Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0432222 (SEM)
 47,337 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

An investigation was undertaken to evaluate the effect of both photoinitiators (camphor-quinone-amine systems) and the adhesion promoting monomer (4-MET) on photopolymerization of bonding liners and their adhesion to dentin. Photopolymerization of bonding liners was measured with differential scanning calorimetry (DSC). The bonding liner containing 2-(dimethylamino)ethyl methacrylate (DMAEMA) as a reducing agent decreased the rate of polymerization in the presence of 4-MET. On the other hand, the bonding liners containing N-phenylglycine (NPG) and N,N-dimethylaniline derivatives as a reducing agent showed good polymerization in the presence of 4-MET. The results of the tensile bond test suggested that bonding liners containing NPG and 4-(dimethylamino)benzoic acid (DMABA), one of the N,N-dimethylaniline derivatives, with or without 4-MET bonded well to dentin treated with EDTA 3-2. NPG and DMABA are recommended not only as reducing agents but also as aids in the diffusion of monomers into the dentin substrate. The relationship between the strength of the bond to dentin and photoirradiation of the bonding liner and composite resin was studied. Elongation of photoirradiation of both the bonding liner and composite resin was effective in impacting the strength of the bond to dentin. Furthermore, sufficient photoirradiation of the bonding liner prior to any filling of composite resin was especially important to obtain high bond strengths. SEM and TEM observations supported good adhesion being achieved by hybrid formations between photocurable bonding liners and dentin.
 ...
PMID:[Formulation of photocurable bonding liner and adhesion to dentin. Effect of photoinitiator, monomer and photoirradiation]. 248 1

The isolated perfused working rat heart model of cardiopulmonary bypass and ischaemic cardiac arrest has been used to investigate whether addition of various organic anti-oxidants to the St Thomas' Hospital cardioplegic solution can enhance the recovery of function of the rat myocardium after normothermic (37 degrees C) global ischaemic arrest. Five anti-oxidants were studied: (i) ascorbate (1.0 and 10.0 mmol.litre-1), (ii) methionine (1.0 and 10.0 mmol.litre-1), (iii) reduced glutathione (1.0 and 10.0 mmol.litre-1), (iv) dimethylthiourea (0.1, 1.0, 10.0 and 50.0 mmol.litre-1), (v) N-2-mercaptopropionyl glycine (0.1, 1.0 and 10.0 mmol.litre-1). The recovery of aortic flow in control hearts which were free of anti-oxidant was 50.7(SEM 0.5)%; ascorbate (1.0 or 10.0 mmol.litre-1) improved this recovery to 72.1(1.7) and 70.2(0.3)% respectively; methionine (1.0 and 10.0 mmol.litre-1) improved the recovery to 74.1(5.7)% and 67.7(1.7)%, respectively; reduced glutathione (1.0 and 10.0 mmol.litre-1) improved the recovery to 66.7(1.4)% and 74.0(1.7)% respectively. In further studies, the addition of dimethylthiourea (0.1, 1.0 and 10.0 mmol.litre-1) to the cardioplegic solution failed to improve recovery of aortic flow [47.3(8.0), 24.6(7.3), 48.0(7.7)% respectively] when compared to its anti-oxidant free control value of 40.4(6.1)% and at a concentration of 50.0 mmol.litre-1 a very poor recovery of aortic flow of 7.7(4.8)% was observed. Mercaptopropionyl glycine (0.1, 1.0 and 10.0 mmol.litre-1) also failed to improve the recovery of aortic flow [34.7(1.6), 34.7(7.7) and 25.6(5.4)% respectively.2+ Since biological membranes are highly permeable to dimethylthiourea and mercaptopropionyl glycine, it is possible that they accumulate in the intracellular compartment.(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:Free radicals and cardioplegia: organic anti-oxidants as additives to the St Thomas' Hospital cardioplegic solution. 251 9

The retinal pigment epithelium (RPE) from the chick embryo was cultured on permeable support. Using confluent cultures and analysis of the incubation medium, the present study demonstrates that RPE cells cultured on permeable membrane retain functional polarity, a characteristic of the RPE in vivo. The degree of intercellular permeability in the confluent RPE cultures was estimated by following [3H]inulin movement from the apical side to the basal side of the cultures. Twenty-four hours after exposure of the apical side of the culture to [3H]inulin, the 3H concentration in the apical medium remained at 3.4 to 4.4 times of that in the basal medium. The barrier function of RPE disappears in the presence of EDTA. Net unidirectional fluid movement from the apical side of the cultures to the basal side of the cultures is regularly observed in confluent RPE cultures. The rate varies among different preparations of cultures and the highest is 1.60-1.84 microliters/cm2/h. When cultures are given 26 h of [35S]methionine, more than 20 bands with molecular weights ranging from 20,000 to greater than 250,000 Da can be detected in the medium as assessed by autoradiography of SDS-polyacrylamide gels. While six macromolecules appear to be equally concentrated in the basal medium and the apical medium, the majority are in higher concentration in the basal medium. Analysis of the 10% TCA-precipitable fraction of the medium showed that the specific activities in the apical medium and basal medium were 24.0 +/- 0.4 X 10(6) and 46.4 +/- 0.2 X 10(6) (mean +/- SEM, N = 8) cpm/ml/mg RPE protein, respectively. When cultures react with VIP (vasoactive intestinal peptide), the elevated intracellular cyclic AMP is extruded into the medium bathing the cells. However, the rate of extrusion into the basal medium is twice as fast as that into the apical medium. Electron microscopy of the confluent RPE cultures shows morphological polarization of the cells. The intercellular spaces appear to be closed at the apical side of the cells by junctional complexes consisting of tight junctions, zonular adherens junctions, and gap junctions.
 ...
PMID:The chick retinal pigment epithelium grown on permeable support demonstrates functional polarity. 253 34

The kinetics of appearance of amino acids (AA) in portal blood following the ingestion of casein or rapeseed protein were compared. Six pigs, fitted with permanent catheters in the portal vein and in the carotid artery, as well as with an electromagnetic flow probe around the portal vein, received three 800 g test meals, one containing 12% rapeseed proteins (RA12) and the others containing 12% and 24% casein (CA12 and CA24), at 1-week intervals and according to a double Latin square design. Portal and arterial blood samples were collected and portal blood flow rate was recorded for 8 h after the test meals. At the end of measurement, an average of 76.1 +/- 5.6% (mean +/- SEM) of total AA from the CA24 diet had appeared in portal blood, compared with 94.3 +/- 10.4% for the CA12 diet and 103.5 +/- 12.6% for the RA12 diet. Similar results were obtained for essential AA. Differences were found in the kinetics of appearance of individual AA. Eight hours after the meal, 79% of lysine, 84% of methionine, and 73% of valine from the CA24 diet had appeared in portal blood compared, respectively, with 100, 89, and 83% from the CA12 diet and 99, 86, and 106% from the RA12 diet. Arginine from rapeseed had a net appearance level lower (82%) than the overall mixture of essential AA. With casein diets, the net appearance of arginine reached 97% (CA12) and 82% (CA24). Following the ingestion of rapeseed proteins, there seemed to be a significant appearance of endogenous AA in portal blood.(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:Net appearance of amino acids in portal blood during the digestion of casein or rapeseed proteins in the pig. 262 81

Platelet-activating factor (PAF) is a proinflammatory lipid that has both platelet- and phagocyte-stimulating properties. Because several known activators of calcium-, phospholipid-dependent protein kinase (protein kinase c, PKC) also stimulate neutrophil responses and because neutrophil stimuli such as phorbol diesters and the chemotactic peptide f-Met-Leu-Phe are reported to increase protein kinase activity in neutrophil (PMN) particulate fractions, we investigated the effect of PAF on neutrophil protein kinase activities. In neutrophils exposed to 10(-6) mol/L PAF, cytosolic PKC activity was 521 +/- 38 pmol 32P/10(7) PMN/min (mean +/- SEM), which was not significantly lower than cystolic activity in buffer-treated controls (558 +/- 32 pmol 32P/10(7) PMN/min, n = 14). PAF-exposed cells exhibited a concomitant rise in protein kinase activity associated with the particulate fraction with 53 +/- 4 pmol 32P/10(7) PMN/min compared with 32 +/- 2 pmol in control cells (n = 14). Particulate protein kinase activity was independent of the presence of calcium and phospholipid in the assay medium. The specific PKC inhibitor H-7 inhibited particulate protein kinase activity, however, which suggested that the enzyme activity assayed in this fraction may be PKC in a constitutively activated form. The increase in particulate protein kinase activity induced by PAF required the presence of cytochalasin B, was detectable within 5 seconds of exposure to PAF, and was not reversed by washing the cells free of extracellular PAF after initial exposure. Although PAF did not have a direct effect on PKC activity from cytosolic fractions from resting cells, the increase in particulate protein kinase activity induced by PAF was inhibited when the cells were first depleted of calcium by incubation with Quin 2. These results suggest that PAF induces an increase in particulate protein kinase activity in neutrophils by a calcium-dependent mechanism and that the induction of membrane-associated protein kinase activity may be involved in neutrophil-stimulating actions such as superoxide production, which occur at higher concentrations of PAF.
 ...
PMID:Platelet-activating factor induces protein kinase activity in the particulate fraction of human neutrophils. 282 44

beta-Endorphin (beta-EP) and methionine-enkephalin (Met-Enk) have been detected in human follicular fluid in concentrations several times higher than those in plasma. These data stimulated us to study the possible physiological role of ovarian opioids. We, therefore, determined the effects of both beta-EP and Met-Enk, alone or in combination with naloxone, on FSH-induced progesterone (P) secretion by cultured granulosa cells. Granulosa cells were collected from follicular fluid recovered at laparoscopy in seven superovulated women. The cells were preincubated with RPMI-1640 medium containing 20% fetal calf serum in 5% CO2 for 48 h, followed by the addition of 100 mU purified FSH and the various test substances for 48 more h. beta-EP (10 nM to 1 pM) had no effect on P secretion either alone or in combination with FSH and/or naloxone. Micro- to picomolar amounts of Met-Enk increased FSH-induced P secretion up to 186.9 +/- 35.1% (+/- SEM). Met-Enk had no affect in the absence of FSH, and its action was significantly blunted by the concomitant addition of 10(-5) M naloxone. These data provide evidence for a dose-dependent naloxone-reversible synergistic action of Met-Enk and FSH on P secretion by cultured granulosa cells. This finding supports the hypothesis of the existence of an ovarian opioid system.
 ...
PMID:Met-enkephalin enhances follicle-stimulating hormone-dependent progesterone production from cultured granulosa cells. 294 12

Specific receptors for insulin-like growth factor I (IGF-I) on cultured human choriocarcinoma cells (JEG-3 and BeWo) were characterized. The binding of 125I-labeled recombinant (Thr59)IGF-I to the cells was reversible and time, temperature, and pH dependent. Steady state of binding occurred after 16 h at 4 C, pH 7.4. Natural human IGF-I (hIGF-I), hIGF-II, recombinant (N-Met)IGF-I, rat multiplication-stimulating activity, and insulin were 200%, 37%, 37%, 1.6%, and 0.1% as potent as (Thr59)IGF-I in inhibiting the binding of [125I]iodo-(Thr59)IGF-I to JEG-3 cells, respectively. Epidermal growth factor was ineffective. The half-maximal displacement of [125I]iodo-(Thr59)IGF-I by unlabeled (Thr59)IGF-I occurred at 11 +/- 2 ng/ml (mean +/- SEM) in both JEG-3 and BeWo cells. Scatchard analysis of the competitive binding data revealed linear plots indicating a single species of binding sites with an association constant of 0.8 X 10(9) M-1 for the binding of [125I]iodo-(Thr59)IGF-I to both cell lines. The binding capacity was 30,000 and 20,000 sites/cell for JEG-3 and BeWo cells, respectively. Chemical cross-linking of [125I]iodo-(Thr59)IGF-I to JEG-3 cells revealed two receptor complexes of 130K and 260K. Their formation was completely inhibited by an excess of unlabeled (Thr59)IGF-I or hIGF-II. Increasing amounts of insulin affected both labeled bands equally, suggesting that the 130K and 260K bands represent the monomer and dimer forms, respectively, of the ligand-binding alpha-subunit of type I IGF receptor. (Thr59)IGF-I, in a dose-dependent manner, stimulated uptake of nonmetabolizable alpha-[3H]aminoisobutyric acid by JEG-3 cells, showing that the receptor is biologically active. Our results demonstrate that choriocarcinoma cells possess functional high affinity type I IGF receptors and suggest that IGF-I is involved in the growth-regulating processes of JEG-3 and BeWo cells. These cells may provide a useful model to study the role of IGFs in trophoblast physiology.
 ...
PMID:Characterization of functional type I insulin-like growth factor receptors from human choriocarcinoma cells. 296 49

We examined the role of reactive oxygen metabolites in the degradation of human glomerular basement membrane (GBM) by stimulated human neutrophils. Neutrophils stimulated with phorbol myristate acetate (PMA) caused a significant degradation of GBM over 3 h resulting in 11.4 +/- 0.9% (SEM), n = 11 release of hydroxyproline compared with 0.3 +/- 0.09%, n = 11 release by unstimulated neutrophils. Superoxide dismutase, a scavenger of superoxide, did not inhibit the GBM degradation, whereas catalase, a scavenger of hydrogen peroxide, caused a marked inhibition (-60 +/- 7%, n = 4, P less than 0.001) of hydroxyproline release. Neither alpha-1 proteinase inhibitor, an inhibitor of elastase, nor soya bean trypsin inhibitor, an inhibitor of cathepsin G, caused any significant inhibition of GBM degradation. GBM degradation by cell-free supernatants obtained from stimulated neutrophils was markedly impaired in the presence of metal chelators EDTA (-72 +/- 7, n = 6, P less than 0.001) and 1,10,phenanthroline (-85 +/- 5%, n = 3, P less than 0.001). Considering these results, we postulated that reactive oxygen metabolites generated by the stimulated neutrophils activate a latent GBM degrading metalloproteinase(s). GBM degradation by supernatants obtained from incubations with catalase, azide, an inhibitor of myeloperoxidase, and methionine and taurine, scavengers of hypochlorous acid, was markedly reduced. Our data thus indicate that degradation of the GBM by PMA-stimulated neutrophils is due to activation of a latent metalloproteinase by hypochlorous acid or a similar oxidant generated by the myeloperoxidase-hydrogen peroxide-halide system.
 ...
PMID:Degradation of human glomerular basement membrane by stimulated neutrophils. Activation of a metalloproteinase(s) by reactive oxygen metabolites. 302 61

We studied the methyl acceptor capacity of insulin and glucagon in vitro. The levels of carboxylmethylation of pancreatic hormones (dpm x 10(3], when incubated with S-adenosyl-L-(3H-methyl)-methionine as methyl donor and purified protein carboxylmethylase, were: insulin (n = 6) 8.1 +/- 0.2 and 11.1 +/- 1.5 (mean +/- SEM) for 0.25 and 1.0 mg/ml, respectively; glucagon (n = 6) 17.0 +/- 3.2 and 40.2 +/- 2.5 (mean +/- SEM) for 0.5 and 1.0 mg/ml, respectively. On a molar basis, the methyl acceptor capacity was 1.0 dpm/pmol for insulin and 9.5 dpm/pmol for glucagon. Polyacrylamide gel electrophoresis of carboxylmethylated hormones showed a radioactivity (3H-methyl) peak that co-migrated with the corresponding 125I-hormone. Glucagon, but not insulin, seems to be a relatively good substrate for carboxylmethylation.
 ...
PMID:Carboxylmethylation of insulin and glucagon in vitro. 306 84

Taurine concentrations in plasma, platelets, lymphocytes, granulocytes, erythrocytes, and urine were measured in 19 children who were undergoing long-term home parenteral nutrition for 27.4 +/- 7.1 (SEM) months. The parenteral solutions contained methionine, but not taurine or cysteine. The patients' plasma, platelet, and urine taurine concentrations were significantly reduced to 54, 48, and 16%, respectively, of the values from normal children of similar ages. The most significant reductions in plasma and platelet taurine concentrations were observed in the children who were estimated to absorb less than 5% of their daily calorie needs from the enteral tract. Lymphocyte and erythrocyte taurine levels tended to be lower but were not significantly different from those in normal children. The patients' plasma methionine and cystine levels were not different from normal. There was a direct correlation between plasma and platelet taurine concentrations and between plasma and urine taurine. Both plasma and platelet taurine tended to be directly correlated with age and, after the 1st yr of total parenteral nutrition, with the duration of total parenteral nutrition therapy.
 ...
PMID:Taurine concentrations in plasma, blood cells, and urine of children undergoing long-term total parenteral nutrition. 310 24


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>