Hyperbranched, Functional Polyethoxysiloxanes: Tunable Molecular Building Blocks.

Functional silanes are multifaceted cross-linkers, compatibilizers, coupling agents, and surface modifiers. Herein, we present organofunctional polysiloxane building blocks that offer great versatility in terms of molecular weight, degree of condensation, and the choice and loading of organic substituent groups. The organofunctional polyethoxysilanes (funPEOS) are prepared in a one-pot, two-step process: synthesis of the PEOS carrier/substrate, followed by grafting a functional silane "shell", both based on condensation with acetic anhydride. The reaction was optimized at the lab scale and scaled up to a 7 L reactor. The acetylation, condensation, and hyperbranched structure of the carrier were confirmed by 29Si NMR, while 29Si-29Si 2D INADEQUATE NMR provides strong evidence for the grafting of functional silanes onto the carrier (Q-T coupling). IR, 1H, and 13C NMR spectroscopy demonstrate that the functional groups remain intact. The molar mass can be tailored by stoichiometric control of the acetic anhydride to silane monomer ratio (M n 3500-20,000 g/mol). The compounds are stable organic liquids with a long shelf life. Selected applications are presented: scratch-resistant coatings with water contact angles of ∼90°, stable water emulsions, and surfactant-free, mesoporous silica foams.

Huperzine aggravated neurochemical and volumetric changes induced by D-galactose in the model of neurodegeneration in rats.

The multimodal MRI and 1H MRS study was designed to provide a structural and neurochemical view of D-galactose induced rat brain degeneration and its treatment with huperzine A. The volume changes were captured using MRI focused on the hippocampal region and a neurochemical profile was obtained from the same area using in vivo localized 1H MRS, which was compared with in vitro1H MRS hippocampal spectra at the high field after the animals were culled. At the four week point, we observed a small decrease in N-acetylaspartate/creatine (NAA/tCr), myo-inositol/creatine (mIns/tCr) and glutamine/creatine (Gln/tCr) in the group in which neurodegeneration was induced. At the eight week point, we found only slight but statistically significant decreases in NAA/tCr, mIns/tCr and glutamate/creatine (Glu/tCr) in this group in vivo. However, in the treated group, the decrease in NAA/tCr and Glu/tCr was much more pronounced compared to the D-gal group. In vitro1H MRS analysis from rat hippocampal samples showed very similar changes in metabolites, which were also much more pronounced in the treated group. Neurodegeneration was also confirmed by a significant decrease in γ-aminobutyrate/creatine (GABA/tCr) observed only in the treated group, but not in the D-gal group. MRI image data and subsequent volumetric quantification showed mild hippocampal degeneration at the four week point in D-gal group. At the eight week point, we observed a decrease in hippocampal volume in both experimental groups, with a more pronounced decrease in the huperzine-treated group. In conclusion, in our experimental design huperzine A treatment worsened the neurodegeneration of the rat brain, which was supported by all of the used MRI and 1H MRS methods.

D-galactose-induced aging in rats - The effect of metformin on bioenergetics of brain, skeletal muscle and liver.

Chronic D-galactose administration induces accelerated aging in rodents. The aim of the study was to find by in vivo31P MRS suitable markers of early stages of brain degeneration on this metabolic model in rats. Additionally, we studied the therapeutic effect of antidiabetic drug metformin. The study has been extended by in vitro determination of mitochondrial function in brain, skeletal muscle and liver mitochondria, oxidative stress parameter thiobarbituric acid reactive substances (TBARS), and lipophilic antioxidants levels. In vivo31P MRS revealed lower intracellular pH (pHi) and lower inorganic phosphate to ATP ratio (Pi/ATP), with higher index of oxidative phosphorylation - phosphocreatine (PCr) to Pi ratio - in brain of rats chronically administered with D-galactose. The function of brain mitochondria was not affected. Administration of metformin diminished changes in brain pHi and plasma TBARS. The function of skeletal muscle mitochondria and their coenzyme Q (CoQ) content were considerably reduced after D-galactose administration. Metformin administered simultaneously with D-galactose did not prevent these changes. The results of in vivo31P MRS revealed evidence of early stage of neurodegeneration that may indicate pre-inflammation. Our data show different susceptibility of brain, skeletal muscle, and liver to the chronic exposure to D-galactose and metformin. The D-galactose model presented in the literature as a model for "age-related dementia" had much more devastating effects on skeletal muscle than on the brain.

[Interpretation of Arterial Blood Gas Analysis]. / Wie interpretiere ich eine ABGA?

Interpretation of Arterial Blood Gas Analysis Abstract. Arterial blood gas test is a common diagnostic method in clinical practice. It can detect the presence and identify the causes of acid-base and oxygenation disturbances. The correct interpretation of the results begins with a careful clinical evaluation of the patient and the knowledge of the basic principles of acid-base regulation. A systematic stepwise approach is recommended to find an accurate diagnosis and to better identify mixed acid-base disorders. Here, a possible approach according to the physiological model is presented.

Patients presenting to the emergency department with non-specific complaints: the Basel Non-specific Complaints (BANC) study.

OBJECTIVES: Patient management in emergency departments (EDs) is often based on management protocols developed for specific complaints like dyspnea, chest pain, or syncope. To the best of our knowledge, to date no protocols exist for patients with nonspecific complaints (NSCs) such as "weakness,""dizziness," or "feeling unwell." The objectives of this study were to provide a framework for research and a description of patients with NSCs presenting to EDs. METHODS: Nonspecific complaints were defined as the entity of complaints not part of the set of specific complaints for which evidence-based management protocols for emergency physicians (EPs) exist. "Serious conditions" were defined as potentially life-threatening or those requiring early intervention to prevent health status deterioration. During a 6-month period, all adult nontrauma patients with an Emergency Severity Index (ESI) of 2 or 3 were prospectively enrolled, and serious conditions were identified within a 30-day period. RESULTS: The authors screened 18,261 patients for inclusion. A total of 218 of 1,611 (13.5%) nontrauma ESI 2 and 3 patients presented with NSCs. Median age was 82 years (interquartile range [IQR]=72 to 87), and 24 of 218 (11%) were nursing home inhabitants. A median of 4 (IQR=3 to 5) comorbidities were recorded, most often chronic hypertension, coronary artery disease, and dementia. During the 30-day follow-up period a serious condition was diagnosed in 128 of 218 patients (59%). The 30-day mortality rate was 6%. CONCLUSIONS: Patients with NSC presenting to the ED are at high risk of suffering from serious conditions. Sensitive risk stratification tools are needed to identify patients with potentially adverse health outcomes.