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Biomedical subjects

H Hauser

Publications and source records attributed to H Hauser.

At least 253 records · Page 14Linked to original sources
PubMed1981

Crystallization of phosphatidylserine bilayers induced by lithium.

Utilizing differential scanning calorimetry and x-ray diffraction, 1,2-dimyristoyl-L-glycero-3-phospho-L-serine (DMPS) was shown to form hydrated bilayer membrane structures exhibiting a gel leads to liquid crystalline transition at 39 degrees C (delta H = 7.2 kcal/mol). Addition of up to molar concentrations of the alkali halides NaCl, KCl, Rl Cl, and CsCl produced relatively minor changes in DMPS bilayer structure or stability. For example, in the presence of 0.5 M NaCl, the transition temperature (Tc = 42 degrees C) and transition enthalpy (delta H = 7.0 kcal/mol) show only minor changes. In marked contrast, addition of LiCl results in "'crystallization" of the DMPS bilayer membrane structure. At 0.5 M LiCl, the crystalline DMPS exhibits a bilayer gel leads to liquid crystal transition at 89 degrees C accompanied by a high enthalpy change, delta H = 16.0 kcal/mol. Thus, Li+ induces an isothermal crystallization of DMPS bilayers, the hydrocarbon chains adopting a more ordered packing mode than the "hexagonal" arrangement of the gel state. In view of the widespread use of lithium in the treatment of manic-depressive illness, we also raise the possibility that interaction of Li+ with anionic membrane phospholipids could play a role in its pharmacological action.

Calorimetry, Differential Scanning↗
PubMed1981

Detergent-induced proteolysis of rabbit intestinal brush border vesicles.

Proteolysis of brush border vesicle proteins is induced by detergent solubilisation. This proteolysis is selective in that some of the proteins are more susceptible than others. The rate of induced proteolysis is decreased by decreasing the temperature, has a minimum of about pH 6 and is effectively prevented by a combination of the protease inhibitors, EDTA, diisopropylfluorophosphate and iodoacetamide.

Actins↗
PubMed1981

[Dilated Wirsung's ducts: contribution of axial tomometry].

The normal pancreatic main duct is not visualized by CT except with the latest equipment permitting a slice thickness of 1-2 mm. In our series the main duct dilatation is due to benign lesions in 46% of the cases and due to malignancies in 54%. In the absence of typical signs of chronic pancreatitis and of clinical features of acute pancreatitis, the duct dilatation is usually of tumoral origin. CT frequently is sufficiently diagnostic for surgery to be performed. In duct dilatation with evidence of obstructive lesion, E.R.C.P. is still required.

Aged↗
PubMed1981

5'-Terminal sequences of eucaryotic mRNA can be cloned with high efficiency.

A method for cloning mRNAs has been used which results in a high yield of recombinants containing complete 5'-terminal mRNA sequences. It is not dependent on self-priming to generate double-stranded DNA and therefore the S1 nuclease digestion step is not required. Instead, the cDNA is dCMP-tailed at its 3'-end with terminal deoxynucleotidyl transferase (TdT). The synthesis of the second strand is primed by oligo(dG) hybridized to the 3'-tail. Double-stranded cDNA is subsequently tailed with dCTP and annealed to dGMP-tailed vector DNA. This approach overcomes the loss of the 5'-terminal mRNA sequences and the problem of artifacts which may be introduced into cloned cDNA sequences. Chicken lysozyme cDNA was cloned into pBR322 by this procedure with a transformation efficiency of 5 x 10(3) recombinant clones per ng of ds-cDNA. Sequence analysis revealed that at least nine out of nineteen randomly isolated plasmids contained the entire 5'-untranslated mRNA sequence. The data strongly support the conclusion that the 5'-untranslated region of the lysozyme mRNA is heterogeneous in length.

Avian Myeloblastosis Virus↗
PubMed1981

[Health maintenance organizations: starting point of a market economical reform of health care].

The present work was based on the observations that, as regards health care costs, the major problem in most present systems is that those who are responsible for the treatment decision (physician and patient) do not bear a direct financial responsibility for it, and that the overall system is very fragmented, which leads to numerous externalities. In accordance with this diagnosis, a reform strategy should particularly aim at creating units which are responsible for the provision and the financial coverage of comprehensive health services to a given population. Health Maintenance Organizations (HMOs) are a private economy oriented solution in this direction. They have proved to be a real possibility in the USA over years, at least for part of the population, and show interesting performances as regards costs. They were able to develop and evolve in the largely open US institutional framework. In Switzerland, we have more strongly structured systems, which appear to stand in relative contradiction to the HMO solution. A potential adaptation of the concept to our country would therefore require a preliminary in depth discussion about the meaning of the present collective (insurance) contract structure, the position of hospitals in a private economy health care system as well as about the conditions of the sought for competition in the HMO model.

Comprehensive Health Care↗
PubMed1981

[Value of transverse radiotomography in the control of the permeability of aortocoronary bypasses, compared with coronary angiography].

The object of this study was to determine whether transverse radiotomography, despite cardiac movement, could be used to visualise aortocoronary bypass grafts to confirm their patency or obstruction. The results were then compared with those of coronary angiography. 20 patients with a total of 38 grafts (18 on the left anterior descending, 8 on the circumflex and 12 on the right coronary artery) underwent tomography. 1 or 2 60 ml boluses of iodide contrast medium were injected into a fore arm vein and 3-5 films were exposed after each injection at 15 sec intervals. Coronary angiography was performed in 16 patients and the results of tomography were identical to those of coronary angiography : 23 patent and 6 occluded grafts. In one case, subtotal proximal stenosis of the left anterior descending artery allowed sufficient flow for the graft to be opacified and considered patent on tomography. The correlation between transverse radiotomography and coronary angiography was excellent. Transverse radiotomography, a non-invasive technique, is very useful in operated patients with atypical chest pain and in those with recurrent angina in whom obstruction of the graft is feared. It does not seem destined to replace control coronary angiography after bypass surgery, but it may be indicated is selected cases.

Adult↗
PubMed1980

Ion and sugar permeabilities of lecithin bilayers: comparison of curved and planar bilayers.

Na+ and sugar permeabilities of egg lecithin bilayers were measured using curved bilayers and planar bilayers as represented by single-bilayer vesicles and black lipid films, respectively. The Na+ permeability coefficient measured with single-bilayer vesicles at 25 degrees C is (2.1 +/- 0.6) x 10(-13) cm sec-1. Because of technical difficulties it has been impossible to measure ionic permeabilities of values lower than about 10(-10) cm sec-1 in planar (black) lipid bilayers using tracer methods. The D-glucose and D-fructose permeabilities were measured with both curved and planar bilayers. The permeability coefficients measured with vesicles at 25 degrees C are (0.3 +/- 0.2) x 10(-10) cm sec-1 for glucose and (4 +/- 1) x 10(-10) cm sec-1 for D-fructose; these are in reasonable agreement with the corresponding values obtained for planar (black) lipid bilayers which are (1.1 +/- 0.3) x 10(-10) cm sec-1 for D-fructose, respectively.

Animals↗
PubMed1980

Rabbit small intestinal brush border membrane preparation and lipid composition.

1. Rabbit intestinal brush border membrane vesicles were prepared either from frozen or fresh tissue and the lipid composition was analysed. 2. Lipids extracted from membranes prepared by the Ca2+-precipitation method (Schmitz, J., Preiser, H., Maestracci, D., Ghosh, B.K., Cerda, J.J. and Crane, R.K. (1973) Biochim. Biophys. Acta 323, 98--112; Kessler, M., Acuto, O., Storelli, C., Murer, H., Müller, M. and Semenza, G. (1978) Biochim. Biophys. Acta 506, 136--154) had exceptionally high levels of lysophospholipids and free fatty acids. An intrinsic, Ca2+-activated phospholipase A is responsible for the lipid decomposition. 3. It was necessary to modify the preparation of brush border membranes. Essentially, EGTA is used to keep the free Ca2+ concentration low so that phospholipases are inactivated, and Mg2+ instead of Ca2+ is employed to aggregate selectively contaminating membranes. The modified procedure gives membranes suitable for lipid analysis. 4. The molar ratio of neutral, phospholipid and glycolipid is about 1 : 1 : 1. The major neutral lipids are free cholesterol and fatty acids. The major phospholipids are phosphocholine-containing (approx. 45%) and phosphatidyl-ethanolamine (approx. 40%). The remainder (15--20%) is made up ppf acidic phospholipids, mainly phosphatidylserine and phosphatidylinositol. The major glycolipid is ceramide monohexodise. 5. The major fatty acids of total lipids and phospholipids are palmitic, stearic, oleic and linoleic acids. Individual phospholipids are characterised by distinct fatty acid compositions and differ markedly in the ratio of unsaturated-to-saturated fatty acid. X

Animals↗
PubMed1980

[The value and advantage of computer assisted tomography as compared to angiography in evaluating patency of aorto-coronary grafts].

Sixteen patients with 31 aorto-coronary grafts have been studied by CT and by coronary arteriography to compare the results of the two methods in the evaluation of graft patency or occlusion. Correlation of the two technics is excellent (100%). However, graft stenoses are not visualized on CT in its present state of technical performance and are the limiting factor for this noninvasive procedure. In patients with precordial pain and aorto-coronary grafts, CT should be done first to evaluate graft patency and only be checked by coronary arteriography if there is disagreement between the CT result and clinical assessment of the case.

Coronary Angiography↗