor blood vessel formation in this animal model. These results indicate that heparins do not affect colon cancer metastasis in liver. Further studies in other animal models are required to establish the mechanisms by which heparins potentially affect cancer.     

Efficacy of competitive vs noncompetitive blockade of the NMDA channel following traumatic brain injury

N-methyl-d-aspartate (NMDA) receptor antagonists have been demonstrated widely to be neuroprotective in cerebral ischemia, hypoxia, and traumatic brain injury. However, although noncompetitive NMDA antagonists have typically proven efficacious under all of these conditions, competitive antagonists have not been shown to be beneficial following moderate traumatic brain injury. The present study has used phosphorus magnetic resonance spectroscopy ([³¹P]MRS) to examine the effects of the competitive antagonist cis-4-(phosphonomethyl) piperidine-2-carboxylic acid (CGS-19755) and the noncompetitive antagonist dextromethorphan on biochemical outcome following fluid percussion-induced traumatic brain injury in rats. Five minutes prior to induction of moderate (2.8±0.2 atm) fluid percussion brain injury, animals received either CGS-19755 (10 mg/kg iv), dextromethorphan (10 mg/kg iv), or equal volume saline vehicle. [³¹P]MRS spectra were then acquired for 4 h post-trauma and intracellular pH, free magnesium concentration, cytosolic phosphorylation potential, and oxidative capacity determined. Both CGS-19755-treated animals and saline treated controls demonstrated significant and sustained declines in intracellular free magnesium concentration and bioenergetic status following trauma. In contrast, administration of dextromethorphan significantly attenuated free magnesium decline and improved bioenergetic state during the post-traumatic monitoring period. These results suggest that the neuroprotective actions of NMDA antagonists following traumatic brain injury are associated with attenuation of free magnesium decline and that such actions seem to be preferentially mediated by noncompetitive blockers.     

A rat cytomegalovirus strain with a disruption of the r144 MHC class I-like gene is attenuated in the acute phase of infection in neonatal rats

Summary.  We previously generated an RCMV strain in which the r144 gene, encoding a major histocompatibility complex class I homolog, had been deleted (RCMVΔr144). To investigate the role of r144 during acute infection of neonatal rats, we infected three days-old neonatal rats with either RCMVΔr144 or wild type (wt) RCMV and the presence of infectious virus as well as viral DNA in various organs was determined at either 3, 5 or 21 days p.i.. In addition, we as-sessed both type and number of inflammatory cells in these organs. Interestingly, a significantly lower concentration of infectious virus as well as viral DNA was found in spleens of RCMVΔr144-infected rats than in those of wt RCMV-infected animals at 3 days p.i.. At the same time point, a significantly lower amount of infiltrating NK cells and monocytes/macrophages was seen in the spleens of RCMVΔr144-infected rats than in spleens of rats infected with wt RCMV. At 21 days p.i., RCMVΔr144-infected rats were found to have lower virus titers in the salivary glands than wt RCMV-infected animals. Significant differences between RCMVΔr144- and wt RCMV-infected rats were detected neither at other time points nor at other sites. We conclude that after infection of neonatal rats, the replication of RCMVΔr144 is severely restricted compared to wt RCMV. Received May 4, 2001 Accepted July 4, 2001     

Genetic Moderation of Stress Effects on Corticolimbic Circuitry

Stress exposure is associated with individual differences in corticolimbic structure and function that often mirror patterns observed in psychopathology. Gene x environment interaction research suggests that genetic variation moderates the impact of stress on risk for psychopathology. On the basis of these findings, imaging genetics, which attempts to link variability in DNA sequence and structure to neural phenotypes, has begun to incorporate measures of the environment. This research paradigm, known as imaging gene x environment interaction (iGxE), is beginning to contribute to our understanding of the neural mechanisms through which genetic variation and stress increase psychopathology risk. Although awaiting replication, evidence suggests that genetic variation within the canonical neuroendocrine stress hormone system, the hypothalamic-pituitary-adrenal axis, contributes to variability in stress-related corticolimbic structure and function, which, in turn, confers risk for psychopathology. For iGxE research to reach its full potential it will have to address many challenges, of which we discuss: (i) small effects, (ii) measuring the environment and neural phenotypes, (iii) the absence of detailed mechanisms, and (iv) incorporating development. By actively addressing these challenges, iGxE research is poised to help identify the neural mechanisms underlying genetic and environmental associations with psychopathology.