An aluminium semisphere system with 120 points of entry and eight detection areas, assembled on a meridian covering 0.0026 steradian each, was put over a solid bulk sample (e.g., aluminium), which was mounted in the eucentric point so that the incident electron beam could be varied by a polar rotation of the sphere in steps of 11.25 degrees. The complete angular distribution of the backscattered electrons became available by a rotation in steps of 11.25 degrees azimuthally. For this particular setup, the signals from the detection areas as well as the signal from the rest of the semisphere were amplified by operational amplifiers (Burr-Brown OPA128LM). However the signal of the semisphere was not available at that time. Specimen current measurements made the total amount of electrons accessible, providing a possibility for normalization of the results and comparison with total backscattering coefficients. By use of counter voltage variable up to 10 kV inside the detection assembly, it was possible to measure an energy resolution of the backscattered electrons for each detection area at the same time. Details of the construction and calibration procedures, possible errors, and sources of systematic deviations as well as first test results are discussed.

Journal Article↗

PubMedDate not supplied

Analysis of submicron particles by scanning electron microscopy-energy-dispersive X-ray spectrometry-accuracy of size measurement.

Scanning electron microscopy combined with energy-dispersive x-ray spectrometry (SEM-EDXS) is widely used for particle analysis. In the case of submicron particles, especially for particles that are smaller than 300 nm, the measured particle size is influenced by specimen preparation, SEM operating parameters, the mean atomic number of the particles, and the threshold value used for binarization. The use of uncoated particles on a conductive substrate and image acquisition using an in-lens detector are recommended for precise morphologic results in this size range.

Journal Article↗

PubMedDate not supplied

Glutamine stabilizes intestinal permeability and reduces pancreatic infection in acute experimental pancreatitis.

Intestinal barrier failure and subsequent translocation of bacteria from the gut play a decisive role in the development of systemic infections in severe acute pancreatitis. Glutamine (GLN) has been shown to stabilize gut barrier function and to reduce bacterial translocation in various experimental settings. The aim of this study was to evaluate whether GLN reduces gut permeability and bacterial infection in a model of acute necrotizing pancreatitis. Acute necrotizing pancreatitis was induced in 50 rats under sterile conditions by intraductal infusion of glycodeoxycholic acid and intravenous infusion of cerulein. Six hours after the induction of pancreatitis, animals were randomly assigned to one of two groups: standard total parental nutrition (TPN) or TPN combined with GLN (0.5 g/kg(-1)/day(-1)). After 96 hours, the animals were killed. The pancreas was prepared for bacteriologic examination, and the ascending colon was mounted in a Ussing chamber for determination of transmucosal resistance and mannitol flux as indicators of intestinal permeability. Transmucosal resistance was 31% higher in the animals treated with GLN- supplemented TPN compared to the animals given standard TPN. Mannitol flux through the epithelium was decreased by 40%. The prevalence of pancreatic infections was 33% in animals given GLN-enriched TPN as compared to 86% in animals receiving standard TPN (P < 0.05). Adding GLN to standard TPN not only reduces the permeability of the colon but decreases pancreatic infections in acute necrotizing pancreatitis in the rat. This confirms previous reports that GLN decreases bacterial translocation by stabilizing the intestinal mucosal barrier. The present findings provide the first evidence suggesting that stabilizing the intestinal barrier can reduce the prevalence of pancreatic infection in acute pancreatitis and that GLN may be useful in preventing septic complications in clinical pancreatitis.

Acute Disease↗

PubMedDate not supplied

[The permeability of isolated phosphatides from normal and atherosclerotic human aortas].

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Aorta↗

PubMedDate not supplied

Relations between spontaneous and induced arterial lesions in swine and arteriosclerosis in humans.

The rabbit which for practical reasons is so frequently used for experimental arteriosclerosis considerably differs from humans in its metabolism, nourishment, and arterial wall responses to atherogenic noxae. In this respect, domestic pigs show more resemblance to the conditions in man, and they have recently been used for experimental research work in the field of atherosclerosis. Our own investigations performed with a view to constructing an antherosclerosis model being as far as possible resemblant to conditions prevailing in humans have shown that among various forms of diets only one combined form which is rich in cholesterol (1.5 percent) and lipids (15 percent) produces changes in the intima that in certain arterial regions correspond to lesions found in humans. These are lipofibrous beds up to complicated atheromas. The location of the spontaneous changes (without atherogenic diet) suggest that these may be considered as early stages. The various forms of development were studied light- and electron-microscopically; moreover the development of the blood lipids was determined biochemically during the experiment.

Animals↗