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At least 919 records · Page 51Linked to original sources
PubMed1991

Improved wound healing with a modified electrosurgical electrode.

Previous studies comparing standard electrosurgical (ES) electrode and steel scalpel (SS) wound healing have reported poor initial tensile strength, a delay in reaching maximum tensile strength and an increased inflammatory response in the ES wounds. The hypothesis that a smaller needle (modified) electrode would give better wound healing than a standard electrode was tested. Using histology as a parameter of wound healing, incisions created by a modified electrode, a standard electrode and a steel scalpel were compared. Sixty Sha Sha mice were divided into 10 groups. Standardised dorsal skin incisions were made using steel scalpel, standard and modified electrosurgical cutting electrodes. Mice were sacrificed on days 0, 1, 2, 3, 5, 7, 9, 14, 28 and 42. The incised skin was processed for standard and immunohistochemical staining. The standard ES wound had significantly higher numbers of polymorphonuclear leukocytes in comparison to the SS and modified ES wounds (p less than or equal to 0.01). However, macrophage numbers were found to be significantly lower in the ES wounds when compared to the SS wounds on days two and five (p less than or equal to 0.05). The fibroblast response was delayed by up to two days in the ES wounds when compared to the SS wounds. Epithelialisation was completed by day two in the SS and modified ES groups but was only complete by day three in the standard ES group (p less than or equal to 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1986

Significant frequency of cytotoxic T lymphocyte precursor cells specific for TNP-modified allogeneic cells in normal lymphocytes.

It was tested whether the cytotoxic T-lymphocyte precursor (CLP) repertoire in normal mice is biased toward recognizing foreign antigen in association with self H-2 as opposed to allogeneic H-2. The frequencies of CLPs in normal mice (H-2b,k,d) specific for TNP-modified syngeneic and TNP-modified allogeneic cells have been compared by limiting dilution analysis. Normal spleen cells were cultured at a limiting dilution with TNP-modified (TNP-self) or TNP-modified allogeneic (TNP-allo) stimulator cells. Cultures were split into four aliquots and assayed against TNP-self, TNP-allo, unmodified syngeneic, and unmodified allogeneic Concanavalin A blast targets and classified for cytotoxic activity directed against TNP-self, TNP-allo, and allo H-2 determinants. In disagreement with our expectations from the literature, the frequencies of CLPs in H-2b and H-2d responder cells recognizing TNP-modified H-2k were higher than the frequencies of CLPs recognizing TNP-self. There was no clear preference for TNP-self in the case of H-2b responder and H-2d allogeneic cells, nor vice versa. Only in the case of H-2k responder cells was there a distinct preference for TNP-self. The significance of a considerable number of TNP-specific, allo H-2-restricted CLPs in normal lymphocytes is discussed.

Animals↗
PubMed1983

Enzymatic methylation of DNA and poly(dG-dC) X poly(dG-dC) modified by 4-acetoxyaminoquinoline-1-oxide, the ultimate carcinogen of 4-nitroquinoline-1-oxide.

Both the initial velocity and the overall methylation of Ac-4HAQO modified DNA by a calf brain DNA (cytosine-5-)-methyltransferase are increased as compared to native DNA. The affinity of the modified DNA for the enzyme decreases as a function of the extent of the modification. Heat-denatured, single-stranded DNA shows exactly the opposite results: the more it is modified, the less it is methylated. The poly(dG-dC) X poly(dG-dC) modified by 4NQO is as well methylated as the non-modified one. The carcinogen may induce a tertiary structure favouring the 'walking' of the enzyme along the DNA. The hypermethylation caused by this carcinogen could have a significance in gene activity and cellular differentiation.

Aminoquinolines↗
PubMed1988

Extracts of human atherosclerotic lesions can modify low density lipoproteins leading to enhanced uptake by macrophages.

Plasma low density lipoproteins (LDL) and/or other lipoproteins containing apo B that accumulate in atherosclerotic lesions of human aortas exhibit structural changes that are associated with enhanced uptake in an unregulated fashion by macrophages in culture, resulting in the formation of foam cells in vitro. In an attempt to better characterize the structure-function modifications, we have incubated plasma LDL with extracts of human atherosclerotic plaques obtained at surgery, and determined whether such plaque-modified LDL also demonstrates enhanced uptake by cultured mouse peritoneal macrophages (MPM). Enhanced uptake was found which was linear over a concentration range of 100 micrograms lipoprotein protein/ml, as assessed by enhanced degradation of [125I]LDL and by stimulation of cholesterol esterification. Extracts of non-arterial human tissue were unable to induce this modification, suggesting tissue specificity. When delipidated apo B from tissue-treated [125I]LDL was subjected to SDS-PAGE, autoradiograms demonstrated, in addition to the B-100 band of apo B, a doublet of higher molecular weight than B-100 and a band just entering the gel, both at the expense of the B-100 band. No lower molecular weight bands suggestive of apo B degradation were seen. Modest increases in LDL electrophoretic mobility and thiobarbituric acid reactive substances were found following the incubation of LDL with plaque extracts. These changes could be inhibited by butylated hydroxytoluene (BHT), suggesting that free radical-induced lipid peroxidation was responsible for these modifications. However, since BHT did not inhibit the uptake of the tissue-incubated LDL by macrophages, the actual modification responsible for enhanced macrophage recognition did not appear to be free radical-induced. Uptake of plaque-modified [125I]LDL was inhibited by only 22% by a 20-fold excess of acetyl LDL or plaque-modified LDL. If the latter did not represent a mixture of modified and unmodified particles, this result would suggest that uptake was not mediated by the scavenger receptor. It is possible that foam cells are formed in vivo when LDL particles, which have been modified by interacting with components of the arterial wall, are taken up by tissue macrophages.

Animals↗
PubMed1992

Binding of modified high density lipoproteins to endothelial cells: relation with cellular cholesterol efflux?

Human endothelial cells (EA.hy 926 line) were enriched with cholesterol using cationized low density lipoprotein (LDL). Cholesterol-loaded cells interacted with native apolipoprotein (apo) E-free high density lipoprotein3 (HDL)3 as well as with dimethyl suberimidate-modified HDL3 (DMS-HDL3). At 4 degrees C both HDL preparations showed a saturable high affinity binding with a KD of 31 and 50 micrograms of protein/ml and a Bmax of 226 and 436 ng/mg cell protein for native HDL3 and DMS-HDL3 particles, respectively. Competition of binding of 5 micrograms apo E-free 125I-labelled HDL3/ml by unlabelled DMS-HDL3 and tetranitromethane-treated HDL3 (TNM-HDL3) was very poor, whereas unlabelled native HDL3 competed very effectively with 125I-labelled HDL3 binding. Thus, both types of modified HDL did not compete for the high affinity binding sites for native HDL. Unlabelled native HDL3 and unlabelled DMS-HDL3 both competed for the binding of 125I-labelled DMS-HDL3 very effectively. These experiments indicate that there are two distinct high affinity binding sites for HDL on cationized LDL-loaded EA.hy 926 cells: one specific HDL binding site, which only binds native HDL, and a second binding site for both native HDL and DMS-HDL. The modified HDL fractions were used to study the relation between HDL binding and HDL-mediated efflux. Efflux of cell cholesterol was measured as the increase of cholesterol mass in the medium after 24 h of incubation with 0.2 mg native HDL3/ml, or the same amount of modified HDL3. DMS-HDL3-mediated efflux was identical to efflux mediated by native HDL3. TNM-HDL3 also induced efflux of cell cholesterol; however, efflux induced by TNM-HDL3 was only 45-50% of the amount obtained with native HDL3. So both DMS- and TNM-modified HDL3 induced efflux of cholesterol, although these particles do not bind to the specific high affinity sites for native HDL. These results do not indicate a link between binding of HDL to specific receptors for native HDL and HDL-mediated efflux of cholesterol from loaded endothelial cells.

Cell Line↗
PubMed1992

Structural and functional properties of apolipoprotein B in chemically modified low density lipoproteins.

The structural and compositional changes occurring during in vitro chemical modification of apolipoprotein B-100 (apo B), the apolipoprotein component of low density lipoproteins (LDL), were investigated in this study. The functional properties of chemically modified apo B and especially its potential to induce accumulation of cholesterol esters in macrophages were related to the structural changes of apo B. Acetylation, maleylation or malondialdehyde conjugation did not significantly affect the lipid composition of LDL. However, the unsaturated cholesteryl esters content, especially that of cholesteryl arachidonate was significantly decreased through Cu-oxidation. The number of reactive lysine residues in apo B was decreased by Cu-catalyzed LDL oxidation, acetylation, maleylation and by malondialdehyde conjugation. The number of free cysteines decreased from six in native apo B-100 to three in Cu-oxidized LDL. The tryptophan fluorescence intensity decreased most in malondialdehyde-conjugated LDL and in Cu-oxidized LDL, compared with acetylated and maleylated LDL. The secondary structure of native and chemically modified LDL was measured by attenuated total reflection infrared spectroscopy and by circular dichroism. No significant changes were observed in the secondary structure of any of the modified LDL. These data suggest that neither acetylation, malondialdehyde treatment or even Cu-oxidation substantially altered the secondary structure of apo B, in spite of significant modifications in the primary structure. Incubation of chemically modified LDL with J774 macrophages induced an accumulation of cellular cholesteryl esters and foam cell formation. The highest cholesterol accumulation was induced after malondialdehyde treatment of LDL. These data suggest that the cellular uptake and accumulation of modified LDL is not modulated by changes in the apo B structure. Rather it seems dependent upon the net charge of the apo B protein and probably involves the modification of critical lysine residues.

Acetylation↗
PubMed1993

Effects of organic mobile phase modifiers on elution and separation of beta-blockers in micellar electrokinetic capillary chromatography.

A study was made of the effect of organic modifiers (acetone, acetonitrile, ethanol, ethylene glycol, methanol and 2-propanol) in phosphate buffer (0.08 M) containing 15 mM cetyltrimethylammonium bromide as surfactant on the elution and separation of eleven common beta-adrenergic blocking agents. The amount of the modifier was varied from 0.1 to 10.0% (v/v). At maximum addition, the organic solvents increased the viscosity of the buffer solution as follows: acetone 16%, acetonitrile 9%, ethanol 26%, ethylene glycol 27%, methanol 20% and 2-propanol 29%. In contrast to the migration time of the other beta-blockers, that of labetalol was not increased by the addition of organic solvent to the buffer solution. Rather, labetalol eluted more quickly with increase in the amount of modifier, and thereby effected changes in the elution order of the beta-blockers. The addition of modifiers also affected the resolution, and the best resolution values were achieved with the following amounts of organic solvent in MEKC buffer: acetone 0.1%, acetonitrile 0.1-0.5%, ethanol 5.0-7.5%, ethylene glycol 1.0-2.5%, methanol 5.0% and 2-propanol 1.0-2.5% (v/v). No significant relationship was found between the elution order and separation and the structure of the beta-blockers in micellar electrokinetic capillary chromatography with an organic modifier in buffer solutions.

Adrenergic beta-Antagonists↗
PubMed1983

Improved conditions for the production of monoclonal antibodies to carcinogen-modified DNA, for use in enzyme-linked immunosorbent assays (ELISA).

The methodology for the production of monoclonal antibodies to chemical carcinogen-modified DNA has been improved to provide high yields of hybridomas, using guanine-imidazole ring-opened aflatoxin B1-modified DNA as an example (iro-AFB1 DNA). The percentage of immunised mice which responded to iro-AFB1 DNA-protein immunisation and the number of specific hybridomas produced was dependent on the level of modification of DNA. One in three BALB/c mice had detectable (but low) antibody titre when 0.3% modified iro-AFB1 DNA was used and this yielded 2 specific hybridomas, whereas all mice responded at reasonable titres and 6 specific hybridomas were obtained when 3% modified iro-AFB1 DNA was used. Other factors found to improve the number and titre of mice responding to immunisation and the yield of hybridomas were: KLH greater than BSA as carrier protein, C57 BL/6 X BALB/c F1 greater than BALB/c mice for antibody production, fusion success and ascites growth. The conditions limiting the sensitivity and reproducibility of an enzyme-linked immunosorbent assay (ELISA) using these monoclonal antibodies with beta-galactosidase-linked sheep F(ab')2 anti-mouse IgG as the second antibody were also tested. Present experience with AFB1 and other carcinogens indicates that these methods should be applicable to the production of monoclonal antibodies to DNA modified by a wide variety of chemical carcinogens.

Aflatoxin B1↗
PubMed1991

Refined X-ray crystal structures of the reactive site modified ovomucoid inhibitor third domains from silver pheasant (OMSVP3*) and from Japanese quail (OMJPQ3*).

Tetragonal and triclinic crystals of two ovomucoid inhibitor third domains from silver pheasant and Japanese quail, modified at their reactive site bonds Met18-Glu19 (OMSVP3*) and Lys18-Asp19 (OMJPQ3*), respectively, were obtained. Their molecular and crystal structures were solved using X-ray data to 2.5 A and 1.55 A by means of Patterson search methods using truncated models of the intact (virgin) inhibitors as search models. Both structures were crystallographically refined to R-values of 0.185 and 0.192, respectively, applying an energy restraint reciprocal space refinement procedure. Both modified inhibitors show large deviations from the intact derivatives only in the proteinase binding loops (Pro14 to Arg21) and in the amino-terminal segments (Leu1 to Val6). In the modified inhibitors the residues immediately adjacent to the cleavage site (in particular P2, P1, P1') are mobile and able to adapt to varying crystal environments. The charged end-groups, i.e. Met18 COO- and Glu19 NH3+ in OMSVP3*, and Lys18 COO- and Asp19 NH3+ in OMJPQ3*, do not form ion pairs with one another. The hydrogen bond connecting the side-chains of Thr17 and Glu19 (i.e. residues on either side of the scissile peptide bond) in OMSVP3 is broken in the modified form, and the hydrogen-bond interactions observed in the intact molecules between the Asn33 side-chain and the carbonyl groups of loop residues P2 and P1' are absent or weak in the modified inhibitors. The reactive site cleavage, however, has little effect on specific interactions within the protein scaffold such as the side-chain hydrogen bond between Asp27 and Tyr31 or the side-chain stacking of Tyr20 and Pro22. The conformational differences in the amino-terminal segment Leu1 to Val6 are explained by their ability to move freely, either to associate with segments of symmetry-related molecules under formation of a four-stranded beta-barrel (OMSVP3* and OMJPQ3) or to bind to surrounding molecules. Together with the results given in the accompanying paper, these findings probably explain why Khyd of small protein inhibitors of serine proteinases is generally found to be so small.

Amino Acid Sequence↗
PubMed1987

Activity of tralomethrin to modify the nerve membrane sodium channel.

Deltamethrin is a potent type II pyrethroid insecticide which can modify sodium channel gating kinetics in nerve membranes. The actions of another type II pyrethroid tralomethrin to modify sodium channel kinetics have been ascribed to deltamethrin, to which tralomethrin is known to be converted under certain experimental conditions. The objective of this study was to determine if tralomethrin was intrinsically active in modifying the nerve membrane sodium channel, the major target site of pyrethroids. Experiments were performed using the squid giant axon under voltage-clamp conditions. In axons treated with either pyrethroid, a large sodium tail current was generated upon repolarization from a depolarized level and decayed slowly with a dual exponential time course. The fast time constant for tralomethrin was 165 +/- 110 msec and the slow time constant was 3793 +/- 802 msec. For deltamethrin the time constants were significantly shorter, the fast time constant being 34 +/- 6 msec and the slow time constant being 835 +/- 282 msec. The cumulative dose-response relation of tralomethrin revealed two binding sites with apparent dissociation constants of 0.06 and 5 microM. Deltamethrin appeared to bind to only one site with an apparent dissociation constant of 0.25 microM. It is clear that there are large differences in the gating kinetics of the sodium channels modified by tralomethrin and deltamethrin which are incompatible with the idea that tralomethrin is active only after conversion to deltamethrin. The differences in sodium channel gating kinetics after modification by tralomethrin versus deltamethrin indicate that tralomethrin is intrinsically active in modifying the nerve membrane sodium channels.

Animals↗
PubMed1983

Studies on the in vitro uncoating of poliovirus. IV. Characteristics of solubilized membrane-modifying and -stabilizing factors.

Previous studies in our laboratory on the in vitro uncoating of poliovirus have shown that HeLa cell membrane contains a modifying factor which induces early modification of virus (the loss of VP4) and a stabilizing factor which protects virus against heat-induced degradation. It has now been found that membrane-modifying factor is dependent on the presence of phospholipid for activity. Modifying activity was lost after exposure of membrane (Mem) to phospholipase C. Triton X-100-solubilized modifying factor prepared from phospholipase C-treated Mem was reactivated by phospholipid. Lecithin, phosphatidylethanolamine, phosphatidylserine, and sphingomyelin were found to exhibit a reactivating effect. Lecithin was the most effective individual phospholipid in terms of maximal reactivation. Partial purification of Triton X-100-solubilized modifying factor was achieved by concanavalin A-Sepharose chromatography. Membrane-stabilizing factor was extracted from HeLa cell membrane by solubilization with sodium deoxycholate (DOC). Some properties of DOC-solubilized stabilizing factor were studied. The solubilized stabilizing factor was inactivated by treatment with trypsin or chymotrypsin. Treatment of the solubilized stabilizing factor with certain lipid solvents, lipolytic enzymes, or lectins had no detectable effect on stabilizing activity.

Capsid↗
PubMed1984

Catalytic and regulatory functions of N-bromosuccinimide-modified bovine thrombin.

At pH 4.1, bovine thrombin reacts rapidly with N-bromo-succinimide to yield modified enzyme containing oxidized tryptophan residue. Both fibrinogen clotting activity and esterase activity are reduced considerably when three moles of tryptophan residues per mole of thrombin are oxidized, but the Michaelis constants for synthetic substrates are not appreciably altered. Reaction of NBS also results in a decrease in the affinity of thrombin for heparin. The dissociation constant for heparin-thrombin complex is increased by 2.6-fold due to the modification of one tryptophan residue. However, the magnitude of the increase in the dissociation constant remains the same for modified enzymes containing approximately two or three oxidized tryptophan residues. The rate constant for the inactivation of thrombin by antithrombin III is increased by 2.5-fold due to the modification of a single tryptophan residue. This increase in rate constant is not further amplified when more than one tryptophan residue is oxidized. In contrast, in the presence of heparin the rate of inactivation of modified and unmodified thrombins by antithrombin III are not significantly different. Thus, the heparin-sensitized inactivation of thrombin by antithrombin III is affected by the modification of one tryptophan residue. Spectrophotometric titrations of the phenolic hydroxyl groups suggest that the structural environments of tyrosyl groups for both unmodified and modified thrombin containing one oxidized tryptophan residue, are similar. The temperature for half loss of catalytic activity of control and NBS-modified thrombin, containing one oxidized tryptophan, are 52 and 51.5 degrees C respectively. It appears that the one tryptophan residue of thrombin is situated at or close to the binding site of heparin.

Animals↗
PubMed1987

New modified activated partial thromboplastin time and prothrombin time methods using a synthetic chromogenic substrate in combination with diazotization.

A chromogenic substrate, H-D-Phe-Pip-Arg-pNA (S-2238) is a highly specific substrate to thrombin and releases p-nitroaniline (pNA) by the action of thrombin. We describe new modified APTT and PT methods using S-2238 in combination with the diazotization of pNA. In the modified APTT method, 100 microliter citrated plasma (diluted to 10-fold), 90 microliter 1 mM S-2238, 100 microliter 20 mM CaCl2 and 100 microliter Actin were mixed in an ice-bath, then incubated for 8 min at 37 degrees C. The reaction was stopped, and the generated pNA was diazotized by adding the following solutions sequentially: 975 microliter 0.04% sodium nitrite, 975 microliter 0.3% ammonium sulfamate and 975 microliter 0.07% N-(l-naphthyl)-ethylenediamine dihydrochloride. Diazotization changed pNA from yellow to pink. Then, absorbance at 545 nm was read, and values were expressed as thrombin units/ml plasma. In the modified PT method, 100 microliter citrated plasma (diluted to 20-fold), 90 microliter 1 mM S-2238 and 200 microliter tissue thromboplastin-C solution were mixed and processed as above. Correlations of the present modified APTT and APTT methods, and of modified PT and PT methods were significant (r = 0.426, p less than 0.01 and r = 0.561, p less than 0.01, respectively).

Aniline Compounds↗
PubMed1989

Modified forms of low density lipoprotein affect platelet aggregation in vitro.

Modified forms of low density lipoprotein (LDL) unlike native LDL can lead to macrophage cholesterol accumulation and foam cell formation. Since platelets interact with both lipoprotein and macrophages in the atherosclerotic plaque, the present study was designed to analyze the effect of modified LDL on washed human platelet composition and aggregation. Platelet aggregation was increased following 2 h of incubation with native LDL. Phospholipase C modified LDL and hepatic lipase modified LDL but not acetyl LDL further increased collagen induced platelet aggregation in a dose dependent manner by up to 15% (p less than 0.01). Oxidized LDL, however, demonstrated 25% reduction in both collagen and ADP induced platelet aggregation in comparison to the effect of native LDL. Platelet aggregation was found to be directly related to changes in platelet phospholipid content whereas platelet cholesterol content was similarly affected by all lipoproteins. Platelet cholesterol/phospholipid ratio was directly related to platelet aggregation. Our study thus demonstrates that modified forms of LDL significantly affect platelet lipid composition and function and if similar interactions occur in vivo it might also affect the atherogenic process.

Acetic Anhydrides↗
PubMed1992

A comparative study of radical vulvectomy and modified radical vulvectomy for the treatment of invasive squamous cell carcinoma of the vulva.

Forty-five patients who underwent a modified radical vulvectomy for invasive squamous cell carcinoma of the vulva were compared with forty-five patients who underwent radical vulvectomy for similar lesions. Vulvar wound infection and breakdown were infrequent in both groups. Anal incontinence developed postoperatively in five of the modified radical vulvectomy patients and in none of the radical vulvectomy patients. Urinary incontinence developed postoperatively in two of the modified radical vulvectomy patients and in seven of the radical vulvectomy patients. Possible reasons for these differences are discussed. One invasive local recurrence (2.2%) developed in the modified radical vulvectomy group and two (4.4%) local recurrences developed in the radical vulvectomy group. A modified radical vulvectomy appears to be efficacious for the vulvar phase of treatment of localized invasive squamous cell carcinoma of the vulva.

Aged↗
PubMed1990

Platelet deposition studies on copolyether urethanes modified with poly(ethylene oxide).

Pellethane 2363 80A films and tubings were chemically modified and the effect of these modifications on platelet deposition was studied. Grafting of high molecular weight poly(ethylene oxide) and graft polymerization of methoxy poly(ethylene glycol) 400 methacrylate resulted in surfaces with a good water wettability. The increased hydrophilicity of these modified surfaces could be demonstrated by contact angle measurements. The platelet deposition was investigated with tubings in a capillary flow system, using different types of perfusates. Platelet deposition from a buffer-containing perfusate on surfaces modified with either high molecular weight poly(ethylene oxide) or methoxy poly(ethylene glycol) 400 methacrylate was almost absent and less than on Pellethane 2363 80A. Using a citrated plasma-containing perfusate the amount of deposited platelets on Pellethane 2363 80A modified with high molecular weight poly(ethylene oxide) was low and about the same as on unmodified surfaces. However, a marked reduced platelet deposition compared to unmodified Pellethane 2363 80A was found when the platelets were activated by Ca2+ ionophore. The improved blood compatibility of the modified Pellethane 2363 80A tubings obviously indicates the favourable effect of the presence of grafted PEO on the surface.

Biocompatible Materials↗
PubMed1995

Surface characterization and ex vivo blood compatibility study of plasma-modified small diameter tubing: effect of sulphur dioxide and hexamethyldisiloxane plasmas.

The development of a small diameter artificial vascular graft or prosthesis is limited by rapid thrombus formation and subsequent embolization upon blood contact. Plasma surface modification was employed to modify the inner surface of small diameter low density polyethylene (LDPE) tubing without varying the outer surface chemistry and physical properties of the tubing. A sulphur dioxide (SO2) plasma was used to form sulphonate functionality on the surface. In addition, a hexamethyldisiloxane (HMDSO) plasma and different gas flow ratios of SO2-HMDSO gas mixture plasmas were used to form ultrathin polysiloxane-like coatings inside the LDPE tubing. X-ray photoelectron spectroscopy (XPS) indicated that the inner surface of the tubing can be modified uniformly with this treatment. In addition, XPS results showed that the percentage of sulphur atoms bound to two or three oxygen atoms (sulphone or sulphonate) increased with the SO2-HMDSO mass flow rate ratio. The blood compatibility of the plasma-modified model materials was evaluated using an ex vivo canine arteriovenous shunt model. Similar thrombogenicity was observed comparing the untreated control and the surfaces modified by HMDSO plasma and SO2-HMDSO gas mixture plasmas, despite the differences in surface chemistry. The SO2 plasma-modified surface, which is the most hydrophilic as measured by the captive bubble contact angle measurement technique, was more thrombogenic than the untreated control. This may be attributed to the combined effect of the surface chemistry and surface hydrophilicity.

Animals↗
PubMed1984

H-2 hierarchy in the IR-gene controlled responses to hapten-modified mouse serum albumin.

Five hapten-modified autogenous mouse serum albumins (MSA), TNP11MSA, FITC8MSA, DNP64MSA, DNP5MSA, and PC2MSA, were tested for their ability to induce hapten-specific antibody responses in H-2 congenic mice of the H2d, H-2b, H-2a, and H-2f haplotypes. Four of the five modified MSAs, TNP11MSA, FITC8MSA, DNP64MSA, and PC2MSA, stimulated responses found to be under H-2-linked Ir gene control, whereas DNP5MSA failed to induce responses in any strain tested. H-2d, H-2D, and H-2a mice responded to FITC8MSA; H-2d and H-2b responded to TNP11MSA; and only H-2d mice were high responders to DNP64MSA and PC2MSA. H-2f mice failed to respond to any of the stimulating antigens. Thus, a hierarchy of H-2 haplotypes was observed in the responsiveness to modified MSA with H-2d greater than H-2b greater than H-2a greater than H-2f. Primed lymph node cells from PC2MSA immunized H-2d mice were challenged with antigen in vitro to assess the nature of the determinant recognized by T cells in the response to modified MSA. Lymph node cells proliferated only when challenged with PC2MSA. Unmodified MSA or TNP11MSA did not stimulate a proliferative response, suggesting that the immune T cells recognize a neodeterminant present on the modified PC2MSA.

Animals↗