The anti-apoptotic factor Bcl-2 can functionally substitute for the B cell survival but not for the marginal zone B cell differentiation activity of BAFF

The TNF family ligand B cell-activating factor (BAFF, BLyS, TALL-1) is an essential factor for B cell development. BAFF binds to three receptors, BAFF-R, transmembrane activator and CAML interactor (TACI), and B cell maturation antigen (BCMA), but only BAFF-R is required for successful survival and maturation of splenic B cells. To test whether the effect of BAFF is due to the up-regulation of anti-apoptotic factors, TACI-Ig-transgenic mice, in which BAFF function is inhibited, were crossed with transgenic mice expressing FLICE-inhibitory protein (FLIP) or Bcl-2 in the B cell compartment. FLIP expression did not rescue B cells, while enforced Bcl-2 expression restored peripheral B cells and the ability to mount T-dependent antibody responses. However, many B cells retained immaturity markers and failed to express normal amounts of CD21. Marginal zone B cells were not restored and the T-independent IgG3, but not IgM, response was impaired in the TACI-IgxBcl-2 mice. These results suggest that BAFF is required not only to inhibit apoptosis of maturating B cells, but also to promote differentiation events, in particular those leading to the generation of marginal zone B cells.     

Hospital comparisons using a Euro Health Data Base for resource management and strategic planning

A European approach for resource management and strategic planning has been implemented in the HOSCOM project of AIM by defining information standards needed across countries, as well as a methodology to measure resources and costs at the institutional and interinstitutional level. A Euro Health Data Base (EHDB) has been obtained in order to test data availability and comparability as well as to validate models through macrocomparisons using case-mix (DRG's, refined grouping, disease staging) and microcomparisons based on three diseases (cardiac valve replacement, diabetes mellitus and hip fracture). The EHDB's presently based on 274 164 medical record summaries sampled from 7 countries allowed us to build prototypes (using Clipper, Prolog and SQL) in order to export uniform aggregates in the different countries, with standard software tools for statistical comparisons. It showed the present feasibility of using case-mix based on the European Minimum Basic Data Set (MBDS) and the difficulty of obtaining uniform data on resources and costs other than length of stay across countries. Medical data confidentiality was assured but not yet population-based representativity. Given the present state of the EHDB, problems have been clearly identified in order to be solved by international research and development projects in the near future.     

Erythropoiesis and renal transplant pregnancy

OBJECTIVE: To examine erythropoiesis in renal transplant pregnancies. METHODS: Retrospective cohort study of 30 renal transplant cases and 30 age, smoking and parity-matched healthy controls with normal index pregnancy. Retrospective chart review and assay of frozen antenatal serum (for serum erythropoietin concentration [serum EPO]), transferrin receptor protein [TfR], ferritin, folate and B12) were performed. The linear regression equation for normal pregnancy controls was used to calculate predicted [serum EPO] and the observed/predicted (O/P) log [serum EPO] was plotted. The relationship between [serum EPO] and haemoglobin (Hb) among transplant cases was considered to be different from that among controls if the slope of the O/P log [serum EPO] versus Hb regression was significantly different from zero. RESULTS: The transplant (14 cadaveric) to conception interval was (median [range]) 33.5 [4, 189] months. Immunosuppressants were azathioprine (n = 25), cyclosporine (n = 22) and/or prednisone (n = 25). Cases were more often primiparous (20 vs. 7 [controls]; p = 0.01), had pre-existent hypertension (20 vs. 0 [controls]; p < 0.001), developed new/increased hypertension or pre-eclampsia (28 vs. 0 [controls]; p < 0.001) and an antenatal rise in creatinine (14 vs. 2 [controls]; p < 0.001). In early pregnancy, cases had similar EPO (15.2 [2.6, 84.6] vs. 15.7 [6.4, 41.0] [controls] U/L) but lower Hb (101 [65, 129] vs. 116 [106, 150] g/L; p < 0.001). Twenty-two (73%) cases had Hb < 100 g/L (vs. 4 [controls]; p < 0.0001); Hb was comparable at 6 wk postpartum. With advancing gestational age (GA), Hb remained stable and serum EPO increased in both groups. The slope of the O/P log [serum EPO] versus Hb for transplant cases was significantly different from zero within both the 17-28 wk (slope +/- SEM: 0.010 +/- 0.002; p < 0.0001) and the 29-42 wk GA categories (0.006 +/- 0.003; p = 0.02). Cases showed smaller rises in serum TfR (change 481 [- 1471, 2780]) vs. 1119 [- 698, 4195] [controls] ng/mL; p = 0.005). CONCLUSIONS: Anaemia frequently complicates renal transplant pregnancies, in which serum EPO is inappropriately low and the rate of erythropoiesis blunted.     

Crystal structure and functional mapping of human ASMT,the last enzyme of the melatonin synthesis pathway

Abstract: Melatonin is a synchronizer of many physiological processes. Abnormal melatonin signaling is associated with human disorders related to sleep, metabolism, and neurodevelopment. Here, we present the X‐ray crystal structure of human N‐acetyl serotonin methyltransferase (ASMT), the last enzyme of the melatonin biosynthesis pathway. The polypeptide chain of ASMT consists of a C‐terminal domain, which is typical of other SAM‐dependent O‐methyltransferases, and an N‐terminal domain, which intertwines several helices with another monomer to form the physiologically active dimer. Using radioenzymology, we analyzed 20 nonsynonymous variants identified through the 1000 genomes project and in patients with neuropsychiatric disorders. We found that the majority of these mutations reduced or abolished ASMT activity including one relatively frequent polymorphism in the Han Chinese population (N17K, rs17149149). Overall, we estimate that the allelic frequency of ASMT deleterious mutations ranges from 0.66% in Europe to 2.97% in Asia. Mapping of the variants on to the 3‐dimensional structure clarifies why some are harmful and provides a structural basis for understanding melatonin deficiency in humans.     

A Belgian consensus protocol for autologous hematopoietic stem cell transplantation in multiple sclerosis

Multiple sclerosis is considered to be an immune mediated inflammatory disorder of the central nervous system. It mainly affects young, socioeconomic active patients. Although our armamentarium for this disease has significantly evolved in recent years some patients remain refractory to conventional therapies. In these cases, autologous hematopoietic stem cell transplantation can be considered as a therapeutic option. Decreasing morbidity, mortality, and increasing patient awareness have led to rising inquiry by our patients about this treatment option. With the aim of a standardized protocol and data registration, a Belgian working party on stem cell therapy in multiple sclerosis was established. In this paper, we report the consensus protocol of this working party on autologous hematopoietic stem cell transplantation in multiple sclerosis.     

Efficient Detection of Carbapenemase Activity in Enterobacteriaceae by Matrix-Assisted Laser Desorption Ionization?Time of Flight Mass Spectrometry in Less Than 30 Minutes

The recognition of carbapenemase-producing Enterobacteriaceae (CPE) isolates is a major laboratory challenge, and their inappropriate or delayed detection may have negative impacts on patient management and on the implementation of infection control measures. We describe here a matrix-assisted laser desorption ionization−time of flight (MALDI-TOF)-based method to detect carbapenemase activity in Enterobacteriaceae. After a 20-min incubation of the isolate with 0.5 mg/ml imipenem at 37°C, supernatants were analyzed by MALDI-TOF in order to identify peaks corresponding to imipenem (300 Da) and an imipenem metabolite (254 Da). A total of 223 strains, 77 CPE (OXA-48 variants, KPC, NDM, VIM, IMI, IMP, and NMC-A) and 146 non-CPE (cephalosporinases, extended-spectrum β-lactamases [ESBLs], and porin defects), were tested and used to calculate a ratio of imipenem hydrolysis: mass spectrometry [MS] ratio = metabolite/(imipenem + metabolite). An MS ratio cutoff was statistically determined to classify strains as carbapenemase producers (MS ratio of ≥0.82). We validated this method first by testing 30 of our 223 isolates (15 CPE and 15 non-CPE) 10 times to calculate an intraclass correlation coefficient (ICC of 0.98), showing the excellent repeatability of the method. Second, 43 strains (25 CPE and 18 non-CPE) different from the 223 strains used to calculate the ratio cutoff were used as external controls and blind tested. They yielded sensitivity and specificity of 100%. The total cost per test is <0.10 U.S. dollars (USD). This easy-to-perform assay is time-saving, cost-efficient, and highly reliable and might be used in any routine laboratory, given the availability of mass spectrometry, to detect CPE.