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Alkaline sphingomyelinase activity in rat gastrointestinal tract: distribution and characteristics.

Previous studies indicated that there was an alkaline sphingomyelinase (SMase) activity in small intestine, but its properties have not been studied in detail. In the present work, we studied the distribution of this enzyme activity in rat gastrointestinal tract and characterized it in intestinal mucosal homogenates. Little alkaline SMase activity was detected in the stomach and the duodenum. The

Protein phosphatase inhibitors potentiate Ca2+/calmodulin-dependent protein kinase II activity in rat pancreatic acinar cells.

Cholecystokinin (CCK) is known to rapidly and transiently increase both [Ca2+]iand autonomous CaM kinase II activity in rat pancreatic acini. Because induction of autonomous activity may involve intramolecular autophosphorylation, the effects of protein phosphatase inhibitors were examined. None of the inhibitors tested (okadaic acid, calyculin A, and cyclosporin A) affected basal activity. Okadai

Identification of an alkaline sphingomyelinase activity in human bile

The hydrolysis of sphingomyelin has been found to generate important signals regulating cell proliferation, differentiation and apoptosis. However, the enzymes responsible for digestion of dietary sphingomyelin have not been well documented. This study demonstrates the occurrence of a sphingomyelinase (SMase) in both human hepatic bile and gallbladder bile. The enzyme was equally found in both bac

Role of the ceramide signalling pathway in cytokine responses to P fimbriated Escherichia coli.

Escherichia coli express fimbriae-associated adhesins through which they attach to mucosal cells and activate a cytokine response. The receptors for E. coli P fimbriae are the globoseries of glycosphingolipids; Gal alpha 1-->4Gal beta-containing oligosaccharides bound to ceramide in the outer leaflet of the lipid bilayer. The receptors for type 1 fimbriae are mannosylated glycoproteins rather than

Bacterial adherence and mucosal cytokine responses : Receptors and transmembrane signaling

By attaching to cells or secreted mucosal components, microbes are thought to avoid elimination by the flow of secretions that constantly wash mucosal surfaces. The attached state enhances their ability to trap nutrients and allows the bacteria to multiply more efficiently than do unattached bacterial cells. Attachment is therefore regarded as an end result in itself, and emphasis has been placed

Purification of a newly identified alkaline sphingomyelinase in human bile and effects of bile salts and phosphatidylcholine on enzyme activity.

The hydrolysis of sphingomyelin (SM) generates important signals regulating cell proliferation and apoptosis. Acid and neutral sphingomyelinases (SMase) have been identified and their biological effects intensively studied. We recently found in human bile a novel alkaline SMase that may have important roles in hepatobiliary diseases. In this work, we purified the enzyme and studied the factors inf

Thermal Reduction of NOx in a Double Compression Expansion Engine by Injection of AAS 25 and AUS 32 in the Exhaust Gases

The double compression expansion engine (DCEE) is a promising concept for high engine efficiency while fulfilling the most stringent European and US emission legislation. The complete thermodynamic cycle of the engine is split among several cylinders. Combustion of fuel occurs in the combustion cylinder and in the expansion cylinder the exhaust gases are over expanded to obtain high efficiency. A

Optical Investigation on the Combustion Process Differences between Double-Pilot and Closely-Coupled Triple-Pilot Injection Strategies in a LD Diesel Engine

The combustion processes of three injection strategies in a light-duty (LD) diesel engine at a medium load point are captured with a high speed video camera. A double-pilot/main/single-post injection strategy representative of a LD Euro 6 calibration is considered as the reference. There is a modest temporal spacing (dwell) after the first pilot (P1) and second pilot (P2). A second strategy, "A,"

Simulation of System Brake Efficiency in a Double Compression-Expansion Engine-Concept (DCEE) Based on Experimental Combustion Data

The double compression-expansion engine concepts (DCEE) are split-cycle concepts where the compression, combustion, expansion and gas exchange strokes occur in two or more different cylinders. Previous simulation studies reveal there is a potential to improve brake efficiency with these engine concepts due to improved thermodynamic and mechanical efficiencies. As a continuation of this project thiThe double compression-expansion engine concepts (DCEE) are split-cycle concepts where the compression, combustion, expansion and gas exchange strokes occur in two or more different cylinders. Previous simulation studies reveal there is a potential to improve brake efficiency with these engine concepts due to improved thermodynamic and mechanical efficiencies. As a continuation of this project thi

Analytical model of sand spit evolution

Spits typically consist of sand or gravel and are commonly occurring morphological features at inlets, river mouths, and the down-drift ends of barrier islands. Thus, they may form at the ocean-, lake-, or bay-side of inlets, entrances, and river mouths. Apart from the scientific interest in spits and their evolution, engineers have often studied spits with regard to their penetration into river m

Hydrogen peroxide vapour treatment inactivates norovirus but has limited effect on post-treatment viral RNA levels

Background: Hydrogen peroxide vapour is used as a room disinfectant. Its activity against murine norovirus, a surrogate viability marker for human norovirus, indicates that it is also active against human norovirus. Aim: The aim of this study is to assess how this effect on viability is reflected in measurements of RNA by quantitative PCR (qPCR). Methods: Faeces suspensions of two human norovirus

Evaluating the usability of two salutogenic instruments on health and work experience, using cognitive interviewing

Workplace surveys are used in workplace health promotion as a basis for improvements at the workplace. But there is lack of psychometrically and qualitatively validated work-health related instruments with a salutogenic approach. The purpose of this study was, therefore, to evaluate the two instruments, the Salutogenic Health Indicator Scale and the Work Experience Measurement Scale, among staff o

An analytical tool for long-term dune management

Climate change calls for coastal management to consider longer time scales. The main objective of this study is to develop an analytical tool for long-term dune management to help evaluate the risk associated with high water levels, high waves, and their joint probability, as well as the probability of dune erosion, overwash, and breaching to occur. The tool also aims to identify vulnerable dune s

On the molecular mechanisms of the amyloid β-peptide aggregation

Proteins are tiny chemical machines that play many critical roles in our body. Some proteins send important messages, some carry crucial supplies, some fight with invaders and protect body from diseases, some clear trash etc. Proteins are strings of hundreds and thousands of small units called amino acids. If the string is built from less than hundred amino acids, it is called a peptide. DNA, a loThe pathogenesis of Alzheimer’s disease is widely believed to be due to production and deposition of the amyloid β-peptide. Several variants of the Aβ peptide are known to exist in in vivo. Variations include mutations or additional functional groups attached to residue side chains and may affect the aggregation process. Early on-set Alzheimer’s is caused by a variety of single amino acid substitu