Putative intermediates in the nerve cell differentiation pathway in hydra have properties of multipotent stem cells

We have investigated the properties of nerve cell precursors in hydra by analyzing the differentiation and proliferation capacity of interstitial cells in the peduncle of Hydra oligactis, which is a region of active nerve cell differentiation. Our results indicate that about 50% of the interstitial cells in the peduncle can grow rapidly and also give rise to nematocyte precursors when transplanted into a gastric environment. If these cells were committed nerve cell precursors, one would not expect them to differentiate into nematocytes nor to proliferate apparently without limit. Therefore we conclude that cycling interstitial cells in peduncles are not intermediates in the nerve cell differentiation pathway but are stem cells. The remaining interstitial cells in the peduncle are in G1 and have the properties of committed nerve cell precursors (Holstein and David, 1986). Thus, the interstitial cell population in the peduncle contains both stem cells and noncycling nerve precursors. The presence of stem cells in this region makes it likely that these cells are the immediate targets of signals which give rise to nerve cells

Systematics of molecular self-assembled networks at topological insulators surfaces

The success of topological insulators (TI) in creating devices with unique functionalities is directly connected to the ability of coupling their helical spin states to well defined perturbations. However, up to now, TI-based heterostructures always resulted in very disordered interfaces, characterized by strong mesoscopic fluctuations of the chemical potential which make the spin-momentum locking ill-defined over length scales of few nanometers or even completely destroy topological states. These limitations call for the ability to control topological interfaces with atomic precision. Here, we demonstrate that molecular self-assembly processes driven by inherent interactions among the constituents offer the opportunity to create well-defined networks at TIs surfaces. Even more remarkably, we show that the symmetry of the overlayer can be finely controlled by appropriate chemical modifications. By analyzing the influence of the molecules on the TI electronic properties, we rationalize our results in terms of the charge redistribution taking place at the interface. Overall, our approach offers a precise and fast way to produce tailor-made nanoscale surface landscapes. In particular, our findings make organic materials ideal TIs counterparts, since they offer the possibility to chemically tune both electronic and magnetic properties within the same family of molecules, thereby bringing us a significant step closer towards an application of this fascinating class of materials.Comment: Nano Letters (2015

In-depth investigations into Salmonella infection sources, reservoirs, and intervention measures in herds with a high hygiene level

The paper describes the in-depth analysis of the reasons for an extreme high Salmonella load of a high-health and well-managed pork production system and the measures that were taken to reduce the prevalence of Salmonella antibody positive finisher pigs produced by the system. The results and experiences gained during the study are discussed

Cell cycle length, cell size, and proliferation rate in hydra stem cells

We have analyzed the cell cycle parameters of interstitial cells in Hydra oligactis. Three subpopulations of cells with short, medium, and long cell cycles were identified. Short-cycle cells are stem cells; medium-cycle cells are precursors to nematocyte differentiation; long-cycle cells are precursors to gamete differentiation. We have also determined the effect of different cell densities on the population doubling time, cell cycle length, and cell size of interstitial cells. Our results indicate that decreasing the interstitial cell density from 0.35 to 0.1 interstitial cells/epithelial cell (1) shortens the population doubling time from 4 to 1.8 days, (2) increases the [3H]thymidine labeling index from 0.5 to 0.75 and shifts the nuclear DNA distribution from G2 to S phase cells, and (3) decreases the length of G2 in stem cells from 6 to 3 hr. The shortened cell cycle is correlated with a significant decrease in the size of interstitial stem cells. Coincident with the shortened cell cycle and increased growth rate there is an increase in stem cell self-renewal and a decrease in stem cell differentiation

Co-existence of Ventricular Septal Defect and Bronchial Asthma in Two Nigerian Children

Congenital heart diseases (CHD) often present with recurrent or chronic breathing difficulties, as do chronic airway diseases such as asthma. Both are relatively common, and may sometimes co-exist. However, there is a paucity of literature from developing countries to that effect. We present two children diagnosed with ventricular septal defect, later also found to have clinical features consistent with co-existing asthma. We highlight the diagnostic challenges we encountered as well as the crucial role of a careful family respiratory history in children with congenital heart disease

Renal sizes in healthy term newborns in Jos, Nigeria

Introduction Knowledge of the range of normal measurements of body organs including the kidneys in the healthy population is essential. Such reference values provide a quick guide for prompt and accurate evaluation of the abnormal. This study sought to determine renal size by ultrasound measurement in term neonates at the Jos University Teaching Hospital (JUTH).Materials and Methods: Healthy term neonates aged 12 to 72 hours were consecutively enrolled. Ultrasound measurements of their renal sizes were determined. Mean renal dimensions and their 95% confidence intervals (CI) were computed. The renal sizes were correlated with the infants’ anthropometric parameters and gestational ages using Pearson’s correlation coefficient. Sizes of left and right kidneys and of male and female subjects were compared using student’s t-test.Results: Two hundred term newborns consisting of 105 (52.50 %) females and 95 (47.50%) males were enrolled. Their mean renal length was 4.09(95% CI, 3.72, 4.46) cm and 4.08 (95% CI, 3.72, 4.44)cm for right and left kidneys; width2.11 (95% CI, 1.89, 2.33) cm and 2.08 (95% CI, 1.85, 2.31) cm for right and left kidneys, and volume9.66(95% CI, 7.49, 9.87) cm3and 9.41 (95% CI, 7.23, 11.59) cm3 for right and left kidneys respectively. Renal dimensions increased consistently with birth weight. No significant difference in renal dimensions between the right and left kidneys was found.Conclusion: The mean renal dimensions for right and left weresimilar and correlated with birth weight.Key Words: Healthy, Term, Newborn, Ultrasound, Renal Size

Early Heparin Administration Reduces Risk for Left Atrial Thrombus Formation during Atrial Fibrillation Ablation Procedures

Objective. Despite the use of anticoagulation during left atrial (LA) ablation procedures, ischemic cerebrovascular accidents (CVAs) are recognized as a serious complication. Heparin is usually given after safe transseptal access has been obtained, resulting in a short unprotected dwell time of catheters within the LA, which may account for CVAs. We investigated the frequency of CVAs and LA thrombus formation as detected by intracardiac ultrasound (ICE) depending on the timing of heparin administration. Methods and Results. Sixty LA ablation procedures with the use of ICE were performed in 55 patients. Patients were grouped by heparin administration after (Group I, n = 13) and before (Group II, n = 47) transseptal access. Group I patients were younger (56.6 ± 13.7 versus 65.9 ± 9.9 years, P = .01); other clinical and echocardiographic characteristics did not differ between groups. Early thrombus formation was observed in 2 (15.4%) of group I patients as compared to 0% of group II patients (P = .04). One CVA (2.1%) occurred in one group II patient without prior thrombus detection, and none occurred in group I patients (P = ns). Conclusion. Early administration of heparin reduces the risk of early intracardiac thrombus formation during LA ablation procedures. This did not result in reduced rate of CVAs

A ring trial for testing the comparability of the laboratory results of three commercial Salmonella antibody ELISA tests in Germany, Denmark and The Netherlands

Three commercial and one non-commercial ELISA test kits for detecting Salmonella antibodies in meat juice of pigs were tested in an international ring test. All test kits proved to produce highly comparable results. The result has relevance for the upcoming Salmonella control strategy in the EU, if the national Salmonella reduction measures are planned to be based on a serological risk categonsation of pig herds