On the mechanism of the stimulation by anionic amphipaths of lecithin hydrolysis by phospholipase B of penicillium notatum.
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Chemical Phenomena↗
Biomedical subjects
H Hauser
Publications and source records attributed to H Hauser.
The binding of calcium at lipid-water interfaces.
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Calcium↗
Stability of unimolecular films of 32P-labeled lecithin.
1. The stability of monolayers of a highly unsaturated yeast lecithin labelled with (32)P has been investigated by a surface radioactivity technique. 2. Lecithin films on distilled water at all surface pressures between 6 and 48dynes/cm. were completely stable on rapid perfusion of the subphase and on addition of ionic amphipathic substances to the film. 3. Ultrasonically treated lecithin added to the subphase caused a slow loss of surface radioactivity but little pressure change. 4. The addition of proteins to the subphase caused negligible changes in the film even when conditions were favourable for electrostatic heterocoagulation and penetration. 5. Lecithin films were not hydrolysed by a strongly acid subphase at room temperature. The very low rate of hydrolysis produced by alkali was proportional to the subphase OH(-)ion concentration: the apparent activation energy and temperature coefficient (Q(10)) of the reaction were 14250 cal. and 2.37 respectively. 6. Alkaline hydrolysis of lecithin monolayers was markedly stimulated by adding methanol (10-20%, v/v) to the subphase. The addition of ionic amphipaths to the monolayer had the expected type of effect on the hydrolysis rate, but its magnitude was far less than that suggested by an application of the Poisson-Boltzmann equation for ion distribution at a charged interface (Davies & Rideal, 1963).
Chemical Phenomena↗
[History of construction and conception of the Department of Veterinary Medicine of the Bern University].
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Hospital Design and Construction↗
Pyogenic liver abscess: studies of therapy and analysis of risk factors.
Experience with 46 patients diagnosed with liver abscesses over a 13-year period was reviewed to ascertain the impact of percutaneous versus surgical drainage. In most of the cases the abscesses were diagnosed by sonography or computed tomography. The most common pathogenetic mechanism was ascending biliary tract infection. Of the 46 total patients, 27 were primarily treated surgically, whereas 19 underwent percutaneous drainage. In the surgical group five (18.5%) patients required reoperation. Percutaneous drainage failed in four patients (21.1%). Multivariate stepwise logistic regression analysis revealed that a high APACHE II score, low hemoglobin level, and high serum bilirubin level were significant predictors of a complicated clinical course. Death was related more closely to the overall condition of the patient, as expressed by a high APACHE II score, and the underlying disease (malignancy) than to the mode of therapy.
Adult↗
Aneurysms of hemodialysis access grafts: treatment with covered stents: a report of three cases.
Three patients with dialysis access graft shunts, having a symptomatic pseudoaneurysm and a hemodynamically significant stenosis at the anastomosis between the graft shunt and the subclavian vein, were treated with percutaneous transluminal angioplasty and insertion of a Wallstent. Pseudoaneurysms were excluded by percutaneous insertion of a Cragg Endo-Pro stent-graft with a diameter of 6 mm and a length of 6-10 cm. All three aneurysms were excluded successfully. In two patients, the stent-graft was punctured repeatedly during follow-up and the aneurysms recurred after 7 and 8 months, respectively. The patency of the dialysis shunt after stent-graft insertion was 8 (n = 1) and 9 months (n = 2). Due to the recurrence of the aneurysm (n = 2) or recurrent thrombosis (n = 1) the use of these shunts was discontinued.
Aged↗
Monolayer characteristics and thermal behaviour of phosphatidic acids.
The monolayer and thermal behaviour of different phosphatidic acids are presented. At neutral pH and 22 degrees C dilauroylphosphatidic acid and unsaturated phosphatidic acids form liquid-expanded monolayers, while dipalmitoyl- and distearoylphosphatidic acid form condensed monolayers. Dimyristoylphosphatidic acid undergoes a transition from the liquid-expanded to the condensed state. With long-chain saturated and unsaturated phosphatidic acids little change in molecular area is observed between pH 2 and 7. In contrast, the short chain saturated phosphatidic acids, dilauroyl- and dimyristoylphosphatidic acids, undergo a condensation in the pH range 2 to 7. This is so in spite of the fact that the phosphoric acid group dissociates and the phosphatidic acid molecule attains one negative charge over this pH range. This finding is interpreted to indicate that the electrostatic repulsion between negatively charged phosphatidic acid molecules is compensated for or even outweighed by other intermolecular forces. Hydrogen bonding at the lipid/water interface is supposed to play a major role. All phosphatidates studied exhibit a significant expansion in the pH range 7 to 12. The second apparent pK of the primary phosphate group of phosphatidic acids is 8.6 and the expansion observed in this pH range is therefore due to electrostatic repulsion. At neutral pH the ether analogues of saturated phosphatidic acids have monolayer properties similar to those of the ester compounds. Considering the total pH range of 2 to 12 studied the force-area curves of the ether analogues are more condensed compared to the ester compounds. Synthetic phosphatidates and their ether analogues give reversible sharp crystal(gel)-to-liquid crystal transitions while the naturally occurring egg phosphatidate gives a broad, asymmetric one. The transition temperature Tm of saturated phosphatidates increases with increasing hydrocarbon chain length and at a given chain length Tm decreases markedly with unsaturation. The Tm values of the ether analogues are about 10 degrees C higher and the delta H values are 10-15% lower than those of the corresponding esters.
Calorimetry, Differential Scanning↗
In vivo formation of IRF-1 homodimers.
Interferon regulatory factor 1 (IRF-1) is a transcriptional activator which exerts different biological activities. IRF-1 activates interferon induced genes as well as genes which are not directly linked to the interferon system, such as the ICE protease gene. IRF-1 activity is post-transcriptionally regulated in addition to transcriptional regulation by interferons, cytokines, hormones and many other factors. This includes heterodimerisation with activators and repressors of transcription. These protein interactions modulate the transactivating capacity of IRF-1. By using a two-hybrid system, we demonstrate that IRF-1 forms homodimers in vivo. The homodimerization domain was determined to be located in the N-terminal part of IRF-1 which belongs to the DNA-binding domain. Since this sequence is highly conserved between members of the IRF-family, our observation raises the question of homodimerization of other IRFs through this domain.
DNA-Binding Proteins↗
Miliary tuberculosis associated with adrenal enlargement: CT appearance.
In two patients with miliary tuberculosis the diagnosis was first suggested with CT and then proven by histology in both and bacteriology in one case: Adrenal involvement was demonstrated with unilateral and bilateral enlargement, respectively.
Adrenal Gland Diseases↗
A unique feature of lipid dynamics in small intestinal brush border membrane.
The lipid composition of the brush border membrane (BBM) or apical plasma membrane of enterocytes is characterized by a remarkably high glycosphingolipid content (glycosphingolipid: phospholipid:neutral lipid mole ratio of about 1:1:1). A manifestation of the high glycolipid content of the BBM is the lipid fluidity which is low compared to other mammalian plasma membranes and related to it a steep flexibility gradient: hydrocarbon chain segments close to the lipid-water interface have quasi-crystalline packing while hydrocarbon chain segments close to the centre of the lipid bilayer behave like a fluid. An important function of the BBM is the absorption of dietary lipids. The absorption of cholesterol from bile salt micelles has been shown to be protein-mediated. The integral membrane protein responsible for this activity has features similar to non-specific lipid transfer proteins. Another remarkable property of the BBM is described here: phospholipids are exchanged between the lipid bilayer of the BBM and the lipid bilayers of small unilamellar egg phosphatidylcholine (PC) vesicles. In the course of this probably 1:1 exchange, endogenous BBM phospholipids move out of the BBM and the lipid loss is compensated by the insertion of exogenous PC from the small unilamellar vesicles. This exchange activity is probably due to the same protein(s) responsible for lipid absorption in this membrane or at least related to the absorptive capacity of the BBM. The unique feature of small intestinal BBM is that the on- and off-rate of certain lipids is remarkably high: the underlying structure of this activity is still unknown.
Animals↗
Preoperative differential diagnosis of benign and malignant pancreatic lesions--the value of pancreatic secretory trypsin inhibitor, procarboxypeptidase B, CA19-9 and CEA.
BACKGROUND/AIMS: Pancreatic secretory trypsin inhibitor (PSTI). Procarboxypeptidase B (PCPB or Human pancreas-specific protein HPASP), CA19-9 and CEA were evaluated for their performance in preoperative differential diagnosis of benign and malignant pancreatic lesions. METHODOLOGY: Our prospective study included 92 patients with pancreatic lesions diagnosed by imaging techniques. In 45 of them (group I), the lesions turned out to be malignant tumors (35 pancreatic cancer, 10 other carcinoma of the pancreatic region); 47 patients (group II) had benign lesions (38 inflammatory disease of the pancreas, 9 other benign lesions). RESULTS: Statistical analysis showed significant differences between these two groups for PSTI, PCPB and CA19-9, but not for CEA. When only pancreatitis versus pancreatic cancer was analyzed, differences were more significant for PSTI and PCPB, but less significant for CA19-9. Because of a strong trend toward false positive values in patients with pancreatic inflammation, the specificity of CA19-9 in our selected patient group was only 67%, but in combination with normal PSTI (< 13.5 ng/ml), it reached 96%. CONCLUSION: In our study, PSTI and PCPB were useful markers for pancreatitis. PSTI also showed good correlation with the severity of the inflammation and provided additional preoperative information, in combination with CA19-9.
Adult↗
Antioxidant treatment during liver resection for alleviation of ischemia-reperfusion injury.
BACKGROUND/AIMS: Many experimental studies on ischemia-reperfusion injury in animals suggest a preventive effect of antioxidants, but the clinical significance of these findings is still unclear. The aim of our study was to evaluate the effect of antioxidant treatment with vitamins on liver function parameters during liver resection. METHODOLOGY: Our prospective randomized study comprised 58 patients undergoing major liver surgery, including the Pringle maneuver. In the treatment group 32 patients received a multivitamin infusion (Omnibionta) which included 10 mg of alpha-tocopherol acetate, 2 mg of DL-alpha-tocopherol and 1 g of ascorbate. The control group consisted of 26 patients. Various parameters associated with liver function, such as transaminases, lactate, ammonia, bilirubin, cholinesterase and clotting parameters were measured preoperatively, at the beginning of liver ischemia, 15, 30 and 60 minutes after reperfusion onset and every 12 hours after the operation. RESULTS: The Mann-Whitney-Wilcoxon-Test showed statistically significant differences in the postischemic changes between the treatment group and the control group for the Quick test (prothrombin time): p = 0.01. The transaminases were also markedly better in the treatment group (splitting-up slightly more delayed than with the Quick test). A smaller effect was seen with cholinesterase. Lactate, however, increased intraoperatively with a strong correlation to the duration of ischemia and returned quickly to baseline values without any remarkable influence of the antioxidant treatment. CONCLUSION: In our study, antioxidant treatment with a multivitamin infusion showed a positive effect on postischemic liver function parameters.
Alanine Transaminase↗