N-acetyl-L-cysteine suppresses constitutive expression of CD11a/LFA-1alpha protein in myeloid lineage

We investigated the possible involvement of redox regulation in constitutive expression of CD11a/LFA-1alpha, a leukocyte integrin alpha subunit, in myeloid cells using antioxidants. In unstimulated HL-60 cells, CD11a/LFA-1alpha was highly expressed, however, no expression of CD11b and CD11c proteins was detected. N-acetyl-L-cysteine (NAC) markedly down-regulated CD11a/LFA-1alpha expression in a dose-dependent manner. The down-regulated CD11a/LFA-1alpha expression was gradually recovered when NAC was deprived 24h after treatment. Pyrrolidine dithiocarbamate (PDTC) also suppressed the level of expression CD11a/LFA-1alpha protein, although the effect of PDTC was less potent than NAC. Both NAC and PDTC suppressed NF-kappaB binding activity to consensus DNA probe, and this result was correlated with a suppressive effect to CD11a/LFA-1alpha expression. Furthermore, NAC also down-regulated CD11a/LFA-1alpha expression in both U937 cells and peripheral blood monocytes. These results indicated that the constitutive CD11a/LFA-1alpha expression in the myeloid lineage is implicated in oxidative stress occurring spontaneously, suggesting that alteration of the intracellular redox state using antioxidants may be effective in the modulation of cell adhesion associated with extravasation in leukocytes, at least, in myeloid cells.     

Acute humoral rejection and C4d immunostaining in ABO blood type-incompatible liver transplantation.

Complement C4d deposition in graft capillaries has been reported to be associated with antibody-mediated rejection in kidney and other solid organ transplantation. The correlation of C4d deposits and humoral rejection in liver transplants, however, is not well understood. We investigated the C4d immunostaining pattern in 34 patients whose liver biopsy was taken within the first 3 postoperative weeks for suspected acute rejection after ABO blood type-incompatible liver transplantation. The staining pattern was classified as positive (portal stromal staining), indeterminate (endothelial staining only), and negative (no staining). Positive C4d immunostaining was seen in 17 (50%) patients and was significantly associated with high (x64 or more) postoperative antidonor A/B antibody (immunoglobulin M (IgM)) titers (88 vs. 35%, P = 0.002) and poorer overall survival rate (41 vs. 88%, P = 0.007). Ten of 11 (91%) cases with histological acute humoral rejection (periportal edema and necrosis (PEN) or portal hemorrhagic edema) were positive for C4d, all of which showed high postoperative antibody titers. The other histologies associated with C4d positivity was purulent cholangitis (n = 4), coagulative hepatocyte necrosis (n = 1), acute cellular rejection (n = 1), and hepatocanalicular cholestasis (n = 1). Full clinical recovery was observed in only 6 of 17 (35%) C4d-positive patients, and tended to be associated with a lower rejection activity index (RAI). In conclusion, our study indicates that C4d deposits in the portal stroma can be a hallmark of acute humoral rejection in ABO-incompatible liver transplantation, and allograft damage can be reversible in a minority of cases.     

67Ga-Binding substances in abscess and normal tissues

Abscess-induced animals and normal animals were treated with ⁶⁷Ga-citrate. Abscess, kidney, heart, lung, and spleen were excised and homogenized. After removal of the nuclear fraction, each of these homogenates was digested with protease. After digestion, the supernatants of the reaction mixtures were applied to a Sephadex G-100 column. Resultant eluates were analyzed for radioactivity, protein, uronic acids, and sialic acids. Sodium sulfate-²⁵S was administered to animals that were then treated by the same procedure as that followed for animals treated with ⁶⁷Ga-citrate. In abscess, kidney, lung, heart, and spleen, sizeable amounts of ⁶⁷Ga had been bound to the sulfated acid mucopolysaccharides with molecular weights of about 10,000, and to the sulfated acid mucopolysaccharides, a species whose molecular weights exceeded 40,000. Based on the results presented here, it is clear that ⁶⁷Ga-binding substances in abscess and also in the above four organs are sulfated acid nucopolysaccharides.     

Effect of pitavastatin on macrophage cholesterol metabolism

OBJECTIVES: Pitavastatin is the first totally synthetic HMG-Co A reductase inhibitor in Japan that significantly reduces LDL cholesterol while raising HDL cholesterol. Clinical trial showed that pitavastatin has potent effects for LDL cholesterol lowering and is expected effectively to prevent atherosclerosis. To clarify the mechanism of reduction of atherosclerosis by pitavastatin, we examined the effect of pitavastatin on foam cell formation of RAW264.7 macrophages. METHODS & RESULTS: Macrophages were cultured with pitavastatin for 24 h and exposed to oxidized LDL with pitavastatin for 3 days. Pitavastatin decreased the cellular cholesteryl ester content in a dose-dependent manner, and this effect was not via inhibition of HMG-CoA reductase because the 3-30 nM pitavastatin did not inhibit [14C]cholesterol synthesis from [14C]acetic acid and the effect was not influenced by addition of mevalonic acid. Pitavastatin increased neutral cholesterol esterase (NCEase) activity and did not affect ACAT activity, and decreased the expression of CD36 and ABCA1 mRNA. The mechanism of the increase of NCEase activity was that pitavastatin directly modified the substrate state, which was cholesterol oleate emulsified with lecithin. CONCLUSION: Clinical blood concentrations of pitavastatin prevent foam cell formation of RAW macrophages by oxidized LDL, and this was not via inhibition of HMG-CoA reductase, and modify substrate condition.     

Fundamental evaluation of apolipoprotein B-48 by chemiluminescence enzyme immunoassay--identification of apolipoprotein B-48 with immunoblotting

BACKGROUND: Apolipoprotein B-48 (apo B-48) is a constituent of chylomicrons and chylomicron remnants, and its fasting concentration has been reported to be a marker of postprandial hyperlipidemia, which is thought to be a risk factor of atherosclerosis. AIM: We evaluated the serum apo B-48 concentrations by chemiluminescence enzyme immunoassay (CLEIA), which was recently introduced as Lumipulse f fully automated immunosaasy analyzer by Fujirebio Inc (Tokyo, Japan), and performed immunoblotting on agarose gel electrophoresis with anti-apo B-48 antibody. RESULTS: Apo B-48 assay was intra-assay reproducible (CVs: 1.9-3.1%) and inter-assay reproducible (CVs: 2.2-4.4%). The assay range for apo B-48 was from 0.2 to 40.0 microg/ml. The effects of interfering substances such as free/conjugated birirubin, hemoglobin, Intrafat, ascorbic acid and rheumatoid factor were negligible. For storage, it was preferable to freeze, and to avoid frozen-thaw process as much as possible. Anti-apo B-48 antibody was reactive over a wide range from origin to the position of very-low-density lipoproteins in immunoblotting after agarose gel electrophoresis. CONCLUSION: Apo B-48 measurement by CLEIA was feasible to clinical use for the assessment of lipoprotein metabolism.