Pseudohypocalcemia caused by perchlorate (Irenat (R))

Background: Blood gas analysis (BGA), including measurement of ionized calcium, is performed routinely in patients with end stage renal disease on renal replacement therapy, especially when using citrate for regional anticoagulation. After installation of a new blood gas analyzer (RAPIDpoint (R) 405; BGA), we observed lower ionized calcium concentrations in a few patients without signs of hypocalcemia, whereas calcium concentrations were normal using a standard laboratory method. Pseudohypocalcemia was of limited duration and correlated with the short-term intake of sodium perchlorate monohydrate (Irenat (R)). Methods: We prepared dilution series from whole blood samples and stock solutions of calcium and perchlorate with different concentrations of ionized calcium and perchlorate. Measurement of ionized calcium concentrations was performed using two different blood gas analyzers (RAPIDpoint (R) 405; BGA and Roche AVL 9180; standard laboratory method). Results: After addition of different amounts of perchlorate, significant lower ionized calcium concentrations were measured with BGA compared to the standard laboratory method using either preparations from whole blood samples or stock solutions. The addition of potassium or methylene blue known to complex perchlorate had no effect on the concentrations of ionized calcium measured with BGA. Using different mathematical methods, a calculation of the "real" ionized calcium concentration from the value measured with BGA was not possible. Conclusions: Based on our experiments, we confirm the hypothesis that perchlorate can influence the measurement of ionized calcium by BGA. As the effect depends on the ion selective electrode that is used, it is advisable to test the blood gas analyzer with calcium and perchlorate solutions

Ascending Axonal Degeneration of the Corticospinal Tract in Pure Hereditary Spastic Paraplegia: A Cross-Sectional DTI Study

Objective: To identify structural white matter alterations in patients with pure hereditary spastic paraplegia (HSP) using high angular resolution diffusion tensor imaging (DTI). Methods: We examined 37 individuals with high resolution DTI, 20 patients with pure forms of hereditary spastic paraplegia and 17 age and gender matched healthy controls. DTI was performed using a 3 T clinical scanner with whole brain tract-based spatial statistical (TBSS) analysis of the obtained fractional anisotropy (FA) data as well as a region-of-interest (ROI)-based analysis of affected tracts including the cervical spinal cord. We further conducted correlation analyses between DTI data and clinical characteristics. Results: TBSS analysis in HSP patients showed significantly decreased fractional anisotropy of the corpus callosum and the corticospinal tract compared to healthy controls. ROI-based analysis confirmed significantly lower FA in HSP compared to controls in the internal capsule (0.77 vs. 0.80, p = 0.048), the corpus callosum (0.84 vs. 0.87, p = 0.048) and the cervical spinal cord (0.72 vs. 0.79, p = 0.003). FA values of the cervical spinal cord significantly correlated with disease duration. Conclusion: DTI metrics of the corticospinal tract from the internal capsule to the cervical spine suggest microstructural damage and axonal degeneration of motor neurons. The CST at the level of the cervical spinal cord is thereby more severely affected than the intracranial part of the CST, suggesting an ascending axonal degeneration of the CST. Since there is a significant correlation with disease duration, FA may serve as a future progression marker for assessment of the disease course in HSP

Lipoprotein-associated phospholipase A2 activity and low-density lipoprotein subfractions after a 2-year treatment with atorvastatin in adolescents with type 1 diabetes

AbstractBackground: The objective of the study was to assess the effect of atorvastatin on inflammation markers and low-density lipoprotein (LDL) subfractions. Methods: In a prospective, randomized, double-blind pilot study involving 28 adolescents with type 1 diabetes (T1D), lipoprotein-associated phospholipase A2 (Lp-PLA2) activity, high-sensitivity C-reactive protein (hsCRP), and subfractions of LDL were measured at baseline, after 1 year and 2 years of treatment with atorvastatin (10 mg/day) vs. placebo. Results: For the atorvastatin group, we found posttreatment reductions of Lp-PLA2 activity (p<0.001), LDL cholesterol (p=0.001), non-small dense LDL cholesterol (p<0.001), total cholesterol (p<0.001), and apolipoprotein B (apo B) (p<0.001), whereas small dense LDL cholesterol and hsCRP did not change significantly. Conclusions: In adolescents with T1D, long-term treatment with atorvastatin is safe and may reduce cardiovascular risk by significant decreases of Lp-PLA2 activity and LDL cholesterol

Calibration of PMP Condensation Particle Number Counters - Effect of Material on Linearity and Counting Efficiency

Recently the particle number method was proposed to the light duty regulation, so the proper calibration of Particle Number Counters (PNCs) will be very important. Calibration includes the linearity measurement and the counting efficiency measurement. Labs will have to demonstrate compliance of their PNCs with a traceable standard within a 12 month period prior to the emissions test. Compliance can be demonstrated by: -Primary method: By comparison of the response of the PNC under calibration with that of a calibrated aerosol electrometer when simultaneously sampling electrostatically classified calibration particles, or -Secondary method: By comparison of the response of the PNC under calibration with that of a second PNC which has been directly calibrated by the above method. Compliance testing includes linearity and detection efficiency with particles of 23 nm electrical mobility diameter. A check of the counting efficiency with 41 nm particles is not required. A workshop was organised to investigate the effect of the material on the calibration procedures and the uncertainties of the suggested procedure. GRIMM and TSI provided PNCs and AEA, MATTER, GRIMM, TSI provided five particle generators. The experiments were conducted in the European¿s Commissions laboratories (JRC). Heavy duty diesel engine (w/o aftertreatment) particles were also produced (measurements downstream a thermodenuder) at idle and a medium load mode. The measured data were evaluated by JRC. The results showed that there was an effect of the material used and suggestions were given. In addition the uncertainties of the procedure were quantified. Theoretical calculations showed the corrections that should be applied.JRC.H.4-Transport and air qualit

RHAMM deficiency disrupts folliculogenesis resulting in female hypofertility

The postnatal mammalian ovary contains the primary follicles, each comprising an immature oocyte surrounded by a layer of somatic granulosa cells. Oocytes reach meiotic and developmental competence via folliculogenesis. During this process, the granulosa cells proliferate massively around the oocyte, form an extensive extracellular matrix (ECM) and differentiate into cumulus cells. As the ECM component hyaluronic acid (HA) is thought to form the backbone of the oocyte-granulosa cell complex, we deleted the relevant domain of the Receptor for HA Mediated Motility (RHAMM) gene in the mouse. This resulted in folliculogenesis defects and female hypofertility, although HA-induced signalling was not affected. We report that wild-type RHAMM localises at the mitotic spindle of granulosa cells, surrounding the oocyte. Deletion of the RHAMM C-terminus in vivo abolishes its spindle association, resulting in impaired spindle orientation in the dividing granulosa cells, folliculogenesis defects and subsequent female hypofertility. These data reveal the first identified physiological function for RHAMM, during oogenesis, and the importance of this spindle-associated function for female fertility

RHAMM deficiency disrupts folliculogenesis resulting in female hypofertility

The postnatal mammalian ovary contains the primary follicles, each comprising an immature oocyte surrounded by a layer of somatic granulosa cells. Oocytes reach meiotic and developmental competence via folliculogenesis. During this process, the granulosa cells proliferate massively around the oocyte, form an extensive extracellular matrix (ECM) and differentiate into cumulus cells. As the ECM component hyaluronic acid (HA) is thought to form the backbone of the oocyte-granulosa cell complex, we deleted the relevant domain of the Receptor for HA Mediated Motility (RHAMM) gene in the mouse. This resulted in folliculogenesis defects and female hypofertility, although HA-induced signalling was not affected. We report that wild-type RHAMM localises at the mitotic spindle of granulosa cells, surrounding the oocyte. Deletion of the RHAMM C-terminus in vivo abolishes its spindle association, resulting in impaired spindle orientation in the dividing granulosa cells, folliculogenesis defects and subsequent female hypofertility. These data reveal the first identified physiological function for RHAMM, during oogenesis, and the importance of this spindle-associated function for female fertility

A reversible state of hypometabolism in a human cellular model of sporadic Parkinson's disease

Sporadic Parkinson's Disease (sPD) is a progressive neurodegenerative disorder caused by multiple genetic and environmental factors. Mitochondrial dysfunction is one contributing factor, but its role at different stages of disease progression is not fully understood. Here, we showed that neural precursor cells and dopaminergic neurons derived from induced pluripotent stem cells (hiPSCs) from sPD patients exhibited a hypometabolism. Further analysis based on transcriptomics, proteomics, and metabolomics identified the citric acid cycle, specifically the alpha-ketoglutarate dehydrogenase complex (OGDHC), as bottleneck in sPD metabolism. A follow-up study of the patients approximately 10 years after initial biopsy demonstrated a correlation between OGDHC activity in our cellular model and the disease progression. In addition, the alterations in cellular metabolism observed in our cellular model were restored by interfering with the enhanced SHH signal transduction in sPD. Thus, inhibiting overactive SHH signaling may have potential as neuroprotective therapy during early stages of sPD. Mitochondrial dysfunction is a contributing factor in Parkinson's disease. Here the authors carry out a multilayered omics analysis of Parkinson's disease patient-derived neuronal cells, which reveals a reversible hypometabolism mediated by alpha-ketoglutarate dehydrogenase deficiency, which is correlated with disease progression in the donating patients

Human in vitro reporter model of neuronal development and early differentiation processes

<p>Abstract</p> <p>Background</p> <p>During developmental and adult neurogenesis, doublecortin is an early neuronal marker expressed when neural stem cells assume a neuronal cell fate. To understand mechanisms involved in early processes of neuronal fate decision, we investigated cell lines for their capacity to induce expression of doublecortin upon neuronal differentiation and develop <it>in vitro </it>reporter models using doublecortin promoter sequences.</p> <p>Results</p> <p>Among various cell lines investigated, the human teratocarcinoma cell line NTERA-2 was found to fulfill our criteria. Following induction of differentiation using retinoic acid treatment, we observed a 16-fold increase in doublecortin mRNA expression, as well as strong induction of doublecortin polypeptide expression. The acquisition of a neuronal precursor phenotype was also substantiated by the establishment of a multipolar neuronal morphology and expression of additional neuronal markers, such as Map2, βIII-tubulin and neuron-specific enolase. Moreover, stable transfection in NTERA-2 cells of reporter constructs encoding fluorescent or luminescent genes under the control of the doublecortin promoter allowed us to directly detect induction of neuronal differentiation in cell culture, such as following retinoic acid treatment or mouse Ngn2 transient overexpression.</p> <p>Conclusion</p> <p>Induction of doublecortin expression in differentiating NTERA-2 cells suggests that these cells accurately recapitulate some of the very early events of neuronal determination. Hence, the use of reporter genes under the control of the doublecortin promoter in NTERA-2 cells will help us to investigate factors involved early in the course of neuronal differentiation processes. Moreover the ease to detect the induction of a neuronal program in this model will permit to perform high throughput screening for compounds acting on the early neuronal differentiation mechanisms.</p