Biomedical subjects
Publications and source records attributed to R Teyssier.
Perturbation imprinting at a flat interface by a rippled shock has been observed in a laser hydrodynamics experiment. A strong shock was driven through a three-layer target, with the first interface rippled, and the second flat. The chosen thickness of the second layer gave instability growth with opposite phases at the two interfaces, consistent with two-dimensional simulations and rippled shock theory.
The line width test has been realised on twelve normal healthy persons (seven men and five women). Blood was collected at different time during one day. The results obtained when blood samples was taking after eating, showed an appreciable decrease in the average methylene and methyl line width. The same test realised on clear serum samples added up with increasing quantities of triglycerids rich lipoproteins leads to the same result.
Relaxation times T1 and T2 of water protons for stimulated and unstimulated parotid and submandibular saliva from healthy patients were measured in the conventional way using the Bruker PC 20 Minispec. Some measurements of dispersion were also carried out. An interpretation of the average values for T1 and T2 observed in the 20 MHz range is proposed for these types of saliva in relation to biochemical composition (total proteins, amylase activity, sialic acids and hexosamins) and viscosity. For parotid saliva T2(-1)-T1(-1) correlates significantly with amylase activity. In the submandibular saliva T2(-1)-T1(-1) correlates significantly with both mucins and alpha-amylase activity.
The differentiation between inflammatory and non inflammatory states has been performed using Nuclear Magnetic Resonance (NMR) in vitro by measuring relaxation times T1 and T2 in 84 synovials fluids obtained from various rheumatologic diseases. The results show that the T1/T2 ratio is more sensitive to distinguish these two situations rather than the isolated T1 or T2 values. In particular, high values of T1/T2 ratio are found in septic arthritis.
An investigation of the liquefaction of human semen was performed using the technique of Nuclear Magnetic Resonance, by measuring the time of spin-spin proton relaxation. Measurements which were made at 24 degrees C and 37 degrees C over a 15-day period showed that significant degradation processes and protein transformations occurred during the first 3-5 days. Different phases of these processes were identified.
A simple, precise and rapid pulse nuclear magnetic resonance technique for measuring the rate of water exchange across the erythrocyte membrane is presented. The effects of cell volume on cell water lifetime may be eliminated by the introduction of a cell water diffusion coefficient. This parameter is applied to the study of eleven blood samples.
An investigation of the liquefaction of human semen was performed using a technique of nuclear magnetic resonance, by measuring the time of spin-spin proton relaxation. Measurements made at 24 degrees C over a 15-day period showed that significant degradation processes and protein transformations occurred during the first 5 days. Different phases of these processes were identified.
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The frozen tissue was sliced and then homogenized at 20 degree C in LiCl, 2 M; lauryl-trimethyl ammonium chloride (K & K No. 4484), 5%; pronase, B grade (calbiochem), 1 mg/ml and Tris-HCl 10 mM pH 7.5. The homogenate was left to stand 15 min at 20 degree C with occasional shaking. After centrifugation at 35 000 X g for 30 min at 0 degree C, the supernatant containing the crude DNA was purified by filtration on Ultrogel A 2 (LKB, Sweden). The Ultrogel A 2 column (2.5 X 45 cm) was equilibrated with a solution containing NaCl 2 M, EDTA 2.5 mM, Tris-HCl 10 mM pH 7.5. The flow rate was 3 ml cm-2 h-1. Five ml of the supernatant were placed on the column. The first peak contained highly polymerized (as demonstrated by ultracentrifugation) pure DNA (A260/A230 = 3.19; A260/A280 = 1.82). The yield was 2.26 mg of DNA/g of fresh liver.
Total HMW-RNAs were prepared by three different methods (method with phenol, method with NaClO4, method without phenol using Ultrogel AcA 22 filtration). Giant RNAs were obtained in the void volume by filtration on Sepharose 2B. The giant RNAs/total HMW-RNA ratio is higher (6.77%) with the gel filtration method than with phenol or NaClO4 methods (1.41% and 1.00% respectively). The nucleotide composition of these RNAs is DNA-like and the sedimentation constants are approximately 70-100 S.