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PubMed1983

The effect of a vitamin B-6 antagonist, 4-deoxypyridoxine, on the cross-linking of collagen in the developing chick embryo.

The vitamin B-6 antimetabolite 4-deoxypyridoxine, when injected into 13-day chick embryos, has the effect of increasing the amount of collagen solubilized from the leg bones by buffered saline solutions, 24 h after the injection. This effect is similar to, but less marked than, that produced by the administration of the lathyrogen beta-amino-propionitrile. Since that fraction of the total collagen which is solubilized by saline represents the least-cross-linked pool, it is concluded that 4-deoxypyridoxine is a lathyrogen, decreasing the cross-linking in the developing embryo, and confirming the importance of vitamin B-6 in that process. Lysyl oxidase, the cross-linking enzyme, was measured in extracts made from the epiphysial cartilages of embryos 24 h after the injection of either 4-deoxypyridoxine or beta-aminopropionitrile. The injection of 5 mg of beta-aminopropionitrile causes the lysyl oxidase activity to fall to 61% of that of saline-injected controls; after treatment with 4-deoxypyridoxine, the activity is 74% of the control value. In the latter case, full activity is not restored to the extracts by preincubation with pyridoxal phosphate. The results are discussed in relation to the early development of the connective tissues.

Aminopropionitrile↗
PubMed1985

Assembly of chick and bovine lens-capsule collagen.

Chick-embryo and adult bovine lens-capsular epithelia in organ culture synthesized 4-hydroxy[3H]proline-containing polypeptides when incubated in the presence of [3H]proline. These collagenous polypeptides of apparent Mr 180 000, 175 000 and 160 000 became incorporated with time into aggregates of higher molecular size. The formation of such aggregates was inhibited when the tissues were labelled in the presence of beta-aminopropionitrile, thereby implicating lysine-derived cross-links in aggregate formation. When the tissues were incubated in the presence of tunicamycin, the collagenous polypeptides synthesized exhibited increased electrophoretic mobilities on sodium dodecyl sulphate/polyacrylamide-gel electrophoresis. The addition to lens-capsule incubation medium of alpha alpha'-bipyridine led to the synthesis of underhydroxylated type IV collagen, also of increased electrophoretic mobility. Extended pulse-chase experiments indicated that such underhydroxylated collagen did not participate in aggregate formation, but was at least as stable as fully hydroxylated non-cross-linked collagen synthesized in the presence of beta-aminopropionitrile. Native type IV collagen, recovered from the culture medium when capsules were incubated with [3H]proline for 24h, was purified by ion-exchange chromatography. Separations conducted on CM-cellulose under denaturing and nondenaturing conditions suggested that the alpha 1(IV) and alpha 2(IV) chains occur in the same heterologous triple helix. Densitometric analyses of appropriate fluorograms indicated that these two polypeptides occur in a 2:1 ratio, suggesting that lens-capsule collagen is synthesized as a triple-helical molecule of composition [alpha 1(IV)]2 alpha 2(IV).

2,2'-Dipyridyl↗
PubMed1978

Peptide excretion in experimental Fanconi syndrome in the rat.

A study has been made of urinary peptide output in rats before and after production of a Fanconi syndrome induced by a single injection of sodium maleate. There was an unequivocal increase of urinary peptides on the first and second days after the injection, without any detectable change in the concentration of plasma peptides. 2. Similar results were obtained in osteolathyritic rats in which skeletal lesions had been produced by ingestion of beta-aminopropionitrile. 3. The fractional amino acid content of urinary peptides after maleate and beta-aminopropionitrile is shown to be significantly different from that in control animals. 4. Evidence is presented that the increased output of peptides is mainly due to increased renal clearance similar to that previously described for amino acids, glucose and several electrolytes in this type of experimental Fanconi syndrome.

Aminopropionitrile↗
PubMedDate not supplied

Animal model of cerebral aneurysms: pathology and pathogenesis of induced cerebral aneurysms in rats.

Saccular cerebral aneurysms are induced in rats treated with ligation of one or both of the common carotid arteries, experimental hypertension, and beta-aminopropionitrile feeding. Combination of ligation of the carotid artery and experimental hypertension is the minimal requirement for inducing aneurysms within a few months. beta-aminopropionitrile makes the arterial wall fragile, increasing the incidence of aneurysmal development. Induced aneurysms are strongly related to haemodynamic stresses. They are located on the large arteries at the base of the brain. Some of them apparently originate from the apex of bifurcation. The macroscopic and microscopic findings are generally in accordance with those of spontaneous lesions in man. The results of electron microscope and histochemical studies indicate the participation of leukocytes and their lysosomal enzymes in the development and growth of aneurysms. Adventitial cells are also suggested to be responsible for the growth of aneurysms.

Aminopropionitrile↗
PubMed1976

The smooth muscle cell. III. Elastin synthesis in arterial smooth muscle cell culture.

Primate arterial smooth muscle cells and skin fibroblasts were examined for their ability to synthesize elastin in culture. In the presence of the lathyrogen beta-aminopropionitrile, the smooth muscle cells incorporate [3H]lysine into a lysyl oxidase substrate that was present in the medium and associated with the cell layer. A component having a mol wt of 72,000 and an electrophoretic mobility similar to that of authentic tropoelastin was isolated from the labeled smooth muscle cells by coacervation and fractionation with organic solvents. In the absence of beta-aminopropionitrile, long-term cultures of smooth muscle cells incorporated [14C]lysine into desmosine and isodesmosine, the cross-link amino acids unique to elastin. In contrast, no desmosine formation occurred in the fibroblast cultures. These characteristics demonstrate that arterial smooth muscle cells are capable of synthesizing both soluble and cross-lined elastin in culture.

Aminopropionitrile↗
PubMed1961

The lathyrogenic effect of isonicotinic acid hydrazide (INAH) on the chick embryo and its reversal by pyridoxal.

When applied to the chorio-allantoic membrane of the chick embryo, isoniazid was shown to produce an increase in the fragility of the embryo and in the amount of collagen which was extractable from the bones with cold 1 M sodium chloride. The administration of pyridoxal reversed these phenomena almost completely. The effect of isoniazid differed from that of beta-aminopropionitrile in that the latter was of greater magnitude, and was not affected by pyridoxal; whereas beta-aminopropionitrile caused skeletal deformities, isoniazid even at 12 times the concentration produced no deformities. The aldehyde group of pyridoxal was shown to be necessary for its interaction with isoniazid.

Aminopropionitrile↗
PubMed1994

Cell-extracellular matrix interactions under in vivo conditions during interstitial cell migration in Hydra vulgaris.

Interstitial cell (I-cell) migration in hydra is essential for establishment of the regional cell differentiation pattern in the organism. All previous in vivo studies have indicated that cell migration in hydra is a result of cell-cell interactions and chemotaxic gradients. Recently, in vitro cell adhesion studies indicated that isolated nematocytes could bind to substrata coated with isolated hydra mesoglea, fibronectin and type IV collagen. Under these conditions, nematocytes could be observed to migrate on some of these extracellular matrix components. By modifying previously described hydra grafting techniques, two procedures were developed to test specifically the role of extracellular matrix components during in vivo I-cell migration in hydra. In one approach, the extracellular matrix structure of the apical half of the hydra graft was perturbed using beta-aminopropionitrile and beta-xyloside. In the second approach, grafts were treated with fibronectin, RGDS synthetic peptide and antibody to fibronectin after grafting was performed. In both cases, I-cell migration from the basal half to the apical half of the grafts was quantitatively analyzed. Statistical analysis indicated that beta-aminopropionitrile, fibronectin, RGDS synthetic peptide and antibody to fibronectin all were inhibitory to I-cell migration as compared to their respective controls. beta-xyloside treatment had no effect on interstitial cell migration. These results indicate the potential importance of cell-extracellular matrix interactions during in vivo I-cell migration in hydra.

Aminopropionitrile↗
PubMed2002

A molecular role for lysyl oxidase in breast cancer invasion.

We identified previously an up-regulation in lysyl oxidase (LOX) expression,an extracellular matrix remodeling enzyme, in a highly invasive/metastatic human breast cancer cell line, MDA-MB-231, compared with MCF-7, a poorly invasive/nonmetastatic breast cancer cell line. In this study, we demonstrate that the mRNA expression of LOX and other LOX family members [lysyl oxidase-like (LOXL), LOXL2, LOXL3, and LOXL4] was observed only in breast cancer cells with a highly invasive/metastatic phenotype but not in poorly invasive/nonmetastatic breast cancer cells. LOX and LOXL2 showed the strongest association with invasive potential in both highly invasive/metastatic breast cancer cell lines tested (MDA-MB-231 and Hs578T). To determine whether LOX is directly involved in breast cancer invasion, LOX antisense oligonucleotides were transfected into MDA-MB-231 and Hs578T cells, and found to inhibit invasion through a collagen IV/laminin/gelatin matrix in vitro compared with LOX sense oligonucleotide-treated and untreated controls. In addition, treatment of MDA-MB-231 and Hs578T cells with beta-aminopropionitrile (an irreversible inhibitor of LOX enzymatic activity) decreased invasive activity. Conversely, MCF-7 cells transfected with the murine LOX gene demonstrated a 2-fold increase in invasiveness that was reversible by the addition of beta-aminopropionitrile in a dose-dependent manner. In addition, endogenous LOX mRNA expression was induced when MCF-7 cells were cultured in the presence of fibroblast conditioned medium or conditioned matrix, suggesting a role for stromal fibroblasts in LOX regulation in breast cancer cells. Moreover, the correlation of LOX up-regulation and invasive/metastatic potential was additionally demonstrated in rat prostatic tumor cell lines, and human cutaneous and uveal melanoma cell lines. These results provide substantial new evidence that LOX is involved in cancer cell invasion.

Aminopropionitrile↗
PubMed1979

Experimentally induced cerebral aneurysms in rats: part II.

An experimental condition that permits easy inducement of cerebral aneurysms in rats is reported. Previously, we demonstrated that saccular cerebral aneurysms were inducible in experimental animals and suggested that adult rats might be more preferable for inducing the lesion. Therefore, a longer-term study was performed intending to increase the incidence of cerebral aneurysms, using only adult rats. Adult rats were treated with ligation of one common carotid arter, deoxycorticosterone and salt hypertension, and beta-aminopropionitrile. Cerebral aneurysms developed in eleven of 30 rats which died 11-21 weeks after the start of the beta-aminopropionitrile feeding. All aneurysms were located on the anterior cerebral-anterior communicating arterial complex. Contributory mechanisms are discussed.

Aminopropionitrile↗
PubMed1978

Experimentally induced cerebral aneurysms in rats.

Saccular cerebral aneurysms were successfully induced in rats treated with beta-aminopropionitrile, deoxycorticosterone and salt hypertension and ligation of unilateral common carotid artery. This experiment was performed on the hypothesis that if hemodynamic stresses were increased on the fragile, cerebral arterial wall of beta-aminopropionitrile-fed animals, cerebral aneurysms might be produced. Although the incidence of cerebral aneurysms was low and the contributory mechanisms of these procedures must be more clearly elucidated, the present results show that saccular cerebral aneurysms are really inducible in experimental animals.

Aminopropionitrile↗
PubMed1977

The synthesis and chromatography of peptine nitriles.

Di- and tripeptide nitriles, glycylaminoacetonitrile (Gly-AAN), diglycylaminoacetonitrile (Gly-Gly-AAN), alany-alpha-aminopropionitrile (Ala-APN), and dialanyl-alpha-aminopropionitrile (Ala-Ala-APN) were synthesized first. These peptide nitriles and related peptides and peptide amides were analyzed by means of ion-exchange chromatography. The every two diastereomers of dialanine, dialanine amide, and Ala-APN were separated into two peaks by using a pH 3.25 buffer as an eluent. The four isomers of trialanine, trialanine amide, and Ala--Ala APN gave four, two, and one peak, respectively under the same conditions. The trimethylsilyl derivatives of alanyl peptides and related compounds were analyzed by means of gas chromatogrpahy combined with mass-spectrometry. The parent (M+ and/or M+-15) and other mass numbers observed in their mass-spectra supported the introduction of various numbers of trimethylsilyl groups.

Chromatography, Gas↗
PubMed1991

Mechanism of insulin incorporation into alpha 2-macroglobulin: implications for the study of peptide and growth factor binding.

In recent years, many studies have suggested a direct role for alpha 2-macroglobulin (alpha 2M), a plasma proteinase inhibitor, in growth factor regulation. When coincubated in the presence of either trypsin, pancreatic elastase, human neutrophil elastase, or plasmin, 125I-insulin rapidly formed a complex with alpha 2M which was greater than 80% covalent. The covalent binding was stable to reduction but abolished by competition with beta-aminopropionitrile. Neither native alpha 2M nor alpha 2M pretreated with proteinase or methylamine incorporated 125I-insulin. Experiments utilizing alpha 2M cross-linked with cis-dichlorodiammineplatinum(II) indicated that 125I-insulin must be present during alpha 2M conformational change to covalently bind. A maximum stoichiometry of 4 mol of insulin bound per mole of alpha 2M and the short half-life of the alpha 2M intermediate capable of covalent incorporation were consistent with thiol ester involvement. Protein sequence analysis of unlabeled insulin-alpha 2M complexes, together with results of beta-aminopropionitrile competition, confirmed that insulin incorporation occurs via the same gamma-glutamyl amide linkage responsible for covalent proteinase and methylamine binding to alpha 2M. Although intact insulin apparently incorporated through its sole lysine residue on the B chain, we found that isolated A chain also bound covalently to alpha 2M. Phenyl isothiocyanate derivatization of the N-terminus had no effect on A-chain binding, supporting the possibility of heretofore unreported gamma-glutamyl ester linkages to alpha 2M.

Binding Sites↗
PubMed1992

The human rhabdomyosarcoma cell line A204 lays down a highly insoluble matrix composed mainly of alpha 1 type-XI and alpha 2 type-V collagen chains.

The biosynthesis of collagen by the A204 cell line was examined using polyclonal antibodies raised against collagen type V and type XI. The study of the pepsin-digested collagen showed that it is composed mainly of alpha 1(XI) and alpha 2(V) collagen chains in an apparent 2:1 ratio, suggesting the formation of heterotypic molecules [alpha 1(XI)]2 alpha 2(V). The existence of this chain stoichiometry was further demonstrated by immunoprecipitation of the molecule with an antibody recognizing alpha 2(V) but not alpha 1(XI) collagen chains. Electron microscopy analyses of 24-h cultures showed that this matrix is composed of thin fibrils, that can be decorated with immunogold-labelled anti-(type-V collagen) IgG, but not with anti-(type-XI collagen) IgG. The collagen matrix laid down by A204 cells is highly insoluble. In the presence of beta-aminopropionitrile, an inhibitor of lysyl oxidase, only a small proportion of intact collagen could be extracted without proteolytic treatment. Immunoblotting of intact medium collagen from cultures performed in the presence of beta-aminopropionitrile showed four distinct bands with each antibody. The migration of the bands, stained with anti-(type-V collagen) IgG, had apparent molecular masses of 127, 149, 161 and 198 kDa (compared to globular standards) while the bands stained with anti-(type-XI collagen) IgG had apparent masses of 145, 182, 207 and 225 kDa. These data indicate that type-V and type-XI collagen chains can assemble in heterotypic isoforms. In this system, the synthesized isoforms are able to aggregate into a highly cohesive matrix and they undergo a proteolytic processing closely similar to that of other fibrillar collagens.

Blotting, Western↗
PubMed2004

Tropoelastin inhibits vascular calcification via 67-kDa elastin binding protein in cultured bovine aortic smooth muscle cells.

In cases of vascular calcification, the expression of tropoelastin is down-regulated, which most likely decreases elastic fiber formation. However, the function of tropoelastin in vascular calcification remains unknown. We investigated whether tropoelastin affects the induction of vascular calcification. Calcification was induced using inorganic phosphate in cultured bovine aortic smooth muscle cells. The increase in tropoelastin due to the addition of recombinant bovine tropoelastin (ReBTE; 1 or 10 microg/ml) or beta-aminopropionitrile (25 microg/ml) significantly inhibited calcification at day 6, as assessed by the o-cresolphthalein complexone method. The addition of an elastin-derived peptide, VGVAPG peptide (0.1-1,000 nM), inhibited calcification at day 6 in a dose-dependent manner. In addition, these responses of beta-aminopropionitrile, ReBTE, and VGVAPG peptide were confirmed using von Kossa staining. To examine whether ReBTE inhibited calcium deposition via the elastin binding protein, lactose and elastin-specific antibody were used. The combination of lactose (20 mM) or this antibody (50 microg/ml) with ReBTE (10 microg/ml) attenuated the inhibition of calcification. These results suggest that increased tropoelastin inhibits vascular calcification in this model via the interaction between tropoelastin and elastin binding protein.

Animals↗
PubMed1996

Increased vascular collagen and noncollagenous protein synthesis contributes to sustain chronic phase of two-kidney, one-clip renovascular hypertension.

PURPOSE: Although the enhanced renin-angiotensin (R-A) system responsible for two-kidney, one-clip (2K-1C) hypertension is well known, there may be a shift with time so that this, hemodynamic factor plays a less important role and increased vascular resistance is predominant in sustaining hypertension. While increased vascular protein synthesis has been demonstrated in genetically hypertensive rats, we evaluated the possible relationship between vascular protein synthesis and 2K-1C hypertension with special reference to the R-A system. MATERIALS AND METHODS: Two-kidney one-clip rats were treated with splanchnicotomy, beta-aminopropionitrile (collagen inhibitor), or captopril (angiotensin converting enzyme inhibitor) in the acute or chronic hypertensive phase. 3H-proline was injected into rats, and incorporation rates of 3H-proline into vascular collagen, noncollagenous protein and elastin were counted. The plasma level of the R-A system was assayed. RESULTS: In the acute phase of 2K-1C hypertensive rats whose R-A system was enhanced, captopril treatment further enhanced plasma renin activity and plasma angiotensin I and suppressed plasma angiotensin II while reducing blood pressure. Synthesis of the vascular proteins was almost identical. In the chronic phase of 2K-1C hypertensive rats whose R-A system was within normal limits, increased incorporation rates of 3H-proline into noncollagenous protein or collagen of mesenteric arteries were decreased by splanchnicotomy or beta-aminopropionitrile and hypertension was lowered. Captopril failed to reduce protein synthesis. CONCLUSIONS: An enhanced R-A system participates in the pathogenesis of the acute phase of 2K-1C hypertension while increased noncollagenous protein and collagen syntheses of small arteries appear to play some role in the etiology of the chronic phase of hypertension.

Acute Disease↗
PubMed1964

EXPERIMENTAL LATHYRISM. AN AUTORADIOGRAPHIC STUDY.

In normal and lathyritic chick embryos bone collagen was synthesized primarily in the periosteum of the femurs, and was organized as radioactive spicules in these bones. Saline extraction of the lathyritic bones removed the radioactive spicules, although they eventually seemed to become non-extractable. Normal bone seemed to be unaffected by saline extraction. Marked variation in the degree of isotope incorporation was seen in collagenous and non-collagenous tissues. All the tissues of any one embryo, however, showed a similar degree of isotope incorporation. Tritiated beta-aminopropionitrile was diffusely distributed throughout bone and was completely removed by saline extraction. This autoradiographic study supports the postulate that a portion of extractable lathyritic collagen is recently synthesized and is organized in fibrous structures in bone.

Aminopropionitrile↗
PubMed1981

Control of wound healing and scar formation in surgical patients.

Research in wound-healing biology has reached the developmental or practical application stage in the following major areas: reduction of liver collagen, prevention of secondary remodeling of peritoneal fibrous adhesions to produce tendinous bands that cause mechanical intestinal obstruction, reduction in the amount of scar tissue on the surface of the skin, alteration of mechanical properties of restricting a scar on gliding surfaces, and prevention of conduit stenosis after a circumferential internal injury. Pharmacologic agents, such as beta-aminopropionitrile, penicillamine, and colchicine, are being used as adjuvants to familiar surgical techniques. Control of collagen deposition and collagenolysis in the eye, lung, kidney, and around joints that are affected by rheumatoid arthritis will be possible in the next few years.

Adolescent↗
PubMed1997

Evidence of osteolathyrism among patients suffering from neurolathyrism in Bangladesh.

In a study of 500 patients suffering from neurolathyrism in Bangladesh it was found that 60 (all male) complained of bone pain and showed skeletal deformities suggestive of osteolathyrism. On X-ray examination a failure of fusion in both vertebral and iliac epiphyses was found in two patients. At the age of these patients (30 and 37 years) such failure was considered a clear evidence of osteolathyrism. All 60 patients were accustomed to eating the green parts of Lathyrus sativus, which contain 2-cyanoethyl-isoxazolin-5-one, a compound that chemically and metabolically can produce the osteolathyrogen beta-aminopropionitrile (BAPN), as well as foods made from the seeds of the same plant which contain the neurotoxin 3-N-oxalyl-2,3-diaminopropanoic acid (beta-ODAP).

Adult↗