Serum-Mediane von Placentaprotein-Markern: Relevanz der Unterschiede zwischen spontanen und nach-in-vitro-Fertilisation eingetretenen Schwangerschaften für das fetale Trisomie-Screening.

Trisomy-21 (Down syndrome) is the most frequent chromosomal abnorm- ality but only one third of cases would be detected by amniocentesis based on maternal age alone. Serum screening tests in the early second trimester increase the detec- tion rate to 60-65%, and more recently it was found that such screening was also possible in the first trimester by quantifying a diffe- rent panel of markers. The concen- trations of these placental proteins are strongly dependent on gestatio- nal age; thus control medians must be established and precise dating is essential. Serum chorionic gonado- trophin (HCG) levels were recently found to be increased in IVF preg- nancies compared to spontaneous gestations, leading to a falsely ele- vated trisomy screening risk. The aim of this preliminary study was to find out whether, in the first-trime- ster screening, the markers similarly differed between IVF and spontane- ous pregnancies which would call for the establishment of separate normal medians for IVF patients. We compared 24 pregnancies ob- tained after ovarian stimulation and IVF with six women after thawed embryo transfer (unstimulated cycle) and 63 gestation- and maternal-age matched spontaneously pregnant controls. A single serum was ob- tained between 6 and 16 weeks of gestation and various placental protein levels determined by im- munometric assays. Serum levels of pregnancy-associated plasma protein A (PAPP-A), which is the major marker in the first-trimes- ter screening test, were reduced in IVF pregnancies: after 9 weeks of gestation, multiples of median (MoMs) ranged between 0.23 and 3.58 (logarithmic mean 0.743). For the frozen/thawed transfers, this value was 1.08. In the 9-12 week group containing 6 cases of IVF, three thawed transfers and 25 con- trols, PAPP-A was significantly redu- ced in the stimulated compared to the nonstimulated cycles. In the late first and early second trimester the difference was not significant in our small group but the trend persisted. Pregnancies after IVF will thus show an increased incidence of false positive results in fetal trisomy-21 screening, and special medians should be established for these pati- ents.

Patient-ventilator asynchrony during noninvasive ventilation: a bench and clinical study.

BACKGROUND: Different kinds of ventilators are available to perform noninvasive ventilation (NIV) in ICUs. Which type allows the best patient-ventilator synchrony is unknown. The objective was to compare patient-ventilator synchrony during NIV between ICU, transport-both with and without the NIV algorithm engaged-and dedicated NIV ventilators. METHODS: First, a bench model simulating spontaneous breathing efforts was used to assess the respective impact of inspiratory and expiratory leaks on cycling and triggering functions in 19 ventilators. Second, a clinical study evaluated the incidence of patient-ventilator asynchronies in 15 patients during three randomized, consecutive, 20-min periods of NIV using an ICU ventilator with and without its NIV algorithm engaged and a dedicated NIV ventilator. Patient-ventilator asynchrony was assessed using flow, airway pressure, and respiratory muscles surface electromyogram recordings. RESULTS: On the bench, frequent auto-triggering and delayed cycling occurred in the presence of leaks using ICU and transport ventilators. NIV algorithms unevenly minimized these asynchronies, whereas no asynchrony was observed with the dedicated NIV ventilators in all except one. These results were reproduced during the clinical study: The asynchrony index was significantly lower with a dedicated NIV ventilator than with ICU ventilators without or with their NIV algorithm engaged (0.5% [0.4%-1.2%] vs 3.7% [1.4%-10.3%] and 2.0% [1.5%-6.6%], P < .01), especially because of less auto-triggering. CONCLUSIONS: Dedicated NIV ventilators allow better patient-ventilator synchrony than ICU and transport ventilators, even with their NIV algorithm. However, the NIV algorithm improves, at least slightly and with a wide variation among ventilators, triggering and/or cycling off synchronization.

Denosumab for prevention of fractures in postmenopausal women with osteoporosis.

BACKGROUND: Denosumab is a fully human monoclonal antibody to the receptor activator of nuclear factor-kappaB ligand (RANKL) that blocks its binding to RANK, inhibiting the development and activity of osteoclasts, decreasing bone resorption, and increasing bone density. Given its unique actions, denosumab may be useful in the treatment of osteoporosis. METHODS: We enrolled 7868 women between the ages of 60 and 90 years who had a bone mineral density T score of less than -2.5 but not less than -4.0 at the lumbar spine or total hip. Subjects were randomly assigned to receive either 60 mg of denosumab or placebo subcutaneously every 6 months for 36 months. The primary end point was new vertebral fracture. Secondary end points included nonvertebral and hip fractures. RESULTS: As compared with placebo, denosumab reduced the risk of new radiographic vertebral fracture, with a cumulative incidence of 2.3% in the denosumab group, versus 7.2% in the placebo group (risk ratio, 0.32; 95% confidence interval [CI], 0.26 to 0.41; P<0.001)--a relative decrease of 68%. Denosumab reduced the risk of hip fracture, with a cumulative incidence of 0.7% in the denosumab group, versus 1.2% in the placebo group (hazard ratio, 0.60; 95% CI, 0.37 to 0.97; P=0.04)--a relative decrease of 40%. Denosumab also reduced the risk of nonvertebral fracture, with a cumulative incidence of 6.5% in the denosumab group, versus 8.0% in the placebo group (hazard ratio, 0.80; 95% CI, 0.67 to 0.95; P=0.01)--a relative decrease of 20%. There was no increase in the risk of cancer, infection, cardiovascular disease, delayed fracture healing, or hypocalcemia, and there were no cases of osteonecrosis of the jaw and no adverse reactions to the injection of denosumab. CONCLUSIONS: Denosumab given subcutaneously twice yearly for 36 months was associated with a reduction in the risk of vertebral, nonvertebral, and hip fractures in women with osteoporosis. (ClinicalTrials.gov number, NCT00089791.)

Implication of Nerve Growth Factor in intestinal mucosal mast cell activity and colonic motor alterations in a model of ovalbumin-induced gut dysfunction in rats

We determined NGF involvement in MMCs and colonic motor alterations in an ovalbumin (OVA)-induced gut dysfunction model in rats. Animals received OVA (6 weeks), with/without simultaneous K252a (TrkA antagonist) treatment. MMCs, rat mast cell protease II (RMCPII) levels and colonic contractility in vitro were assessed. OVA increased MMC density and RMCPII concentration. Spontaneous contractility was similar in both groups and inhibited by K252a. Carbachol responses were increased by OVA in a K252a-independent manner. NO-synthase inhibition increased spontaneous activity in OVA-treated animals in a K252a-dependent manner. These observations support an involvement of NGF in the functional changes observed in this model.

Mycoplasma hominis in mid-trimester amniotic fluid : relation to pregnangy outcome

RESUME Introduction : Les naissances prématurées compliquent 6-10 % des grossesses dans les pays industrialisés et contribuent de façon notable aux taux de mortalité périnatale et de morbidité néonatale. Il a été démontré que la colonisation bactérienne du liquide amniotique joue un rôle dans l'étiologie des accouchements prématurés spontanés et des ruptures prématurées des membranes. Le but de ce travail était d'évaluer la présence de Mycoplasma hominis dans le liquide amniotique prélevé au 2eme trimestre de grossesse chez des patientes asymptomatiques et de déterminer son association avec une issue défavorable de la grossesse. Matériels et méthodes : Les échantillons de liquide amniotique de 456 patientes ayant subi une amniocentèse trans-abdominale entre les 15eme et I7eme semaines de grossesse pour diverses indications ont été testés par PCR (Polymerase Chain Reaction) afin d'identifier Mycoplasma hominis. Les produits ainsi amplifiés étaient ensuite détectés par ELISA (Enzyme-Linked Immunosorbent Assay). Les données cliniques étaient obtenues après l'accouchement. Résultats : Mycoplasma hominis a été identifié dans 29 (6,4%) des échantillons de liquide amniotique. Le taux de menace d'accouchement prématuré chez les patientes positives pour Mycoplasma hominis (14,3%) était plus élevé que chez les patientes négatives (3,3 %) (p=0,01). De même, les naissances prématurées spontanées avec membranes intactes étaient plus fréquentes chez les patientes positives (10,7%) que chez les patientes négatives (1,9 %) (p=0,02). Le taux de menace d'accouchement prématuré lors d'une grossesse antérieure était plus de trois fois plus élevé chez les patientes positives, cependant ce résultat n'était pas statistiquement significatif. Finalement, la présence du mycoplasme n'était pas corrélée à la gestose, au retard de croissance intra-utérin ou aux anomalies chromosomiques foetales. Conclusions : Les résultats montrent que la présence de Mycoplasma hominis dans le liquide amniotique prélevé entre les 15eme et I7eme semaines d' aménorrhée chez des patientes asymptomatiques est associée à un taux plus élevé de menace d'accouchement prématuré et de naissances prématurées spontanées. La détection de ce microorganisme au 2eme trimestre de la grossesse peut donc identifier les patientes à risque de menace d'accouchement et de naissance prématurées. Abstract Objective: The relationship between detection of Mycoplasma hominis in mid-trimester amniotic fluid and subsequent pregnancy outcome was investigated. Study design: Amniotic fluids from 456 women of European background who underwent a transabdominal amniocentesis at weeks 15-17 of pregnancy were tested for M. hominis by polymerase chain reaction (PCR). The amplicons were hybridized to an internal probe and detected by ELISA. Pregnancy outcomes and clinical data were subsequently obtained. Results: M. hominis were identified in 29 (6.4%) of the amniotic fluids. The rate of preterm labor in women positive for M. hominis (14.3%) was higher than in the negative women (3.3%) (p = 0.01). Similarly, a spontaneous preterm birth with intact membranes occurred in 10.7% of the M. hominis-posltive women as opposed to only 1.9% of the negative women (p = 0.02). The presence of this mycoplasma was not correlated with fetal chromosomal aberrations, intrauterine growth restriction or preeclampsia. Conclusions: Detection of M. hominis in second-trimester amniotic fluids can identify women at increased risk for subsequent preterm labor and delivery.

'Hearts and bones': the ups and downs of 'plasticity' in stem cell biology.

More than a decade ago, 'plasticity' suddenly became a 'fashionable' topic with overemphasized implications for regenerative medicine. The concept of 'plasticity' is supported by old transplantation work, at least for embryonic cells, and metaplasia is a classic example of plasticity observed in patients. Nevertheless, the publication of a series of papers showing rare conversion of a given cell type into another unrelated cell raised the possibility of using any unaffected tissue to create at will new cells to replace a different failing tissue or organ. This resulted in disingenuous interpretations and a reason not to fund anymore research on embryonic stem cells (ESc). Moreover, many papers on plasticity were difficult to reproduce and thus questioned; raising issues about plasticity as a technical artefact or a consequence of rare spontaneous cells fusion. More recently, reprogramming adult differentiated cells to a pluripotent state (iPS) became possible, and later, one type of differentiated cell could be directly reprogrammed into another (e.g. fibroblasts into neurons) without reverting to pluripotency. Although the latter results from different and more robust experimental protocols, these phenomena also exemplify 'plasticity'. In this review, we want to place 'plasticity' in a historical perspective still taking into account ethical and political implications.

Muscimol-induced death of GABAergic neurons in rat brain aggregating cell cultures.

During brain development, spontaneous neuronal activity has been shown to play a crucial role in the maturation of neuronal circuitries. Activity-related signals may cause selective neuronal cell death and/or rearrangement of neuronal connectivity. To study the effects of sustained inhibitory activity on developing inhibitory (GABAergic) neurons, three-dimensional primary cell cultures of fetal rat telencephalon were used. In relatively immature cultures, muscimol (10 microns), a GABAA receptor agonist, induced a transient increase in apoptotic cell death, as evidenced by a cycloheximide-sensitive increase of free nucleosomes and an increased frequency of DNA double strand breaks (TUNEL labeling). Furthermore, muscimol caused an irreversible reduction of glutamic acid decarboxylase activity, indicating a loss of GABAergic neurons. The muscimol-induced death of GABAergic neurons was attenuated by the GABAA receptor blockers bicuculline (100 microns) and picrotoxin (100 microns), by depolarizing potassium concentrations (30 mM KCl) and by the L-type calcium channel activator BAY K8644 (2 microns). As compared to the cholinergic marker (choline acetyltransferase activity), glutamic acid decarboxylase activity was significantly more affected by various agents known to inhibit neuronal activity, including tetrodotoxin (1 micron), flunarizine (5 microns), MK 801 (50 microns) and propofol (40 microns). The present results suggest that the survival of a subpopulation of immature GABAergic neurons is dependent on sustained neuronal activity and that these neurons may undergo apoptotic cell death in response to GABAA autoreceptor activation.

Sub-cortical and brainstem sites associated with chemo-stimulated increases in ventilation in humans.

We investigated the neural basis for spontaneous chemo-stimulated increases in ventilation in awake, healthy humans. Blood oxygen level dependent (BOLD) functional MRI was performed in nine healthy subjects using T2 weighted echo planar imaging. Brain volumes (52 transverse slices, cortex to high spinal cord) were acquired every 3.9 s. The 30 min paradigm consisted of six, 5-min cycles, each cycle comprising 45 s of hypoxic-isocapnia, 45 s of isooxic-hypercapnia and 45 s of hypoxic-hypercapnia, with 55 s of non-stimulatory hyperoxic-isocapnia (control) separating each stimulus period. Ventilation was significantly (p<0.001) increased during hypoxic-isocapnia, isooxic-hypercapnia and hypoxic-hypercapnia (17.0, 13.8, 24.9 L/min respectively) vs. control (8.4 L/min) and was associated with significant (p<0.05, corrected for multiple comparisons) signal increases within a bilateral network that included the basal ganglia, thalamus, red nucleus, cerebellum, parietal cortex, cingulate and superior mid pons. The neuroanatomical structures identified provide evidence for the spontaneous control of breathing to be mediated by higher brain centres, as well as respiratory nuclei in the brainstem.

Effects of physiological self-crowding of DNA on shape and biological properties of DNA molecules with various levels of supercoiling.

DNA in bacterial chromosomes and bacterial plasmids is supercoiled. DNA supercoiling is essential for DNA replication and gene regulation. However, the density of supercoiling in vivo is circa twice smaller than in deproteinized DNA molecules isolated from bacteria. What are then the specific advantages of reduced supercoiling density that is maintained in vivo? Using Brownian dynamics simulations and atomic force microscopy we show here that thanks to physiological DNA-DNA crowding DNA molecules with reduced supercoiling density are still sufficiently supercoiled to stimulate interaction between cis-regulatory elements. On the other hand, weak supercoiling permits DNA molecules to modulate their overall shape in response to physiological changes in DNA crowding. This plasticity of DNA shapes may have regulatory role and be important for the postreplicative spontaneous segregation of bacterial chromosomes.

Variability of gait patterns during unconstrained walking assessed by satellite positioning (GPS).

It is established that the ratio between step length (SL) and step frequency (SF) is constant over a large range of walking speed. However, few data are available about the spontaneous variability of this ratio during unconstrained outdoor walking, in particular over a sufficient number of steps. The purpose of the present study was to assess the inter- and intra-subject variability of spatio-temporal gait characteristics [SL, SF and walk ratio (WR=SL/SF)] while walking at different freely selected speeds. Twelve healthy subjects walked three times along a 100-m athletic track at: (1). a slower than preferred speed, (2). preferred speed and (3). a faster than preferred speed. Two professional GPS receivers providing 3D positions assessed the walking speed and SF with high precision (less than 0.5% error). Intra-subject variability was calculated as the variation among eight consecutive 5-s samples. WR was found to be constant at preferred and fast speeds [0.41 (0.04) m.s and 0.41 (0.05) m.s respectively] but was higher at slow speeds [0.44 (0.05) m.s]. In other words, between slow and preferred speed, the speed increase was mediated more by a change in SF than SL. The intra-subject variability of WR was low under preferred [CV, coefficient of variation = 1.9 (0.6)%] and fast [CV=1.8 (0.5)%] speed conditions, but higher under low speed condition [CV=4.1 (1.5)%]. On the other hand, the inter-subject variability of WR was 11%, 10% and 12% at slow, preferred and fast walking speeds respectively. It is concluded that the GPS method is able to capture basic gait parameters over a short period of time (5 s). A specific gait pattern for slow walking was observed. Furthermore, it seems that the walking patterns in free-living conditions exhibit low intra-individual variability, but that there is substantial variability between subjects.

The beta-catenin--TCF-1 pathway ensures CD4(+)CD8(+) thymocyte survival.

The association of trans-acting T cell factors (TCFs) or lymphoid enhancer factor 1 (LEF-1) with their coactivator beta-catenin mediates transient transcriptional responses to extracellular Wnt signals. We show here that T cell maturation depends on the presence of the beta-catenin--binding domain in TCF-1. This domain is necessary to mediate the survival of immature CD4(+)CD8(+) double-positive (DP) thymocytes. Accelerated spontaneous thymocyte death in the absence of TCF-1 correlates with aberrantly low expression of the anti-apoptotic protein Bcl-x(L). Increasing anti-apoptotic effectors in thymocytes by the use of a Bcl-2 transgene rescued TCF-1-deficient DP thymocytes from apoptosis. Thus, TCF-1, upon association with beta-catenin, transiently ensures the survival of immature T cells, which enables them to generate and edit T cell receptor (TCR) alpha chains and attempt TCR-mediated positive selection.

NLRP3 Suppresses NK Cell-Mediated Responses to Carcinogen-Induced Tumors and Metastases.

The NLRP3 inflammasome acts as a danger signal sensor that triggers and coordinates the inflammatory response upon infectious insults or tissue injury and damage. However, the role of the NLRP3 inflammasome in natural killer (NK) cell-mediated control of tumor immunity is poorly understood. Here, we show in a model of chemical-induced carcinogenesis and a series of experimental and spontaneous metastases models that mice lacking NLRP3 display significantly reduced tumor burden than control wild-type (WT) mice. The suppression of spontaneous and experimental tumor metastases and methylcholanthrene (MCA)-induced sarcomas in mice deficient for NLRP3 was NK cell and IFN-γ-dependent. Focusing on the amenable B16F10 experimental lung metastases model, we determined that expression of NLRP3 in bone marrow-derived cells was necessary for optimal tumor metastasis. Tumor-driven expansion of CD11b(+)Gr-1(intermediate) (Gr-1(int)) myeloid cells within the lung tumor microenvironment of NLRP3(-/-) mice was coincident with increased lung infiltrating activated NK cells and an enhanced antimetastatic response. The CD11b(+)Gr-1(int) myeloid cells displayed a unique cell surface phenotype and were characterized by their elevated production of CCL5 and CXCL9 chemokines. Adoptive transfer of this population into WT mice enhanced NK cell numbers in, and suppression of, B16F10 lung metastases. Together, these data suggested that NLRP3 is an important suppressor of NK cell-mediated control of carcinogenesis and metastases and identify CD11b(+)Gr-1(int) myeloid cells that promote NK cell antimetastatic function. Cancer Res; 72(22); 5721-32. ©2012 AACR.

Narcolepsy and familial advanced sleep-phase syndrome: molecular genetics of sleep disorders.

Sleep disorders are very prevalent and represent an emerging worldwide epidemic. However, research into the molecular genetics of sleep disorders remains surprisingly one of the least active fields. Nevertheless, rapid progress is being made in several prototypical disorders, leading recently to the identification of the molecular pathways underlying narcolepsy and familial advanced sleep-phase syndrome. Since the first reports of spontaneous and induced loss-of-function mutations leading to hypocretin deficiency in human and animal models of narcolepsy, the role of this novel neurotransmission pathway in sleep and several other behaviors has gained extensive interest. Also, very recent studies using an animal model of familial advanced sleep-phase syndrome shed new light on the regulation of circadian rhythms.

Cardiac dysfunction and impaired compensatory response to pressure overload in mice deficient in stem cell antigen-1.

Stem cell antigen-1 (Sca-1) has been used to identify cardiac stem cells in the mouse heart. To investigate the function of Sca-1 in aging and during the cardiac adaptation to stress, we used Sca-1-deficient mice. These mice developed dilated cardiomyopathy [end-diastolic left ventricular diameter at 18 wk of age: wild-type (WT) mice, 4.2 mm ± 0.3; Sca-1-knockout (Sca-1-KO) mice, 4.6 mm ± 0.1; ejection fraction: WT mice, 51.1 ± 2.7%; Sca-1-KO mice, 42.9 ± 2.7%]. Furthermore, the hearts of mice lacking Sca-1 demonstrated exacerbated susceptibility to pressure overload [ejection fraction after transaortic constriction (TAC): WT mice, 43.5 ± 3.2%; Sca-1-KO mice, 30.8% ± 4.0] and increased apoptosis, as shown by the 2.5-fold increase in TUNEL(+) cells in Sca-1-deficient hearts under stress. Sca-1 deficiency affected primarily the nonmyocyte cell fraction. Indeed, the number of Nkx2.5(+) nonmyocyte cells, which represent a population of cardiac precursor cells (CPCs), was 2-fold smaller in Sca-1 deficient neonatal hearts. In vitro, the ability of CPCs to differentiate into cardiomyocytes was not affected by Sca-1 deletion. In contrast, these cells demonstrated unrestricted differentiation into cardiomyocytes. Interestingly, proliferation of cardiac nonmyocyte cells in response to stress, as judged by BrdU incorporation, was higher in mice lacking Sca-1 (percentages of BrdU(+) cells in the heart after TAC: WT mice, 4.4 ± 2.1%; Sca-1-KO mice, 19.3 ± 4.2%). These data demonstrate the crucial role of Sca-1 in the maintenance of cardiac integrity and suggest that Sca-1 restrains spontaneous differentiation in the precursor population. The absence of Sca-1 results in uncontrolled precursor recruitment, exhaustion of the precursor pool, and cardiac dysfunction.