Peripheral alpha-linked N-acetylglucosamine on the carbohydrate moiety of mucin derived from mammalian gastric gland mucous cells: epitope recognized by a newly characterized monoclonal antibody

To obtain a tool to study the structural characterization and the detection of mucin derived from the gastric gland mucous cells, we developed a monoclonal antibody, designated HIK1083, against mucin purified from rat gastric mucosa. In an ELISA, HIK1083 reacted strongly with the mucin purified from a deep layer of the corpus and antrum but only slightly reacted with that obtained from the surface mucosal layer. The reaction of mucin and HIK1083 was inhibited by the oligosaccharides obtained by the alkaline borohydride reduction of antigenic mucin. Two purified oligosaccharide alditols reacting with the monoclonal antibody obtained from the antigenic mucin had one and two peripheral alpha-linked N-acetylglucosamine residues, respectively, according to the evidence from NMR spectroscopy. Moreover, among the commercially available p-nitrophenyl derivatives of monosaccharides, only p-nitrophenyl-N-acetyl-alpha-D-glucosaminide inhibited the reaction of this monoclonal antibody and the antigenic mucin in a concentration-dependent manner. These results, as well as the immunohistochemical observations, indicate that alpha-linked N-acetylglucosamine residues are specifically attached to the peripheral region of the carbohydrate moiety of the mucin synthesized in and secreted from the gastric-gland-type cells, and indicate that the monoclonal antibody HIK 1083 recognizes this structure.

Cleavage specificity of coxsackievirus 3C proteinase for peptide substrate (2): Importance of the P2 and P4 residues

Coxsackievirus 3C proteinase (3Cpro) cleaves between Gln and Gly, but additional amino acids are required to constitute a cleavage site. To investigate the additional sequence requirements, cleavages of the peptide substrate, and its derivatives were examined. Substitutions of each residue from the P2 to P5 positions showed the importance of the P2 Phe and P4 Ala for recognition by 3Cpro.

Interaction of the Rho family small G proteins with kinectin, an anchoring protein of kinesin motor

The Rho family small G proteins are implicated in various cell functions, such as cell morphological change, cell motility, and cytokinesis. However, their modes of action in regulating these cell functions remain to be clarified. In the present study, we have isolated a cDNA encoding a protein which interacts with the GTP-bound form, but not with the GDP-bound form, of the Rho family members, including RhoA, Racl, and Cdc42, by the yeast two-hybrid method. This protein is kinectin, known to be a vesicle membrane anchoring protein of kinesin, which is an ATPase motor transporting vesicles along microtubules.

Estimation of the number of O-linked oligosaccharides per heavy chain of human serum IgA1 by matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOFMS) analysis of the hinge glycopeptide

In our previous study, gas-phase hydrazinolysis was used to analyze the glycoform of the O-linked oligosaccharide of human serum IgA1. All O-linked oligosaccharide chains are known to be present in the hinge portion. However, the number of O-linked oligosaccharide chains on IgA1 remained unclear. In order to determine the number of linked sugar chains, we applied matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOFMS) to the hinge glycopeptide prepared from human serum IgA1. MALDI-TOFMS did not show clear peaks, probably due to the microheterogeneity of the structure of each sugar chain. However, elimination of peripheral sialic acid and galactose residues by sequential treatment with neuraminidase and beta-galactosidase gave clear mass spectra with several sharp peaks. On the basis of these spectra, we conclude that IgA1 prepared from normal human serum carries different numbers of sugar chains. There are two major populations, one contains five GalNAc residues and the other four GalNAc residues. On the other hand, the hinge glycopeptide prepared from myeloma IgA1 was composed mainly of one population containing four GalNAc residues. Earlier, we reported incomplete glycosylation of IgA1 isolated from the serum of an IgA1 myeloma patient. In this experiment, the presence of four O-linked oligosaccharides per heavy chain of IgA1 from a myeloma patient was found. The reason why only four out of five sites on the hinge glycopeptide were fully glycosylated in the IgA1 from the IgA1 myeloma patient is not clear.

[Emergency internal carotid artery ligation using near infrared spectroscopy]

We anesthetized a patient who received an emergency internal carotid artery ligation. Regional cerebral oxygen saturation (rSO2) was measured with near infrared spectroscopy (NIRS) during the whole anesthetic course. The sensor was placed on the left forehead of the patient. Decrease in blood pressure was reflected in the decrease in rSO2. The rSO2 was not altered by internal carotid ligation. However, cerebral infarction in the middle cerebral artery region, the onset of which remained unclear, was revealed postoperatively, regardless of a stable rSO2 during the operation. This monitor may provide useful information regarding the cerebral circulation during the operation in such a case as the present one, but this monitor reflects only the oxygenation of the region on which the sensor was placed. Thus, we should keep in mind the limitation in detecting cerebral dysfunction using NIRS.

[Clinical evaluation of a new programmable syringe infusion pump]

A new programmable syringe infusion pump, Auto Syringe Model AS 40 A, was evaluated for infusion of muscle relaxants, vasodilators and opioids in 4 surgical patients. Every drug mentioned above was easily adjusted according to surgical requirement in these patients. Auto Syringe Model AS40A is light and compact. Its major advantages lie in the mechanisms for delivery of a bolus dose and automated delivery of intermittent doses, automatic rate calculation, and the applicability to various sizes of syringes. Auto Syringe Model AS40A was found to be very useful for intravenous infusion of drugs.

ROM7/BEM4 encodes a novel protein that interacts with the Rho1p small GTP-binding protein in Saccharomyces cerevisiae

The RHO1 gene encodes a homolog of the mammalian RhoA small GTP-binding protein in the yeast Saccharomyces cerevisiae. Rho1p is localized at the growth site and is required for bud formation. The RHO1(G22S, D125N) mutation is a temperature-sensitive and dominant negative mutation of RHO1, and a multicopy suppressor of RHO1(G22S, D125N), ROM7, was isolated. Nucleotide sequencing of ROM7 revealed that it is identical to the BEM4 gene (GenBank accession number L27816), although its physiological function has not yet been reported. Disruption of BEM4 resulted in the cold- and temperature-sensitive growth phenotypes, and cells of the deltabem4 mutant showed abnormal morphology, suggesting that BEM4 is involved in the budding process. The temperature-sensitive growth phenotype was suppressed by overexpression of RHO1, ROM2, which encodes a Rho1p-specific GDP/GTP exchange factor, or PKC1, which encodes a target of Rho1p. Moreover, glucan synthase activity, which is activated by Rho1p, was significantly reduced in the deltabem4 mutant. Two-hybrid and biochemical experiments revealed that Bem4p directly interacts with the nucleotide-free form of Rho1p and, to lesser extents, with the GDP- and GTP-bound forms of Rho1p, although Bem4p showed neither GDP/GTP exchange factor, GDP dissociation inhibitor, nor GTPase-activating protein activity toward Rho1p. These results indicate that Bem4p is a novel protein directly interacting with Rho1p and is involved in the RHO1-mediated signaling pathway.

Abundance of Gal beta 1,3GalNAc in O-linked oligosaccharide on hinge region of polymerized IgA1 and heat-aggregated IgA1 from normal human serum

Gas-phase hydrazinolysis was used to analyze the glycoform of the O-linked oligosaccharide of human serum IgA1. In our previous report, only one glycoform was obtained from the IgA1 of healthy individuals. However, it was found to be composed of heterogeneous IgA1 components having mutually different glycoforms. First, the IgA1 was separated into two subfractions having different affinities toward jacalin. Among them, the high-affinity subfraction was mainly composed of polymerized IgA1. Comparative study of the carbohydrate chain showed a relative abundance of Gal beta 1,3GalNAc in the polymerized form. A simultaneous analysis of the N-glycan of these subfractions was also carried out. Three major components, two biantennary and one triantennary oligosaccharides, were obtained from both subfractions and the relative contents of these components were almost the same. On the other hand, IgA1 was artificially polymerized by heating at 63 degrees C for 2 h. The heat-stable IgA1 was separated from the heat-aggregated material on a Sephacryl S-300 column. The obtained heat-stable IgA1 (approximately 20%) was not further aggregated by more heating under the same conditions. The heat-stable IgA1 contained a much higher amount of the sialylated Gal beta 1,3GalNAc. Thus, it was shown that the degree of completeness of the hinge O-linked oligosaccharide might be correlated with the stability and polymerization process of the IgA1 molecule.

Mechanism of multiple aminoglycoside resistance of kasugamycin-producing Streptomyces kasugaensis MB273: involvement of two types of acetyltransferases in resistance to astromicin group antibiotics

The biochemical basis for the multiple resistance to aminoglycoside antibiotics (AGs) of kasugamycin-producing Streptomyces kasugaensis MB273 was studied. The strain was resistant to a wide range of deoxystreptamine (DOS)-containing AGs as well as astromicin (ASTM) group antibiotics. These AGs strongly inhibited in vitro polyU-directed polyphenylalanine-synthesis using ribosomes from the strain, while they were acetylated and inactivated by the MB273 cell free extract supplemented with acetyl-CoA. It seemed thus likely that the acetyltransferase activity played a critical role for the multiple AG resistance. The acetylation was selective to AGs with 2'-NH2, suggesting the involvement of aminoglycoside 2'-N-acetyltransferase, AAC (2'). Interestingly, the acetylation of istamycin B (ISM-B; an ASTM group AG) resulted in the formation of two different products (1-N-acetyl ISM-B and 2"-N-acetyl ISM-B) at a similar ratio. In this context, an AAC (2') gene cloned as an ISM-B resistance gene from the strain MB273 directed the conversion of ISM-B to only 1-N-acetyl ISM-B. It seemed likely that two types of AACs [AAC(2') and a novel one] were involved in the mechanism of resistance to ASTM group AGs.

Association of asialo-galactosyl beta 1-3N-acetylgalactosamine on the hinge with a conformational instability of Jacalin-reactive immunoglobulin A1 in immunoglobulin A nephropathy

The O-glycans in Jacalin-binding immunoglobulin A1 (IgA1) were released by gas-phase hydrazinolysis and were fractionated by gel filtration and reversed-phase HPLC. Four peaks (P1 to P4) were obtained. There was a significant shift from Peak 2 (monosialylated Gal beta 1-3GalNAc) to Peak 4 (asialo-Gal beta 1-3GalNAc) in the IgA-nephropathy group compared with the negative control group (P < 0.05). One of the functions of the carbohydrate side chains is to stabilize the three-dimensional structure of the glycopeptides. In order to evaluate the stability of the Jacalin-binding IgA1 molecule, the increase in turbidity as a consequence of the increase of the aggregated IgA1 level under the condition of high temperature (63 degrees C) was observed. The increase in the turbidity was significantly higher in the IgA nephropathy group compared with the negative control group (21.7 vs. 5.9% at 150 min, P < 0.02). From a sample of IgA1 solution that had originated from a pooled normal serum, heat-tolerant (nonaggregated) and intolerant (aggregated) IgA1 molecules were separated by gel filtration. The heat-intolerant IgA1 had lower amounts of sialic acid (27.4 micrograms/mg IgA1) than the tolerant IgA1 (37.6 micrograms/mg IgA1). Further, the analysis of the O-glycans released from another IgA1 sample by the hydrazinolysis revealed that the ratio of the asialo-Gal beta 1-3GalNAc/total Gal beta 1-3GalNAc in the heat-in-tolerant IgA1 (27.2%) was increased compared with that in the heat-tolerant IgA1 (18.2%). From these results, it was suggested that unusual glycosylation on the hinge region of Jacalin-binding IgA1 induced an insufficient conformational stiffness to the hinge peptide, resulting in the aggregation of the IgA1 molecule in IgA nephropathy.

Disordered expression of glycolytic and gluconeogenic liver enzymes of juvenile visceral steatosis mice with systemic carnitine deficiency

A quantitative study of the effect of carnitine deficiency on expression of glycolytic and gluconeogenic enzymes was performed using juvenile visceral steatosis mice which are systemically deficient in carnitine. The amounts of glucokinase and L-type pyruvate kinase mRNA were reduced in homozygotes, compared to heterozygotes and normal controls at 2 and 8 weeks. Liver-type phosphofructokinase, however, did not differ significantly. The abundance of fructose 1,6-bisphosphatase mRNA was unchanged at 2 and 8 weeks. The level of phosphoenolpyruvate carboxykinase mRNA was increased slightly at 2 weeks, but not at 8 weeks. A part of these changes could not be explained by the plasma glucose or insulin level. Carnitine administration restored the mRNA of these enzymes to normal levels. These results suggest that carnitine deficiency affects the expression of these liver enzymes.

Enzymatic 2'-N-acetylation of arbekacin and antibiotic activity of its product

Aminoglycoside antibiotics (AGs) with a free 2'-amino group were subjected to enzymatic N-acetylation using a cell free extract that contained an aminoglycoside 2'-N-acetyltransferase, AAC (2'), derived from a kasugamycin-producing strain of Streptomyces kasugaensis. TLC and antibiotic assay of the incubated reaction mixtures revealed that a modified compound retaining substantial antibiotic activity was formed from arbekacin (ABK), while modification of the other AGs resulted in the marked decrease in antibiotic activity. Structure determination following isolation from a large scale reaction mixture showed the modified ABK to be 2'-N-acetyl ABK. In addition, 2',6'-di-N-acetyl ABK was formed as a minor product. The same conversion also occurred with dibekacin (DKB) resulting in the formation of 2'-N-acetyl DKB and 2',6'-di-N-acetyl DKB. MIC determination showed antibacterial activity (1.56 approximately 3.13 micrograms/ml) of 2'-N-acetyl ABK against a variety of organisms. By contrast, 2'-N-acetyl DKB showed no substantial antibiotic activity. We believe 2'-N-acetyl ABK has the highest and broadest antibacterial activity, compared with known N-acetylated AGs.

Stimulation of mucin biosynthesis in rat gastric mucosa by FRG-8813 and its structural analogs

Certain chemical properties, which may determine the stimulatory actions of the new histamine H2 receptor antagonist, FRG-8813 (2-(furfurylsulfinyl)-N-(4-[4-(piperidinomethyl)-2-pyridyl]o xy-(Z)- 2-butenyl)acetamide), on mucin biosynthesis, were identified by considering the derivation of this drug using an organ culture system of the rat stomach. [3H]Glucosamine and [35S]sulfate incorporation was stimulated in the corpus region by FRG-8813 and its structural analog, compound A (N-[4-[[4- (piperidinylmethyl)pyridyl]-2-oxy]-(Z)-2-butenyl]phthalimide). The chronotropic response to histamine in the guinea pig right atria was suppressed by FRG-8813 in a concentration-dependent fashion. In contrast, compound A did not suppress the histamine-induced response. Ranitidine at 10(-4) M did not suppress the FRG-8813-induced increase in [3H]glucosamine incorporation into mucin. These results suggest that the pyridine derivative and amide structure are chemically important in FRG-8813 as a stimulant on mucus metabolism. Also, this effect is not directly due to histamine H2 receptor antagonism.

Altered expression of carnitine palmitoyltransferase II in liver, muscle, and heart of mouse strain with juvenile visceral steatosis

We conducted a quantitative study of the effect of carnitine deficiency on the mRNA level of carnitine palmitoyltransferase II in the liver, muscle and heart of mice with juvenile visceral steatosis, a strain that is systematically deficient in carnitine. The amount of carnitine palmitoyltransferase II mRNA was increased in liver and muscle of homozygotes, as compared with heterozygotes and normal controls, at 2, 4, and 8 wk of age. The mRNA levels of this enzyme were normalized after carnitine administration. The mRNA level of carnitine palmitoyltransferase II in the heart was increased only at 8 wk, and was not affected by carnitine administration. These results suggest that carnitine displays some effect on the mRNA level of the carnitine palmitoyltransferase II gene in liver and muscle, probably through fatty acid metabolic change.

Disordered expression of hepatic glycolytic and gluconeogenic enzymes in Otsuka Long-Evans Tokushima fatty rats with spontanteous long-term hyperglycemia

Expression of key regulatory enzymes involved in glucose metabolism was studied in the livers of Otsuka Long-Evans Tokushima fatty (OLETF) rats, a model of non-insulin dependent diabetes mellitus. The activity and mRNA levels of glucokinase and L-type pyruvate kinase was increased in the liver of OLETF rats compared with control rats. There was no such remarkable change in liver-type phosphofructokinase. The activities of glucose-6-phosphatase and fructose-1,6-biphosphatase also increase despite high plasma levels of glucose and insulin. The activity of phosphoenolpyruvate carboxykinase did not show any significant change. The mRNA levels for fructose-1,6-biphosphatase, and phosphoenolpyruvate carboxykinase exhibited no marked changes. These results suggest that the expression of glucose-6-phosphatase and fructose-1,6-biphosphatase is disordered in OLETF rats.

Reactivity of glomerular and serum IgA1 to jacalin in IgA nephropathy

To analyze O-linked oligosaccharides (O-glycans) in the hinge region of IgA1 in IgA nephropathy (IgAN), the reactivity of IgA1 to jacalin, which specifically binds to O-glycans, was investigated. Initially, renal biopsy specimens from 5 patients with IgAN and 3 patients with other renal diseases were investigated in an immunofluorescence study with jacalin, monoclonal antihuman IgA1 and IgA2 antibodies. All of the renal biopsy specimens of IgAN and none of other renal diseases were positively stained by both FITC-labeled jacalin and monoclonal anti-IgA1 antibody. The glomerular staining patterns of FITC-jacalin were similar to those of the monoclonal anti-IgA1 antibody. IgA2 was negative in all specimens. Based on the positive reactivity of deposited IgA1 to jacalin, the binding ability of serum IgA1 to jacalin was evaluated by inhibition assay using D-galactose in patients with IgAN (n = 58), other primary glomerulonephritides (PGN) (n = 41), and healthy controls (n = 52). The frequencies of the patients with serum IgA1 having a high affinity for jacalin were significantly greater in IgAN (19/58, 32.8%) compared with the healthy controls (2/52, 3.8%) and other PGN (4/41, 9.8%). These results suggested that the increased reactivity of O-glycan(s) in the IgA1 hinge region to jacalin is due to an unusual glycosylation of serum IgA1 in IgAN.

Effects of traditional herbal medicine on gastric mucin against ethanol-induced gastric injury in rats

The effect of the traditional herbal medicine, Rikkunshi-to and its component crude drugs, Zingiberis Rhizoma and Glycyrrhizae Radix, on the gastric mucin was studied using a method developed to separate and quantify the mucin localized in the different layers of rat gastric mucosa. The oral administration of spray-dried extract to Rikkunshi-to (1000 mg/kg), Zingiberis Rhizoma (500 mg/kg) and Glycyrrhizae Radix (500 mg/kg) significantly prevented gastric mucosal damage induced by 70% ethanol in rats. In ethanol-treated rats the mucin content of the deep mucosa was reduced, and the reduction of the deep corpus mucin content was significantly inhibited by pretreatment of Rikkunshi-to and Zingiberis Rhizoma. Rikkunshi-to and Glycyrrhizae Radix pretreatment increased the surface mucin content by 140 and 146%, respectively. The effect on the gastric mucin by each drug differed in the different layers of the gastric mucosa.

Mechanisms for cytoprotection by vitamin U from ethanol-induced gastric mucosal damage in rats

A comparison was made of the effects of a nonsulfhydryl compound, vitamin U (methylmethioninesulfonium chloride, MMSC), and a sulfhydryl compound, cysteine (Cys), with regard to the inducement of acute gastric mucosal damage in the presence and absence of N-ethylmaleimide (NEM), a sulfhydryl-blocking reagent. The effects of MMSC, Cys, or NEM on gastric mucin content were examined using a newly developed biochemical method. MMSC and Cys inhibited mucosal damage due to 50% ethanol. The preinjection of NEM had no effect on cytoprotection of prostaglandins, but prevented the effects of Cys and MMSC. MMSC and Cys increased surface mucin content but lessened that of deep mucin. NEM decreased surface mucin and increased deep mucin. It thus follows that sulfhydryl compounds accelerate the secretion of deep mucin and accumulate surface mucin. The cytoprotective mechanism of MMSC may thus be mediated by sulfhydryl compounds, and the increase in surface mucosal mucin may possibly be related to cytoprotection.

Gastric mucosal damage accompanying changes in mucin induced by histamine in rats

The present study was carried out to clarify the mechanism of histamine-induced gastric mucosal damage in rats. Following an injection of histamine (80 mg/kg), pH dropped within 30 min. and then recovered control value (pH = 4-5) 4 hr later. The decrease in mucosal mucin content and the appearance of haemorrhagic erosions followed the drop in pH. The recovery of mucosal mucin content preceded the healing of haemorrhagic erosions and pH recovery to the control level. Histamine also caused qualitative changes in corpus mucins. These qualitative changes induced by histamine were eliminated at 7 hr following the administration of histamine. It appears from the present results that increase in HCl and decrease in mucins induced by histamine bring about gastric damage.

PCR inhibition assay for DNA-targeted antibiotics

DNA amplification by polymerase chain reaction (PCR) should be inhibited if the target for amplification region in the template DNA is nicked or cut. Based on this premise, we established a sensitive and differential assay using PCR to detect antibiotics that act on DNA. After template lambda DNA (10 pg) was incubated with antibiotics (10 approximately 20 ng) at 37 degrees C for 30 minutes in a 5 microliters reaction volume, a PCR assay (10 microliters reaction volume; 25 approximately 30 cycles) was performed under the conditions we modified, resulting in amplification of a 500 bp fragment of lambda DNA which was monitored by agarose gel electrophoresis. Among the several antibiotics examined, the anthracyclines, bleomycin, D-cycloserine and mitomycin C clearly inhibited the PCR amplification reaction, whereas actinomycin D and ofloxacin did not. Preincubation of template DNA in the presence of Fe++ was necessary for bleomycin and cycloserine to exhibit marked inhibition of PCR. Mitomycin C exhibited the inhibition in the presence of DTT and Cu+. By contrast, non-DNA-acting antibiotics (200 ng) such as aminoglycosides, beta-lactams, and macrolides showed no inhibition. The PCR-amplified fragment from lambda DNA was not degraded by incubation with the antibiotics (20 ng) that inhibited PCR. Furthermore, ethylacetate extracts of the cultured broths of actinomycetes proved to be suitable as samples for this PCR inhibition assay.

[Binding of IgA1 to monocyte/macrophage cell lines (THP-1, U937) in IgA nephropathy--a possible role of O-glycan in the IgA1 molecule]

IgA1 is an exceptional serum glycoprotein because it has O-glycans in the hinge region. It has been observed that the monocyte/macrophages infiltrate within the glomeruli in IgA-N. On the other hand, it is well established that the carbohydrate side chains (N-glycans) of the IgG molecule play a role in the binding of IgG to Fc receptors. Therefore, the binding of IgA1 to monocyte/macrophage cell lines was observed with the aim of clarifying the role of the O-glycan side chains in IgA-N in the initial mechanism of glomerular damage due to the interaction between the O-glycan chains on the IgA1 molecule and infiltrating monocyte/macrophages. Two human myelomonocytic cell lines, THP-1 and U-937, were activated and incubated with separated IgA1 (IgA-N, n = 16; other glomerulonephritides (other GN), n = 15; healthy controls, n = 9). The binding attitude of IgA1 to the cell lines was observed by flow immunofluorometry using a FACScan. FACScan showed that the binding of IgA1 to both of the stimulated monocyte/macrophage cell lines was increased in IgA-N compared to the normal controls and other GN. The binding of IgA1 to THP-1 was partially, but definitely inhibited by adding 100 mM melibiose (19.6 +/- 7.7%) and galactose (13.1 +/- 2.9%), but not glucose (2.9 +/- 2.2%), lactose (4.7 +/- 4.7%) and mannose (3.3 +/- 3.3%). These results suggested that THP-1 had a receptor that recognized the O-glycan in the IgA1 hinge region.(ABSTRACT TRUNCATED AT 250 WORDS)

Concentration of soluble vascular cell adhesion molecule-1 (VCAM-1) correlated with expression of VCAM-1 mRNA in the human atherosclerotic aorta

BACKGROUND

Adherence of circulating monocytes and lymphocytes to arterial endothelium is detectable early in experimental and human atherosclerotic plaque formation. The purpose of the present study was to assess vascular cell adhesion molecule-1 (VCAM-1) mRNA expression and the properties of soluble VCAM-1 in patients with atherosclerotic aortic disease.

METHODS

Thirteen patients with aortic disease (mean age 64 years) and 40 healthy volunteers (mean age 32 years) were included in the study. We investigated the expression of VCAM-1 mRNA in eight human aortic specimens obtained during surgery. Of these, two showed no evidence of atherosclerotic plaque formation [aortic dissection (n = 1) and annuloaortic ectasia (n = 1)], whereas six had demonstrable complex atherosclerotic formation [abdominal aneurysm (n = 5) and aortic dissection (n = 1)]. The RNase protection assay was performed using an alpha 32P-labeled 121 base pair VCAM-1 cRNA probe. We also measured concentrations of the soluble VCAM-1 using two-site enzyme immunoassays in 40 healthy volunteers and in 13 patients with abdominal and thoracic aortic aneurysms.

RESULTS

In human samples, VCAM-1 mRNA expression was found to be higher in the six patients with complex atherosclerotic formation [optical density (OD), 0.71 +/- 0.14] than in the two patients with no evidence of atherosclerotic plaque formation (OD, 0.53 and 0.49). The concentration of serum soluble VCAM-1 was higher (850 +/- 298 ng/ml) in patients with aortic or thoracic disease than in the healthy volunteers (494 +/- 94 ng/ml). In addition, there was a relationship between VCAM-1 mRNA expression and the concentration of soluble VCAM-1 (y = 2088x-554, r2 = 0.73).

CONCLUSION

VCAM-1 expression is higher in the human aorta in patients with atheromatous changes. Furthermore, concentrations of soluble VCAM-1 may provide important information about endothelial activation or in-vivo damage.

The presence of 2-keto-3-deoxygluconic acid and oxoaldehyde dehydrogenase activity in human erythrocytes

2-Keto-3-deoxygluconic acid (3-DGA) is produced from 3-deoxyglucosone (3-DG:a highly reactive glycation intermediate) through oxidation by the enzyme oxoaldehyde dehydrogenase (OAD) in animals. We developed a specific assay method for 3-DGA using high-performance liquid chromatography [Fujii, E. et al. (1994) J. Chromatogr. B 660, 265-270] and measured it in the hemolysate and plasma of diabetic patients and healthy subjects. Both human erythrocytes and plasma contained considerable amounts of 3-DGA. However, human erythrocyte contained about 30-50 times higher 3-DGA than human plasma did and also had the same ability to convert 3-DG to 3-DGA as OAD had. Erythrocyte 3-DGA levels of diabetic patients were 990 +/- 370 nmol/gHb (n = 57, Mean +/- SD) and were significantly higher compared with healthy subjects (527 +/- 194 nmol/gHb, n = 7, p < 0.01). In all diabetic patients and healthy subjects (n = 64), there was only one patient who had a very low level of erythrocyte 3-DGA and lacked the ability to convert 3-DG to 3-DGA. When erythrocytes were incubated at 37 degrees C for 8 hours in phosphate buffer containing 0.35 mM 3-DG, 3-DG was easily taken into the erythrocytes and was converted to 3-DGA. Our results suggest the contribution of OAD not only to the prevention of glycation of hemoglobin but also to that of blood vessels by scavenging plasma 3-DG into erythrocytes.