Inhibition of human immunodeficiency virus infection by heparin derivatives

Heparin (Hep) and sulfated polysaccharides (SPs) have been reported to inhibit HIV infection in vitro. In vivo, anticoagulant activity and reduced bioavailability were found to limit the antiviral effects of Hep. In this investigation, three nonanticoagulant N-acylated Hep conjugates [OI1:3Hep, Pal1:5Hep, and Pal1:5Hep(SO4)] were compared to Hep for their ability to interact with HIV replication in CD4-positive cell lines and PBMCs. Resulfated palmitoyl-Hep [Pal1:5Hep(SO4)] exhibited the strongest anti-HIV effects. For instance, no provirus HIV DNA was detected in the genome of HIV-1-LAI-infected PBMCs treated with this heparin derivative. Cell-to-cell fusion and RT activity were explored to explain these differences. Hep and Pal1:5Hep(SO4) derivative exerted identical effects on cell-to-cell fusion. On the other hand, Pal1:5Hep(SO4) displayed the strongest inhibitory effects in the acellular RT inhibition assay. This suggests that RT might be a second target for N-acylated Hep, even though SP uptake and the preferential effects of SPs on RT as opposed to DNA polymerase have not yet been demonstrated. Nevertheless, considering the anticoagulant, antiviral, and antiinflammatory effects of N-acylated Hep, the N-acylated Hep derivatives might be excellent candidates as new anti-HIV pharmacological tools.

Inhibition of human leucocyte elastase by fatty acyl-benzisothiazolinone, 1,1-dioxide conjugates (fatty acyl-saccharins)

Derivatives of benzisothiazolinone 1,1-dioxide (saccharin) N-acetylated with aliphatic and aromatic substituted aliphatic acyl groups were prepared. The inhibitory activity of the compounds was assayed against human leucocyte elastase (EC 3.4.21.37) and several other proteases. The IC50 values for inhibition of the human leucocyte elastase decreased with increasing length of the acyl residue, and reached a minimum value at C16 (2 microM). This phenomenon and the decrease of the inhibition by surfactants or by saturation of the enzyme with palmitic acid, indicates that in addition to acylation, hydrophobic interactions are also involved in the inhibition of this proteinase by compounds substituted with acyl groups containing at least 12 carbon atoms. The inhibitory activity of N-palmitoyl-benzisothiazolinone 1,1-dioxide (palmitoyl-saccharin) is about 14 times higher toward human leucocyte elastase than for thrombin (EC 3.4.21.5), and several hundred times, compared to porcine pancreatic elastase (EC 3.4.21.36) and to plasmin (EC 3.4.21.7). Fatty acylated saccharin derivatives were seen to bind in a saturable fashion to insoluble elastin, and decreased the susceptibility of this protein to hydrolysis by human leucocyte elastase.

Protective effect of oleoyl peptide conjugates against elastolysis by neutrophil elastase and kappa elastin-induced monocyte chemotaxis

Elastin can impair the human neutrophil elastase (HNE) inhibitory capacity of elastase inhibitors. We synthesized oleoyl-alanyl-alanyl-prolyl-valine (Ol-Ala-Ala-Pro-Val-OH) (oleoyl peptide) and the amides (NH2 and NH-C3H7) of this peptide and studied their HNE-inhibitory potencies using succinyl-alanyl-alanyl-alanine-p-nitroanilide (Suc-Ala-Ala-Ala-pNA) or 3H-labeled elastin as substrates, as well as cryostat sections of rabbit skin as an ex vivo substrate. Using Suc-Ala-Ala-Ala-pNA, Ol-Ala-Ala-Pro-Val-OH had an IC50 of 3 microM. When the COOH terminal of the oleoyl peptide was derivatized to amide forms, the compound lost its ability to interact with HNE while keeping its elastin-protecting function: IC50 values for NH2 and NH-C3H7 derivatives were 22 and 17 microM, respectively. Also, the HNE-inhibitory capacity of Ol-Ala-Ala-Pro-Val-OH was only reduced 2-fold by using elastin as a substrate. This decrease was much lower than those determined with other HNE inhibitors of similar potency and could be accounted for by the ability of oleoyl peptide to bind to elastin. Cryostat sections of rabbit skin were also used as an ex vivo substrate for assessing the elastin-protecting property of Ol-Ala-Ala-Pro-Val-OH. Preincubating HNE and oleoyl peptide before application to tissue sections led to an IC50 of 8 microM, close to the value determined with elastin as a substrate. Treatment of sections with oleoyl peptide before adding HNE gave a lower IC50 (4 microM).(ABSTRACT TRUNCATED AT 250 WORDS)

A lipophilic heparin derivative protects elastin against degradation by leucocyte elastase

An oleolylated derivative (I) of partially N-desulphated heparin was prepared containing an average number of three oleoyl residues for one molecule of heparin. The inhibitory capacity of I (IC50 = 0.55 microM) for leucocyte elastase resembles that of heparin (IC50 = 0.2 microM). In contrast to heparin, I is also an inhibitor of porcine pancreatic elastase (IC50 = 0.68 microM) and it also has the capacity to protect elastin fibres against the degradation by leucocyte elastase. When insoluble elastin is pretreated with I its degradation by leucocyte elastase is inhibited by almost 90% while pretreatment of elastin with heparin exhibited only a moderate effect on elastolysis (10% inhibition).

Effects of glycosaminoglycans and extracellular matrix components on metastatic rat rhabdomyosarcoma tumor and myoblast cell proliferation

Experiments were performed to determine the relative effects of glycosaminoglycans and extracellular matrix components alone or in association with various substrates, including extracellular matrix, on the proliferation of rat rhabdomyosarcoma (RMS) cell lines of different metastatic potential and nontumorigenic rat myoblast L6 cells. The assays used various substrates: tissue culture plastic, type I and IV collagen, fibronectin, laminin and extracellular matrix deposited by corneal endothelial cells. In control experiments, tumor cells grew faster on fibronectin and extracellular matrix than on the other substrates, and their proliferation rate was decreased slightly by laminin. Collagens were growth-inhibitory only for the highly metastatic line. The proliferation rate of L6 myoblasts was not greatly affected by the different substrates. The addition of exogenous glycosaminoglycans to the culture medium modified cell proliferation on the various substrates. Heparin inhibited the growth of all the cell lines tested, independent of the substrate. When cultured on laminin substrate the proliferation rates of the cell lines were depressed by addition of heparan sulfate to the medium, and this effect was more pronounced in the metastatic RMS lines. Chondroitin sulfate and dermatan sulfate enhanced the growth rates of the tumorigenic cells when cultured on collagen type I surfaces. Hydrocortisone, which induces myogenic differentiation, decreased the cell proliferation rates of all the cell lines tested and intensified the inhibitory effects of heparin when added simultaneously to the culture medium. The results showed that glycosaminoglycans and other matrix components can affect the proliferation rates of rhabdomyosarcoma cell lines.

Galactosylated glycan expression and macrophage sensitivity of Lewis lung tumor cells with different metastatic phenotype

Biochemical and cytochemical analysis of Lewis lung tumor variants revealed that the low metastatic cells contained more galactose/N-acetylgalactosamine residues in a high-molecular-mass (15-20 kDa) mixed N- and O-glycan fraction than the highly metastatic ones. It was also found that the highly metastatic variant was less sensitive to macrophage cytotoxicity in vitro. The cytotoxicity against the low metastatic target cells was inhibited by asialofetuin (10-20 microM), and, to a small degree--and at much higher concentration--by lactose, while galactose and other monosaccharides were ineffective. We suppose that complex galactosylated tumor cell membrane glycans could play a role in the antitumoral cytotoxicity of macrophages.

Hyaluronate-binding proteins in weakly and highly metastatic variants of rat rhabdomyosarcoma cells

Weakly (RMS8) and highly (RMS0) metastatic rat rhabdomyosarcoma cells were assayed for their interaction with hyaluronate. The cells in subconfluent cultures were incubated with 35S methionine, the cells were fractionated and the labelled proteins were separated by affinity chromatography on hyaluronate-Sepharose and by HPLC. The RMS8 cells expressed about twice the amount of labelled hyaluronate-binding proteins seen in the RMS0 cells. The molecular sizes of the main hyaluronate-binding proteins were similar in both cell types. Unlike the RMS0 cells, the RMS8 cells took up exogenous, radioactively labelled hyaluronate at 4 degrees C in a saturable and specific way with high affinity. Cells were also incubated with 3H glucosamine. The isolation of the glycosaminoglycans from these cultures by ion-exchange chromatography indicated that the RMS8 cells retained more endogenous 3H hyaluronate in their pericellular domain than did the RMS0 cells. The attachment of trypsinized cells could be inhibited with exogenous hyaluronate, indicating that the proteins with affinity for hyaluronate may act as hyaluronate-binding sites on these cells.

Comparative study on Lewis lung tumour lines with 'low' and 'high' metastatic capacity. III. Glycosaminoglycan synthesis, transport and degradation in cell lines

The glycosaminoglycans (GAGs) of low (LM) and highly metastatic (HM) cell lines of the Lewis lung tumour (3LL) were compared using [3H]glucosamine labelling techniques. The GAGs isolated from nuclei, cytoplasm, pericellular fractions and medium were analysed by cellulose acetate electrophoresis and by digestion with specific enzymes, and the following conclusions were drawn. 1. Increased cellular uptake and incorporation of [3H]glucosamine into glycoconjugates of the cytoplasm was a typical feature of the highly metastatic cell line after a 48-h labelling. However, there was no elevated radioactivity in glycolipids. 2. Radioactivity of the purified GAGs was two and three times higher in nuclear and cytoplasmic fractions of HM cells than in those of LM cells. There was much less difference between the two cell lines in the pericellular fractions. 3. A definite change from chondroitin sulphate to dermatan sulphate dominancy was recorded in each GAG fraction. Higher heparan sulphate labelling was observed in the cytoplasmic and pericellular GAGs of HM cultures. 4. In the post-labelling period about three times more GAG was present in the extracellular compartment of the HM cultures compared with the LM cultures. 5. In the LM cultures the total GAG-associated radioactivity decreased by 73 per cent in the 48-h chase period whereas in the HM cultures it decreased by only 30 per cent. This indicates a higher rate of GAG degradation in the LM cultures.

Binding and internalization of exogenous glycosaminoglycans in weakly and highly metastatic rhabdomyosarcoma cells

The fate of exogenous glycosaminoglycans in cultures of strongly (RMS 0) and weakly (RMS 8) metastatic rat rhabdomyosarcoma cells was studied. The time course and concentration dependence of binding and internalization of the radiolabeled sulfated glycosaminoglycans were determined. Weakly metastatic cells took up heparin, heparan and dermatan sulfates into their pericellular compartment at a higher rate than the strongly metastatic RMS 0 cells. The RMS 8 cells exhibited about two times more binding sites for these iduronic acid containing glycosaminoglycans, and internalized higher amounts of them than the RMS 0 cells. The uptake of the chondroitin sulfate into the peri- and intracellular compartments of both cell types was about 5-15% of that of the other glycosaminoglycans studied. The specificity of displacement of the pericellular heparin and dermatan sulfate by the unlabeled glycosaminoglycans indicates the involvement of specific structural features of the polysaccharide chains in the interactions of glycosaminoglycans with the surface of rhabdomyosarcoma cells, beside ionic forces due to the polyanionic character of the glycosaminoglycans. Heparin and heparan sulfate degradation products, mainly large oligosaccharides, were recovered from the surface of RMS 0 cells but were absent on the surface of the RMS 8 cells. About 30% of the internalized heparin and heparan sulfate was present in the partially degraded form in both cell types. Oligosaccharides derived from glycosaminoglycans were not released into the medium. The decrease in the amount of iduronic acid containing glycosaminoglycans internalized by the highly invasive cells seems to be correlated with an increased cell-associated degradation and with an apparent loss of glycosaminoglycan binding sites on the cell surface.

Inhibition by elastase inhibitors of the formyl Met Leu Phe-induced chemotaxis of rat polymorphonuclear leukocytes

Rat leukocyte elastase has been purified successively by AH-Sepharose Kappa-elastin affinity chromatography and by ion exchange chromatography on a carboxymethyl Sephadex resin. It has great similarities with human leukocyte elastase in its molecular weight, substrate specificity and inhibitory profile. The effect of rat leukocyte elastase inhibitors in influencing the chemotactic response of rat PMN to fMetLeuPhe has been compared to that of other proteinase inhibitors. The results indicated that oleoyl (Ala)2ProValCH2Cl, a specific inhibitor of human and rat leukocyte elastases and Eglin C, which also inhibits human and rat cathepsin G, are among the powerful inhibitors of rat PMN chemotaxis induced by the formyl oligopeptide. This suggests that these neutral proteinases, in addition to their known participation in connective tissue catabolism, could play a role in PMN locomotion and chemotaxis.

Cell surface glycosaminoglycans of rat rhabdomyosarcoma lines with different metastatic potentials and of non-malignant rat myoblasts

Glycosaminoglycans of cultured nickel-induced rat rhabdomyosarcoma cell lines with different metastatic potentials and of non-malignant myoblasts, grown in the presence or in the absence of hydrocortisone, were studied comparatively. The newly formed [3H]glucosamine-labelled cell surface proteoglycans and glycosaminoglycans were separated by ion exchange chromatography and partially characterized. The overall incorporation of the label in the glycosaminoglycan fractions and the average molecular weight of the heparan and of the chondroitin sulfate proteoglycans was lower in the malignant cells than in the non-malignant L6 myoblasts. The strongly metastatic 9-4/0 parental line and the 6 subline were relatively richer in chondroitin sulfate and poorer in dermatan sulfate labels than the very weakly metastatic 8 subline and the L6 myoblasts. Hyaluronic acid and heparan sulfate labels were inversely related to the metastatic capacity of the cell lines studied. Hydrocortisone treatment induced an increase in the cell surface chondroitin and dermatan sulfate labels in the case of the strongly metastatic lines, and a decrease of the same parameters in the case of the weakly metastatic 8 line.

Solubilization and degradation of extracellular matrix by various metastatic cell lines derived from a rat rhabdomyosarcoma

Examination by use of WAG syngeneic female rats was made on 4 rat rhabdomyosarcoma sublines expressing different metastatic potentials for their abilities to degrade proteoglycans and glycoproteins of the extracellular matrix (ECM), deposited by corneal endothelial cells and metabolically labeled with [3H]glycosamine and [35S]sulfate. Of the label incorporated in ECM, 10-20% was released in the culture medium in 3 days by the cell lines studied. The proteoglycans, glycosaminoglycans, and glycoproteins released by the cells from ECM were separated and partially characterized. Most of the ECM glycoproteins were recovered in the region of 200,000 (200K) on gel chromatography. Glycopeptides of 10K-20K apparent molecular weight were minor components. The glycosaminoglycan chains of the proteoheparan sulfate were partially hydrolyzed to 20K fragments. Tumor cells increased also the solubilization of the nondegraded matrix macromolecules. About 5-8% of the radioactivity of the ECM remained associated with the tumor cells detached from the ECM. ECM degrading activity of the sublines did not correlate with their ability to colonize the lungs after iv injection but did correlate with their ability to metastasize to the lungs from the primary subcutaneous site.

Modulation of proteoglycan metabolism by hydrocortisone and by growth factors in rhabdomyosarcoma cell lines of different metastatic potentials

Glycosaminoglycans of cultured nickel-induced rat rhabdomyosarcoma cell lines with different metastatic potentials, grown in the presence or in the absence of hydrocortisone and of growth factor (EDF and EDGF) were investigated comparatively. The newly formed [35S]sulphate and [3H]glucosamine-labelled glycosaminoglycans were analysed in the extra-, peri- and intra-cellular compartments of the following cell lines: the strongly metastatic and colonizing 9-4/0 parental line, the very weakly metastatic and weakly colonizing subline 8 and the very weakly metastatic but colonizing subline 13a2. The cell surface of the weakly metastatic 8 and 13a2 lines was richer at least 5 and 2 times respectively in sulphated glycosaminoglycan label than the surface of the strongly metastatic 9-4/0 parental line. Hydrocortisone provoked an approximately four-fold increase in the label of the sulphated cell surface glycosaminoglycans of the 9-4/0 line. The pattern of the labelled cell surface glycosaminoglycans of these cells become similar to that of cells from the very weakly invading subline 8. Hydrocortisone induced only minor changes in the distribution of the glycosaminoglycans in the 8 and 13a2 lines, and at the same time, their proliferation rate and differentiation state was only slightly affected by this drug. Conversely to hydrocortisone, EGF increases the proliferation of the 9-4/0 line and also increases the label in sulphated cell surface glycosaminoglycans. This increase is about 50 per cent of that obtained by hydrocortisone. Thus, the accumulation of the glycosaminoglycan label on the cell surface is not directly related to the cell growth in the case of these cells. The results suggest that sulphated cell surface glycosaminoglycans, especially chondroitin sulphate, are involved in the inhibition of metastasis formation of the rhabdomyosarcoma cell lines studied.

Primary structure of two major glycans of bovine fibrinogen

After pronase digestion of bovine fibrinogen, the asparagine-linked glycans were released from the resulting glycopeptides by hydrazinolysis, and subsequently re-N-acetylated. Two sialylated glycans were isolated by ion-exchange chromatography. Their primary structure has been determined by methylation analysis and 360-MHz 1H-NMR spectroscopy. The structures proposed to be present in the native glycoprotein are as follows: (formula: see text).

Fatty acid peptide derivatives as model compounds to protect elastin against degradation by elastases

Peptide sequences which fit the extended binding sites of porcine pancreatic elastase and human leukocyte elastase were covalently coupled to oleic acid. These compounds behave as competitive inhibitors towards both elastases. The coupling of fatty acid moiety to the peptide greatly decreases its inhibitor constant (Ki) vs human leukocyte elastase (Ki for Oleoyl(Ala)2ProValine: 3.0 (10(-6)M). It is less active on porcine pancreatic elastase (Ki for Oleoyl(Ala)2ProAlanine: 3.8 10(-4)M). The modifications of the carboxylic end group of the peptide to an aldehyde further greatly enhanced the inhibition capacity of the compound towards leukocyte elastase (Ki for Oleoyl(Ala)2ProAlaninal: 0.7 microM). Oleoyl peptide derivatives were seen to bind in a saturable fashion to purified insoluble elastin, and decreased the susceptibility of the macromolecule to hydrolysis by both pancreatic and leukocyte elastases. As stoichiometric quantities of elastase (vs inhibitor) could not desorb 3H-oleoyl(Ala)2Pro-Val bound to insoluble elastin, it is postulated that oleoyl peptide derivatives may act as bifunctional agents. This contention was further strengthened by the comparison of the adsorption curves of elastase to untreated insoluble elastin and elastin saturated with oleoyl peptide derivatives respectively. It was shown finally that Oleoyl(Ala)2Pro-Valine was also capable of inhibiting elastases in their adsorbed form to insoluble elastin.

Interaction of bovine epithelial lens (BEL) cells with extracellular matrix (ECM) and eye-derived growth factor (EDGF). III. Control of glycoprotein and proteoglycan synthesis

Bovine epithelial lens (BEL) cells, cultured in the presence or absence of an eye-derived growth factor (EDGF) on plastic surfaces or on extracellular matrix (ECM) laid down by corneal endothelial cells, were metabolically labelled with [3H] glucosamine and with [35S]O2+4. The newly formed glycoproteins and proteoglycans were determined and studied in the extracellular compartment. EDGF reduces radiosulfate incorporation and provides the formation of low molecular weight (LMW) proteoglycans and glycosaminoglycans. [3H]Glucosamine incorporation into the glycoprotein fractions is affected by EDGF and by ECM, but in a different manner. EDGF and ECM reduce the formation of the glycoproteins with an affinity towards the collagen, but the effect of EDGF and ECM on the other glycoproteins is different. It is suggested that the actions of EDGF and of ECM are at least partially different and mutually independent.

Structural glycoproteins from rabbit aortic media

Rabbit aortic intima-media fragments were incubated with [14C]mannose and [3H]fucose for 6 h to detect glycoproteins synthesized in situ. The radioactively labelled and the non-labelled samples were extracted with 0.2 mM-CaCl2/0.5 mM-dithiothreitol/0.5 mM-ATP and chloroform/methanol/water (4:4:1, by vol.). The delipidated residue was extracted with 5 M-guanidinium chloride/0.05 M-dithiothreitol/0.1 M-Tris/0.4% Na2EDTA, pH 7.5, before (extract 1) and after hydrolysis with collagenase (extract 2). The proteins in extracts 1 and 2 were S-carboxamidomethylated and separated by molecular-sieve chromatography, polyacrylamide-gel electrophoresis and isoelectric focusing in sucrose gradients in urea. The apparent molecular weights of glycoproteins were 36 000 (glycoprotein I) from extract 1, 50 000 (glycoprotein II) and 130 000 (glycoprotein III) from extract 2. The molecular weights of the non-labelled and radioactively labelled glycoproteins were identical. Glycoproteins I, II and III contain large amounts of polar amino acids and methionine. They contain neither hydroxyproline nor 3-methylhistidine. A hydroxyproline-containing component of 160 000-apparent-mol.wt. relatively rich in polar amino acids and labelled with incorporated sugars was isolated from extract 1. The incorporation in vitro of radioactive sugars into glycoproteins I, II, III and collagenous glycoproteins indicates that they are synthesized in the surviving aorta by the smooth-muscle cells.

Alterations in glycopeptide and glycosaminoglycan biosynthesis in bovine lens epithelial cells cultured in the presence of an eye-derived growth factor

D-[3H]glucosamine-labeled glycosaminoglycans and glycopeptides, obtained by Pronase digestion from bovine lens epithelial cells grown in the presence and in the absence of an eye-derived growth factor, were investigated comparatively in the extra- and pericellular compartments of 16-17th subcultures. Glycosaminoglycans and glycopeptides were separated on Ultrogel AcA 202 column and the retained glycopeptides were further separated by the successive application of affinity, ion-exchange and exclusion chromatographic methods. The following results were obtained: (1) the proportion of the label increased in hyaluronic acid and decreased in the glycopeptide fraction on stimulation with the growth factor: (2) the comparison of the chromatographic elution profiles of the glycopeptides from control and stimulated cells revealed that differences between the two cell groups were largely quantitative. An increase in the high molecular weight glycopeptides, as it was found in transformed cells, could not be demonstrated in eye-derived growth factor-treated cells.

Effects of retinal growth factor and of the increase of the number of subcultures on sulfated glycosaminoglycans of bovine lens epithelial cells

Sulfated glycosaminoglycans of cultured bovine lens epithelial cells grown in the presence and in the absence of a retinal growth factor were investigated comparatively. The newly formed [35S]sulfate-labeled glycosaminoglycans were analysed in the extra-, peri- and intracellular compartments of early (4--5th) and late 17--18 h) subcultures. The following results were obtained: (1) Cultured lens epithelial cells grown in the presence or in the absence of the growth factor synthesize chondroitin 4- and 6-sulfates and dermatan sulfate, with heparan sulfate as the main component, the pericellular compartments were particularly rich in heparan sulfate; (2) The distribution pattern of the glycosaminoglycans changes during successive subcultures; the proportion of heparan sulfate increases in the pericellular compartment, the dermatan sulfate to chondroitin sulfate ratio increases in all three compartments; (3) IN contrast to the drastic decrease in the fibronectin levels in the presence of growth factor in the early subcultures, only minor differences were found between the glycosaminoglycan patterns of the treated and non-treated cells.

Partial characterization of peptide fragment purified by isoelectrofocusing after organo alkaline hydrolysis of bovine ligamentum nuchae elastin

Highly purified elastin from bovine ligamentum nuchae was submitted to partial alkaline hydrolysis (37 degree C, 72 H, 1 N KOH in 80 p. 100 aqueous ethanol). The non-coacervable fractions were submitted to isoelectrofocusing and five kappa-elastin fractions were obtained. The amino-acid compositions, the N-terminal amino-acids, the molecular weights and the thermolysin digests of each fraction were determined by various techniques. The average MW was about 14,500 (150 - 166 amino-acids). These results suggest that the distribution of cross-linking agents in fibrous elastin may not be uniform. The results also show that in certain cross-linked regions of similar molecular weight and size appearing to be composed of different polypeptides sequences containing different amounts of cross-links.

Biodegradable arterial prosthesis from rat aorta

The preparation and potential clinical use of biodegradable microarterial grafts from rat aorta were investigated. Trypsin treated arterial segments were coated with heparin or chondroitin sulfate to reduce thrombogenicity. The samples were crosslinked with formaldehyde vapors at 4 degrees C. 50 - 100 microgram glycosaminoglycans taken up per mg aorta dry weight were resistant to washing with water for 24 hrs. The covalent crosslinks introduced by formaldehyde and resistance of the grafts to proteolytic degradation. The treated grafts were implanted on 70 rats in an infrarenal aortic position. The permeability of the aldehyde crosslinked prosthesis after 21 days by patency test was lower than the patency ratio measured with fresh autologous grafts. The glycosaminoglycans associated with the prosthesis improve the patency of the crosslinked grafts by about 48%. The resistance to bacterial collagenase of the excised grafts decreased with progressing time of implantation. In the permeable prosthesis and in the contiguous aorta, elastolytic activity was demonstrated by radial diffusion in elastin-agar gels. The grafts removed after 21 days of implantation were surrounded with scar tissue. In contrast to fresh aorta, the macromolecular hydroxyprolin in the scar was readily solubilized with pepsin. The presence of the fragmented elastin and collagen fibers in the excised graft is in favour of their resorption "in vivo".

The specificity of sialytransferases using glycosylated lysozyme derivatives as substrates

Galactose, lactose, N-acetylgalactosamine, N-acetylglucosamine and fibrinoglycopeptides were bound to lysozyme by different linkages. These glycosylated lysozymes were tested as N-acetylneuraminic acid acceptors using particular sialytransferase preparations from frog and bovine liver and from bovine and porcine submandibular glands. Desialylated fetuin served as reference compound. Galactose residues of desialo-fetuin and lysozyme-lactose are sialylated by all four sialytransferases tested, galactose bound to lysozyme via a phenylazo group is inactive with the enzyme from bovine submandibular gland, and galactose bound directly to lysozyme serves as substrate only for the frog liver sialytransferase. Lysozyme-phenylazo-N-acetylgalactosamine is active only with the sialytransferase from bovine sumbandibular gland. N-Acetylglucosamine derivatives of lysozyme are inactive with all sialytransferases tested. These observations are discussed in the light of the natural substrates for the sialytransferases investigated.

Guanidination of kappa-elastin from bovine ligamentum nuchae

Kappa-Elastin is exhaustively guanidinated in order to chemically modify the pre-existing lysine content to homoarginine. However the pre-existing lysine content is only modified to homoarginine content about 50 p.cent. The other lysyl-bonds are buried or/and engaged to aldi-imine bonds or other bonds. Therefore the first guanidinated kappa-Elastin is submitted to partial acide hydrolysis (HCL, 1 N, 110 degrees C for 2 hours) and submitted to a second exhaustive guanidination. The pre-existing lysin content in kappa-Elastin almost quantitively disappeared and is transformed to the corresponding homoarginine. These results are similar to those obtained by photolysis of (Iso) desmosine residues by UV light which will liberate "new" lysine containing peptides from kappa-Elastin.

Biochemical and pharmacological properties of a neurotoxic protein isolated from the blood serum of heavily burned patients

Blood serum of heavily burned patients contains neurotoxic substances which are not present in normal control sera. In the present paper, we describe the purification by gel filtration and ultracentrifugation of such a neurotoxic factor. The purified factor appeared to be a high molecular weight (2 to 3.10(6) daltons) lipoprotein. This factor was present in all the sera of patients with more than 35 per cent of the body surface burned. When injected into rabbits the lipoprotein caused a flattening of the EEG tracing, then trembling and convulsions with bursts of spikes on the EEG. The activity of this neurotoxic substance was enhanced when the permeability of the blood-brain barrier was increased by previous intraventricular injection of collagenase. The presence of such a neurotoxic factor in the blood serum of burned patients, together with the increased serum collagenase activity they exhibit may explain the neurotoxic symptoms observed in them.

Biochemical and pharmacological properties of a cardiotoxic factor isolated from the blood serum of burned patients

Blood serum of severely burned patients contains several substances which are not present in normal sera. One of these substances, a small protein of an approximate molecular weight of 12 to 14,000 daltons displayed a toxic action on the circulatory system. This cardiotoxic factor was obtained in a purified form by alcohol precipitation followed by gel filtration and carboxymethyl cellulose chromatography. The purified preparation seems to be a low molecular weight protein of about 8000 daltons. The biological effects of this substance consist essentially of alterations of the ECG pattern, indicating decreased cardiac output and ischaemia of the cardial muscle. The blood pressure decreases and respiratory function is also altered. The presence of such a toxic factor in sufficient concentration in the blood serum may explain the cardiovascular complications observed in some burned patients.

Glycoproteins from the aorta

This review deals with the data on isolation techniques, structure, physicochemical properties and biological function of glycoproteins isolated from the aorta. Some glycoproteins extracted at low ionic strengths (soluble glycoproteins) are immunologically distinct from serum glycoproteins. The designation "structural glycoprotein" was proposed for glycoproteins associated with the collagen elastin matrix. These glycoproteins are solubilized by dissociative and reducing buffers. A selective hydrolysis of the insoluble collagen prior to their extraction was also reported. The molecular weights are in the range of 53 - 72.000 and 35.000 - 27.000 daltons for the soluble and the structural glycoproteins respectively. The aorta glycoproteins are rich in polar aminoacids. The primary structure of glycoproteins from aorta is not yet established. The electrophoretic mobility and sugar content of some glycoproteins extracted at low ionic forces change with the maturation and sex. The biosynthesis of a soluble glycoprotein (glycoprotein B) and of structural glycoproteins by aortic smooth muscle cells was demonstrated "in vitro". The structural glycoproteins appear as microfibrillae in electron microscopy. Their self-aggregation may be due to hydrophobic interactions. The association of microfibrillar glycoprotein with elastin in connective tissues and in the culture medium of aortic smooth muscle cells suggests the role of glycoprotein-elastin interactions in morphogenesis.

Structural glycoprotein from the media of pig aorta. Aggregation of the S-carboxamidomethyl subunits

Media of pig aorta was extracted with 1 M NaCl and 2 M MgCl2 to remove most of the soluble collagen, proteoglycans and glycoproteins. The glycoproteins remaining in the residue were extracted with 6 M urea-0.1 M mercaptoethanol. The urea soluble proteins were precipitated by dialysis, redissolved in 4 M guanidine-0.05 M DTT and were S-carboxamidomethylated (CM-guanidine extract). This extract was further fractionated by a variety of methods in order to separate a glycoprotein from collagen and proteoglycans. Caesium chloride density-gradient ultracentrifugation of the CM-guanidine extract separated a minor proteoglycan peak from a major glycoprotein fraction still containing some hydroxyproline. This major glycoprotein fraction was excluded as a single peak from Sephadex G 100 and G 200 in 4 M guanidinium chloride or in 6 M urea-0.2 per cent SDS. Sodium dodecylsulphate gel electrophoresis separated this high molecular weight Sephadex fraction into a major low molecular weight (approximately 35000 daltons) component and a minor high molecular weight component. This glycoprotein fraction could also be separated from a collagenous fraction and from proteoglycans by ion exchange chromatography on DEAE cellulose or by gelfiltration on Sepharose 4 B in 6 M urea-0.02 M EDTA-0.2 per cent SDS at pH 7.0. The isolated glycoprotein fraction is rich in dicarboxylic amino acids, contains galactose, mannose, (glucose), N-acetylglucosamine and sialic acid. The S-carboxamidomethyl glycoprotein preparation interacts with acid soluble calf skin collagen on isoelectric focusing in sucrose gradient in urea. This interaction is in favour of the biological role claimed for structural glycoproteins during fibrogenesis and differentiation.

Biochemical studies on dacron arterial prostheses

Dacron arterial prostheses, treated or not with biopolymers (gelatin, glycosaminoglycans) were implanted in the abdominal aorta of dogs and the connective tissue synthetised inside and outside the prosthesis was studied. After 3 and 9 months of implantation the prosthesis, a joining portion and a piece of aorta were excised and put in organ culture with 14C-lysine for 3 days. Representative macromolecular extracts were then obtained by a "chemical dissection" procedure. The radioactivity and the chemical composition of these extracts was studied. The DNA content of the prosthesis was higher than that of the adjacent aorta showing a dense cellular repopulation of the prosthesis. This was confirmed by histology also which revealed the presence of a newly formed limiting elastic membrane and the presence of numerous elastic fibrils. Collagen, elastin and glycosaminoglycans could be detected in the macromolecular extracts showing that the cells which repopulated the prosthesis expressed a complete biosynthetic capacity as far as matrix macromolecules are concerned. The distribution of proteins in the extracts was as follows: 4% of total proteins were extracted in a 1M CaCl2-buffer 80% of total proteins in the collagenase extracts, 10% in the 6M urea extract. Only 0,2% of proteins were in the final elastase extract, 10 times less than in the joining aorta fragment. The proportion of the other proteins was similar in aorta and in the prosthesis as well as the chemical composition (hexosamine and hydroxyproline content) of the extracts. The proportion of collagenase-extractable proteins decreased with the time of implantation (from 3 to 9 months) and the proportion of urea-extractable proteins increased. This type of modification is similar to that found in aging aorta wall. 14C-lysine was actively incorporated in all macromolecular fractions studied. The incorporation pattern of the prothesis tissue was similar to that found for the joining host aorta, showing a similar regulatory tendency for matrix macromolecules. It appears therefore that a valid hemocompatible vascular type of connective tissue can be synthesised on the dacron arterial prosthesis and nature of this connective tissue can be influenced by previous biopolymer treatment of the synthetic prosthesis. The described procedure (incorporation of labelled precursors in organ culture) appears to be a valid method for the exploration of the regulatory processes underlying the synthetic capacity for matrix macromolecules of the newly formed tissue in the synthetic prosthesis.

[Condensation of D-glycosamines with proteins]

4-O-beta-D-Galactopyranosyl-alpha,beta-D-glucopyranosylamine (lactosylamine), beta-D-gluco-, alpha- and beta-D-galacto-, and beta-D-manno-pyranosylamines were bound to the carbodiimide-activated carboxyl groups of lysozyme. Of the 11 free carboxyl groups of the protein, approximately 3 were substituted by alpha,beta-lactosylamine, and approximately 2 by the monohexosylamines. One of the 4 glycopeptides isolated from the tryptic digest of the lysozyme-lactosylamine conjugate was identical to synthetic 1-N-L-leucinoyl-4-O-beta-D-galactopyranosyl-beta-D-glucopyranosylamine, indicating the substitution of the carboxyl group of the C-terminal leucine residue. The isolation of a glycopeptide containing the aspartic acid residue in position 117 indicates that the second alpha,beta-lactosylamine residue is linked to the carboxyl group of this amino acid. Both of the 2 other glycopeptides contain the same free carboxyl groups (one glutamic and two aspartic acid residues in positions 35, 48, and 52, respectively). The third alpha,beta-lactosylamine residue seems to be linked to one of these carboxyl groups.

Heterosaccharides derived from structural glycoproteins of the skin of two isogenic mouse (Mus musculus) strains C3H/He and C57BL/6

1) Glycopeptides were prepared by pronase digestion of the urea extract of dermis of two isogenic mouse strains C3H/He and C57BL/6. 2) The major glycopeptide fractions from both strains contain, glucosamine, galactose, mannose, fucose and sialic acid. 3) The sugar composition, the behaviour on gel filtration and yields of the glycopeptides with identical electrophoretic mobilities, isolated from the two strains, were identical.