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Biomedical subjects

N Sakata

Publications and source records attributed to N Sakata.

At least 73 records · Page 4Linked to original sources
PubMed1999

Emergency abdominal surgery for small bowel perforation secondary to metastatic lung cancer.

Emergency surgery for bowel perforation caused by metastases from lung cancer is rare. Two cases of small bowel perforation due to metastasizing lung cancer are reported. Both patients were admitted as a surgical emergency case. One of the two patients presented herein survived and was discharged from the hospital. Perforated small bowel due to metastatic lung cancer is a highly fatal event that occurs in the late phases of the disease. Despite the poor prognosis, early and appropriate therapy will occasionally yield successful surgical palliation. Patients with known lung cancer who develop abdominal complaints should be examined thoroughly and treated quickly.

Adenocarcinoma↗
PubMed1999

[Clinicopathological and morphometrical analysis of 5 cases from 4 families of fibronectin glomerulopathy].

Fibronectin glomerulopathy (FNG) is an inherited disease, characterized by massive fibronectin (FN) deposits in the glomeruli. We semiquantitatively analyzed glomerular lesions and their progression in 5 cases with FNG from 4 different families: a 4 year-old male, a 19 year-old female, a 27 year-old male, a 58 year-old male (the father of the former case) and a 75 year-old male. All subjects showed a 201 times higher value of mean glomerular-tuft area (GA) and a 2.0 times higher mean number of mesangial cells (No. of MC) relative to control (p < 0.001). Strong positive correlations were observed between GA and the No. of MC (r = 0.86, p < 0.001). The younger cases showed markedly higher value of GA and No. of MC than the older cases. Mean individual capillary luminal area was decreased in all but one case and the mean total capillary luminal area, which is roughly estimated as the glomerular filtration area, was less changed compared with the control. The number of capillary loops tended to increase, indicating elongation of the capillary loops. The fractional area of FN (%FN), collagen IV (%Coll. IV) and laminin (%Lam) were high in all cases except for the first Bx in the 27 year-old case. The %FN strongly correlated with %Coll. IV and %Lam (r = 0.86, r = 0.69, p < 0.001, respectively). Serial biopsy (Bx) with a 10 year-interval was examined in the 27 year-old case and his father: GA and No. of MC were increased 1.4 and 1.9 times in the son, compared with his first Bx (p < 0.001, respectively), while no change was observed in the father. The %FN, %Coll. IV and %Lam were significantly increased in their second Bx (p < 0.001). These results suggest that 1) enlargement of the glomeruli in FNG is caused by intraglomerular accumulation of FN, Coll. IV and Lam and proliferated mesangial cells, 2) there is a strong influence from the aging factor, and 3) compensatory elongation of the loops (increase in the capillary luminal area) may maintain the glomerular filtration.

Adult↗
PubMed1999

Evidence for a link between glycoxidation and lipoperoxidation in patients with chronic renal failure.

AIM: The purpose of this study is to examine whether or not there is a relationship between glycoxidation and lipid peroxidation in patients with chronic renal failure. SUBJECTS AND METHODS: Dermal samples from 26 living or autopsied subjects were sequentially extracted with NaCl, pepsin, collagenase, and NaOH to obtain four fractions (salt-soluble fraction: SSF; pepsin-soluble fraction: PSF; collagenase-soluble fraction: CSF; and insoluble fraction: ISF). The glycoxidation product was measured by pentosidine-linked fluorescence (ex: 335/em: 385) and the levels of lipid peroxide, malondialdehyde (MDA), were assessed by determining the MDA-linked fluorescence (ex: 390/em: 460) which was further confirmed by HPLC. RESULTS: In patients undergoing hemodialysis, MDA-linked fluorescence markedly increased in collagen-rich fractions, PSF, CSF, and ISF, while pentosidine-linked fluorescence increased in PSF and CSF, in comparison to the controls and the pre-dialysis patients with CRF. Interestingly, the increase in the lipid peroxides strongly correlated with the level of glycoxidation product in PSF, CSF, and ISF (p < 0.0001 in PSF, CSF; p < 0.01 in ISF). The HPLC data of MDA in the PSF was in good correlation with logistic levels of both MDA- (n = 9, r = 0.738, p = 0.023) and pentosidine-linked fluorescence (n = 9, r = 0.721, p = 0.028). In contrast, in SSF, the collagen-poor fraction (collagen content: less than 3% of the total extracted collagen), the data showed a significant increase in the MDA-linked fluorescence only in the pre-dialysis patients with CRF, but not in the HD patients with no correlation with the glycoxidation products. CONCLUSION: These findings suggest that both the lipid peroxidation and glycoxidation increased in close relation to each other in the matrix collagen and thus demonstrate a synergetic contribution to the tissue damage observed in patients with CRF

Female↗
PubMed1998

Requirement for dual signals by anti-CD40 and IL-4 for the induction of nuclear factor-kappa B, IL-6, and IgE in human B lymphocytes.

Stimulation of human peripheral B cells via the CD40 receptor and IL-4R together lead to IgE synthesis and secretion, but the intracellular signaling mechanisms by which these signals lead to IgE production are unclear. Roles for the transcription factor NF-kappa B and IL-6 have been postulated in the induction of IgE synthesis by IL-4/CD40. We found that neither anti-CD40 Ab nor IL-4 alone was able to induce significant proliferation of human B cells. However, the combination of anti-CD40 and IL-4 was a potent inducer of B cell proliferation in addition to IgE production from purified human B cells. Furthermore, IL-4 and anti-CD40 synergized for the production of IL-6. While neither IL-4 alone nor anti-CD40 alone was able to induce significant NF-kappa B DNA binding activity, the combination of IL-4 and anti-CD40 induced a strong activation of NF-kappa B, a transcription factor that regulates IL-6 production. These data indicate that both IL-4 and anti-CD40 are required to induce NF-kappa B activation and IL-6 transcription and production, and implicate these events in a signaling pathway augmenting IgE production in human B lymphocytes.

Adjuvants, Immunologic↗
PubMed1998

Immunochemical approaches to AGE-structures: characterization of anti-AGE antibodies.

Recent immunological approaches have greatly helped broaden our understanding of the biomedical significance of advanced glycation end products (AGEs) in aging and age-enhanced disease processes. Recently, Nepsilon-(carboxymethyl) lysine (CML), one of the glycoxidation products of AGEs, was demonstrated to be a major immunological epitope among AGEs. In the subsequent study, we characterized 13 different polyclonal anti-AGE antibodies and showed that these antibodies could be classified into three groups (Groups I, II and III). Group I was specific for CML and both Group II and Group III were specific for other epitopes (non-CML). Time-course study suggested that the epitope of Group II was formed earlier than that of Group III. In the present study, we prepared two monoclonal anti-AGE antibodies (2A2 and 3A3) whose epitope structures appeared to be closely related to Group III and Group II, respectively. The result indicates that AGE-proteins express at least two major non-CML epitopes.

Animals↗
PubMed1998

Oxidative damage of vascular smooth muscle cells by the glycated protein-cupric ion system.

To clarify the mechanism of cellular injury through the nonenzymatic reaction of glucose with proteins, we studied the cytotoxic effect of glycated bovine serum albumin on cultured smooth muscle cells in the presence of cupric ion. Glycated proteins were prepared by incubating bovine serum albumin with 0.5 M D-glucose in 0.3 M sodium phosphate buffer at 37 degrees C for 2, 4 and 16 weeks (g-BSA-2, g-BSA-4 and g-BSA-16, respectively). Early glycation products, such as fructosamine, were formed more than two weeks after incubation. However, the immunoreactivity of glycated proteins to anti-AGE antibody was 12-fold higher in g-BSA-16 than in g-BSA-2. Both g-BSA-2 and g-BSA-16 showed a concentration-dependent cytotoxicity in smooth muscle cells in the presence of 80 microM cupric ion by an MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide) dye reduction assay and dye exclusion test. Flow cytometry and spectrofluorophotometry using dihydrorhodamine 123 showed that the extracellular generation of oxidants was dose-dependently enhanced with increasing concentrations of g-BSA-2 or g-BSA-16 in the presence of cupric ion. However, no difference was observed in the intracellular generation of oxidants between the presence and absence of glycated proteins by flow cytometry using 2', 7'-dichlorofluorescein diacetate. Cytotoxicity and oxidant generation were prevented by catalase and tiron, but not by superoxide dismutase or mannitol, a hydroxyl radical scavenger. These results indicate that smooth muscle cells may be damaged by reactive oxygen species which are produced extracellularly by the interaction with the early glycation products and cupric ion, and suggest that hydrogen peroxide may be a candidate for reactive oxygen species which contribute to such oxidative damage of smooth muscle cells.

1,2-Dihydroxybenzene-3,5-Disulfonic Acid Disodium ↗
PubMed1998

Glycoxidation in aortic collagen from STZ-induced diabetic rats and its relevance to vascular damage.

Glycoxidation reactions lead to the formation of permanent, irreversible chemical modifications and cross-links in protein, such as the glycoxidation products carboxymethyllysine (CML) and pentosidine. It has been implicated that CML as well as Amadori products play a role in the formation of superoxidative products, such as H2O2 and advanced glycosylation endproducts in trapping LDL. Therefore, a possible relationship between glycoxidation and lipoperoxidation might exist because oxidized lipoprotein, which has been directly linked to atheroma formation, could be produced by the superoxidative products released from the pathway of CML formation. Using a CML-specific monoclonal antibody (6D12) and a specific antiserum against hexitol-lysine (HL), an Amadori product, we studied the relationship between glycoxidation and lipoperoxidation by determining the aortic CML contents with ELISA and the fluorescence levels of lipoperoxidation side products, malondialdehyde (MDA) and hydroxynonenal (HNE) from STZ-induced diabetic rats and age-matched control rats. The immunohistochemical and ultrastructural changes relevant to glycoxidation and lipoperoxidation were also studied. The CML content measured by ELISA in DM rats was significantly higher than that in the control rats at 28 weeks (n = 11, P < 0.01). The levels of MDA-linked and HNE-linked fluorescence in the DM rats increased in a similar way and were significantly higher than the levels in control rats at 28 weeks (n = 11, both P < 0.01 at 28 weeks). The CML contents correlated with the fluorescence levels of both MDA-linked (n = 19, r = 0.638, P < 0.01) and HNE-linked fluorescence (n = 19, r = 0.629, P < 0.01) only in the DM rats, but not in the control rats. Our immunohistochemical study thus demonstrated that CML was initially formed in the aortic media of diabetic rats in the 16th week of diabetes, localized primarily in the extracellular matrix surrounding the aortic smooth muscle cells after HL occurred early in the 2nd week of diabetes. Consequently, a significant increase in the extracellular matrix and decrease in the area of the SMCs were observed in the aortic media in the DM rats by a morphometrical study. The in vivo results of this study provided the first evidence that CML correlated with fluorescence levels of MDA and HNE, and thus suggested the existence of a close relationship between glycoxidation and lipoperoxidation in vivo. This information is thus considered to shed some new light on the etiology of atherogenesis in diabetes.

Aldehydes↗
PubMed1998

Immunohistochemical localization of different epitopes of advanced glycation end products in human atherosclerotic lesions.

To better understand the role of advanced glycation end products (AGEs) in atherogenesis, we developed specific antibodies against different immunological epitopes of AGE structures, including Nepsilon-(carboxymethyl)lysine-protein adduct (CML) and a structure(s) other than CML (nonCML), and demonstrated the immunohistochemical localization of CML- and nonCML-epitopes in atherosclerotic lesions of human aorta, which were obtained at autopsy from 20 nondiabetic patients (12 males and eight females; mean age, 60.8+/-16.7 years). Monoclonal anti-CML antibody (6D12) recognized not only AGE-modified proteins, but also CML-modified proteins. On the other hand, polyclonal anti-nonCML antibody reacted to AGE-modified proteins, but not to CML-modified proteins. Both antibodies were unreactive to the early-stage products of glycation, including fructose-modified butyloxycarbonyl-lysine and fructose-epsilon-aminocaproic acid. Atherosclerotic lesions included diffuse intimal thickening (DIT), fatty streaks (FS), atherosclerotic plaques (AP) and complicated lesions. An immunohistochemical analysis showed both CML- and nonCML-epitopes to be found along the collagen fibers in DIT in subjects more than 40 years old, but not in subjects less than 40 years old. CML-epitopes accumulated mainly in the cytoplasm of macrophage/foam cells, while nonCML-epitopes accumulated exclusively in the extracellular spaces in FS. APs showed the CML-epitope stored macrophage/foam cells, and the accumulation of both CML- and nonCML-epitopes in the lipid-rich fibrous area. An immunohistochemical analysis with a monoclonal antibody against oxidized low density lipoprotein (FOH1a/DLH3) showed the presence of this antigen within the cytoplasm of the macrophage/foam cells in atherosclerotic lesions, which were also positive for the CML-epitopes. These findings thus suggest that the heterogeneous localization of AGEs in atherosclerotic lesions depends on their different epitopes, and that a close link, therefore, exists between the peroxidation of LDL and the formation of AGEs in atherosclerotic lesions.

Adult↗
PubMed1997

Cytokine production regulating Th1 and Th2 cytokines in hemophagocytic lymphohistiocytosis.

Hemophagocytic lymphohistiocytosis (HLH) is caused by the hyperactivation of T cells and macrophages. The clinical characteristics associated with this disease result from overproduction of Th1 cytokines including interferon-gamma (IFN-gamma), interleukin-2 (IL-2), and tumor necrosis factor-alpha (TNF-alpha). In this study, we analyzed the production of IL-12 and IL-4, which determine Th1 and Th2 response, respectively, and IL-10, which antagonizes Th1 cytokines, in 11 patients with HLH. IL-12 was detected in plasma in all patients (mean peak value, 30.0 +/- 5.0 pg/mL), while IFN-gamma was massively produced in nine patients (mean peak value, 79.2 +/- 112.0 U/mL). IL-4 was not detected in any of the patients. Plasma IL-10 levels were elevated in all patients (mean peak value, 2,698.0 +/- 3,535.0 pg/mL). There was a positive correlation between the levels of IFN-gamma and IL-10 (P < .01). The plasma concentrations of these cytokines were initially high, before decreasing after the acute phase. However, the decrease in IL-10 levels was slower than that of IFN-gamma. Although the concentration of IL-12 was high at the acute phase, in some patients, a peak in the level was delayed until the chronic phase. Thus, in HLH, production of cytokines that promote development of Th1 cells appears to be predominant over that for Th2 cell development. Overproduction of IL-10 was also observed indicating that a mechanism suppressing hyperactivation of Th1 cells and monocytes/macrophages functions in patients with this disease.

Child↗
PubMed1997

A two-site model for ApoB degradation in HepG2 cells.

Newly synthesized apolipoprotein B (apoB) undergoes rapid degradation in a pre-Golgi compartment in HepG2 cells. A major site of this early degradation seems to be on the cytosolic side of the endoplasmic reticulum (ER) membrane and is sensitive to N-acetyl-leucinyl-leucinyl-norleucinal (ALLN), which can inhibit neutral cysteine proteases and/or proteasome activity. Oleate (OA) treatment, which facilitates translocation of nascent apoB across the ER membrane, also reduces early degradation. In the present studies, we have used brefeldin A (BFA), which inhibits vesicular transport from the ER to the Golgi, to demonstrate that apoB can also be degraded by an ER luminal proteolytic activity that is distinct from the ALLN-sensitive proteases. Thus, when BFA-treated HepG2 cells were co-treated with ALLN, which protects apoB but does not facilitate its translocation into the ER lumen, degradation of newly synthesized apoB was significantly reduced compared with cells incubated with BFA alone. However, apoB degradation was rapid and complete when OA was added to media containing either BFA or ALLN/BFA. These results suggested that OA, by increasing translocation of nascent apoB into the ER lumen, exposed apoB to an ALLN-resistant proteolytic pathway. When we incubated HepG2 cells with dithiothreitol (DTT)/OA/BFA or DTT/OA/ALLN/BFA, degradation of apoB was inhibited. Furthermore, addition of DTT resulted in the accumulation of a 70-kDa amino-terminal fragment of apoB. Both full-length and amino-terminal apoB were degraded if DTT was removed from the incubation media; both were secreted if only BFA was removed. Thus, even after apoB is translocated into the ER lumen (thereby avoiding the initial proteolytic pathway), it can potentially be degraded by a lumenal proteolytic process that is ALLN-resistant but DTT-sensitive. The present results, together with previous studies, suggest that at least two distinct steps may be involved in the posttranslational degradation of apoB: 1) the first occurs while apoB is partially translocated and is ALLN-sensitive; and 2) the second occurs in the ER lumen and is DTT-sensitive. Finally, our results support the hypothesis that degradation of partially translocated apoB generates a 70-kDa amino-terminal fragment that is mainly degraded in the ER lumen by a DTT-sensitive pathway.

Apolipoproteins B↗
PubMed1997

Rapamycin potentiates dexamethasone-induced apoptosis and inhibits JNK activity in lymphoblastoid cells.

The immunosuppressant rapamycin (RAP) potentiated apoptosis of the murine T lymphoblastoid cell line S49 induced by dexamethasone (DEX), while RAP by itself did not induce apoptosis of the cells. FK506, in contrast, had no effect on DEX-induced apoptosis; moreover, an excess of FK506 reversed the potentiation of apoptosis by RAP, indicating that RAP exerts its effects through binding to FKBP. Both RAP and FK506 enhanced the MMTV promoter activity by dexamethasone, suggesting that the potentiation of apoptosis is not likely explained by the selective enhancement of transcriptional activity of the glucocorticoid receptor. Of interest, the basal activity of c-Jun kinase (JNK), whose activation has been recently suggested to be involved in cell survival signals in lymphocytes, was reduced by RAP in S49 cells. The reduction of JNK activity by RAP was reversed by the addition of an excess of FK506. In summary, we demonstrate for the first time that RAP has the ability to inhibit JNK activity in lymphocytes where the drug enhances apoptosis.

3T3 Cells↗
PubMed1997

Comparison between dietary soybean protein and casein of the inhibiting effect on atherogenesis in the thoracic aorta of hypercholesterolemic (ExHC) rats treated with experimental hypervitamin D.

Atherosclerotic lesions of the thoracic aorta were induced in exogenously hypercholesterolemic (ExHC) rats by treating initially with hypervitamin D2 and subsequently feeding on hypercholesterolemic diets for 180 days. Dietary soybean protein, in comparison with casein, substantially decreased the degree of atherosclerotic lesions, which was evaluated by intimal thickening, although with a similar topographical distribution. The casein-fed rats tended to maintain a high concentration of serum cholesterol, particularly in triacylglycerol-rich lipoproteins. The concentrations of apo A-I and TBARS in the serum was comparable between the dietary protein groups. The data suggest that dietary soybean protein, compared to casein, produced lipoproteins which were less atherosclerotic by partitioning cholesterol in the triacylglycerol-poor lipoproteins.

Animals↗
PubMed1997

Rapid disappearance of AML1/ETO fusion transcripts in patients with t(8;21) acute myeloid leukemia following bone marrow transplantation and chemotherapy.

To assess the clinical significance of monitoring minimal residual disease in t(8;21)(q22;q22) AML, RT-PCR assay was conducted during the clinical course of 12 patients who had undergone BMT or conventional chemotherapy. Two cases relapsed after BMT and chimeric RNA was detected soon after BMT in their bone marrow cells. The other three cases, in whom chimeric RNA was not detected after BMT, are in CR at 21 to 33 months following BMT. Similarly, four out of 7 cases who showed negative chimeric RNA after completion of chemotherapy have been in CR at 11 to 34 months following completion of chemotherapy. The present findings appear different from other studies which reported the detection of AML1-ETO chimeric RNA in long-term CR patients.

Adolescent↗
PubMed1997

Cloning of the enomycin structural gene from Streptomyces mauvecolor and production of recombinant enomycin in Escherichia coli.

A genomic DNA library from the enomycin (ENM) producer, Streptomyces mauvecolor, was screened for the ENM structural gene (enm) by use of a segment of the phenomycin gene (phm) as the probe, and a plasmid, pENI, was constructed. By primer-walking along the insert, a 573 bp DNA sequence that contain an ORF corresponding to preENM was determined. The deduced amino acid composition of ENM was close to that previously reported (MIZUNO, S.; K. NITTA & H. UMEZAWA: Mode of action of enomycin, an antitumor antibiotic of high molecular weight. I. Inhibition of protein synthesis. J. Biochem. 61: 373 approximately 381, 1967). The producer cells expressed enm during an ENM-productive fermentation. An enm-expression plasmid, pENE 1, was constructed, with which E. coli AD202 was transformed. The transformant produced a fusion protein consisting of glutathione-S-transferase (GST) and ENM. The genetically engineered ENM (rENM) inhibited the growth of Hela cells in vitro. Comparison of the base sequence spanning enm with that spanning phm showed that the structural genes were conserved more extensively than were the flanking regions, though the genes were unlikely to be essential to the lives of the producers.

Amino Acid Sequence↗
PubMed1997

[Analysis of mechanism of increased platelet counts during preoperative autologous blood donation].

Autologous blood transfusion is advantageous in that it eliminates the risk of transfusion-transmitted infection or complications caused by the immune reaction. Increased platelet counts after repeated phlebotomy are commonly observed. This study was carried out to clarify the mechanism of increased platelets during preoperative autologous blood donation. Eleven patients of elective surgery in which is in good preoperative condition and there is no emergency were selected for this study. Blood cell counts, platelet size distribution(PDW, MPV, P-LCR) and serum concentration of erythropoietin(EPO), interleukin-3(IL-3) and interleukin-6(IL-6)were measured. A transient increase in platelet was seen in almost patients during preoperative autologous blood donation. No marked changes in platelet size distribution and serum concentration of EPO, IL-3 and IL-6. These results suggest that increased platelet counts during preoperative autologous blood donation might be caused by some specific cytokines related to megakaryocyte differentiation such as c-MPL ligand.

Adult↗
PubMed1996

Aggregation of the FcepsilonRI on mast cells stimulates c-Jun amino-terminal kinase activity. A response inhibited by wortmannin.

Aggregation of the high-affinity Fc receptors for immunoglobulin E (IgE) (FcepsilonRI) on the surface of mast cells initiates intracellular signal transduction pathways including the tyrosine phosphorylation of cellular proteins, phosphoinositide hydrolysis, an increase in intracellular calcium, and protein kinase C activation. These signals are believed to be involved in the exocytic release of inflammatory mediators such as vasoactive amines, cytokines, and lipid metabolites. However, the downstream consequences of these early activation events are not well defined. One exception is the activation of the extracellular signal-regulated kinases/mitogen-activated protein kinases. One member of the mitogen-activated protein kinase superfamily, designated c-Jun amino-terminal kinase (JNK), has been recently identified. JNK is activated following dual phosphorylation at a Thr-Pro-Tyr motif in response to diverse stimuli including tumor necrosis factor-alpha, heat shock, or ultraviolet irradiation. We found that JNK was strongly activated by antigen cross-linking in a mouse mast cell line passively sensitized with ovalbumin-specific IgE. Anti-mouse IgE antibody also activated JNK. MEK kinase 1 (MEKK1) which activates the JNK activator, JNK kinase (JNKK), was similarly activated by antigen stimulation. JNK but not p42(erk2) activation induced by antigen was significantly inhibited in the presence of wortmannin, a known inhibitor of phosphatidylinositol 3-kinase. These results indicate that in response to the aggregation of FcepsilonRI on mast cells, phosphatidylinositol 3-kinase activation is involved in the stimulation of the MEKK1, JNKK, JNK pathway.

Amino Acid Sequence↗
PubMed1996

Advanced glycation end products of the Maillard reaction in aortic pepsin-insoluble and pepsin-soluble collagen from diabetic rats.

Recent immunohistological studies using antibodies against advanced glycation end products (AGEs) have demonstrated the presence of AGEs in several tissues. By an enzyme-linked immunosorbent assay using the monoclonal anti-AGE antibody, the present study aimed to determine AGEs in pepsin-insoluble collagen (PIC) as well as in pepsin-soluble collagen (PSC) from the aortas of streptozotocin (STZ)-induced diabetic rats (at 4, 16, and 28 weeks after STZ injection) and those of age-matched control rats. Addition of EDTA to the immunoassay buffer has led us to successful determination of AGEs in the aortic PIC samples with following results: 1) in diabetic rats, there was a time-related increase in the AGE contents at 28 weeks (n = 9, 226.4 +/- 13.5 ng/mg collagen [mean +/- SE]), compared with that at 4 and 16 weeks (n = 6, 79.6 +/- 9.5 ng/mg collagen, and n = 8, 149.4 +/- 30.9 ng/mg collagen at 4 and 16 weeks, respectively; both P < 0.05, between 4 and 16 weeks and 28 weeks); 2) after 28 weeks of diabetes, the AGE contents in PIC of aortas were significantly higher in diabetic rats than in controls (n = 9, 226.4 +/- 13.5 ng/mg collagen vs. n = 8, 129.6 +/- 14.9 ng/mg collagen, P < 0.01, diabetic vs. control); and 3) the level of the AGE content was strongly correlated with the PIC/total collagen (TC) ratio (n = 45, r = 0.698, P = 0.0001). By treating the samples of PSC with alkaline solution, the AGE content of PSC was also determined. In the PSC fraction, the AGE levels in the diabetic rats tended to increase with time and to be higher than those of control rats at 28 weeks although these changes were not statistically significant (diabetic: n = 4, 19.4 +/- 9.7; n = 6, 22.3 +/- 6.2; n = 6, 39.6 +/- 10.8; control: n = 4, 19.7 +/- 9.8; n = 6, 22.9 +/- 7.3; n = 7, 30.7 +/- 7.2; at 4, 16, and 28 weeks, respectively). Compared with the AGE levels of PSC, those of PIC were about four to seven times and four to five times higher in diabetic and control rats, respectively (PIC versus PSC in diabetic or control rats, all P < 0.001, at 4, 16, and 28 weeks, respectively). These findings provide the first immunochemical evidence that AGE adducts are present in the materials extracted sequentially by pepsin and collagenase and that these adducts in PIC accumulated as a function of the increase in the aortic PIC/TC ratio.

Animals↗