Stimulation side-dependent asymmetrical secretion of poly I:poly C-induced interferon-beta from polarized epithelial cell lines

Mode of secretion of poly I:poly C-induced IFN was examined using epithelial cell lines in a bicameral culture system. Although the cell lines formed a tight cell sheet and produced IFN-beta following poly I:poly C treatment in spite of its application to the upper or lower compartment, IFN secretion differed between the apical and basolateral cell membranes. When poly I:poly C was applied to the upper compartment, IFN was secreted predominantly from the apical membrane. Inversely, poly I:poly C applied to the lower compartment caused preferential IFN secretion from the basolateral membrane. These results suggest that in epithelial cells poly I:poly C stimulation induces intracellular membrane traffic toward the stimulation side.

Novel selective inhibitors for human topoisomerase I, BM2419-1 and -2 derived from saintopin

Compounds BM2419-1 and -2 were isolated from a culture broth of a fungus Paecilomyces sp. BM2419. It was shown that these novel compounds were artifacts derived from saintopin, a dual inhibitor of topoisomerase I and II by independent processes. In the human topoisomerase I inhibition assay using the recombinant Saccharomyces cerevisiae, BM2419-1 and -2 inhibited selectively the yeast growth dependent on human topoisomerase I induction with IC50 values of 0.3 ng/ml and 6.0 ng/ml, respectively.

Asialoglycoprotein receptor-mediated gene transfer using novel galactosylated cationic liposomes

We synthesized three novel galactosylated cholesterol derivatives, cholesten-5-yloxy-N-(4-((1-imino-c-beta-D-thiogalactosyl+ ++-ethyl)amino) butyl)formamide (Gal-C4-Chol) and its ethyl formamide and hexyl formamide analogues (Gal-C2-Chol, Gal-C6-Chol), to prepare liposomal gene carriers possessing the cationic charge necessary for plasmid DNA binding and galactose residues as a targetable ligand for liver parenchymal cells. Liposome/DNA complexes prepared with these lipids showed low cytotoxicity in human hepatoma HepG2 cells. Gal-C4-Chol/DC-Chol/DOPE(3:3:4) liposomes, consisting of 3:3:4 mixtures of Gal-C4-Chol, 3beta[N',N', N'-dimethylaminoethane)-carbamoyl] cholesterol (DC-Chol), and dioleoylphosphatidylethanolamine (DOPE), showed higher transfection activity and [32P]DNA uptake than DC-Chol/DOPE(6:4) liposomes. The presence of 20 mM galactose significantly inhibited both transfection efficiency and uptake of DNA of Gal-C4-Chol/DC-Chol/DOPE(3:3:4) and Gal-C4-Chol/DOPE(6:4) liposomes, but not those of DC-Chol/DOPE(6:4) liposomes. These results indicate that the liposome/DNA complexes prepared using novel galactosylated cholesterol derivatives are efficiently recognized by asialoglycoprotein receptors and internalized and lead to gene expression. In addition, we found that the galactosylated cholesterol derivative with a longer spacer showed higher transfection activity.

Dipeptide uptake and transport characteristics in rabbit tracheal epithelial cell layers cultured at an air interface

PURPOSE

To determine the functional presence ofa H+/peptide cotransport process in rabbit tracheal epithelial cell layers cultured at an air-interface and its contribution to transepithelial dipeptide transport.

METHODS

Rabbit tracheocytes were isolated, plated on Transwells, and cultured at an air-interface. After 5 or 6 days in culture, uptake and transepithelial transport of carnosine were examined.

RESULTS

Carnosine uptake by tracheocytes was pH-dependent and was saturable with a Michaelis-Menten constant of 170 microM. Moreover, carnosine uptake was inhibited 94% by Gly-L-Phe, 28% by beta-Ala-Gly, but not at all by Gly-D-Phe or by the amino acids beta-Ala and L-His. Unexpectedly. transepithelial carnosine transport at pH 7.4 (i.e., in the absence of a transepithelial pH gradient) was similar in both the apical-to-basolateral (ab) and basolateral-to-apical (ba) directions. Lowering the apical fluid pH to 6.5 reduced ab transport 1.6 times without affecting ba transport, consistent with predominantly paracellular diffusion of carnosine under an electrochemical potential gradient.

CONCLUSIONS

The kinetic behavior of carnosine uptake into cultured tracheal epithelial cell layers is characteristic of a H+-coupled dipeptide transport process known to exist in the small intestine and the kidney. Such a process does not appear to be rate-limiting in the transport of carnosine across the tracheal epithelial barrier.

A crossover study of oral administration of UFT in chronic liver disease: comparison of continuous and intermittent schedules

This study was aimed at evaluating the tolerance to an intermittently administered oral UFT for hepatocellular carcinoma (HCC) with chronic liver disease (CLD). Ten patients who had received curative therapy for HCC with CLD (Child's classification A or B) were randomly assigned either an intermittent schedule (IS), oral administration of UFT (130 mg/m2/b.i.d.) with 2 days rest a week, or a continuous schedule (CS), consecutive administration of UFT with the same dose. On day 12, the serum concentration of 5-fluorouracil (5-FU) was measured. After 2 weeks rest, the patients were switched to the other schedule for 10 weeks and the concentration of 5-FU was measured on day 12. The median values of the area under the curve (AUC) and maximum concentration (Cmax) of 5-FU in IS and CS were 187.7 and 263.2 ng/ml/h, 57.1 and 93.0 ng/ml, respectively. Both the AUC and Cmax for IS were significantly lower than those for CS. One IS patient had tolerable diarrhea, while three of the CS patients had intolerable nausea and one had hemorrhagic gastritis. IS seemed to be a suitable measure for CLD.

Control of plasma cholesterol-lowering action of probucol with various lipid carrier systems

In order to explore the relationship between the pharmacokinetic properties and pharmacological actions of lipophilic drugs injected with lipid carrier systems, probucol was selected as a model drug with high lipophilicity, and the effect of disposition control on cholesterol-lowering activities was evaluated. Both large emulsion, with mean diameter of 280 nm, and long-circulating type small emulsion containing egg sphingomyelin with mean diameter of 100 nm, showed stable incorporation of probucol. The former produced rapid accumulation of probucol in the liver, while the latter demonstrated prolonged systemic circulation and gradual hepatic uptake. On the other hand, injection of a micellar solution with HCO-60 (polyoxyethylene hydrogenated castor oil) showed a rapid decrease in plasma concentration and a high hepatic uptake of probucol, similar to injections with serum, suggesting the rapid release of the drug from the micelles. However, probucol in a micellar solution showed higher cholesterol-lowering action than that in emulsion formulations. These results suggested that the pharmacological action of probucol in the liver might be affected by the uptake mode and sequential disposition in the organ, depending on the drug retention properties of the lipid carrier particles.

Pharmacokinetic characteristics and therapeutic effects of mitomycin C-dextran conjugates after intratumoural injection

The pharmacokinetics and therapeutic effects of macromolecular prodrugs of mitomycin C (MMC), MMC-dextran conjugates (MMC-D) were studied after intratumoural injection in rats bearing Walker 256 carcinosarcoma. As the first step, the intratumoural disposition characteristics of these drugs were delineated in perfusion experiments employing a tissue-isolated tumour preparation. While MMC immediately disappeared from the tumour preparation following direct intratumoural injection, cationic and anionic MMC-D were retained in the tumour longer, demonstrating that the intratumoural clearance of MMC can be greatly retarded by dextran conjugation. The effect was more pronounced in the case of the cationic conjugate. Venous outflow data in the perfusion experiments were analyzed based on a compartment model in which the tumour tissue was assumed to consist of two compartments, one well- and the other poorly-perfused. The pharmacokinetic analysis revealed that macromolecular conjugation reduced elimination of MMC from the poorly-perfused region rather than well-perfused region. Simulation of conjugated and free MMC levels in the tissue using the calculated parameters clearly showed that intratumoural injection of MMC-D, especially the cationic form, can maintain a certain level of active free MMC in the tissue for a much longer time period. The long retention of cationic MMC-D in tumour after intratumoural injection was also confirmed by an in vivo pharmacokinetic study and whole body autoradiography in rats bearing subcutaneous Walker 256 carcinosarcoma. In addition, superior antitumour activity of cationic MMC-D was observed against subcutaneous tumours after intratumoural injection. Together with the finding that MMC is selectively toxic to hypoxic tumour cells at low concentrations, these pharmacokinetic studies strongly support the therapeutic efficacy of the macromolecular prodrugs.

Defective stratum corneum and early neonatal death in mice lacking the gene for transglutaminase 1 (keratinocyte transglutaminase)

The stratum corneum of the skin serves as an effective barrier for maintenance of the internal milieu against the external environment. At the cell periphery of the stratum corneum is the cell envelope, a highly insoluble membranous structure composed of precursor proteins cross-linked by epsilon-(gamma-glutamyl)lysine bonds. Transglutaminase 1 (TGase 1; keratinocyte TGase), a membrane-bound isozyme of the TGase family, has been proposed to catalyze this process of assembly. Deficient cross-linking of the cell envelope in some patients with the autosomal recessive skin disorder lamellar ichthyosis (LI) and several mutations of the TGase 1 gene that have been identified in families with LI suggest the importance of this gene in production of the cell envelope. In this study, we generated mice lacking the TGase 1 gene, and we report that they have erythrodermic skin with abnormal keratinization. In their stratum corneum, degradation of nuclei and keratohyalin F-granules was incomplete and cell envelope assembly was defective. The skin barrier function of TGase 1-null mice was markedly impaired, and these mice died within 4-5 h after birth. These results clearly demonstrate that the TGase 1 gene is essential to the development and maturation of the stratum corneum and to adaptation to the environment after birth. Thus, these TGase 1 knockout mice may be a useful model for severe cases of LI.

Effect of particle size and charge on the disposition of lipid carriers after intratumoral injection into tissue-isolated tumors

PURPOSE

Pharmacokinetic properties of various lipid carriers (liposome and emulsions) after intratumoral injection were studied in perfusion experiments using tissue-isolated tumor preparations of Walker 256 carcinosarcoma.

METHODS

Four types of lipid carriers, large emulsion (254 nm), small emulsion (85 nm), neutral liposomes (120 nm) and cationic liposomes (125 nm) were prepared. We quantified their recovery from the tumor, leakage from the tumor surface and venous outflow after intratumoral injection into perfused tissue-isolated tumors, and analyzed venous appearance curves based on a pharmacokinetic model.

RESULTS

In contrast to the small emulsion and neutral liposomes, which immediately appeared in the venous outflow perfusate following intratumoral injection, the appearance of the cationic liposomes and the large emulsion was highly restricted, clearly demonstrating that intratumoral clearance of these formulations can be greatly retarded by the cationic charge and large particle size, respectively. The venous appearance rate-time profiles were fitted to equations derived from a two-compartment model by nonlinear regression analysis. When the calculated parameters were compared among these four formulations, the venous appearance rate did not exhibit such a large difference; however, the rate of transfer from the injected site to the compartment which involves clearance by venous outflow was all very different.

CONCLUSIONS

The results of this study indicate that the determining factor which alters the pharmacokinetic properties of these lipid carriers after intratumoral injection is not the rate of transfer from the interstitial space to the vascular side but the rate of intratumoral transfer from the injection site to the well-vascularized region.

Inhibition of the metallo-beta-lactamase produced from Serratia marcescens by thiol compounds

Low molecular weight thiol compounds have been found to be strong inhibitors of metallo-beta-lactamase (IMP-1) produced by Serratia marcescens TN9106, which was expressed by Echerichia coli JM109 cells. Mercaptoacetic acid and 2-mercaptopropionic acid strongly and competitively inhibited IMP-1 with Ki of 0.23 and 0.19 microM, respectively. 2-Mercaptoethanol reversibly inhibited IMP-1 but did not show simple competitive inhibition.

Intratumoral pharmacokinetics and in vivo gene expression of naked plasmid DNA and its cationic liposome complexes after direct gene transfer

The pharmacokinetic properties and gene expression of naked plasmid DNA and its cationic liposome complexes were studied after direct intratumoral injection. Using a Walker 256 tissue-isolated tumor perfusion system, we quantified the recovery of naked plasmid DNA and cationic liposome complexes in the tumor, leakage from the tumor surface, and the venous outflow after intratumoral injection. Approximately 50% of naked plasmid DNA had been eliminated from the tumor 2 h after injection, whereas more than 90% of plasmid DNA was retained in the tumor when it was complexed with cationic liposomes. However, the distribution of these complexes in the tumor was restricted to the tissue surrounding the injection site. Pharmacokinetic analysis of the venous outflow profiles suggested that the rate-limiting process that determines the retention of plasmid DNA in the tumor is transferred from the injection site in the tumor tissue and that complexation with cationic liposomes may retard this process. Furthermore, we examined the gene expression of chloramphenicol acetyltransferase DNA constructs (naked pCMV-CAT) and the corresponding cationic liposome [3-beta-(N-(N',N'-dimethylaminoethane)carbamoyl)cholesterol] complexes. A similar level of gene expression was observed in vivo after direct intratumoral injection of naked DNA and its cationic liposome complexes. In both cases, a great variation was observed between tumors, and localization of gene-transduced cells in the tumor tissue was limited to the area in the vicinity of the injection site. Thus, these pharmacokinetic and gene expression studies have demonstrated that cationic liposomes can enhance the retention of injected DNA in the tumor model, whereas cationic liposome complex does not necessarily improve gene expression because of its poor dissemination in this tumor. The present study also suggested that there is a need to control the behavior of the injected naked plasmid DNA and its cationic liposome complexes to ensure better distribution throughout the tumor.

A novel chemotherapy for advanced hepatocellular carcinoma with tumor thrombosis of the main trunk of the portal vein

BACKGROUND

Hepatocellular carcinoma (HCC) with tumor thrombosis of the main trunk of the portal vein (PVTT) has a poor prognosis. This study was designed to evaluate the efficacy of arterial infusion chemotherapy for advanced HCC of this type.

METHODS

Nine patients with HCC were treated by arterial infusion of a chemotherapeutic agent via a subcutaneously implanted injection port. One course consisted of the daily administration of cisplatin (10 mg for 1 hour on Days 1-5) and the subsequent infusion of 5-fluorouracil (250 mg for 5 hours on Days 1-5). In principle, patients were to receive four serial courses of chemotherapy.

RESULTS

The mean course of chemotherapy was 4.6 (range, 2.6-7.6) months. The serum total concentrations of alpha-fetoprotein and des-gamma-carboxyprothrombin were reduced after chemotherapy in most of the patients. Two patients showed complete response (CR) with disappearance of HCC and PVTT after treatment, and the other two showed partial response (PR) (response rate [CR + PR/All cases], 44.4%). The 3-year survival rate was 40%. The mean survival after the therapy was 14.9 (range, 4.1-48.9) months. The 50% survival was 9.2 months. Adverse reactions were tolerable nausea and loss of appetite.

CONCLUSIONS

This chemotherapeutic regimen achieved favorable results and may be useful in treating patients with HCC with tumor thrombosis of the main trunk of the portal vein.

A novel chemotherapy for advanced hepatocellular carcinoma with tumor thrombosis of the main trunk of the portal vein

BACKGROUND

Hepatocellular carcinoma (HCC) with tumor thrombosis of the main trunk of the portal vein (PVTT) has a poor prognosis. This study was designed to evaluate the efficacy of arterial infusion chemotherapy for advanced HCC of this type.

METHODS

Nine patients with HCC were treated by arterial infusion of a chemotherapeutic agent via a subcutaneously implanted injection port. One course consisted of the daily administration of cisplatin (10 mg for 1 hour on Days 1-5) and the subsequent infusion of 5-fluorouracil (250 mg for 5 hours on Days 1-5). In principle, patients were to receive four serial courses of chemotherapy.

RESULTS

The mean course of chemotherapy was 4.6 (range, 2.6-7.6) months. The serum total concentrations of alpha-fetoprotein and des-gamma-carboxyprothrombin were reduced after chemotherapy in most of the patients. Two patients showed complete response (CR) with disappearance of HCC and PVTT after treatment, and the other two showed partial response (PR) (response rate [CR + PR/All cases], 44.4%). The 3-year survival rate was 40%. The mean survival after the therapy was 14.9 (range, 4.1-48.9) months. The 50% survival was 9.2 months. Adverse reactions were tolerable nausea and loss of appetite.

CONCLUSIONS

This chemotherapeutic regimen achieved favorable results and may be useful in treating patients with HCC with tumor thrombosis of the main trunk of the portal vein.

A novel chemotherapy for advanced hepatocellular carcinoma with tumor thrombosis of the main trunk of the portal vein

BACKGROUND

Hepatocellular carcinoma (HCC) with tumor thrombosis of the main trunk of the portal vein (PVTT) has a poor prognosis. This study was designed to evaluate the efficacy of arterial infusion chemotherapy for advanced HCC of this type.

METHODS

Nine patients with HCC were treated by arterial infusion of a chemotherapeutic agent via a subcutaneously implanted injection port. One course consisted of the daily administration of cisplatin (10 mg for 1 hour on Days 1-5) and the subsequent infusion of 5-fluorouracil (250 mg for 5 hours on Days 1-5). In principle, patients were to receive four serial courses of chemotherapy.

RESULTS

The mean course of chemotherapy was 4.6 (range, 2.6-7.6) months. The serum total concentrations of alpha-fetoprotein and des-gamma-carboxyprothrombin were reduced after chemotherapy in most of the patients. Two patients showed complete response (CR) with disappearance of HCC and PVTT after treatment, and the other two showed partial response (PR) (response rate [CR + PR/All cases], 44.4%). The 3-year survival rate was 40%. The mean survival after the therapy was 14.9 (range, 4.1-48.9) months. The 50% survival was 9.2 months. Adverse reactions were tolerable nausea and loss of appetite.

CONCLUSIONS

This chemotherapeutic regimen achieved favorable results and may be useful in treating patients with HCC with tumor thrombosis of the main trunk of the portal vein.

Effects of skin metabolism on percutaneous penetration of lipophilic drugs

Effects of skin metabolism on percutaneous penetration of drugs with high lipophilicity were studied in vitro using rat skin pretreated with and without an esterase inhibitor, diisopropyl phosphorofluoridate [also known as diisopropyl fluorophosphate (DFP)]. Without DFP, about 96% of the total penetrated amount appeared as metabolized p-hydroxybenzoic acid in the receptor fluid after application of butylparaben, whereas about 30% penetrated as intact form after application of propylparaben. On the other hand, metabolized p-hydroxybenzoic acid was not defected in the receptor fluid under pretreatment with DFP. DFP significantly decreased (p < 0.05) the total amount that penetrated after application of butylparaben, but it did not significantly affect that of propylparaben. The results indicate that skin metabolism directly affects total amount that penetrated in the case of highly lipophilic drugs, and it was found that the higher metabolic rate to hydrophilic drugs is, the greater the amount that penetrated the skin would be. Thus, when optimal prodrugs are designed for the purpose of enhancing percutaneous penetration, we propose that the bioconversion rate to parent drugs as well as the lipophilicity of prodrugs becomes an important consideration.

A novel chemotherapy for advanced hepatocellular carcinoma with tumor thrombosis of the main trunk of the portal vein

BACKGROUND

Hepatocellular carcinoma (HCC) with tumor thrombosis of the main trunk of the portal vein (PVTT) has a poor prognosis. This study was designed to evaluate the efficacy of arterial infusion chemotherapy for advanced HCC of this type.

METHODS

Nine patients with HCC were treated by arterial infusion of a chemotherapeutic agent via a subcutaneously implanted injection port. One course consisted of the daily administration of cisplatin (10 mg for 1 hour on Days 1-5) and the subsequent infusion of 5-fluorouracil (250 mg for 5 hours on Days 1-5). In principle, patients were to receive four serial courses of chemotherapy.

RESULTS

The mean course of chemotherapy was 4.6 (range, 2.6-7.6) months. The serum total concentrations of alpha-fetoprotein and des-gamma-carboxyprothrombin were reduced after chemotherapy in most of the patients. Two patients showed complete response (CR) with disappearance of HCC and PVTT after treatment, and the other two showed partial response (PR) (response rate [CR + PR/All cases], 44.4%). The 3-year survival rate was 40%. The mean survival after the therapy was 14.9 (range, 4.1-48.9) months. The 50% survival was 9.2 months. Adverse reactions were tolerable nausea and loss of appetite.

CONCLUSIONS

This chemotherapeutic regimen achieved favorable results and may be useful in treating patients with HCC with tumor thrombosis of the main trunk of the portal vein.

In vivo evaluation of acyclovir prodrug penetration and metabolism through rat skin using a diffusion/bioconversion model

PURPOSE

In order to evaluate the in vivo penetration of prodrugs which undergo metabolism in skin, we analyzed the in vivo penetration profiles of acyclovir prodrugs based on a two-layer skin diffusion model in consideration of metabolic process.

METHODS

Acyclovir prodrugs (e.g., valerate, isovalerate and pivarate) were used as model prodrugs and the amounts excreted in urine were measured after percutaneous application. In vivo penetration profiles were then estimated by employing a deconvolution method and the penetration of acyclovir prodrugs was analyzed using a diffusion model. Subsequently, diffusion, partitioning and metabolic parameters were compared under in vitro and in vivo conditions.

RESULTS

Although total penetration amounts at the end of the experiment were similar for the three prodrugs, the ratio of intact prodrug to total penetration amount differed significantly. Moreover, the excretion and absorption profiles were also very different for each prodrug. Enzymatic hydrolysis rate constants calculated under in vivo conditions were considerably larger than those obtained in the skin homogenate and in vitro penetration experiments.

CONCLUSIONS

The present skin diffusion/bioconversion model combined with computer analysis enables us to comprehensively account for diffusion, partitioning and metabolism during in vivo percutaneous absorption. Nevertheless, different enzymatic hydrolysis rate constants obtained under both in vivo and in vitro conditions demonstrate the difficulty of obtaining accurate values for in vivo enzymatic activity from related in vitro experiments.

Carboplatin as an anticancer agent for transcatheter arterial chemoembolization in patients with hepatocellular carcinoma

Transcatheter arterial chemoembolization (TACE) is a conservative treatment in patients with hepatocellular carcinoma (HCC). In the present study, 30 patients with unresectable HCC underwent TACE using carboplatin (300 mg), and their clinical results were evaluated. After TACE, 18 (60.0%) of 30 patients demonstrated tumor size reduction rates > or = 50%. Of 23 patients with pretreatment serum alpha-fetoprotein (AFP) levels >20 ng/ml (cutoff), 14 (60.9%) showed AFP reduction > or = 75%. The 1-, 2-, 3- and 4-year survival rates were 82.9, 68.1, 45.1 and 37.6%, respectively. The median survival was 2.3 years. The only notable adverse reaction accompanying TACE was a transient myelosuppression. Carboplatin is thought to be a useful anticancer agent in patients with HCC treated with TACE.

Dexamethasone and bacterial meningitis in Pakistan

The objective of this study was to assess, in a developing country setting, the effect of dexamethasone therapy on bacterial meningitis outcomes. A prospective double blind placebo controlled trial was conducted in 89 children aged from 2 months to 12 years suffering from bacterial meningitis. Neurological, developmental, and hearing assessments were conducted at one, four, and 12 months after discharge. Forty eight patients received dexamethasone and 41 placebo. Initial antimicrobial drugs used were ampicillin and chloramphenicol. For all patients at the time of admission the mean duration of illness was 5.7 days; 47% had had seizures and 56% had impaired consciousness. Seventeen of 89 (19%) patients died. The mortality for the dexamethasone group was 25% as compared with 12% in the group receiving placebo. Presentation to the hospital after four days of symptoms and with impaired conscious state were independent predictors of death. Of the dexamethasone group survivors, 26.5% had neurological sequelae and 42.3% had hearing impairment, whereas in the placebo group it was 24% and 30% respectively. Altered state of consciousness was a predictor of neurological sequelae. The presence of neurological sequelae and high cerebrospinal fluid protein independently predicted hearing loss. No beneficial effect of dexamethasone was observed on morbidity or mortality of this group of patients with bacterial meningitis. Dexamethasone is therefore not useful in developing countries as adjunctive treatment in patients seriously ill with bacterial meningitis, who present late for treatment and have been partially treated.

Phospholipase D is involved in cytosolic phospholipase A2-dependent selective release of arachidonic acid by fMLP-stimulated rat neutrophils

When rat polymorphonuclear neutrophils (PMN) were treated with N-formyl-Met-Leu-Phe (fMLP), the release of arachidonic acid in preference to other fatty acids was observed. Levels of arachidonic acid reached a plateau within 5 min, and were accompanied by an approximately 4-fold increase in in vitro phospholipase (PL) A2 and PLD activities in PMN lysates. Treatment of PMN with ethanol (an inhibitor of PLD-mediated phosphatidic acid formation), propranolol (a phosphatidic acid phosphatase inhibitor), or 4-bromophenacylbromide (a PLA2 inhibitor), each suppressed fMLP-stimulated arachidonate release. Treatment with RHC-80267 (a diacylglycerol lipase inhibitor), however, had no such effect. The cytosolic PLA2 (cPLA2) inhibitor, arachidonoyl trifluoromethyl ketone, suppressed PLA2 activity in PMN homogenates and arachidonate release by fMLP-treated PMN. These results suggest that fMLP-elicited arachidonate release is mediated by cPLA2 but not diacylglycerol lipase, and that the activation of cPLA2 is downstream of the PLD-dependent signaling pathway.

Comparison of carbohydrate structures of serum alpha-fetoprotein by sequential glycosidase digestion and lectin affinity electrophoresis

Serum alpha-fetoprotein (AFP) is a glycoprotein of which the sugar chain is considered to show structural changes with malignancies. Microheterogeneity of the serum AFP carbohydrate structure was studied in samples from 35 patients with benign and malignant diseases. Sera were digested directly, extensively, and sequentially with sialidase. beta-galactosidase and beta-N-acetylhexosaminidase. Before and after digestion, sera were examined by means of lectin affinity electrophoresis using eight lectins. Relationships between AFP carbohydrate structures and liver diseases were elucidated by the lectin-reactive profiles and the effect of glycosidase digestion. More than 94% of the AFP carbohydrate structures found in patients with benign and malignant liver diseases were biantennary complex-type oligosaccharides. Changes in the AFP carbohydrate structures at the early stage of hepatocellular carcinoma revealed the addition of alpha 1-->6 fucose to the reducing terminal N-acetylglucosamine and monosialylated AFPs. In both advanced hepatocellular carcinoma and AFP producing extrahepatic malignancies, AFP carbohydrate structures were characterized as the further addition of beta 1-->4 N-acetylglucosamine and heterogeneity in the galactose and N-acetylglucosamine residues. Sequential glycosidase digestion and lectin affinity electrophoresis is useful for analysing the carbohydrate structures of serum glycoprotein.