Redistribution of canalicular cell membrane enzyme in hepatocytes following their isolation and during early cell culture.
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Animals↗
Biomedical subjects
J Graf
Publications and source records attributed to J Graf.
Muscular involvement in the Holt-Oram syndrome.
Holt-Oram syndrome is an autosomal dominant disorder characterised by radial ray and congenital heart defects. Recently, a gene for this disorder has been identified on chromosome 12q24.1, encoding a T box transcription factor. However, the functional role of the gene product is not completely understood. We present results of neurological, radiological, and muscle magnetic resonance imaging (MRI) investigations in 13 patients from eight unrelated families. Besides heart defects, clinical signs ranged from thenar abnormalities to bilateral phocomelia. The former were present in all patients. MRI showed hypoplasia of discrete muscles which clinically showed as non-progressive weakness. The structural pattern of residual muscles was normal on MRI, which together with normal muscular power, electromyography, and muscle enzyme investigations excluded a progressive neuromuscular disorder. The number and location of hypoplastic muscles correlated with the severity of skeletal involvement. Thus, patients with hypoplasia of large and proximal muscles had phocomelia, and those with mere intrinsic hand muscle hypoplasia had only a triphalangeal thumb or no skeletal malformation. On the basis of these observations, we conclude that disturbed fetal limb muscle development is involved in the bony malformations of the upper limbs.
Adult↗
Sheet plastination of the vascularity of the lunate bone--a morphological study.
Using the method of sheet plastination, the vascularity of the lunate bone can be investigated and analyzed. By intraosseous injection, the deep and superficial venous systems are visualized. Transparent sheets with slices of embedded specimens show a three-dimensional presentation of the vascularity of the human carpus different in functional aspects. Comparing hands with a normal and extended wrist position, three mechanisms of impairment of the venous drainage are observed. The anatomical results of this investigation support the hypothesis that venous congestion, resulting from intraosseous hypertension, plays a role in the development of the necrosis of the lunate bone.
Drainage↗
Long-term effects of core decompression by drilling. Demonstration of bone healing and vessel ingrowth in an animal study.
Avascular necrosis of the femoral head is associated with bone marrow hyperpression. Although core decompression by drilling is an accepted treatment regimen, until today no experimental results exist concerning the physiological effects of this procedure. Published clinical data are controversial. In an animal study marrow decompression was carried out by drilling of both hips in 18 healthy male sheep. In the right hip of each animal a resorbable stent was implanted in order to prolong the duration of core decompression. Over a time period of 24 weeks the effects were studied by measurement of the intraosseous pressure, by the plastination method and by morphological examination with light and electron microscopy. Bone drilling is a procedure of high short-time efficacy in decompressing the bone marrow. But decompression lasts only for a short time period. Three weeks postoperatively the drill channel is sealed by hematoma and fibrous tissue in both hips (with/without stent) and no significant decompressive effect is measured. Ingrowth of vessels along the drill channel is found in all hips after a time period of 3 weeks. These vessels originate from the periosteum as well as from the bone marrow and form temporary anastomoses between the periostal-diaphyseal-metaphyseal and the epiphyseal-physeal circulatory system. In conclusion, for the first time an anastomosis induced by drilling between both circulatory systems of bone is demonstrated and the importance of the periosteum is confirmed. The time of decreased core pressure induced by drilling is too short for substitution of a necrotic area and could be the explanation of the inferior clinical results of the procedure.
Animals↗
Characterization of allergens in Apiaceae spices: anise, fennel, coriander and cumin.
BACKGROUND: Symptoms elicited by IgE-mediated food allergy range from mild local to severe systemic reactions. Allergens in spices are particularly dangerous due to their hidden presence in many dishes. OBJECTIVES AND METHODS: According to clinical observations, mugwort and birch pollen allergy, and hypersensitivity to spices are frequently associated, but the crossreacting compounds were not defined so far. We tested sera of 15 patients who experienced adverse reactions to spiced food and characterized their IgE-binding patterns on anise, fennel, coriander and cumin extracts through immunoblot and inhibition experiments. RESULTS: The use of anti-Bet v 1 (MoAb) and anti-profilin (rabbit) antibodies revealed the presence of crossreacting allergens in the tested spice extracts. Inhibition experiments showed that IgE-binding to allergens in Apiaceae spices could be blocked by preincubation of sera with rBet v 1 or rBet v 2 (birch profilin). Moreover, we detected crossreacting allergenic molecules in the molecular weight range of 60 kDa. IgE-binding to spice allergens occurred only with sera of 10/15 (66%) patients with allergy to pollen (birch, mugwort) and/or celeriac. In five out of 15 (33%) patients with a history of adverse reaction to spices, but without pollen and celeriac allergy, no IgE-binding to any spice protein could be demonstrated. It is possible that these clinical reactions could be elicited by other types of hypersensitivity (Type II, III, IV), however, as spices contain highly reactive substances, the symptoms may most likely be classified as food-intolerant. CONCLUSIONS: Bet v 1- and profilin-related allergens may, besides higher molecular weight allergenic molecules, be responsible for Type I allergy to anise, fennel, coriander or cumin, members of the Apiaceae.
Adult↗
Increased platelet and coagulatory activity indicate ongoing thrombogenesis in peripheral arterial disease.
In peripheral arterial disease (PAD) risk of thrombosis is high and systemic haemostatic derangement thought contributory. We investigated platelet and coagulatory activity in patients with PAD and sought to find the best disease indicator. Stagnation point flow adhesion-aggregometry (SPAA) enables real-time quantitative assessment of platelet adhesion and aggregation under well-defined flow conditions. SPAA and agonist-induced aggregometry (Born method) were performed and concentrations of fibrinogen, fibrin monomer (FM), D-dimer, and thrombin-antithrombin complex (TAT) measured in 92 PAD patients and 70 healthy volunteers. Agonist-induced aggregometry detected no differences between patients and controls. SPAA-measured platelet adhesion and spontaneous aggregation (p < 0.001), and concentrations of fibrinogen (p < 0.001), FM (p < 0.001), TAT (p < 0.02) and D-dimer (p < 0.001) were all significantly increased in patients. Neither platelet function nor coagulatory activity was altered in patients receiving aspirin. Sensitivity and specificity in detecting PAD were as follows: SPAA (95%, 93%), fibrinogen (36%, 91%), FM (48%, 84%), TAT (36%, 78%), D-dimer (73%, 80%). Our findings support the concept of ongoing thrombogenesis as being contributory to the progression and possibly to the initiation of PAD. Aspirin alone did not prevent haemostatic hyperreactivity in these patients and flow-mediated platelet function was the most sensitive and specific indicator of advanced disease. This technique thus appears to be valuable, not only for evaluating therapeutic strategies to prevent platelet activation, but also in elaborating platelet-related mechanisms involved in thrombogenesis and atheroma formation.
Adult↗
Platelets of patients with peripheral arterial disease are hypersensitive to heparin.
We sought to verify earlier reports of increased platelet reactivity in patients with peripheral arterial disease (PAD) during perioperative heparin administration, and to test the hypothesis of platelet hypersensitivity to heparin in these patients. Before and after incubation of platelet rich plasma with unfractionated (UH), low molecular weight heparin (LMWH), and a low molecular weight heparinoid, real-time quantitative assessment of platelet function was performed by stagnation point flow adhesio-aggregometry (SPAA) in 21 patients with PAD and 14 healthy volunteers. With SPAA the occurrence of spontaneous aggregation is pathological. In the 15 patients requiring operation, platelet function and count were measured at regular intervals. To detect heparin dependent antibodies, the heparin induced platelet activation assay (HIPA) was performed preoperatively and after 10 days of heparin therapy. Mean baseline platelet adhesion in patients was double that observed in controls (p < 0.001). Spontaneous aggregation was seen in 9 (43%) patients and no controls (p < 0.001). In controls heparinoid reduced, whereas UH and LMWH slightly increased adhesion. Spontaneous aggregation was observed once with UH. Platelets from patients showed significantly enhanced adhesiveness and aggregability (p < 0.05) with UH and LMWH when compared to controls. Effects with the heparinoid were less pronounced and non-significant. In patients requiring operation, postoperative increases in platelet function and reductions in count were significant (p < 0.001). Ten (67%) experienced a fall in platelet count of > 50%. Preoperatively the HIPA assay showed no evidence of antibodies, whereas after heparin administration antibodies were verified in 4 (32%) patients and could not be ruled out in 6 (40%). Three developed postoperative thrombosis, in one case fatal. A hypersensitive in vitro and in vivo platelet response to heparin was verified in patients with PAD and a large number developed the immunological type of heparin-associated thrombocytopenia. Our findings suggest that a thrombin antagonist which does not interact with platelets may give the best perioperative protection in these patients.
Adult↗
The influence of subchondral vascularisation on chondromalacia patellae.
An experiment was carried out on 40 rabbits in which the blood supply to the patella was interrupted for periods from 2 weeks to 6 months. With prolonged ischaemia, there were clear changes in the articular cartilage which were comparable with those seen in chondromalacia patellae.
Animals↗
Gastroschisis increases small bowel nitric oxide synthase activity.
In gastroschisis, the eviscerated fetal bowel frequently is damaged and this results in hypoperistalsis and malabsorption. The mechanistic link that ties gastroschisis-induced intestinal damage to dysfunction may be nitric oxide (NO) and the enzyme responsible for producing it, NO synthase. Using a fetal rabbit model, the authors investigated the hypothesis that the hypoperistalsis and malabsorption associated with gastroschisis may be attributable to abnormal small bowel NO synthase activity. Using the 3H-arginine-to-3H-citrulline conversion assay, they measured NO synthase activity in the small bowel of full-term fetal rabbits with and without gastroschisis. The mean total small bowel NO synthase activity of fetal rabbits with gastroschisis was 2.5 times greater than that of control littermates without gastroschisis (n = 6; 5,726 +/- 834 v 2,208 +/- 537 mean pmol/mg protein/min; P = .004). This increased NO synthase activity also was studied by measuring the individual isoforms of NO synthase, and the site of increased NO synthase activity was localized to the small bowel epithelium and neurons. After detecting and localizing the gastroschisis-induced increase in NO synthase activity, the authors explored the mechanism of this increase using NADPH-diaphorase staining. With this histological staining technique, no quantitative increase was found in the small bowel NO synthase of the rabbits with gastroschisis. This suggests that the increased NO synthase activity found in these rabbits is the result of accelerated enzyme kinetics. These findings suggest that the increased NO synthase activity caused by gastroschisis may contribute to the common clinical sequelae of malabsorption and intestinal dysmotility.
Animals↗
Ion transport in hepatocytes: mechanisms and correlations to cell volume, hormone actions and metabolism.
Intracellular ion homeostasis in liver cell is accomplished through the concerted action of ion pumps, carriers and channels. Description of these elements includes the Na+/K+-ATPase, Na+/H+- and Cl-/ HCO3(-)-exchange and Na+-HCO-3(-)- and Na(+)-K(+)-2 Cl(-)-cotransport as well as K+-, Cl(-)-, Na+ and nonselective cation channels. A short section is devoted to regulation of intracellular Ca2+ concentration. Ion flux through these elements is regulated by hormones and during experimental alterations of cell volume. We describe the effects of hormones and agonists on ion transport (e.g. purinergic agonists, alpha- and beta-adrenergic agonists, vasopressin, glucagon and insulin) and we emphasize the fact that altered ion transport rates may lead to cell swelling or cell shrinkage. Osmotically induced cell swelling or cell shrinkage triggers volume regulatory responses: recovery from cell swelling is accomplished by release of K+ and Cl- through ion channels whereas volume gain following osmotic shrinkage involves uptake of Na+, K+ and Cl- by channels, carriers and the Na+/K+-pump. Osmotic cell volume changes are associated with a broad spectrum of altered cell functions that includes changes of bile flow and bile acid transport, modulation of cytoplasmic and endosomal pH, metabolism of carbohydrate, protein and lipids, transcription and translation and alteration of cytoskeleton components (cf. Häussinger & Schliess; J. Hepatology 1995; 22: 94-100). In conclusion, we stress the concept that transduction of a hormonal signal primarily involves alteration of membrane ion transport followed by a change in cell volume. This change in cell volume appears to assist in executing a hormonal stimulus on cell function.
Animals↗
Increased platelet and coagulatory activity in peripheral atherosclerosis flow mediated platelet function is a sensitive and specific disease indicator.
The importance of flow in both athero- and thrombogenesis is well established. In peripheral arterial disease (PAD) atherosclerosis is disseminated, thrombosis risk high and systemic hemostatic derangement believed contributory. We studied platelet and coagulatory activity in PAD patients, thereby evaluating the clinical efficacy of Stagnation Point Flow Adhesio-Aggregometry (SPAA). SPAA provides real-time quantitative assessment of platelet adhesion and aggregation under convective, low-shear flow conditions. 62 nondiabetic PAD patients and 66 healthy volunteers were examined, whereby SPAA and conventional aggregometry were performed and circulating fibrinogen, fibrin monomer (FM), the fibrin degradation product D-Dimer and thrombin-antithrombin-complex (TAT) assessed. Conventional aggregometry detected no differences between patients and controls. SPAA-measured platelet function (p < 0.001), fibrinogen (p < 0.001), FM (p < 0.001), TAT (p < 0.02) and D-Dimer (p < 0.001) were significantly increased in patients and not effected by aspirin therapy. Respective sensitivity and specificity in detecting PAD was as follows: SPAA (96%/95%), fibrinogen (36%/92%), FM (46%/88%), TAT (40%/73%), D-Dimer (75%/80%). Increased platelet and coagulatory activity was verified in PAD, whereby flow-mediated platelet adhesion and aggregation proved the most sensitive and specific parameter. These findings indicate the usefulness of SPAA for delineating platelet-related disease mechanisms and evaluating therapeutic strategies to prevent platelet activation.
Antithrombin III↗
High precision measurement of electrical resistance across endothelial cell monolayers.
Effects of vasoactive agonists on endothelial permeability was assessed by measurement of transendothelial electrical resistance (TEER) of human umbilical vein endothelial cells (HUVECs) grown on porous polycarbonate supports. Because of the low values of TEER obtained in this preparation (< 5 omega cm2) a design of an Ussing type recording chamber was chosen that provided for a homogeneous electric field across the monolayer and for proper correction of series resistances. Precision current pulses and appropriate rates of sampling and averaging of the voltage signal allowed for measurement of < 0.1 omega resistance changes of the endothelium on top of a 21 omega series resistance of the support and bathing fluid layers. Histamine (10 microM) and thrombin (10 U/ml) induced an abrupt and substantial decrease of TEER, bradykinin (1 microM) was less effective, PAF (380 nM) and LTC4 (1 microM) had no effect. TEER was also reduced by the calcium ionophore A-23187 (10 microM). The technique allows for measurements of TEER in low resistance monolayer cultures with high precision and time resolution. The results obtained extend previous observations in providing quantitative data on the increase of permeability of HUVECs in response to vasoactive agonists.
Bradykinin↗
Osmotic swelling of hepatocytes increases membrane conductance but not membrane capacitance.
We have used the whole-cell patch-clamp technique to study changes in membrane conductance and membrane capacitance after osmotic swelling in rat hepatocytes. Hypoosmotic solutions induced an instantaneous increase in the volume of patch-clamped cells that was followed by a slow decline reminiscent of regulatory volume decrease as seen in intact cells. These morphological changes were associated with a transient increase in membrane conductance. The rise in conductance was not correlated with changes in capacitance, neither in time after the initiation of cell swelling nor in magnitude. Therefore we conclude that an osmotically induced increase in conductance is probably a result of the activation of existent channels in the plasmalemma and not a result of the fusion of vesicle membrane containing ionic channels.
Animals↗
Haemoglobin Tunis-Bizerte: a new alpha 1 globin 129 Leu-->Pro unstable variant with thalassaemic phenotype.
A Leu-->Pro substitution at position 129 of the alpha 1 globin gene was detected in three members of a Tunisian family by sequencing the whole alpha 2 and alpha 1 DNA. The mutation was verified by dot-blot allele-specific hybridization as well as by digestion of PCR and RT-PCR products with Nci I, since the alpha 1(129) T-->C mutation creates an additional recognition site for the above-mentioned enzyme. The alpha 1(129)(H12)Leu-->Pro substitution disturbs helix H resulting in alpha-thal trait most probably because the unstable alpha-globin chain variant cannot form alpha beta dimers. A search for the abnormal Hb and for the abnormal alpha globin chain by isoelectric focusing, carboxymethyl cellulose chromatography and electrospray ionization mass spectrometry was negative. In the heterozygous state, the alpha 1(129)(H12) Leu-->Pro variant is manifested by microcytosis (MCV approximately 73 fl), whereas in the homozygous state there is moderate anaemia with marked microcytosis (Hb 11.6 g/dl, MCV 65 fl).
Adolescent↗
Bile canalicular cationic dye secretion as a model for P-glycoprotein mediated transport.
This study explores properties of P-glycoprotein dependent membrane transport in rat liver with the use of acridine orange as the substrate. We studied the biliary secretion of the dye, its binding to canalicular membrane P-glycoprotein, and effects of the inhibitor cyclosporin A: acridine orange is excreted into bile together with less hydrophobic and glucuronidated metabolites. Cyclosporin A inhibited both the secretion of acridine orange and of its metabolites. In TR- animals, a rat strain that is deficient of the canalicular multi-specific organic anion transport system, non-metabolized acridine orange is the predominant species in bile and its secretion is also inhibited by cyclosporin A. Binding of acridine orange to liver P-glycoprotein was analyzed by photoaffinity labeling with azidopine, a substrate of P-glycoprotein dependent transport in multi-drug resistant tumor cells. Labeling of the immunoprecipitated P-glycoprotein was inhibited by acridine orange, verapamil, and by cyclosporin A. The results show that biliary secretion of acridine orange is highly analogous to P-glycoprotein mediated membrane drug transport in tumor cells that exhibit multi-drug resistance.
ATP Binding Cassette Transporter, Subfamily B, Mem↗
Effect of transposon-induced motility mutations on colonization of the host light organ by Vibrio fischeri.
Vibrio fischeri is found both as a free-living bacterium in seawater and as the specific, mutualistic light organ symbiont of several fish and squid species. To identify those characteristics of symbiosis-competent strains that are required for successful colonization of the nascent light organ of juvenile Euprymna scolopes squids, we generated a mutant pool by using the transposon Mu dI 1681 and screened this pool for strains that were no longer motile. Eighteen independently isolated nonmotile mutants that were either flagellated or nonflagellated were obtained. In contrast to the parent strain, none of these nonmotile mutants was able to colonize the juvenile squid light organ. The flagellated nonmotile mutant strain NM200 possessed a bundle of sheathed polar flagella indistinguishable from that of the wild-type strain, indicating that the presence of flagella alone is not sufficient for colonization and that it is motility itself that is required for successful light organ colonization. This study identifies motility as the first required symbiotic phenotype of V. fischeri.
Animals↗
Organic solvents increase membrane fluidity and affect bile flow and K+ transport in rat liver.
Following the earlier observation that inhalation of volatile lipid solvents and of narcotic gases causes cholestasis, we studied the effects of various organic solvents on bile flow, plasma membrane fluidity and potassium movement in rat liver. Both in vivo and in the isolated perfused liver, applications of CCl4, CHCl3, dichloromethane, trichloroethylene, halothane, benzene and cyclohexane elicited rapid and sustained but reversible cholestasis. A transient phase of choleresis was observed prior to and after cholestasis, during the increase and fall in liver tissue solvent concentrations, respectively. Tissue concentrations required to produce cholestasis were lower the higher the lipophilicity of the solvent. Membrane fluidity was measured in isolated basolateral liver cell membranes by fluorescence polarization. Fluidity increased with increasing solvent concentration, the increase being associated with either biphasic stimulation and inhibition of membrane enzymes (Na+,K(+)-ATPase, 5'nucleotidase) or with inhibition alone (Mg(2+)-ATPase). In the isolated perfused liver, application of organic solvents caused hepatic uptake of K+ that was followed by K+ release upon withdrawal of the solvent. The magnitude of K+ uptake elicited by the solvent was comparable with the effect of blocking K+ channels with 2 mM Ba2+, but Ba2+ was ineffective in the presence of the solvent. In contrast, application of ouabain caused K+ release in equal amounts in the absence and presence of the solvent, indicating that K+ uptake elicited by the solvent results from inhibition of K+ efflux through K+ channels rather than stimulation of the Na+,K+ pump. The data show that cholestasis elicited by lipid solvents is associated with an increase in membrane fluidity and with disturbance of liver K+ homeostasis. The significance of these observations is discussed with respect to other models of experimental cholestasis.
Animals↗
The Haglund imprint on the patella.
Seven hundred and five radiographs of the knee were examined and 17.6% showed a so-called Haglund imprint on the patella. The incidence was the same in patients with chondromalacia and in a control group. There was no statistical difference regarding age, sex and body weight. Haglund's imprint is a variation from the normal and is of no diagnostic value.
Body Weight↗