Phosphatidylethanolamine in Trypanosoma brucei is organized in two separate pools and is synthesized exclusively by the Kennedy pathway

Phosphatidylethanolamine is a major phospholipid class of all eukaryotic cells. It can be synthesized via the CDP-ethanolamine branch of the Kennedy pathway, by decarboxylation of phosphatidylserine, or by base exchange with phosphatidylserine. The contributions of these pathways to total phosphatidylethanolamine synthesis have remained unclear. Although Trypanosoma brucei, the causative agent of human and animal trypanosomiasis, has served as a model organism to elucidate the entire reaction sequence for glycosylphosphatidylinositol biosynthesis, the pathways for the synthesis of the major phospholipid classes have received little attention. We now show that disruption of the CDP-ethanolamine branch of the Kennedy pathway using RNA interference results in dramatic changes in phosphatidylethanolamine, phosphatidylserine, and phosphatidylcholine. By targeting individual enzymes of the pathway, we demonstrate that de novo phosphatidylethanolamine synthesis in T. brucei procyclic forms is strictly dependent on the CDP-ethanolamine route. Interestingly, the last step in the Kennedy pathway can be mediated by two separate activities leading to two distinct pools of phosphatidylethanolamine, consisting of predominantly alk-1-enyl-acyl- or diacyl-type molecular species. In addition, we show that phosphatidylserine in T. brucei procyclic forms is synthesized exclusively by base exchange with phosphatidylethanolamine.

Haematologic data, iron parameters and molecular findings in two new cases of iron-refractory iron deficiency anaemia

Matriptase-2 (Tmprss6), a type II transmembrane serine protease, has an essential role in iron homoeostasis as a hepcidin regulator. Recently, patients with TMPRSS6 mutations and suffering from iron-refractory iron deficiency anaemia (IRIDA) have been reported. We describe two new cases of IRIDA, one patient of Swiss origin and the second of Italian origin. The first case results from a large deletion of 1054 nucleotides corresponding to an in frame deletion of 30 amino acid residues in the low-density lipoprotein receptor-1/-2 (LDLR-1/-2) domains and from a missense mutation in CUB1 (S304L). In the second case, a homozygous G-->C mutation in the last nucleotide of exon 15 and which modified the consensus sequence of the 5' splice donor site of intron 15 (AGgt-->ACgt) was identified. Both patients had a high hepcidin level and low serum iron and transferrin saturation compared to age-matched controls. Continuous perfusion of i.v. iron 4 h/d x 5 d in the first case resulted in a significant rise in haemoglobin. These new cases of IRIDA illustrate the importance of LDLR-1/-2 and CUB1 domains in matriptase-2 function as well as the role of matriptase-2 in hepcidin regulation. Furthermore a deletional form of TMPRSS6 (in LDLR-1/-2 domains) resulting in IRIDA is described for the first time. These cases reinforce the belief that patients suffering from IRIDA have no specific geographical or ethnic distribution and are sporadic secondary to different mutations of the matriptase-2 gene.

[Role of complementary medicine in type 1 diabetes mellitus in two Swiss centres]

Insulin replacement is the only effective treatment of type 1 Diabetes mellitus (T1DM). Nevertheless, many complementary treatments are in use for T1DM. In this study we assessed by questionnaire that out of 342 patients with T1DM, 48 (14%; 13.4% adult, 18.5% paediatric; 20 male, 28 female) used complementary medicine (CM) in addition to their insulin therapy. The purpose of the use of CM was to improve general well-being, ameliorate glucose homeostasis, reduce blood glucose levels as well as insulin doses, improve physical fitness, reduce the frequency of hypoglycaemia, and control appetite. The modalities most frequently used are cinnamon, homeopathy, magnesium and special beverages (mainly teas). Thus, good collaboration between health care professionals will allow optimal patient care.

Bone healing around titanium implants in two rat colitis models

OBJECTIVE Crohn's disease is a chronic inflammatory process that has recently been associated with a higher risk of early implant failure. Herein we provide information on the impact of colitis on peri-implant bone formation using preclinical models of chemically induced colitis. METHODS Colitis was induced by intrarectal instillation of 2,4,6-trinitro-benzene-sulfonic-acid (TNBS). Colitis was also induced by feeding rats dextran-sodium-sulfate (DSS) in drinking water. One week after disease induction, titanium miniscrews were inserted into the tibia. Four weeks after implantation, peri-implant bone volume per tissue volume (BV/TV) and bone-to-implant contacts (BIC) were determined by histomorphometric analysis. RESULTS Cortical histomorphometric parameters were similar in the control (n = 10), DSS (n = 10) and TNBS (n = 8) groups. Cortical BV/TV was 92.2 ± 3.7%, 92.0 ± 3.0% and 92.6 ± 2.7%. Cortical BIC was 81.3 ± 8.8%, 83.2 ± 8.4% and 84.0 ± 7.0%, respectively. No significant differences were observed when comparing the medullary BV/TV and BIC (19.5 ± 6.4%, 16.2 ± 5.6% and 15.4 ± 9.0%) and (48.8 ± 12.9%, 49.2 ± 6.2 and 41.9 ± 11.7%), respectively. Successful induction of colitis was confirmed by loss of body weight and colon morphology. CONCLUSIONS The results suggest bone regeneration around implants is not impaired in chemically induced colitis models. Considering that Crohn's disease can affect any part of the gastrointestinal tract including the mouth, our model only partially reflects the clinical situation.

Seizure activity occurring in two dogs after S-ketamine-induction.

Two healthy dogs were anaesthetized to undergo elective orthopaedic procedures. After premedication with methadone and acepromazine, general anaesthesia was induced with midazolam and S-ketamine. Immediately after anaesthetic induction, seizures occurred in both dogs. In the first dog the syndrome was characterized by tonic and clonic motor activity, muscular hypertone, hypersalivation, urination, defecation and hyperthermia. In the second dog muscular twitches of the temporal and masseter regions were observed, followed by increased skeletal muscles tone, hypersalivation, spontaneous urination and increase in body temperature. Recoveries from anaesthesia were uneventful and no seizures were observed. Considering the temporal association between anaesthetic induction and occurrence of seizures, and the fact that other causative factors could not be identified, it is hypothesized that S-ketamine played a role in determining the convulsive phenomena observed in these patients. S-ketamine might carry the potential for inducing seizures in otherwise healthy dogs, despite the concomitant use of GABA-ergic drugs.

Pelagic molybdenum concentration anomalies and the impact of sediment resuspension on the molybdenum budget in two tidal systems of the North Sea

The seasonal dynamics of molybdenum (Mo) were studied in the water column of two tidal basins of the German Wadden Sea (Sylt-Rømø and Spiekeroog) between 2007 and 2011. In contrast to its conservative behaviour in the open ocean, both, losses of more than 50% of the usual concentration level of Mo in seawater and enrichments up to 20% were observed repeatedly in the water column of the study areas. During early summer, Mo removal by adsorption on algae-derived organic matter (e.g. after Phaeocystis blooms) is postulated to be a possible mechanism. Mo bound to organic aggregates is likely transferred to the surface sediment where microbial decomposition enriches Mo in the pore water. First δ98/95Mo data of the study area disclose residual Mo in the open water column being isotopically heavier than MOMo (Mean Ocean Molybdenum) during a negative Mo concentration anomaly, whereas suspended particulate matter shows distinctly lighter values. Based on field observations a Mo isotope enrichment factor of ε = −0.3‰ has been determined which was used to argue against sorption on metal oxide surfaces. It is suggested here that isotope fractionation is caused by biological activity and association to organic matter. Pelagic Mo concentration anomalies exceeding the theoretical salinity-based concentration level, on the other hand, cannot be explained by replenishment via North Sea waters alone and require a supply of excess Mo. Laboratory experiments with natural anoxic tidal flat sediments and modelled sediment displacement during storm events suggest fast and effective Mo release during the resuspension of anoxic sediments in oxic seawater as an important process for a recycling of sedimentary sulphide bound Mo into the water column.

A nonlinear QCT-based finite element model validation study for the human femur tested in two configurations in vitro

Purpose Femoral fracture is a common medical problem in osteoporotic individuals. Bone mineral density (BMD) is the gold standard measure to evaluate fracture risk in vivo. Quantitative computed tomography (QCT)-based homogenized voxel finite element (hvFE) models have been proved to be more accurate predictors of femoral strength than BMD by adding geometrical and material properties. The aim of this study was to evaluate the ability of hvFE models in predicting femoral stiffness, strength and failure location for a large number of pairs of human femora tested in two different loading scenarios. Methods Thirty-six pairs of femora were scanned with QCT and total proximal BMD and BMC were evaluated. For each pair, one femur was positioned in one-legged stance configuration (STANCE) and the other in a sideways configuration (SIDE). Nonlinear hvFE models were generated from QCT images by reproducing the same loading configurations imposed in the experiments. For experiments and models, the structural properties (stiffness and ultimate load), the failure location and the motion of the femoral head were computed and compared. Results In both configurations, hvFE models predicted both stiffness (R2=0.82 for STANCE and R2=0.74 for SIDE) and femoral ultimate load (R2=0.80 for STANCE and R2=0.85 for SIDE) better than BMD and BMC. Moreover, the models predicted qualitatively well the failure location (66% of cases) and the motion of the femoral head. Conclusions The subject specific QCT-based nonlinear hvFE model cannot only predict femoral apparent mechanical properties better than densitometric measures, but can additionally provide useful qualitative information about failure location.

Lectin binding patterns in two cultured endothelial cell types derived from bovine corpus luteum

Epithelial cells of different phenotypes derived from bovine corpus luteum have been studied intensively in our laboratory. In this study, specific lectin binding was examined for cells of type 1 and 3, which were defined as endothelial cells. In order to confirm differences in their glycocalyx at the light microscopic level, five biotinylated lectins were applied to postconfluent cultures which had been fixed with buffered paraformaldehyde or glutaraldehyde. Cells were not permeabilized with any detergent. Lectin binding was localized with a streptavidin-peroxidase complex which was visualized with two different techniques. The DAB technique detected peroxidase histochemically, while the immunogold technique used an anti-peroxidase gold complex together with silver amplification. Neither cell type 1 nor cell type 3 bound a particular lectin selectively, yet each cell type expressed a particular lectin binding pattern. With the DAB technique, diverse lectin binding patterns were seen, probably indicating either "outside" binding, i.e., a diffuse pattern, a lateral-cell-side pattern and a microvillus-like pattern, or "inside" binding, i.e., a diffuse pattern, and a granule-like pattern. With the immunogold technique, only "outside" binding was observed. In addition, the patterns of single cilia or of single circles were detected, the latter roughly representing 3-micron-sized binding sites for concanavalin A. When localizing them at the ultrastructural level, single circles corresponded with micron-sized discontinuities of the plasma membrane. Shedding vesicles were detected whose outer membrane was labelled with concanavalin A. Our results confirm the diversity of the two cell types under study. The "inside" lectin binding may be caused by way of transient plasma membrane openings and related to shedding of right-side out vesicles ("ectocytosis").

Minimizing the Threat of a Positive Majority Deficit in Two-tier Voting Systems with Equipopulous Units

The mean majority deficit in a two-tier voting system is a function of the partition of the population. We derive a new square-root rule: For odd-numbered population sizes and equipopulous units the mean majority deficit is maximal when the member size of the units in the partition is close to the square root of the population size. Furthermore, within the partitions into roughly equipopulous units, partitions with small even numbers of units or small even-sized units yield high mean majority deficits. We discuss the implications for the winner-takes-all system in the US Electoral College.

Adaptation to Changes in the Coffee Value Chain and the Price of Coiffee among Coffee Producers in Two Villages in Kilimanjaro, Tanzania

Market liberalization in Tanzania has eroded the monopoly of the cooperative unions by allowing private coffee buyers (PCBs) to compete with them on equal footing. Similarly, farmers groups and primary societies are now allowed to sell coffee at auction. Thus, farmers have various options for selling their coffee. Similarly, the coffee industry has experienced large fluctuations in prices and stagnation in production. How do farmers react to these changes? Can and do farmers profit from different market conditions and sell to different traders at the lower end of the value chain, or do they remain with cooperatives or farmers groups? This study was conducted in Mruwia and Mshiri villages in Moshi Rural district. Whereas Mshiri village remains attached to the Kilimanjaro Native Cooperative Union (KNCU), Mruwia has detached from this organization and sells coffee independently. The sample (103) was randomly selected from the coffee farmers in the two villages. Data were collected through surveys, focus group discussions (FGDs), and socio-anthropological methods (participant-observation, biographies, and thematic interviews). Results indicate that the selection of whom to sell coffee depends largely on farmers’ dependence on coffee and prices, other benefits accrued, and whether the initial costs are covered by buyers. Additionally, most respondents did not sell coffee to PCBs. Thus, prices, the institutional infrastructure, and the structure of local communities were important when making decisions about how and with whom to trade.

Feasibility of post mortem cardiac proton density weighted fast field echo imaging in two cases of sudden death

OBJECTIVE The aim of this work is to investigate and compare cardiac proton density (PD) weighted fast field echo (FFE) post-mortem magnetic resonance (PMMR) imaging with standard cardiac PMMR imaging (T1-weighted and T2-weighted turbo spin-echo (TSE)), postmortem CT (PMCT) as well as autopsy. MATERIALS AND METHODS Two human cadavers sequentially underwent cardiac PMCT and PMMR imaging (PD-weighted FFE, T1-weighted and T2-weighted TSE) and autopsy. The cardiac PMMR images were compared to each other as well as to PMCT and autopsy findings. RESULTS For the first case, cardiac PMMR exhibited a focal region of low signal in PD-weighted FFE and T2-weighted TSE images, surrounded by a signal intense rim in the T2-weighted images. T1-weighted TSE and PMCT did not appear to identify any focal abnormality. Macroscopic inspection identified a blood clot; histology confirmed this to be a thrombus with an adhering myocardial infarction. In the second case, a myocardial rupture with heart tamponade was identified in all PMMR images, located at the anterior wall of the left ventricle; PMCT excluded additional ruptures. In PD-weighted FFE and T2-weighted TSE images, it occurred hypo-intense, while resulting in small clustered hyper-intense spots in T1-weighted TSE. Autopsy confirmed the PMMR and PMCT findings. CONCLUSIONS Presented initial results have shown PD-weighted FFE to be a valuable imaging sequence in addition to traditional T2-weighted TSE imaging for blood clots and myocardial haemorrhage with clearer contrast between affected and healthy myocardium.