Partial Characterization of the Calcium-Releasing Activity of Porcine Sperm Cytosolic Extracts

AbstractInjection of sperm cytosolic extracts into mammalian eggs has been shown to elicit intracellular calcium ([Ca2+]i) oscillations that are similar in amplitude, duration, and frequency to those observed following fertilization. Thus, to characterize the Ca2+-release component(s) in porcine sperm cytosolic extracts, a combination of fractionation techniques was used. The fraction with Ca2+releasing activity was precipitated by 50% saturating solutions of ammonium sulfate and Western blot analysis showed that the pellets contained glucosamine-6-phosphate deaminase (gpd)/oscillin, a protein which has been suggested to be the sperm's active component. Single and double isoelectrofocusing (IEF) of porcine sperm extracts generated fractions with different Ca2+-releasing activities. Fractions with maximal Ca2+-releasing activity did not contain material that was immunoreactive with antibodies against gpd/oscillin; adjacent fractions containing gpd/oscillin had no Ca2+-releasing activity. These findings were confirmed by IEF coupled with size exclusion chromatography on Superose 12 and with hydroxyapatite chromatography. These procedures predict an isoelectric point of our active component of 6.5–7.0 and a relative molecular weight ranging from 29 to 68 kDa. In summary, the data show that the Ca2+release-inducing component(s) of porcine sperm extracts can be fractionated and that gpd/oscillin is not the pig sperm Ca2+oscillogen

Composition and performance of research training groups

This chapter analyzes how one particular governance mechanism affects the performance of research teams. We look at an external requirement for interdisciplinarity and internationality of Research Training Groups (RTGs) and study how their performance is affected. We expect to observe two countervailing effects with changes in interdisciplinarity and/or internatio-nality: first, increased performance due to an increase in productive resources and a second, decreased performance due to increased team problems (communication, conflicts etc). Since both effects are expected to vary with the disciplinary field of research, we separate our analysis for the Humanities & Social Sciences in comparison to the Natural & Life Sciences and indeed find different effects in the different disciplinary fields. Furthermore, we separately analyze the effects of interdisciplinarity on the one hand and internationality on the other hand. We conclude that the effectiveness of a particular governance mechanism varies substantially between the disciplinary fields and for the type of heterogeneity under consideration. Therefore governance of research should be either precisely engineered to a particular disciplinary field and a given type of heterogeneity or it should offer a menu of options that allows research teams to choose from according to their specific needs

Dual guidance structure for evaluation of patients with unclear diagnosis in centers for rare diseases (ZSE-DUO): study protocol for a controlled multi-center cohort study

Background: In individuals suffering from a rare disease the diagnostic process and the confirmation of a final diagnosis often extends over many years. Factors contributing to delayed diagnosis include health care professionals' limited knowledge of rare diseases and frequent (co-)occurrence of mental disorders that may complicate and delay the diagnostic process. The ZSE-DUO study aims to assess the benefits of a combination of a physician focusing on somatic aspects with a mental health expert working side by side as a tandem in the diagnostic process. Study design: This multi-center, prospective controlled study has a two-phase cohort design. Methods: Two cohorts of 682 patients each are sequentially recruited from 11 university-based German Centers for Rare Diseases (CRD): the standard care cohort (control, somatic expertise only) and the innovative care cohort (experimental, combined somatic and mental health expertise). Individuals aged 12 years and older presenting with symptoms and signs which are not explained by current diagnoses will be included. Data will be collected prior to the first visit to the CRD's outpatient clinic (T0), at the first visit (T1) and 12 months thereafter (T2). Outcomes: Primary outcome is the percentage of patients with one or more confirmed diagnoses covering the symptomatic spectrum presented. Sample size is calculated to detect a 10 percent increase from 30% in standard care to 40% in the innovative dual expert cohort. Secondary outcomes are (a) time to diagnosis/diagnoses explaining the symptomatology; (b) proportion of patients successfully referred from CRD to standard care; (c) costs of diagnosis including incremental cost effectiveness ratios; (d) predictive value of screening instruments administered at T0 to identify patients with mental disorders; (e) patients' quality of life and evaluation of care; and f) physicians' satisfaction with the innovative care approach. Conclusions: This is the first multi-center study to investigate the effects of a mental health specialist working in tandem with a somatic expert physician in CRDs. If this innovative approach proves successful, it will be made available on a larger scale nationally and promoted internationally. In the best case, ZSE-DUO can significantly shorten the time to diagnosis for a suspected rare disease