Forty-nine regions in 21 proteins were identified as potential heparin-binding sites based on the sequence organizations of their basic and nonbasic residues. Twelve known heparin-binding sequences in vitronectin, apolipoproteins E and B-100, and platelet factor 4 were used to formulate two search strings for identifying potential heparin-binding regions in other proteins. Consensus sequences for glycosaminoglycan recognition were determined as [-X-B-B-X-B-X-] and [-X-B-B-B-X-X-B-X-] where B is the probability of a basic residue and X is a hydropathic residue. Predictions were then made as to the heparin-binding domains in endothelial cell growth factor, purpurin, and antithrombin-III. Many of the natural sequences conforming to these consensus motifs show prominent amphipathic periodicities having both alpha-helical and beta-strand conformations as determined by predictive algorithms and circular dichroism studies. The heparin-binding domain of vitronectin was modeled and formed a hydrophilic pocket that wrapped around and folded over a heparin octasaccharide, yielding a complementary structure. We suggest that these consensus sequence elements form potential nucleation sites for the recognition of polyanions in proteins and may provide a useful guide in identifying heparin-binding regions in other proteins. The possible relevance of protein-glycosaminoglycans interactions in atherosclerosis is discussed.
Also flagged:estrogen receptorbreast cancerERbiotinperoxidaseantibody
Journal Article1989-01-01✓ 2 SnippetsKawakami S, Kojima O, Uehara Y, Takahashi T.
In-Text Gene Mentions
Abstract)
…positive level ofDCCmethod was seen…
Abstract)
…to those ofDCCmethod and to…
Show Full Abstract
Immunocytochemical staining for estrogen receptor (ER) was examined in conventional formalin-fixed paraffin sections in 63 patients with breast cancer. The ER staining was performed by avidin-biotin peroxidase complex method (ABC) using monoclonal antibody against ER (H222). The ER stainability in formalin-fixed paraffin sections was compared with the levels of ER measuring dextran-coated charcoal (DCC) method, and with the stainability of ER in frozen sections. ER positive rates of paraffin sections and frozen sections were 52%, and 65% respectively. ER positive level of DCC method was seen in 62 percent of the cases. Results of ER staining in paraffin sections correlated well to those of DCC method and to those of ER staining in frozen sections. In paraffin sections as well as in frozen sections, ER staining was located at the nuclei of cancer cells. Furthermore, the variety that this method for ER can be used for retrospective studies of ER on stored blocks of breast cancer.
Also flagged:Hyperglycemiaalpha-2-macroglobulinantithrombin IIIalpha 2-macroglobulinalpha 2Mcoagulation
Journal Article1989-01-01✓ 3 SnippetsCeriello A, Quatraro A, Dello Russo P, Marchi E, Barbanti M, Giugliano D.
In-Text Gene Mentions
Abstract)
…reduces antithrombin III (ATIII) activity, while it…
Abstract)
…does not affectATIIIplasma concentration.…
Abstract)
…cemia-determined variations inATIIIactivity and alpha…
Show Full Abstract
Induced hyperglycemia in normal subjects increases alpha 2-macroglobulin (alpha 2M) activity and alpha 2M concentration and reduces antithrombin III (ATIII) activity, while it does not affect ATIII plasma concentration. Hyperglycemia-determined variations in ATIII activity and alpha 2M molecules are correlated in an inverse and parallel fashion. A compensatory role for the increase in alpha 2M in the regulation of the coagulation system may be hypothesized. Moreover, these data provide evidence that hyperglycemia may decrease, directly, the biological function of some proteins and may influence the levels of some risk factors for the development of complications in diabetes.
Two different priming solutions for cardiopulmonary bypass (CPB) were studied in regard to possible influence on the plasma protease systems. The study was performed on 20 patients undergoing elective coronary artery bypass grafting. In ten cases the priming solution contained 1,000 ml dextran (MW 70,000) and in ten it consisted only of Ringer's acetate solution. The same level of haemodilution was established during CPB in the two groups. Clinical variables and laboratory data were monitored. Spontaneous kallikrein activity, plasma prekallikrein, functional kallikrein inhibition capacity, spontaneous plasmin activity, plasminogen, functional antiplasmin activity, prothrombin and antithrombin-III were measured, using chromogenic peptide substrate assays before and during CPB as well as in the postoperative period. The antiplasmin activity decreased more in the dextran than in the Ringer group following cardiopulmonary bypass but the difference was without clinical significance. No statistically significant intergroup difference was found in the other measured variables of the kallikrein-kinin, fibrinolytic and coagulation systems.
Also flagged:heparinheparan sulfatedermatansulfateglycosaminoglycansthrombin
Journal Article1989-01-01✓ 1 SnippetOfosu FA, Buchanan MR, Anvari N, Smith LM, Blajchman MA.
In-Text Gene Mentions
Abstract)
…ibition (assessed by thrombin-antithrombin-IIIand thrombin-heparin-cofactor-…
Show Full Abstract
The relationship between two anticoagulant actions of glycosaminoglycans (GAGs), namely the catalysis of thrombin inhibition (assessed by thrombin-antithrombin-III and thrombin-heparin-cofactor-II formation) and the inhibition of prothrombin activation, was explored by comparing the effects of heparin, heparan sulfate, and dermatan sulfate on the two reactions in plasma. Heparan sulfate and dermatan sulfate were also resulfated in vitro to yield products with sulfate/carboxylate ratios similar to those of heparin. Their effects on thrombin inhibition and the activation of prothrombin were also determined. The catalytic efficiency of the five GAGs on thrombin inhibition and their inhibitory effects on prothrombin activation decreased in the following order: heparin; resulfated dermatan sulfate; resulfated heparan sulfate; heparan sulfate = dermatan sulfate. These results suggest that the catalytic efficiency of a glycosaminoglycan on thrombin inhibition translates to its inhibitory effect on prothrombin activation, since catalysis of thrombin inhibition results in the inhibition of the thrombin-dependent positive feedback reactions of coagulation which facilitate prothrombinase formation.
Assessment of heterogeneity in oestrogen receptor (ER) expression aims to improve prediction of prognosis and treatment assignment in breast cancer. Current assessments are performed manually and are subjective. Automated image analysis as described here objectively quantitates ER in breast cancer nuclei obtained by needle aspiration. ER was visualised by ERICA with diaminobenzidine (DAB) substrate. Various indices of ER positivity were derived from the integrated density and average density measurements of nuclear DAB. Each index was compensated for background staining by non-specific antibody binding and endogenous peroxidase activity. Total nuclear ER content (integrated optical density of stain) was strongly associated with the biopsy ER concentration determined by saturation analysis of radioligand binding (DCC), P less than 0.005. Nuclear ER concentration by image analysis (mean optical density of stain) was not associated with the DCC measurement of ER concentration, P greater than 0.05. This was attributed to technical artefacts of cytocentrifugation. Using threshold values of 5% positive cells and 10 fmol mg-1 concordance of assignment of ER status by image analysis with the DCC assay was 91%, sensitivity was 89% and specificity 100%. It was concluded that image analysis is an appropriate, easy and economic method for determining the nuclear ER status of aspirated cancer cells. Image analysis has the potential to become a powerful diagnostic tool in the assessment of hormone receptor status of breast cancer patients.
Also flagged:Ferritin Hidiopathic hemochromatosisH ferritinrestriction enzymesEcoRIHLA
Journal Article1989-01-01✓ 1 SnippetDavid V, Papadopoulos P, Yaouanq J, Blayau M, Abel L, Zappone E, Perichon M, Drysdale J, Le Gall JY, Simon M.
In-Text Gene Mentions
Abstract)
…polymorphism in 83hemochromatosispatients and 84…
Show Full Abstract
The authors studied the H ferritin restriction polymorphism in 83 hemochromatosis patients and 84 controls as well as in 19 nuclear families. No significant difference was found with the ten restriction enzymes used (HindIII, EcoRI, EcoRV, PvuII, BamHI, PstI, Bg/I, Bg/II, HincII, and TaqI). Hence, the genomic abnormality responsible for idiopathic hemochromatosis is not a major deletion of an H ferritin gene. A higher frequency of one HindIII fragment, although nonsignificant when the number of comparisons made is taken into account, was observed in the patients. This HindIII fragment hybridizes with the H ferritin probe and with a 28 S ribosomal probe, and its segregation with HLA haplotypes (hence its assignment to chromosome 6) is uncertain. Its possible meaning in the expression of the disease is discussed.
The gene for hereditary hemochromatosis is linked to the HLA locus on chromosome 6. Four cloned DNA probes originating from the HLA class I region were used to detect seven restriction fragment length polymorphisms (RFLPs). Allele frequencies and segregation of each RFLP was determined. Analysis of RFLPs in 38 unrelated homozygotes with hemochromatosis revealed differences in allele frequencies between the control and the hemochromatotic groups but these differences did not reach statistical significance. Some differences persisted, however, even when only controls with the A3 antigen were compared with A3 hemochromatotics. Since both control and hemochromatotic groups were small, further studies will be necessary to ascertain whether these RFLPs could serve to locate the gene responsible for hereditary hemochromatosis.
Also flagged:synthesispeptidesdipeptidespeptidelysineamine
Journal Article1989-01-01No SnippetsJuodka B, Sasnauskiene S.
Show Full Abstract
The dipeptides Boc-Thr-Lys(Cbz)-OMe and Boc-Lys(Cbz)-Glu(OEt)-OEt were prepared by the classical method of peptide synthesis. The Cbz protecting group was subsequently removed via hydrogenolysis. AMP was then covalently joined to the free lysine epsilon-amine by the carbodiimide (DCC) method. The resulting RNA-ligase active center model compounds, the adenylyl-(5----N epsilon)-lysylpeptides were then used to study the participation of the amino acid residue functional groups in the hydrolysis of the phosphoamide center.
Also flagged:antibodyprogesterone receptorsestrogen receptorsstress-responsive protein of 27 kDaSRP27uterine leiomyoma
Journal Article1989-01-01No SnippetsNavarro D, Cabrera JJ, Falcón O, Jiménez P, Ruiz A, Chirino R, López A, Rivero JF, Díaz-Chico JC, Díaz-Chico BN.
Show Full Abstract
Uterine leiomyoma occurs in one of every four or five women during their reproductive life. Its origin is unknown but it is accepted that estrogens play a significant role in its development. In order to learn more about the estrogen dependency of leiomyoma, the biochemical and immunological properties of two markers of estrogen response in target cells (the progesterone receptor (PR) and the stress-responsive protein of 27 kDa (SRP27)) were studied in leiomyoma. The ER (estrogen receptor) and PR content were determined by conventional DCC exchange assays. Specific anti-ER, anti-PR and anti-SRP27 monoclonal antibodies were used in immunoblots and immunohistochemical (IHC) studies. The binding properties of PR from cytosol of leiomyoma showed a Kd of 0.8-1.3 nM, which is in the range described for other human tissues. 80% of all studied leiomyoma contained PR, in a range of 805-2000 fmol/mg protein. The Kd for leiomyoma ER was 0.1-0.9 nM, and 84% of the samples were positive for ER. The PR of leiomyoma has the two A and B forms of 120 and 94 kDa, as shown in the immunoblot using the AB52 anti-PR monoclonal antibody. The IHC study revealed that the PR is concentrated in the cell nuclei, in the form of perinuclear bodies, with a homogeneous staining pattern from cell to cell. The leiomyoma fibres contain SRP27 in a higher concentration than the healthy myometrium. The leiomyoma SRP27 shows a typical doublet of 24 kDa and 27 kDa in immunoblot, the same as in MCF-7 cells. The IHC study revealed a high degree of organization of SRP27 in leiomyoma cells, suggesting that this protein may be part of the cytoskeleton. The results obtained show that human leiomyomas contain ER, PR and RSP27 with similar immunological and biochemical properties to those of other human tissues, including the MCF-7 breast cancer cell line.
A simple method for intraoperative autotransfusion (ATF) in open-heart surgery was tested in a prospective clinical trial. The patients were randomly assigned to a control group (33) or to the ATF group (35). The intraoperative ATF was combined with preoperative collection of blood and postoperative ATF. The postoperative chest-tube drainage was reduced by 24.3%, the donor-blood requirement by 43.3% and the consumption of fresh-frozen plasma by 43.9% in the ATF group as compared with the controls (all differences statistically significant). To investigate possible haematologic side effects of ATF, measurements of haemoglobin, haematocrit, fibrinogen concentration, thrombin, prothrombin and partial thromboplastin time, antithrombin-III and fibrinolytic activity were made in all patients preoperatively and on postoperative days 1 and 2. No statistical differences were then found between the controls and the ATF group. Microbiologic tests of blood sampled from the cardiotomy reservoir gave satisfactory results.
In a preliminary paper (Teasdale et al. 1987) comparing the oestrogen receptor (ER) content of breast cancers by the biochemical dextran coated charcoal (DCC) method and by two histochemical methods, peroxidase immunocytochemistry (ERICA) and immunogold-silver staining (IGSS), it was indicated that ERICA is more sensitive than DCC and that IGSS is as specific as ERICA but less sensitive. This paper describes the comparison of the above three assay methods with two other biochemical methods, iso-electric focusing (IEF) and an enzyme immuno-assay (EIA) on a larger number of cancers. All methods gave statistically comparable results except that IGSS remained less sensitive than the rest. Various modifications to IGSS showed that an immunogold streptavidin enhancement method (IG-SAM) produced sensitivity and specificity equal to that of ERICA. Since IGSS and its modifications are the only methods which can be used on archival paraffin-embedded cancers and IG-SAM gives results highly comparable to ERICA, retrospective studies can be performed on patients whose outcome and response to various treatments are known. Most recent studies have shown that ER positive results can be obtained from 10-year-old paraffin blocks.
Also flagged:bindingtetanus toxinmembranesacetategangliosidessialidase
Journal Article1989-01-01No SnippetsParton RG, Davison MD, Critchley DR.
Show Full Abstract
Two different preparations of tetanus toxin (HTT and WTT) were iodinated, and their binding to rat brain membranes characterized. Under optimal binding conditions (25 mM Tris-acetate, pH 6.0), both preparations bound to a large number of high affinity sites, thought to be gangliosides. Binding constants were identical. However, in a physiological buffer (Krebs-Ringer, pH 7.4) binding of the two toxin preparations showed a number of differences. Under these conditions we have previously shown that HTT binding is markedly reduced, and that there are two classes of sites, a small number of heat-, sialidase- and protease-sensitive high affinity sites, and a larger number of sialidase-sensitive, heat- and protease-resistant lower affinity sites, probably gangliosides (PIERCE et al. (1986) Biochem. J. 236, 845-852). Although WTT bound to these same two sites, it displayed a higher affinity for the protease-resistant site than did HTT. WTT also bound to free or immobilized trisialoganglioside with higher affinity than HTT, consistent with the view that the protease-resistant site represents binding to ganglioside. In contrast, both toxin preparations bound to the protease-sensitive site with similar affinities. These observations may explain the four to five-fold higher levels of WTT binding to brain membranes, and the fact that a smaller percentage of total WTT binding is protease sensitive. Despite their different ganglioside-binding properties, both toxin preparations showed comparable neurotoxic activities, and appeared identical on SDS gels.
Binding of a synthetic, high-affinity heparin pentasaccharide and of intact heparin to both native and elastase-modified human antithrombin III have been examined by 1H-n.m.r. spectroscopy. The pentasaccharide perturbs many protein resonances in the same way as does intact heparin. There are, however, differences that seem to arise both from fewer contacts in the heparin binding-site when the pentasaccharide binds and from dissimilar conformational changes in the protein. The resonance of the H-2 atom of the histidine, considered to be the N-terminal residue and to be located in the heparin binding-site, is strongly perturbed by heparin binding both to native and modified antithrombin. The pentasaccharide has little effect on this histidine in either protein. Resonances from two of the remaining four histidine units are sensitive to longer-range conformational changes, and show differences between binding of the two heparin species both in native and modified ATIII. It is concluded that the pentasaccharide only partly fills the heparin binding-site and does not produce a conformational change identical to that caused by intact heparin. This is particularly significant as regards the mechanism of action of heparin, because the synthetic pentasaccharide activates ATIII towards Factor Xa, but not towards thrombin.
…In 25 cases of breast cancer occurring in perimenopausal age, estrogen receptor (ER) content was determined by the dextran-coated charcoal (DCC) assay and both endogenous-bound estradiol and nuclear DNA concentrations were measured by computerized quantitative analysis on formalin-fixed paraffin-embedded tissue samples.…
Show Full Abstract
In 25 cases of breast cancer occurring in perimenopausal age, estrogen receptor (ER) content was determined by the dextran-coated charcoal (DCC) assay and both endogenous-bound estradiol and nuclear DNA concentrations were measured by computerized quantitative analysis on formalin-fixed paraffin-embedded tissue samples. No statistically significant relationship (p greater than 0.05) was found within these parameters. The high incidence (64%) of ER-negative cases in this menopausal age was mainly due (62.5%) to interference of high levels of endogenous estradiol occupying the receptor sites in-vivo. The prevalence of hormone-insensitive and aneuploid cell clones accounted for the remaining true ER-negative tumours (37.5%).
For over 100 years heparin has attracted interest because of its anticoagulant powers. Commercial heparin has now been shown to be a mixture of over 100 different closely related sulfated polysaccharides of which only 10% activate antithrombin-III. Fifty years ago the original research teams in Toronto and Stockholm in demonstrating the clinical uses of heparin observed that antithrombotic activity did not correspond to levels of anticoagulation. It has been shown that: (a) Heparin accumulates rapidly and specifically in the endothelium against a concentration gradient of hundreds- to thousands-fold. (b) Experimental thrombosis, however produced, is accompanied by a marked decrease in the electronegative charge of the vessel wall and the charge is restored in all cases by heparin. (c) The normal electronegative charge is due to glycosaminoglycans. Heparin possesses the strongest electronegative charge of these substances and is present in the vessel wall as a component of a larger heparitin (sulfate) proteoglycan molecule. (d) Maintenance of the normal electronegative charge depends on adequate supply of oxygen (adequate blood flow). (e) Commercial heparin releases enzymes from the endothelium, lipoprotein lipase and histaminase (D.A.O.). Lipoprotein lipase changes the composition of plasma lipids and lipoproteins and histaminase provides a check for fat absorption. The release of these enzymes decrease and prevent atherosclerotic changes. (f) After administration of commercial heparin, heparin isolated from the plasma has higher antithrombin activity than that injected. The heparin taken up by the endothelium is returned with greater activity. The anticoagulant effect of administered heparin does not produce hemorrhage since this requires simultaneous occurrence of defects in the vascular factor of hemostasis (the result of stress or pituitary-adrenal imbalance) or platelet defect. Thus, clinical effectiveness of heparin is an expression of its close relationship to the vessel wall.
Also flagged:heparinglycosaminoglycansOligosaccharidedecasaccharidemonosaccharideDermatan
Journal Article1989-01-01✓ 1 SnippetThomas DP, Merton RE, Barrowcliffe TW.
In-Text Gene Mentions
Abstract)
…or thrombin by non-ATIIIpathways (dermatan sulfate)…
Show Full Abstract
In a standardized animal model, unfractionated heparin (UFH) prevents venous thrombogenesis at a dose of 80 micrograms/kg. Oligosaccharide fragments of heparin, with very high anti-Xa activity both in vitro and in ex vivo plasma samples were less effective than UFH in preventing thrombosis. A decasaccharide fragment was virtually inactive in impairing thrombosis at this dose, although a 20-22 monosaccharide fragment showed some impairment. Dermatan sulfate, which has no anti-factor Xa activity, partially impairs both thrombin generation and stasis thrombosis. However, dermatan sulfate could not suppress thrombin generation below about 35% of control at the doses studied. Neither oligosaccharides nor dermatan sulfate were as effective on a weight basis as UFH in impairing thrombosis, particularly after 20 minutes' stasus. Maximal antithrombotic effects are achieved when both factor Xa and thrombin are inhibited. Drugs which act primarily on factor Xa (oligosaccharides) or thrombin by non-ATIII pathways (dermatan sulfate) are less efficient than UFH as antithrombotic drugs.
In vitro, PF4 is comparable to protamine sulfate in the neutralization of heparin, but the complexes formed with heparin are different. Even with an excess of PF4, no large PF4-heparin complexes are formed and none of the complexes are able to activate ATIII, nor do these complexes dissociate on incubation in plasma at 37 degrees C. The action of PF4 and protamine is complementary. However, excess protamine displaces PF4 or prevents its complexing with heparin. When excess protamine is used to neutralize heparin in the presence of PF4, large heparin-protamine complexes are formed incorporating PF4. In contrast to the heparin-protamine complexes formed without PF4, these do not activate ATIII nor do they dissociate on incubation. Since PF4 is liberated during ECB procedures, its contribution to the stability of heparin-protamine complexes in vivo may influence the amount of protamine needed to neutralize heparin as well as affect the reactions which have been reported on injection of protamine after ECB.
Also flagged:calcitoninCTcarbodiimideBSAalbuminantibody
Journal Article1989-01-01No SnippetsKwok CF, Jap TS, Ho LT.
Show Full Abstract
A sensitive sequential radioimmunoassay of calcitonin (CT) is described. Synthetic human CT was used for 125I-labelling and for preparation of anti-sera. The labelled hormone was purified by QUSO and P10 column. The specific activity of the purified 125I-CT was 39.8 Ci/g. The anti-sera was produced by immunization of guinea pigs with human synthetic CT which was conjugated with carbodiimide onto BSA (bovine serum albumin). Separation of free from antibody bound 125I-labelled CT was performed using DCC precipitation. Standard curves of extracted plasma, extracted plasma plus human CT were parallel to the standard curve. Recovery of 62.5 to 500 pg/ml CT were in the range of 80.72 to 113.4%. The Scatchart plot of the binding data showed a straight line with a kd of 56 pM and Bmax of 35 pM. The specificity of the antiserum was good. The lower limit of detection was 31.25 pg/ml. Our results indicate that this assay system may be useful in both clinical use and research.
Also flagged:Antithrombin IIIthrombinAT-IIIheparinsodiumpartial thromboplastin
Journal Article1989-01-01✓ 1 SnippetDarien BJ, Potempa J, Moore JN, Travis J.
In-Text Gene Mentions
Abstract)
…used to measureantithrombin-III(AT-III) activity (residual…
Show Full Abstract
Two synthetic substrate assays (fluorometric and chromogenic) were used to measure antithrombin-III (AT-III) activity (residual thrombin activity) in non-medicated and heparin (sodium) treated horses. In 18 non-medicated horses the fluorometric substrate assay (FSA) values were similar to previous reports but they reflected inconsistent trends and larger deviations in the heparin-treated groups (Group 2: 40 and 100 U/kg IV, n = 6; Group 3: 240 U/kg IV, n = 5; Group 4: 80 U/kg IV followed by 160 U/kg SC, n = 8) when compared to the chromogenic substrate assay (CSA) values. The CSA values for the 18 non-medicated horses indicated a higher AT-III activity (lower residual thrombin activity) than the FSA. AT-III activity was quantified in 18 non-medicated horses (29 mg/dl) and compared well with values for humans (30 mg/dl) and dogs (40 mg/dl). Plasma heparin concentrations, determined by the FSA, correlated well with the 'therapeutic range' (1.5 fold to 2.5 fold prolongation of the activated partial thromboplastin time (APTT) normal value) and values reported for humans. The effect of heparin therapy on AT-III activity in four treatment regimens was evaluated. AT-III activity was not significantly affected (with one exception) by a single dose of intravenous (IV) heparin (40 and 100 U/kg) nor by repeated subcutaneous (SC) injections of heparin (240 U/kg). A transient increase in residual thrombin activity was measured 12 h after an intravenous (80 U/kg) injection of heparin. Large doses of heparin (80 U/kg IV followed by 160 U/kg SC) given every 12 h produced a progressive prolongation of the APTT. In this group the APTT remained prolonged 48 h after the last treatment.
Also flagged:Hepatic osteodystrophychronic liver diseasepathogenesisosteoporosisGlahepatic disorders
Journal Article1989-01-01✓ 1 SnippetDiamond TH, Stiel D, Lunzer M, McDowall D, Eckstein RP, Posen S.
In-Text Gene Mentions
Abstract)
…alcoholic liver disease,hemochromatosis, and cholestatic liver…
Show Full Abstract
To study the pathogenesis of osteoporosis in patients with chronic liver disease, we performed dynamic bone histomorphometry and measured serum bone Gla-protein in 80 patients with various types of chronic liver disease. These results were compared with results obtained in 40 healthy controls. Mean trabecular bone volume and mean trabecular thickness were significantly reduced in both men and women with chronic liver disease (p less than 0.001 for both measurements in men and p less than 0.01 for both measurements in women). Osteoporosis as defined by histologic parameters was present in 17 (21%) patients with no significant differences in prevalence rates among the various hepatic disorders. No patient had histologic evidence of osteomalacia, although mineralization lag times were prolonged (p less than 0.01 for men and women). Bone formation rates were significantly reduced in 46 (57%) patients, and unlike the static measurements, were related to the type and severity of the underlying liver disease. Patients with alcoholic liver disease, hemochromatosis, and cholestatic liver disease had lower bone turnover rates and osteoblastic surfaces (p less than 0.001 and p less than 0.05, respectively) than patients with chronic active hepatitis. Furthermore, the presence of hepatic cirrhosis was associated with diminished bone formation and lower osteoblast surfaces. Serum bone Gla-protein levels were significantly correlated with bone formation rates and osteoblast surfaces (r = 0.585 and r = 0.434, respectively). A reduction in osteoblast surfaces has not previously been demonstrated in liver disease. This reduction and the associated impairment of osteoblastic activity may contribute to the pathogenesis of osteoporosis and can be assessed by the measurement of serum bone Gla-protein.
The nucleotide sequence coding for the cytotoxic T-lymphocyte (CTL) protein perforin 1 (P1) has been determined and the corresponding protein sequence has been derived. Murine CTL cDNA libraries contained in the vector lambda gt11 were screened by using a monospecific antiserum to purified P1. Three recombinant phages were isolated and their cDNA inserts were sequenced. The derived protein sequence contains 554 amino acids and displays, as expected, considerable homology with certain functional domains in the complement components C9, C8 alpha, C8 beta, and C7. The identity of P1 cDNA clones was verified by prokaryotic expression and the reactivities of antisera produced to the expressed proteins. In addition, antisera were produced to two synthetic peptides located in the center and C-terminal portions of P1. All antisera reacted with purified P1. In Northern blot analyses, P1 cDNA probes recognized a 2.9-kilobase mRNA only in CTL. Perforin mRNA was found in all cloned CTL and in all mixed lymphocyte reactions that gave rise to cytotoxic cells. Perforin mRNA was also detected in virus-specific CTL that had been generated in vivo and isolated from liver tissue of mice infected with lymphocytic choriomeningitis virus. The cell-specific expression of perforin is consistent with its postulated role in cytolysis.
Journal Article1989-01-01✓ 5 SnippetsColman RW, Scott CF, Pixley RA, de la Cadena RA.
In-Text Gene Mentions
Abstract)
…an enzyme byATIIIoccurs via formation…
Abstract)
…formation of anATIII-heparin complex, the degree…
Abstract)
…concentration of theATIII-heparin complex).…
Abstract)
…particular enzyme byATIIIis dependent upon…
Abstract)
…compete for theATIII-heparin complex.…
Show Full Abstract
1. One can accurately predict the contribution of each inhibitor to the total inactivation of an enzyme in plasma once its pseudo-first-order reaction rate constant and concentration are known. 2. Because the mechanism of augmentation of the inactivation rate of an enzyme by ATIII occurs via formation of an ATIII-heparin complex, the degree of potentiation can be predicted by knowing the binding capacity (sites per mole) of the heparin preparation and the concentration of heparin in the reaction (to calculate the concentration of the ATIII-heparin complex). 3. The augmentation by heparin of the inactivation rate of a particular enzyme by ATIII is dependent upon the presence of other enzymes with higher kassoc, since these would strongly compete for the ATIII-heparin complex. 4. In a plasma environment, using therapeutic levels of heparin, there is no augmentation of the inactivation rate of any of the contact enzymes.
Also flagged:ureaseurinary tract infectionurinary tract infectionsureaacetohydroxamic acidnitrosoguanidine
Journal Article1989-01-01No SnippetsGatermann S, John J, Marre R.
Show Full Abstract
We studied the biochemical properties of the urease of Staphylococcus saprophyticus and the possible role of the urease in experimental urinary tract infections. For this purpose, the nonhemagglutinating and nonadherent strain 9325, which was isolated from a case of symptomatic urinary tract infection, was used. The urease was shown to have a Km of 6.64 mM urea and a Vmax of 4.59 mumol NH3.min-1.mg-1. The enzyme was inhibited by acetohydroxamic acid in a noncompetitive manner. By means of Sephacryl S-300 column chromatography, we determined a mean molecular weight (+/- standard error of the mean) of 420,000 +/- 16,000. To assess the contribution of S. saprophyticus urease to uropathogenicity, a urease-negative mutant was constructed by nitrosoguanidine mutagenesis. In the rat model of ascending unobstructed urinary tract infection, higher numbers of CFU.gram of tissue-1 and more-severe lesions were detected with the parent strain. Moreover, bladder stones were found in animals infected with the urease-positive strain only. Interestingly, the difference in mean bacterial counts of the bladders was found to be significant by the Wilcoxon two-sample test (P less than 0.05), whereas that between the kidney bacterial counts was not. Immunoblot studies revealed a faint antibody response in rats infected with the mutant strain, although bacteria could still be detected in the kidneys after 7 days. Sera of animals challenged with the parent strain reacted strongly with many antigens of S. saprophyticus. Our data indicate that urease is a major factor for invasiveness of S. saprophyticus, especially in the tissue of the bladder, whereas persistence in the urinary tract and nephropathogenicity of this organism are governed by factors other than urease.
Heparins from different species and tissues show similar levels of ATIII and HCII mediated anti-IIa activities. On fractionation, chains containing predominantly ATIII or HCII activities could not be separated. Oligosaccharide mapping demonstrates that the concentration of an oligosaccharide comprising a portion of heparin's ATIII binding site in a particular heparin fraction correlates with ATIII mediated anti-IIa activity, but does not correlate with HCII mediated anti-IIa activity. These results suggest that ATIII and HCII do not share a common binding site. Partial enzymatic depolymerization of heparin resulted in large oligosaccharides which could be purified and partially characterized. Although oligosaccharides of degree of polymerization (dp) 18 and 20 showed significant ATIII and HCII mediated anti-IIa activities no separation of these activities resulted. These data suggest however that a minimum chain length of dp18 was required for HCII mediated anti-IIa activity.