Biomedical subjects

S Kawashima

Publications and source records attributed to S Kawashima.

At least 19 recordsLinked to original sources

PubMed2001

Serotonin-induced hypercontraction through 5-hydroxytryptamine 1B receptors in atherosclerotic rabbit coronary arteries.

BACKGROUND: Augmented vasoconstriction to serotonin (5-hydroxytryptamine [5-HT]) in atherosclerotic vessels plays a crucial role in the development of myocardial ischemia. We investigated mechanisms for serotonin-evoked hypercontraction in atherosclerotic rabbit coronary arteries. METHODS AND RESULTS: Contractile responses to serotonergic agents of endothelium-denuded coronary arteries from control and Watanabe heritable hyperlipidemic rabbits (WHHL) were examined. WHHL coronary arteries exhibited hypercontraction to 5-HT(1)-receptor agonists; the constrictor threshold concentrations and E:D(50) to serotonin, 5-carboxamidotryptamine, and sumatriptan in WHHL were significantly lower, and the E:(max) in WHHL to these agents were increased 55% to 59% above those of the control. Serotonin-evoked contractions in both groups were inhibited by GR127935 (5-HT(1B/1D) antagonist; 0.1 to 1 nmol/L) and pertussis toxin but not by ketanserin (5-HT(2) antagonist; 0.01 to 1 micromol/L), suggesting that the hypercontraction is most likely mediated by 5-HT(1B/1D) receptors through a pertussis toxin-sensitive pathway. Furthermore, simultaneous measurements of [Ca(2+)](i) and isometric tension of fura-2-loaded arteries revealed that the hypercontraction was concomitant with the augmented elevation of [Ca(2+)](i) in the smooth muscle. The 5-HT(1B) mRNA levels in WHHL coronary arteries increased to 2.5-fold over those in control arteries, whereas neither 5-HT(1D) nor 5-HT(2A) mRNA was detected in either group. CONCLUSIONS: Atherosclerotic rabbit coronary arteries exhibited the enhancement in contraction and Ca(2+) mobilization in response to serotonin. The 5-HT(1B) receptor, which is upregulated by atherosclerosis, most likely mediates the augmenting effects of serotonin.

Animals↗

PubMed2001

Effects of amyloid-beta-(25-35) on passive avoidance, radial-arm maze learning and choline acetyltransferase activity in the rat.

To investigate the neurotoxicity of amyloid-beta-(25-35), which is thought to be the active site of amyloid-beta, the peptide was injected into the lateral ventricle of rats. A single intracerebroventricular (i.c.v.) injection of amyloid-beta-(25-35) at a dose of 15 nmol/rat induced a marked decrease in latency in step-through passive avoidance task. Amyloid-beta-(35-25), reverse sequence of amyloid-beta-(25-35), was without harmful effects on passive avoidance performance. The amyloid-beta-(25-35) at a dose of 5 or 15 nmol/rat impaired radial-arm maze performance, and induced a decrease in choline acetyltransferase activity in the medial septum, cortex and hippocampus, but not in the basal forebrain. The number of choline acetyltransferase-immunoreactive cells in the medial septum was decreased, in conformity with the decrease in choline acetyltransferase activity of the area. These results suggest that learning and cognitive disturbance induced by i.c.v. injection of amyloid-beta-(25-35) is associated with the dysfunction of cholinergic neuronal system in the brain.

Amyloid beta-Peptides↗

PubMed2001

Synergistic potentiation of thiazolidinedione-induced ST 13 preadipocyte differentiation by RAR synergists.

Peroxisome proliferator-activated receptor gamma (PPAR gamma) belongs to a nuclear receptor super family that functions as a master regulator of adipocyte differentiation. PPAR gamma binds its DNA response element together with a partner, retinoid X receptor (RXR), in fat cells. Five RXR ligands (HX600, HX630, DA022, DA124, LGD1069, referred to as retinoid synergists) by themselves exhibit weak transactivation activity on the PPAR gamma response element. However, addition of PPAR gamma-specific ligand in this assay gave rise to a 5- to 13-fold increase, indicating a strong synergy between these ligands. LGD1069 was the most effective activator of the RXR/PPAR gamma heterodimer on the transactivation of the reporter gene. But, in contrast to the other four RXR ligands, LGD1069 did not show synergistic induction of ST 13 preadipocytes to adipocytes. This apparent contradiction may result from the ligand-binding property of LGD1069. In this article we discuss the fact that retinoid synergists also act as PPAR gamma synergists.

Adipocytes↗

PubMed2001

Inclusion body myositis: expression of extracellular signal-regulated kinase and its substrate.

OBJECTIVE: To assess abnormal intracellular signal transduction in inclusion body myositis (IBM). BACKGROUND: Mitogen-activated protein kinases (MAPKs) play pivotal roles in intracellular signal transduction and regulate cell growth and differentiation. Upon their activation, MAPKs translocate from the cytoplasm into the nucleus. DESIGN/METHODS: The authors investigated the localization of several forms of the MAPK family-extracellular signal-regulated kinase (ERK), c-Jun N-terminal protein kinase (JNK), and p38 MAPK (p38)-in 10 patients with sporadic IBM and in 52 control subjects. The relationship between the localization of immunopositive deposits and nuclei was tested with bis-benzimide. RESULTS: Vacuolated fibers in IBM displayed very strong focal immunoreactivity of ERK, but not of JNK or p38. The ERK-positive deposits in these vacuolated fibers colocalized with the nuclear substrate of ERK, Elk-1. ERK- and Elk-1-positive deposits were located frequently on the surface of the nuclei in vacuolated fibers in IBM. Similar findings to those of sporadic IBM were observed in three patients with distal myopathy with rimmed vacuoles, but not in eight normal or the other 41 disease controls. CONCLUSION: There is evidence for impaired molecular transport to the nucleus from the cytoplasm in the vacuolated fibers in IBM. This could be due to cytoplasmic aggregation of ERK and Elk-1 or to abnormal nuclear pore machinery involved in the transport of ERK and its substrate upon ERK activation.

Adult↗

PubMed2001

Regulation of tight junction permeability and occludin phosphorylation by Rhoa-p160ROCK-dependent and -independent mechanisms.

In epithelial and endothelial cells, tight junctions regulate the paracellular permeability of ions and proteins. Disruption of tight junctions by inflammation is often associated with tissue edema, but regulatory mechanisms are not fully understood. Using ECV304 cells as a model system, lysophosphatidic acid and histamine were found to increase the paracellular permeability of the tracer horseradish peroxidase. Cytoskeletal changes induced by these agents included stimulation of stress fiber formation and myosin light chain phosphorylation. Additionally, occludin, a tight junction protein, was a target for signaling events triggered by lysophosphatidic acid and histamine, events that resulted in its phosphorylation. A dominant-negative mutant of RhoA, RhoA T19N, or a specific inhibitor of Rho-activated kinases, Y-27632, prevented stress fiber formation, myosin light chain phosphorylation, occludin phosphorylation, and the increase in tracer flux in response to lysophosphatidic acid. In contrast, although RhoA T19N and Y-27632 blocked the cytoskeletal events induced by histamine, they had no effect on the stimulation of occludin phosphorylation or increased tracer flux, indicating that occludin phosphorylation may regulate tight junction permeability independently of cytoskeletal events. Thus, occludin is a target for receptor-initiated signaling events regulating its phosphorylation, and this phosphorylation may be a key regulator of tight junction permeability.

Actins↗

PubMed2001

Signaling mechanism underlying COX-2 induction by lysophosphatidylcholine.

Lysophosphatidylcholine, a component of oxidized low density lipoprotein, is critical for pathological conditions including atherosclerosis. However, the signaling mechanism of lysophosphatidylcholine remains poorly understood. Here we reported that lysophosphatidylcholine induces phosphorylation of p38 and the transcription factors, CREB and ATF-1 with concomitant up-regulation of cyclooxygenase-2 expression in cultured vascular endothelial cells. Lysophosphatidylcholine induced p38 phosphorylation in a time- and concentration-dependent manner partly via pathway depending on protein tyrosine kinase. Both lysophosphatidylcholine-stimulated phosphorylation of CREB and ATF-1 and lysophosphatidylcholine-increased expression of cyclooxygenase-2 mRNA and protein were effectively inhibited by a combination of SB203580 and PD98059, specific inhibitors of p38 and MEK1, respectively, as well as Ro31-8220 and H89, potent inhibitors of MSK1. These results suggest that both p38 and ERK may function as upstream signaling pathways capable of activating CREB and ATF-1 with subsequent induction of cyclooxygenase-2 expression by lysophosphatidylcholine.

Activating Transcription Factor 1↗

PubMed2001

On- and off-responses of the photopic electroretinograms in X-linked juvenile retinoschisis.

PURPOSE: To examine the physiologic condition of the middle retinal layer of patients with X-linked juvenile retinoschisis (xlRS) by studying the on- and off-responses of the photopic electroretinograms (ERGs). METHODS: Eleven unrelated Japanese men (mean age; 24.9 +/- 7.6 years) who were clinically diagnosed with xlRS and molecularly confirmed as having XLRS1 mutations were investigated. For the photopic ERGs, the a-, b- and d-wave amplitudes elicited by long duration stimuli were recorded, and the responses from the xlRS patients were compared to those recorded from normal subjects (n = 14, mean age, 27.5 +/- 4.5 years). We also examined the relationship between the photopic ERG responses and the genotype. RESULTS: No significant difference was found between the a- and d-wave amplitudes in the xlRS patients (34.2 +/- 8.7 microV, 52.5 +/- 10.4 microV, respectively), and those in normal subjects (40.4 +/- 10.3 microV, 44.7 +/- 6.3 microV, respectively). The mean b-wave amplitude in the xlRS patients was significantly smaller (10.5 +/- 7.7 microV) than the mean of normal subjects (46.4 +/- 10.2 microV) (P < 0.0001). No significant correlation was found between the ERG responses and the locus of the mutation. CONCLUSION: The photopic ERG demonstrated considerable impairment of the on-pathway arising from an abnormality of the on-bipolar cells or possibly secondary to Müller cell abnormality in xlRS.

Adolescent↗

PubMed2001

Anti-oxidative properties of fluvastatin, an HMG-CoA reductase inhibitor, contribute to prevention of atherosclerosis in cholesterol-fed rabbits.

Studies in vitro reveal that fluvastatin, an HMG-CoA reductase inhibitor, has a strong DPPH radical scavenging activity and achieves concentration-dependent inhibition of copper- and cell-induced oxidation of low-density lipoprotein (LDL). To further examine the anti-oxidative activity of fluvastatin in vivo, we elucidated the effects of chronic treatment with fluvastatin at a dose insufficient to reduce plasma cholesterol levels (2 mg/kg per day) on vasomotion and vascular oxidative stress in thoracic aortas of 0.5% cholesterol-fed rabbits. After 12 weeks of dietary treatment, aortic segments from rabbits fed cholesterol alone showed impaired endothelium-dependent relaxation responses to acetylcholine and A23187 compared to normal chow-fed rabbits in association with a significant increase in plasma total cholesterol levels. In contrast, although plasma total cholesterol levels were not different from those in control cholesterol-fed rabbits, aortic segments from fluvastatin-treated rabbits showed normal relaxation. Compared with rabbits fed cholesterol alone, fluvastatin treatment decreased susceptibility of LDL to ex vivo copper-induced oxidation, reduced vascular superoxide generation, and atheromatous plaque formation. In conclusion, the potent anti-oxidative properties of fluvastatin in addition to its cholesterol-lowering activity appear to contribute to its anti-atherosclerotic effect in vivo.

Animals↗

PubMed2001

Lysophosphatidylcholine increases the secretion of matrix metalloproteinase 2 through the activation of NADH/NADPH oxidase in cultured aortic endothelial cells.

Matrix metalloproteinases (MMPs) play a pivotal role in angiogenesis, atherogenesis, vascular remodeling after vascular injury, and instability of atherosclerotic plaque. The present study was undertaken to investigate the effect of lysophosphatidylcholine, a major component of oxidized low density lipoprotein (LDL), on the regulation of MMPs in cultured bovine aortic endothelial cells (BAECs). Furthermore, we explored the potential role of oxidative stress in the regulation of MMP. LPC increased the secretion of gelatinolytic activity, as well as, protein of MMP-2 from BAECs. The stimulation of BAEC with superoxide increased the production of MMP-2 and it also induced its activation. Electron spin resonance (ESR) with 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) as spin trap agent demonstrated that lysophosphatidycholine (LPC) induced generation of reactive oxygen (ROS) species from BAECs. The inhibition of NADH/NADPH oxidase, one of the potential sources of superoxide in endothelial cells, attenuated the effect of LPC. Our findings suggest that LPC might activate the endothelial NADH/NADPH oxidase to enhance superoxide production, and it might, in turn, enhance MMP-2 induction.

Animals↗

PubMed2001

KF19418, a new compound for hair growth promotion in vitro and in vivo mouse models.

KF19418, a newly synthesized compound, stimulated proliferation of cultured hair bulb cells from new born mice in concentration-dependent manner in the range under 10 microM. In the culture system of whole skin pieces from 4-week-old mice which we earlier established, KF19418 promoted hair follicle elongation as in the case of minoxidil. After topical application for 2 weeks of KF19418 or minoxidil to dorsal skin of hair-clipped mouse alopecia model, KF19418 at 1% suspension accelerated hair regrowth at a rate comparable to 1% minoxidil solution. Thus, it was shown that KF19418 directly stimulated hair follicle in vitro and had hair growth promoting activities in vivo.

Alopecia↗

PubMed2001

A calcium channel blocker, benidipine, inhibits intimal thickening in the carotid artery of mice by increasing nitric oxide production.

OBJECTIVE: Recent studies suggest that several calcium channel blockers exert their protective effects against vascular disorders by increasing nitric oxide (NO) production from the endothelium. The purpose of this study was to clarify the effects of a long-lasting calcium channel blocker, benidipine, on vascular remodeling. METHODS: The left common carotid arteries of mice were completely ligated just proximal to the carotid bifurcation. Treatment with benidipine (3 mg/kg per day) or vehicle was started 1 week before the carotid ligation, and continued throughout the experiments. Four weeks after the carotid ligation, these mice were killed and vascular remodeling was analyzed. Moreover, NO production and endothelial NO synthase (eNOS) expression were assessed. RESULTS: At 4 weeks after ligation, the neointimal area in the vehicle-treated mice was 39,400 +/- 4,900 microm2 (n = 8), whereas that in the drug-treated mice was reduced to 18,300 +/- 3,800 microm2 (n = 10). Consequently, the luminal area was 35% larger in the drug-treated mice. Benidipine increased the basal as well as agonist-induced NO production from the endothelium, detected by Griess method or NOx analyzer. Endothelial NOS expression in vessels of the drug-treated mice was increased compared with that of the vehicle-treated mice. CONCLUSION: Our data provide evidence that benidipine increases NO production via increment of eNOS protein in vessels and prevents intimal thickening in mice. These results show the possibility of benidipine as a protective tool against vascular remodeling independent of its effect on blood pressure.

Animals↗

PubMed2001

TNF-alpha induces protein synthesis through PI3-kinase-Akt/PKB pathway in cardiac myocytes.

The activation of phosphatidylinositol (PI) 3-kinase and Akt/protein kinase B (PKB) by tumor necrosis factor (TNF)-alpha and their roles on stimulation of protein synthesis were investigated in cultured neonatal rat cardiac myocytes. Treatment of cells with TNF-alpha resulted in enlargement of cell surface area and stimulation of protein synthesis without affecting myocyte viability. TNF-alpha induced marked activation of PI3-kinase and Akt/PKB, and the activation of PI3-kinase and Akt/PKB was rapid (maximal at 10 and 15 min, respectively) and concentration dependent. Akt/PKB activation by TNF-alpha was inhibited by a PI3-kinase-specific inhibitor LY-294002 and adenovirus-mediated expression of a dominant negative mutant of PI3-kinase, indicating that TNF-alpha activates Akt/PKB through PI3-kinase activation. Furthermore, TNF-alpha-induced protein synthesis was inhibited by pretreatment with LY-294002 and expression of a dominant negative mutant of PI3-kinase or Akt/PKB. These results indicate that activation of the PI3-kinase-Akt/PKB pathway plays an essential role in protein synthesis induced by TNF-alpha in cardiac myocytes.

Animals↗

PubMed2001

Regulation of tyrosine phosphorylation of PYK2 in vascular endothelial cells by lysophosphatidylcholine.

Lysophosphatidylcholine (LPC), a component of oxidized low-density lipoprotein, exerts various biological effects on vascular endothelial cells. However, the intracellular signaling of LPC is poorly understood. In this study, we investigated the involvement of proline-rich tyrosine kinase (PYK2) in LPC signaling in cultured bovine aortic endothelial cells by immunoprecipitation and Western blotting assays. Treatment of cells with LPC promoted a rapid increase in tyrosine phosphorylation of PYK2. LPC-stimulated PYK2 phosphorylation was inhibited by calcium chelators, 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid-acetoxymethyl ester, EGTA, protein kinase C (PKC) inhibitor, GF-109203X, or PKC depletion by phorbol esters. PYK2 phosphorylation was inhibited by treatment with cytochalasin D but with neither botulinum C3 transferase nor overexpression of a dominant negative mutant of Rho A. LPC stimulated the association of Shc with PYK2, Shc tyrosine phosphorylation, and Grb2 binding to Shc and induced Ras activation. These results provide evidence that 1) LPC tyrosine phosphorylates PYK2 by calcium- and PKC-dependent mechanisms, 2) the intact cytoskeleton is required for LPC-stimulated PYK2 phosphorylation, and 3) LPC-activated Ras via the PYK2/Shc/Grb2 signaling.

ADP Ribose Transferases↗

PubMed2001

Endothelial NO synthase overexpression inhibits lesion formation in mouse model of vascular remodeling.

NO produced by endothelial NO synthase (eNOS) plays important roles in the regulation of vascular tone and structure. The purpose of this study was to clarify the role of eNOS-derived NO on vascular remodeling by use of eNOS-transgenic (eNOS-Tg) mice. The common carotid artery was ligated just proximal to the carotid bifurcation. Four weeks later, the proximal carotid artery of the ligation site was histologically examined. In this vascular remodeling model, the endothelium remains uninjured, but neointimal and medial thickening occurs in combination with a reduction in vascular diameter at the proximal portion of the ligation. At 4 weeks after ligation, the respective neointimal and medial areas in wild-type mice were 17 200+/-1100 and 24 300+/-1500 microm(2), whereas both were reduced to 8000+/-1900 (P:<0.01) and 18 400+/-700 microm(2) (P:<0.01) in eNOS-Tg mice (n=8). Total vascular area was not different between the 2 genotypes. N:(G)-Nitro-L-arginine methyl ester treatment increased neointimal and medial areas to the same extent in both genotypes. Leukocyte infiltration was observed in the luminal side of the vessel, but the number of infiltrating cells was significantly attenuated in eNOS-Tg mice compared with wild-type mice. This reduction of leukocyte infiltration in eNOS-Tg mice was associated with reduced expressions of intracellular adhesion molecule-1 and vascular cellular adhesion molecule-1 on the endothelium. In conclusion, chronic eNOS overexpression in the endothelium reduced leukocyte infiltration and inhibited neointimal formation and medial thickening. Our data provide the evidence for the regulatory role of NO from the endothelium on vascular structure integrity.

Animals↗

PubMed2001

Reduced hypoxic pulmonary vascular remodeling by nitric oxide from the endothelium.

We examined whether overproduction of endogenous nitric oxide (NO) can prevent hypoxia-induced pulmonary hypertension and vascular remodeling by using endothelial NO-overexpressing (eNOS-Tg) mice. Male eNOS-Tg mice and their littermates (wild-type, WT) were maintained in normoxic or 10% hypoxic condition for 3 weeks. In normoxia, eNOS protein levels, Ca(2+)-dependent NOS activity, and cGMP levels in the lung of eNOS-Tg mice were higher than those of WT mice. Activity of eNOS and cGMP production in the lung did not change significantly by hypoxic exposure in either genotype. Chronic hypoxia did not induce iNOS expression nor increase its activity in either genotype. Plasma and lung endothelin-1 levels were increased by chronic hypoxia, but these levels were not significantly different between the 2 genotypes. In hemodynamic analysis, right ventricular systolic pressure (RVSP) in eNOS-Tg mice was similar to that in WT mice in normoxia. Chronic hypoxia increased RVSP and induced right ventricular hypertrophy in both genotypes; however, the degrees of these increases were significantly smaller in eNOS-Tg mice. Histological examination revealed that hypoxic mice showed medial wall thickening in pulmonary arteries. However, the increase of the wall thickening in small arteries (diameter <80 microm) by chronic hypoxia was inhibited in eNOS-Tg mice. Furthermore, muscularization of small arterioles was significantly attenuated in eNOS-Tg mice. Thus, we demonstrated directly that overproduction of eNOS-derived NO can inhibit not only the increase in RVSP associated with pulmonary hypertension but also remodeling of the pulmonary vasculature and right ventricular hypertrophy induced by chronic hypoxia.

Animals↗

PubMed2001

Biodegradation and drug release of chitosan gel beads in subcutaneous air pouches of mice.

Chitosan (CS) gel beads were prepared in 10% amino acid solution (pH 9) and implanted into air pouches (AP) prepared subcutaneously on the dorsal surface of mice. No inflammatory response was observed, and degradation of the beads in the AP increased as their degree of deacetylation decreased. Degradation could be altered by changing the nature of the CS or by increasing the CS concentration. The release of prednisolone (PS) in vivo from CS gel beads was similar to the release in vitro. When a suspension of PS was injected into the AP, the PS had almost completely disappeared 24 h after injection. Retention of PS in the AP was not increased by using a viscous CS solution. Alginate (Alg) gel beads, which were not degraded, released PS slowly into the AP over 3d. The in vitro release profile of PS using 1% CS (deacetylation: 70% (7B) and 80% (8B)) and 1.5% CS (deacetylation: 90% (9B)) gel beads was similar to that with Alg gel beads. However, the in vivo release of PS was affected by the degradability of the gel beads. CS7B and 8B (1%) gel beads had released PS into the AP earlier than 3 d according to their rate of degradation. CS9B (1.5%) gel beads were not degraded after 3 d and went on to release PS into the AP for 3 d similar to the release profile of Alg gel beads. CS9B (2%) gel beads were also not degraded after 3 d and the release of PS from these beads into the AP was sustained; 76% and 27% of administered PS remained in the gel beads after 1 and 3 d, respectively. Therefore, degradation and drug release of CS gel beads can be controlled by changing the structure of the gel matrix, which appears to make these beads a promising biodegradable vehicle for sustained drug delivery.

Animals↗

PubMed2001

[The role of ischemic preconditioning in off-pump CABG: is it really necessary to accomplish scrupulous ischemic preconditioning?].

In an attempt to avoid the deleterious effect of cardiopulmonary bypass, off-pump coronary artery bypass grafting has been rediscovered and spread. We often accomplish the ischemic preconditioning (IP) in off-pump CABG. IP is the phenomenon in which sublethal episode of myocardial ischemia result in increased tolerance to a later, potentially lethal, episode of ischemia. To evaluate the cardioprotective effect of IP and an ATP-sensitive potassium channel (KATP) opener, oxidative radical scavenger, 43 clinical cases were examined. The myocardial tissue oxygen saturation was measured by near-infra red spectroscopy during IP. Twelve cases were subjected to accomplish simple IP (5 min x twice), and 29 cases received pharmacological IP (administrated allopurinol preoperatively and nicorandil intraoperatively; 3 min x once). The result showed that the tissue oxygen of pharmacological IP group is superior to that of simple IP group. The concomitant use of IP and KATP opener, oxidative radical scavenger both ameliorated cardiac dysfunction during the ischemia in anastomotic occlusion of the coronary artery, and improved the postischemic functional recovery. These results suggest that we would be able to decrease both duration and the number of times of IP by using KATP opener and oxidative radical scavenger.

Allopurinol↗

PubMed2000

Possible involvement of aminotelopeptide in self-assembly and thermal stability of collagen I as revealed by its removal with proteases.

The functions of aminotelopeptide and N-terminal cross-linking of collagen I were examined. Acetic acid-soluble collagen I (ASC) was purified from neonatal bovine skin and treated with three kinds of proteases. The amino acid sequencing analysis of the N terminus showed that ASC contained a full-length aminotelopeptide. Pepsin and papain cleaved the aminotelopeptide of the alpha1 chain at the same site and the aminotelopeptide of the alpha2 chain at different sites. Proctase-treated ASC lost the whole aminotelopeptide, and the N-terminal sequence began from the tenth residue inside the triple helical region. The rates of fibril formation of pepsin-treated ASC and proctase-treated ASC were the same and were slower than that of ASC. The denaturation temperatures, monitored by CD ellipticity at 221 nm, of ASC, pepsin-treated, or papain-treated collagens were the same at 41.8 degrees C. Proctase-treated ASC showed a lower denaturation temperature of 39.9 degrees C. We also observed the morphology of the collagen fibrils under an electron microscope. The ASC fibrils were straight and thin, whereas the fibrils of pepsin-treated ASC were slightly twisted, and the fibrils from papain- and proctase-treated ASC were highly twisted and thick. When the collagen gel strength was examined by a modified method of viscosity-measurement, ASC was the strongest, followed by pepsin-treated ASC, and papain- and proctase-treated ASCs were the weakest. These results suggest that the aminotelopeptide plays important roles in fibril formation and thermal stability. In addition, the functions of intermolecular cross-linking in aminotelopeptides may contribute to the formation of fibrils in the correct staggered pattern and to strengthening the collagen gel.

Acetic Acid↗