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C Franzblau

Publications and source records attributed to C Franzblau.

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

Processing of soluble elastin in cultured neonatal rat smooth muscle cells.

The synthesis and extracellular deposition of elastin by cultured neonatal rat aorta smooth muscle cells has been followed. The addition of beta-aminopropionitrile to the culture medium promotes accumulation of soluble precursors of elastin. Under such conditions, a protein possessing characteristics of a soluble elastin precursor with an apparent molecular weight of 77,000 was detected and partially purified. Pulse-chase studies suggested that this 77-kDa protein undergoes an extracellular, enzymatically catalyzed process to a 71-kDa protein. This 71-kDa protein is strikingly similar to tropoelastins isolated from other tissue systems, in which no evidence for higher molecular weight soluble precursors is at present available. Data presented in this communication suggest that the 77-kDa protein, which we have designated protropoelastin, represents a precursor to the tropoelastin moiety produced in the neonatal rat smooth muscle cell culture.

Aminopropionitrile↗
PubMed1985

Dietary fish oil modulates macrophage fatty acids and decreases arthritis susceptibility in mice.

B10.RIII and B10.G mice were transferred from a diet of laboratory rodent chow to a standard diet in which all the fat (5% by weight) was supplied as either fish oil (17% eicosapentaenoic acid [EPA], 12% docosahexaenoic acid [DHA], 0% arachidonic acid [AA], and 2% linoleic acid) or corn oil (0% EPA, 0% DHA, 0% AA, and 65% linoleic acid). The fatty acid composition of the macrophage phospholipids from mice on the chow diet was similar to that of mice on a corn oil diet. Mice fed the fish oil diet for only 1 wk showed substantial increases in macrophage phospholipid levels of the omega-3 fatty acids (of total fatty acid 4% was EPA, 10% docosapentaenoic acid [DPA], and 10% DHA), and decreases in omega-6 fatty acids (12% was AA, 2% docosatetraenoic acid [DTA], and 4% linoleic acid) compared to corn oil-fed mice (0% EPA, 0% DPA, 6% DHA, 20% AA, 9% DTA, and 8% linoleic acid). After 5 wk this difference between the fish oil-fed and corn oil-fed mice was even more pronounced. Further small changes occurred at 5-9 wk. We studied the prostaglandin (PG) and thromboxane (TX) profile of macrophages prepared from mice fed the two diets just before being immunized with collagen. Irrespective of diet, macrophages prepared from female mice and incubated for 24 h had significantly more PG and TX in the medium than similarly prepared macrophages from male mice. The increased percentage of EPA and decreased percentage of AA in the phospholipids of the macrophages prepared from the fish oil-fed mice was reflected in a reduction in the amount of PGE2 and PGI2 in the medium relative to identically incubated macrophages prepared from corn oil-fed mice. When this same fish oil diet was fed to B10.RIII mice for 26 d before immunization with type II collagen, the time of onset of arthritis was increased, and the incidence and severity of arthritis was reduced compared to arthritis induced in corn oil-fed mice. The females, especially those on the fish oil diet, tended to have less arthritis than the males. These alterations in the fatty acid pool available for PG and leukotriene synthesis suggest a pivotal role for the macrophage and PG in the immune and/or inflammatory response to type II collagen.

Animals↗
PubMed1985

Alteration of the extracellular matrix of smooth muscle cells by ascorbate treatment.

The protein composition in the extracellular matrix of cultured neonatal rat aortic smooth muscle cells has been monitored over time in culture. The influence of ascorbate on insoluble elastin and collagen has been described. In the absence of ascorbate, the cells accumulate an insoluble elastin component which can account for as much as 50% of the total protein in the extracellular matrix. In the presence of ascorbate, the amount of insoluble collagen increases, while the insoluble elastin content is significantly less. When ascorbate conditions are varied at different times during the culture, the extracellular matrices are altered with respect to collagen and elastin ratios. The decrease in elastin accumulation in the presence of ascorbate may be explained by an overhydroxylation of tropoelastin. Approximately 1/3 of the prolyl residues in the soluble elastin fractions isolated from cultures grown in the presence of ascorbate are hydroxylated. Since the insoluble elastin accumulated in these cultures contain the unique lysine-derived cross-links in amounts comparable to aortic tissue, this culture system proves ideal for studying the influence of extracellular matrix elastin on cell growth and metabolism.

Amino Acids↗
PubMed1985

Aging effects on the elastin composition in the extracellular matrix of cultured rat aortic smooth muscle cells.

Elastin accumulation in the extracellular matrix of cultured rat aortic smooth muscle cells was monitored as a function of age. The effect of the animal donor age and time in culture in single or consecutive passages on the cells' ability to accumulate total protein as well as elastin was evaluated. Smooth muscle cells were obtained from animals ranging in age from 2 d to 36 mo. Protein accumulation by the cells based on DNA content was similar regardless of which of the above aging parameters was examined. Although there were significant amounts of elastin present in the extracellular matrix of those cells originating from the younger animals (2 d and 6 wk old), little or none was detected in cell cultures derived from the oldest animals. A soluble elastin-like fraction which was isolated from the cultures of the 2-d-old rats seemed to be lacking in the cultures of cells from the 36-mo-old animals. This observation may, in part, explain the absence of insoluble elastin in the matrix of some cultures obtained from older animals. The data strongly suggest that the age of the donor animal from which the cells originate has the greatest influence on in vitro elastin accumulation.

Amino Acids↗
PubMed1985

Pathogenesis of hepatic fibrosis in experimental iron overload.

Significant increases in prolyl hydroxylase activity, a key enzyme in the collagen biosynthetic pathway, were noted in the hepatic homogenates of iron-loaded animals as compared to controls. The increase in prolyl hydroxylase activity was seen without any light microscopic histologic evidence of cell necrosis or accumulation of collagen in the livers from the iron-loaded animals. However, utilizing electron microscopy, collagen fibrils were demonstrated immediately adjacent to the hepatocytes in the iron-loaded animals but not the controls. No fibroblasts or inflammatory cells were noted in this area. There was no evidence of damage to the subcellular organelles of the iron-loaded hepatocytes. The hydroxyproline content of the iron-loaded livers was also shown to be increased. These experimental studies in conjunction with clinical observations described below suggest that in vivo iron overload may have a primary effect on stimulating collagen synthesis by hepatocytes.

Animals↗
PubMed1985

Synthesis and turnover of protein-bound Nt-methylhistidine in cultured vascular smooth muscle cells.

Rabbit aortic smooth muscle cells cultured for 14 days in second passage produce significant amounts of protein-bound radioactive Nt-methylhistidine when pulsed with radiolabelled histidine. Much of the radioactive Nt-methylhistidine is located in the actin synthesized by these cells. Pulse chase data also suggest this newly synthesized Nt-methylhistidine disappears from the cell layer at two distinctly different rates: one with a half-life of 2.4 days, and the other with a half-life of approximately 17 days. Radioactive Nt-methylhistidine to histidine ratio reaches a maximum approximately 8 days following the 1-day [14C]histidine pulse. During the initial 15-day chase period, there is a substantial net accumulation of total Nt-methylhistidine in the culture flasks. The data presented in this communication indicate that methods to evaluate Nt-methylhistidine synthesis and disappearance in cultures are feasible when radiolabelled histidine is employed.

Actins↗
PubMed1985

Serum antielastase and neutrophil elastase levels in PiM phenotype cigarette smokers with airflow obstruction.

In order to assess blood factors which might explain why some cigarette smokers develop airflow obstruction while others do not, we compared two groups of PiM phenotype volunteers matched for age, sex and total pack-years of cigarette smoking; one group had airflow obstruction and the other did not. Functional levels of alpha-2-macroglobulin (alpha-2-M) and alpha-1-protease inhibitor (alpha-1-PI) were separately assessed by a protease binding procedure. Neutrophils were isolated from blood by counterflow centrifugation, and their elastase content was assayed with 3H-elastin-SDS (sodium dodecyl sulfate). The obstructed and nonobstructed groups were not different with respect to functional or immunoreactive levels of alpha-1-PI and alpha-2-M or elastase levels in their neutrophils. We do not find imbalances of circulating elastase or antielastase levels in PiM phenotype smokers with airflow obstruction.

Adult↗
PubMed1985

Effects of reperfusion after coronary artery occlusion on post-infarction scar tissue.

Early reperfusion after a coronary occlusion may reduce myocardial infarct size, but late reperfusion into necrotic myocardium may alter post-infarction healing. In rabbits, we compared 1- or 3-week-old scars resulting from permanent coronary occlusion to those resulting from a 1- or 3-hour occlusion followed by reperfusion. Reperfusion at 1 hour post-occlusion did not affect scar mechanical properties assessed at 1 week post-infarction, but at 3 weeks post-infarction, these scars had a tensile strength significantly lower than those not reperfused (78 +/- 11 vs. 158 +/- 15 g/mm2, P less than 0.001). They also were composed of a mixture of fibrous tissue (58 +/- 8%) and myocytes (43 +/- 8%) with a hydroxyproline content of 23 +/- 2.5 mg/g dry weight. The nonreperfused scars had a higher proportion of fibrous tissue (73 +/- 3%) by histological evaluation and a 35% higher hydroxyproline content (31 +/- 2 mg/g dry weight, P less than 0.001) than the scars reperfused after 1 hour. In contrast, 3-week-old scars resulting from "late" reperfusion at 3 hours post-occlusion were similar to nonreperfused scars in fibrous tissue composition and hydroxyproline content. Nonetheless, the tensile strength of these scars reperfused 3 hours post-occlusion was significantly less than that of the nonreperfused scars (72 +/- 5 vs. 158 +/- 15 g/mm2, P less than 0.001). The lower tensile strength was associated with a lower collagen cross-link density in this reperfused group of scars. At physiological stress levels (approximately 3 g/mm2), all groups of reperfused and nonreperfused scars had similar mechanical properties in terms of natural strain, stiffness, creep, and stress relaxation. Thus, although the reperfused scars ruptured more easily at high stresses, when assessed at physiological stresses their mechanical properties were not significantly different from those of nonreperfused scars.

Animals↗
PubMed1985

Effect of combined human neutrophil cathepsin G and elastase on induction of secretory cell metaplasia and emphysema in hamsters, with in vitro observations on elastolysis by these enzymes.

To determine whether purified human neutrophil cathepsin G (Cat-G) can act by itself or in concert with purified human neutrophil elastase (HNE) in the induction of emphysema and bronchial secretory cell metaplasia (SCM), we gave golden Syrian hamsters 100 micrograms of HNE alone or in combination with either 100 or 200 micrograms of Cat-G. Other groups of animals received intratracheal doses of up to 600 micrograms of Cat-G alone. The severity of emphysema was determined from measurements of lung volumes, compliance, forced expiratory flow, and the mean linear intercept. The severity of SCM in the main airways was graded on sections stained by the alcian blue and periodic acid-Schiff reaction. The Cat-G was a weak inducer of SCM; significant SCM was produced by 400 and 600 micrograms but not by 100 or 200 micrograms or 200 micrograms of Cat-G. The Cat-G (100 and 200 micrograms) did not potentiate the SCM induced by 100 micrograms of HNE. The Cat-G alone did not produce emphysema, and neither 100 nor 200 micrograms of Cat-G potentiated the mild emphysema induced by 100 micrograms of HNE. These results were not consonant with a report that Cat-G and HNE were synergistic in solubilizing human lung elastin. We therefore measured the ability of Cat-G and HNE to solubilize several radiolabeled elastins. The combination of Cat-G and HNE did not solubilize significantly more hamster lung elastin (23%) than the sum of their individual activities.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1985

Myeloperoxidase-induced inactivation of alpha 1-antiprotease in hamsters.

While numerous studies have demonstrated that the myeloperoxidase system found in neutrophils can oxidize and functionally inactivate alpha 1-proteinase inhibitor in vitro, there is little direct evidence that this phenomenon is relevant in vivo. Using incubation with tritiated porcine pancreatic elastase followed by column chromatography to quantitate binding, we demonstrated recovery of microgram amounts of functional alpha 1-protease inhibitor from bronchoalveolar lavage of hamster lungs. When exposed to the myeloperoxidase system in vitro, hamster alpha 1-protease inhibitor was 97% inactivated. Functional alpha 1-protease inhibitor recovered by bronchoalveolar lavage 20 minutes after hamsters were given intratracheal injections with myeloperoxidase and either hydrogen peroxide or glucose plus glucose oxidase was only half that recovered from control animals. These studies suggest that the myeloperoxidase system is effective in oxidizing alpha 1-protease inhibitor in vivo. They support the concept that oxidation of alpha 1-protease inhibitor by myeloperoxidase from neutrophil granules in the presence of H2O2 and halide may produce elastase-antielastase imbalance in vivo and contribute to the development of acute lung injury and emphysema in humans.

Animals↗
PubMed1984

Processing of procollagen types III and I in cultured bovine smooth muscle cells.

The processing of type III and type I procollagen molecules in cultured bovine aortic smooth muscle cells was investigated. The molecular identities of the processing intermediates of type III and type I procollagen were characterized by analysis of the radioactive collagenous components using mammalian collagenase and pepsin digestions and cyanogen bromide peptide mapping. The results indicate that the processed intermediates for procollagen type III and type I are their respective pC components. Although the processing pathways for both collagen types are the same, data from pulse-chase experiments suggest that the rates at which the processing occurs are different. Type I procollagen is processed more rapidly to its intermediate than is type III procollagen. The type I pC intermediate is almost completely processed to alpha-chains and a significant portion of these fully processed molecules remains in a soluble form even after 11 h. In the same time period, the type III pC intermediate is slowly converted to alpha-chains. Since beta-aminopropionitrile was not employed in these studies, significant accumulation of collagen chains into the insoluble extracellular matrix was observed during the chase period.

Animals↗
PubMed1984

The structure of the carbohydrate units of the carboxyl-terminal peptide of procollagen as elucidated by 500 MHz 1H-NMR spectroscopy.

The oligosaccharides of chick embryo type I procollagen were isolated from carboxyl-terminal propeptide fragment by exhaustive digestion with papain and pronase, and then purified as a mixture of glycopeptides. The structures of the oligosaccharides were established by high-resolution 1H-NMR spectroscopy and found to be a mixture with respect to the non-reducing terminal residues as shown below: (formula; see text) The percentages refer to the relative amount of those mannose residues present in the mixture. The data suggest that the oligosaccharides are a microheterogeneous mixture of high-mannose type glycans containing between six and nine mannose residues per carbohydrate unit. Such carbohydrate chains, although not uncommon for glycoproteins, had never been found before for collagen or collagen-related compounds.

Amino Acid Sequence↗
PubMed1984

Effect of varying amounts of ascorbate on collagen, elastin and lysyl oxidase synthesis in aortic smooth muscle cell cultures.

In the presence of ascorbate, there is an increase in collagen synthesis with a concomitant decrease in insoluble elastin and lysyl oxidase activity in cultured rabbit aortic smooth muscle cells. While the addition of 0.5 micrograms ascorbate per ml of medium enhances collagen synthesis and accumulation, detectable insoluble elastin and lysyl oxidase activity remain essentially unchanged. However, at 2 micrograms ascorbate per ml, the integrity of the insoluble elastin is lost and lysyl oxidase activity is decreased. These studies suggest that by modifying the levels of ascorbate in the culture medium one can alter the nature of the extracellular matrix produced by the smooth muscle cells.

Amino Acid Oxidoreductases↗
PubMed1984

Changes in the connective tissue proteins, glycosaminoglycans and calcium in the arteries of the cynomolgus monkey during atherosclerotic induction and regression.

The chemical composition of the aorta, carotid, coronary and cerebral arteries of the cynomolgus monkey was determined during the induction and 'regression' of atherosclerosis. The feeding of a 2% cholesterol and 10% butter diet for 6 months resulted in extensive and severe atherosclerosis involving the aorta, carotid and coronary arteries. The involvement of these vessels was reflected by increases in arterial weight and chemical content of cholesterol, collagen, elastin, glycosaminoglycans (GAGs) and calcium. The cerebral arteries, which showed no atherosclerotic involvement, likewise showed no significant changes in weight and composition. During the 12-month regression period marked changes in the chemical composition of the involved arteries occurred and these included further increases in the collagen, GAG and calcium content of the vessels and decreases in the free and esterified cholesterol content. These changes were consistent with the gross and microscopic findings which revealed that during regression the pre-established lesions had not decreased in size but had become more fibrotic and calcified while the number of foam cells and amount of lipid contained in the lesion had decreased. During induction and regression, much of the cholesterol contained in the involved vessels appeared to be present in a crystalline form as indicated by the appearance of cholesterol clefts in the lesions. Aortic collagen was not altered with respect to amino acid composition and behavior in acrylamide gels throughout the study. However, elastin prepared by hot alkali treatment from diseased vessels, showed minor changes in amino acids during induction and marked changes during regression presumably due to the binding of glycoproteins to the elastin. The GAG composition of the involved arteries did not change during induction, whereas during regression the percent dermatan sulfate increased while the percent of heparan sulfate decreased. The over-all findings are consistent with the concept that the interaction of the connective tissue proteins with the GAGs, lipoproteins and calcium of the artery plays an important role in the development and regression of advanced atherosclerotic disease.

Animals↗
PubMed1984

Ultrastructural studies of attachment site formation in aortic smooth muscle cells cultured on collagen-hydroxyethylmethacrylate hydrogels.

Hydroxyethylmethacrylate (HEMA) hydrogels have a peculiar crater-like topography which renders them ideal for studying cell-to-substrate contact formation. The hydrogel is quite suitable for such studies since it is transparent, which allows for light microscopic observations, it is not toxic, and it will support cell growth only when an additional protein component such as collagen is integrated into its surface. Cultured rabbit aortic smooth muscle cells (SMC) were grown on collagen-HEMA hydrogels, and the ultrastructure of developing cell attachment sites was studied. By 3 hr after cell seeding, both the rounded and the spreading SMC appeared anchored to the hydrogel via extracellular connective tissue-like material. The fully formed attachment site present at 5-8 days was characterized by large bundles of intracellular myofilaments inserting onto areas of increased electron density along the plasmalemmal membrane; large amounts of extracellular connective tissue-like material also appeared attached to the areas of increased electron density. Fully formed cell substratum attachment sites were not observed when either elastin-HEMA hydrogels or hydrogels polymerized in the absence of protein were employed.

Actin Cytoskeleton↗
PubMed1984

Emphysema and bronchial secretory cell metaplasia induced in hamsters by human neutrophil products.

Purified human neutrophil elastase (HNE) and a crude extract of human neutrophils (EXT) were administered intratracheally to hamsters, and their effects were determined 21 and 56 days later by measurement of lung statics and dynamics and by light microscopy and morphometry of the lungs. A dose of 450 micrograms of HNE (HNE 450) produced focal emphysema of moderate severity. The combination of HNE 450 and EXT (HNE 450 + EXT) produced no more severe emphysema than HNE 450 alone; EXT alone did not produce emphysema. The HNE 450, HNE 450 + EXT, and EXT all produced persistent secretory cell metaplasia in large intrapulmonary airways. In a second experiment, 40 micrograms of HNE (elastolytic activity equivalent to that in EXT), designated HNE 40, did not produce secretory cell metaplasia. Neither EXT nor EXT treated with the elastase inhibitor suc-ala-ala-pro-val chloromethyl ketone (EXT + CMK), which had a residual elastolytic activity equivalent to 15 micrograms of HNE, produced emphysema; both preparations caused bronchial secretory cell metaplasia 21 days after treatment. Values of maximal expiratory flow, measured 21 days after treatment, were reduced at points between 20 and 50% of vital capacity for HNE 450 and between 30 and 80% of vital capacity for HNE 450 + EXT; maximal expiratory flows were not significantly different from saline controls for HNE 40, EXT, or EXT + CMK.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1984

Alveolar macrophage modulation of proteolysis by neutrophil elastase in extracellular matrix.

An extracellular connective tissue matrix, made up of components found in the pulmonary alveolar interstitium, was generated in vitro and used as a culture surface and substrate for proteolysis by human alveolar macrophages (AM) and neutrophil elastase (NE). The ability of human AM to modulate NE-mediated degradation of elastin and collagen in the surrounding matrix was studied to gain insights into the inflammatory process that accompanies the pathogenesis of emphysema in humans. Neutrophil elastase that had been internalized by AM showed a diminished but more prolonged time course of matrix proteolysis than did a similar amount of NE added to the matrix in the absence of AM. Collagen and elastin degradation were quantitated by release of hydroxylysine and desmosine, respectively, into the culture medium. Significantly more hydroxylysine and desmosine were released by AM that had internalized NE than by AM or by culture medium alone. When 14 X 10(6) AM were added to the extracellular matrix, followed 2 h later by addition of 2 micrograms of NE, collagen and elastin degradation measured at 24 h were not significantly different from that which occurred when matrix was incubated with NE in the absence of AM. Collagen degradation, determined in the same cultures during the period from 24 to 96 h, was significantly greater when matrix was incubated with both AM and NE. These findings suggest that AM can release previously internalized NE in an enzymatically active form and that AM may enhance collagen degradation in matrix that was also exposed to NE.

Animals↗