PubMed Health⌕ Search

Biomedical subjects

S D Carson

Publications and source records attributed to S D Carson.

At least 73 records · Page 4Linked to original sources
PubMed1985

Monoclonal antibodies against bovine tissue factor, which block interaction with factor VIIa.

Two monoclonal antibodies that recognize bovine tissue factor (coagulation factor III) have been obtained following the fusion of hyperimmune mouse spleen cells with NS-1 plasmacytoma cells. Both antibodies, TF1-E2 and TF1-F7, have gamma 1 heavy chains and lambda light chains. TF1-E2 and TF1-F7 have each been used to purify bovine tissue factor from a crude detergent extract of bovine brain by immunoaffinity chromatography. Both antibodies inhibit tissue factor procoagulant activity and block the association of factor VIIa with tissue factor. The association of TF1-F7 and tissue factor solubilized in Triton X-100 was measured under equilibrium conditions. The Kd for this antibody-antigen interaction was 2.1 +/- 0.2 nmol/L. TF1-E2 effectively competes with TF1-F7 for tissue factor binding, indicating that the monoclonal antibodies recognize overlapping sites on the protein. These antibodies will be useful reagents for large-scale purification and for structure-function studies of bovine tissue factor. In particular, since they appear to bind to the same region of the tissue factor molecule as factor VIIa, they will be useful as specific probes for studying the kinetics of tissue factor-initiated coagulation and for immunocytochemical localization of tissue factor in bovine cells.

Animals↗
PubMed1984

Cadmium binding to human alpha 2-macroglobulin.

alpha 2-Macroglobulin (alpha 2M) is one of the major cadmium-binding proteins of human plasma. As determined with equilibrium dialysis, alpha 2M bound 4.6 (+/- 0.7) mol Cd2+ per mol protein with an apparent dissociation constant of (9.6 (+/- 5.0] X 10(-7) M. Methylamine-modified alpha 2M (alpha 2M-Me) had a similar affinity for Cd2+ (Kd,app = 5.3 X 10(-7) M), but fewer binding sites. Cadmium produced a small increase in the amidolytic activity of trypsin in the presence of alpha 2M and soybean trypsin inhibitor. Using the binding parameters determined from the equilibrium dialysis studies, the Cd2+ concentration which produced a half-maximal increase in amidolytic activity corresponded to saturation of all Cd2+-binding sites in one-half of the alpha 2M molecules. From these results, a model is proposed in which one Cd2+-binding site is present in each of the four polypeptide chains which compose alpha 2M.

Cadmium↗
PubMed1984

A resonance Raman study of Ambystoma tigrinum hemoglobins: evidence for intraspecies hemepocket variations.

Using resonance Raman difference spectroscopy, the Raman-active vibrational modes of hemoglobins from adult, neotenic, and larval forms of the salamander, Ambystoma tigrinum have been compared to each other and to human hemoglobin. The local heme environment of the adult and neotenic proteins were identical and differed from that of the larval protein. Differences were observed in modes sensitive to porphyrin pi electron density and axial ligation. Systematic differences were also observed between human and adult salamander hemoglobins particularly in modes sensitive to the heme vinyl environment. The relationship between these environmental differences, oxygen binding affinity, and the effects of allosteric modulators are discussed.

Aging↗
PubMed1983

Monoclonal antibody recognizing rabbit IgG (Fab). A specific reagent for second antibody applications.

A monoclonal mouse antibody, which recognizes a determinant on the Fab portion of rabbit IgG, has been obtained following fusion of hyperimmune mouse spleen cells with NS-1 plasmacytoma cells. The monoclonal antibody, RIg9C, has a gamma 1 heavy chain and a kappa light chain. RIg9C binds rabbit IgG but not human or bovine IgG. It has been conjugated with horseradish peroxidase for application in an enzyme-linked immunosorbent assay as well as for detection of antigens transferred from polyacrylamide gels to nitrocellulose. In enzyme-linked immunosorbent assays, the RIg9C-peroxidase conjugate was useful for measuring rabbit immunoglobulin either free in solution or in immune complexes. Using the enzyme-linked immunosorbent assay to quantitate antibody-antigen binding, the apparent dissociation constant was found to be 4 X 10(-8) M. Because of its low dissociation constant and specificity, RIg9C will be preferred over other reagents (e.g. second antibody and protein A) where sensitive recognition of only the Fab segment is critical.

Animals↗
PubMed1983

Chromatographic depletion of lipoproteins from plasma and recovery of apolipoproteins.

Selective adsorption of proteins from a complex mixture onto an affinity support presents a very powerful approach to protein purification. High density lipoprotein (HDL) and low density lipoprotein (LDL) have been removed from plasma by hydrophobic adsorption chromatography using phenyl-Sepharose. Plasma chromatographed on phenyl-Sepharose is depleted of beta-lipoprotein and apolipoproteins A-I, A-II and E. Less than 5% of the initial amounts of cholesterol, triacylglycerol, sphingomyelin, and phosphatidylcholine remain in the plasma. Column elution with propylene glycol permits recovery of apolipoproteins A-I, A-II and E. This procedure should provide a convenient alternative to ultracentrifugal removal of lipoproteins from plasma.

Apolipoproteins↗
PubMed1983

Cyclophosphamide, vincristine, lomustine, cisplatin, and doxorubicin in the treatment of non-small cell lung cancer.

Fifty-four patients (47 of whom were evaluable) with non-small cell lung cancer were treated with a five-drug regimen consisting of cyclophosphamide, vincristine, lomustine, cisplatin, and doxorubicin. Six complete and 16 partial responses were achieved, for an overall response rate of 47% (22 of 47 patients). Response by cell type was as follows: epidermoid carcinoma, 41% (seven of 17 patients); adenocarcinoma, 42% (eight of 19); and large cell carcinoma, 64% (seven of 11). Response in patients with limited disease was 48% (11 of 23 patients) and in patients with extensive disease, 46% (11 of 24). Previously untreated patients had response rates of 53%, versus 22% in those with prior therapy.

Adenocarcinoma↗
PubMed1982

Cystic fibrosis. I. Fractionation of the mucociliary inhibitor from plasma.

A protein fraction present in low concentrations in plasma of cystic fibrosis homozygotes and heterozygotes has been identified by its biologic activity in ciliary preparations of gills from Crassostrea virginica, where it causes mucociliary inhibition. In the present study, mucociliary inhibition was shown to be associated with an IgG-rich fraction. The cystic fibrosis mucociliary inhibitor was obtained as a low molecular weight protein after dissociation from IgG in 5 M guanidinium chloride. Gel filtration of the dissociated ultrafiltrate fraction on Bio-Gel P-30 isolated the cystic fibrosis mucociliary inhibitor activity in a pool containing protein of 6,000 to 12,000 MW. The mucociliary inhibitor was heterogeneous upon isoelectric focusing, with inhibition demonstrated in a focused range of pH 4.6 to 6.1 and in a fraction focused near pH 9. Lectin-affinity chromatography of the low molecular weight proteins dissociated from the IgG fraction of a cystic fibrosis homozygote demonstrated that at least one molecular species of the mucociliary inhibitor contained a carbohydrate moiety, since inhibitory fractions were found both in the nonadsorbed fraction and in the fraction eluted with N-acetylglucosamine.

Animals↗
PubMed1981

Low molecular weight plasma proteins isolated from preparations of human immunoglobulin.

Low molecular weight proteins co-purified with IgG constitute 0.22% of the total protein purified from human plasma by ion-exchange chromatography on DEAE-cellulose. We have found that these low molecular weight proteins were obtained free of immunoglobulin by ultrafiltration in 5 M guanidinium chloride. Electrophoresis and isoelectric focusing in polyacrylamide gels demonstrated that this fraction of low molecular weight proteins is remarkably heterogeneous. Chromatography of an Mr 6000 to 12 000 fraction on hydroxyapatite resolved fourteen discrete protein peaks. Three of the peaks contained proteins which appeared to be homogeneous on acid-urea polyacrylamide gels. Two of these proteins were similar in composition to B2 globulin and may represent degradation products of some larger protein. The third protein was found to have an amino-terminal sequence identical to C3a. This population of low molecular weight plasma proteins has previously been shown to contain the cystic fibrosis mucociliary inhibitor and is here shown to contain two proteins similar to B2 globulin, C3a and many proteins remaining to be characterized. The presence of these low molecular weight proteins in measurable concentrations may be insufficiently appreciated in studies using 'purified' immunoglobulins as biological or chemical probes.

Amino Acid Sequence↗
PubMed1981

Coagulation factor III (tissue factor) interaction with phospholipid vesicles induced by cadmium: characterization of the reconstituted protein-membrane complex.

Coagulation factor III (tissue factor) is a membrane glycoprotein which serves as a cofactor in the proteolytic activation of factor X and factor IX by factor VIIa. Mixing of human placental factor III apoprotein with vesicles of bovine brain phospholipids does not produce significant reconstitution of factor III activity, but, when the mixture of apoprotein and vesicles is made 5 mM with CdCl2, the apoprotein is incorporated into the vesicles. Ultracentrifugation on sucrose density gradients demonstrated that the active factor III-lipid complex formed by reconstitution with vesicles had a density indistinguishable from that of the complex formed by detergent dialysis. Vesicles isolated after centrifugation were shown to range in diameter from 20 nm to over 100 nm using the electron microscope. Gel filtration showed that factor-III activity was associated with all size-classes of vesicles. The presence of factor III activity in the smallest vesicles argues for a specific cadmium-mediated reconstitution of the apoprotein with phospholipid vesicles.

Cadmium↗
PubMed1980

Lipid activation of coagulation factor III apoprotein (tissue factor)--reconstitution of the protein-membrane complex.

Coagulation factor III (tissue factor) is required for significant activation of factor X in the presence of factor VIIa. Factor III is a membrane protein which requires bound phospholipids for activity, and removal of lipids during purification of factor III abolishes its activity. The activity can be recovered if lipids are added to the apoprotein under conditions known to favor reconstitution of membrane proteins into phospholipid bilayers. Indeed, incorporation of factor III into vesicular phospholipids is the essential event for recovery of factor III function, and is promoted by cadmium chloride. Using factor III from human placenta, we have studied the interactions of cadmium, phospholipids, and apoprotein which result in successful protein membrane reconstitution. The effects of phospholipids and cadmium can be independently optimized. Cadmium promotes reconstitution of factor III either with preformed phospholipid vesicles or as the vesicles form during slow dialysis. The incorporation of apoprotein into performed vesicles is completed within four minutes. These studies demonstrate successful activation of factor III apoprotein by incorporation into phospholipid vesicles and optimization of this activation using cadmium chloride.

Apoproteins↗
PubMed1980

Cadmium increases tissue factor (coagulation factor III) activity by facilitating its reassociation with lipids.

The coagulant activity of partially purified and delipidated tissue factor (TF) (coagulation Factor III) has previously been recovered by dialysis of the apoprotein after addition of mixed brain lipids and deoxycholate. Inclusion of cadmium chloride in the relipidation mixture greatly increases the recovered activity of highly purified TF from human placenta by promoting incorporation of TF into phospholipid vesicles; TF that had not been incorporated into vesicles showed no coagulant activity. Thus, TF must be present in a lipid bilayer for expression of coagulant activity. In vitro, cadmium induces fusion of lipid vesicles and may contribute to the incorporation of proteins in membranes.

Apoproteins↗
PubMed1980

Positive end-expiratory pressure shifts left ventricular diastolic pressure-area curves.

Positive end-expiratory pressure (PEEP) ventilation is frequently associated with reduction in cardiac output despite unchanged transmural left ventricular (LV) end-diastolic pressure. These findings have been interpreted to indicate decreased contractility, but could also be explained by altered LV diastolic pressure-volume characteristics. To study this possibility, radiopaque markers were inserted into a plane of the LV in nine dogs. Transmural pressure (LV-pericardial) was synchronized with LV area during ventilation with zero end-expiratory pressure and with 15 cmH2O PEEP. Mean polynomial curves derived from the diastolic pressure-area data demonstrated that PEEP shifted the curves upward so that a given diastolic area was associated with a higher transmural LV pressure (P less than 0.0001). PEEP decreased end-diastolic area and stroke area, both of which were normalized with dextran volume expansion. Restoration of stroke area by normalizing end-diastolic area with volume expansion suggests the initial changes with PEEP were due to a decrease in preload rather than in contractility.

Animals↗
PubMed1980

Studies of cystic fibrosis utilizing mucociliary activity in oyster gills.

Crassostrea virginica, the oyster native to the gulf coast, has served as a source of ciliated epithelium for studies on the inhibitory factor in cystic fibrosis. In these studies, protein molecules with biological activity, obtained from serum, urine, saliva, and cells from cystic fibrosis homozygotes and heterozygotes, were detected, purified, and characterized. Properties of these factors are similar to those detected by other ciliated systems in mussel gills and rabbit trachea. Although none of the ciliated assays in their present stage of development offer a reliable means for heterozygote screening or for prenatal diagnosis, they represent powerful tools for characterizing biologically active molecules related to cystic fibrosis. The importance of purifying and characterizing the various cystic fibrosis factors described by several laboratories is based on evidence that their biological activities observed in vitro mimic some of the expressions of the disease observed in vivo and that the concentration of the mucociliary inhibitor in serum and fibroblast medium preparations from cystic fibrosis heterozygotes is approximately one-half of that in serum and fibroblast medium preparations from homozygotes.

Animals↗
PubMed1978

Colon perforation after kidney transplantation.

Between 1962 and 1977 approximately 2% of Denver kidney transplant patients developed colon perforation. The single commonest cause was diverticulitis of the left colon (6/13 cases). In spite of drastic reduction or discontinuation of immunosuppression, only 5/13 patients survived for more than 90 days after operation. Analysis of this experience suggests that the high mortality rate associated with this complication can be reduced by early operation which removes the perforation from the peritoneal cavity (either exteriorization or resection) without primary intestinal reanastomosis. We believe that candidates for kidney transplantation with a history of previously symptomatic diverticulosis coli should have elective colon resection prior to transplantation. Any kidney transplant patient with lower abdominal signs should be investigated and treated aggressively.

Adolescent↗
PubMed1978

Chylothorax and chylopericardial tamponade following Blalock-Taussig anastomosis.

A case of chylothorax following a right-sided Blalock-Taussig shunt is presented. Chylopericardial tamponade eventually developed, because the mediastinal leakage of chyle was sealed off from the pleural cavity and diverted into the pericardium. Chylopericardium is a rare cause of an enlarged cardiac silhouette on a postoperative chest roentgenogram, but the importance of differentiating it from congestive heart failure is illustrated. When chylopericardial tamponade occurs, treatment consists of (1) aspiration for immediate relief and, if there is recurrence, (2) surgical evacuation of the pericardium with tube drainage or pericardiectomy and (3) ligation of the source of chylous drainage.

Cardiac Tamponade↗