Predominant 1,2-insertion of styrene in the Pd-catalyzed alternating copolymerization with carbon monoxide

The regioselectivity of styrene insertion to an acyl-Pd bond was studied by NMR in (i) a stoichiomeric reaction and (ii) a copolymerization with CO. In the stoichiometric reaction of styrene with [(CH(3)CO)Pd(CH(3)CN)[(R,S)-BINAPHOS]].[B[3,5-(CF(3))(2)C(6)H(3)](4)], both 1,2- and 2,1-products were given. To mimic the real polymerization conditions, a polyketone-substituted complex [[CH(3)(CH(2)CHCH(3)CO)(n)]Pd[(R,S)-BINAPHOS]].[B(3,5-(CF(3))(2)C(6)H(3))(4)] (n approximately 14) was prepared. When this polymer-attached Pd species was treated with styrene, the 1,2-insertion product was the only detectable species. Thus, exclusive 1,2-insertion is demonstrated to be responsible for the styrene-CO copolymerization, in sharp contrast to the predominant 2,1-insertion with conventional nitrogen ligands. Chain-end analysis revealed that beta-hydride elimination took place from the 2,1-complex but not from the 1,2-complex. Thus, once 2,1-insertion occurs, rapid beta-hydride elimination proceeds to terminate the polymerization, as is common to the other phosphorus-ligand systems. The resulting Pd-H species re-initiates the copolymerization, as was proven by MALDI-TOF mass analysis of the product copolymers.

The effect of cyclooxygenase-2 inhibitor FK3311 on ischemia-reperfusion injury in a canine total hepatic vascular exclusion model

BACKGROUND

Liver grafts from non-heart-beating donors inevitably suffer from warm ischemic injury. In these grafts, large quantities of inflammatory cytokines and arachidonic acid metabolites are induced, further aggravating injury. Cyclooxygenase (COX) is an intracellular enzyme that converts arachidonic acid into prostaglandin (PG)G2 and PGH2. COX has two isoforms: constitutive COX-1 and inducible COX-2. The aim of this study was to evaluate the effects of COX-2 inhibition by FK3311 (FK) on warm ischemic injury in a canine total hepatic vascular exclusion (THVE) model.

STUDY DESIGN

Sixteen mongrel adult dogs were studied. The portal triad of the hilum and the inferior vena cava above and below the liver was clamped for 1 hour. Splanchnic decompression was achieved by active splenofemorojugular bypass. The animals were divided into two groups. FK (1 mg/kg) was administered in the FK group (n = 8), and saline was administered in the control group (n = 8). Hepatic venous blood was collected to measure serum alanine aminotransferase, aspartate aminotransferase, lactate dehydrogenase (LDH), and hyaluronic acid levels. Serum thromboxane (Tx)B2 and 6-keto-PGF1alpha levels were also measured. Hepatic tissue blood flow was estimated simultaneously. Liver specimens were harvested for histologic study and polymorphonuclear neutrophils were counted.

RESULTS

Alanine aminotransferase, aspartate aminotransferase, and hyaluronic acid 2 and 6 hours after reperfusion and LDH 30 minutes and 2 and 6 hours after reperfusion were significantly (p < 0.05) lower in the FK group than in the control group. Hepatic tissue blood flow remained significantly (p < 0.05) higher in the FK group than in the control group 1, 2, and 6 hours after reperfusion. Histologic tissue damage was mild and polymorphonuclear neutrophil infiltration was significantly lower (p < 0.05) in the FK group than in the control group 1 and 6 hours after reperfusion. Thirty minutes after reperfusion, TxB2 was significantly reduced (p < 0.05) in the FK group, and 6-keto-PGF1alpha was not significantly lower.

CONCLUSIONS

FK protected against hepatic warm ischemia-reperfusion injury by marked inhibition of TxA2.

FR128998 ameliorates liver injury in extended liver resection with ischemia in dogs

BACKGROUND/AIMS

Platelet-activating factor is one of the most potent phospholipid mediators associated with inflammatory conditions such as ischemia and reperfusion injury. FR128998 (FR) is a novel platelet-activating factor receptor antagonist. In this study, we evaluated the effect of FR during an extended liver resection with ischemia in a canine model.

METHODOLOGY

Animals were divided into two groups: the control group (n = 8), and the FR-treated group (n = 7) in which FR was administered via the portal vein. While the right portal pedicle was clamped for 60 min, the left portal branch remained patent to avoid splanchnic congestion. Following reperfusion, 75% of the liver (including the right central, quadrate, left central, left lateral, and papillary lobes) was resected. Hepatic venous blood was collected to measure GPT, GOT, and LDH levels. Hepatic tissue blood flow was measured by a laser Doppler flow meter. The liver specimen was harvested for histological study.

RESULTS

GPT, GOT, and LDH levels after reperfusion were significantly (P < 0.05) lower in the FR-treated group than in the control group. Hepatic tissue blood flow was maintained significantly (P < 0.05) higher in the FR-treated group than in the control group. Histologically, accumulation of polymorphonuclear neutrophils significantly (P < 0.05) decreased in the FR-treated group compared with the control group. The 2-day survival rate was statistically (P < 0.05) better in the FR-treated group than in the control group.

CONCLUSIONS

FR128998 provides a protective effect for liver parenchyma and sinusoidal endothelial cells during extended liver resection with ischemia.

Basic study for stabilization of w/o/w emulsion and its application to transcatheter arterial embolization therapy

Stabilization of w/o/w emulsion and its application to transcatheter arterial embolization (TAE) therapy are reviewed. W/o/w emulsion was stabilized by making inner aqueous phase hypertonic, addition of chitosan in inner phase, and techniques of phase-inversion with porous membrane. Lipiodol w/o/w emulsion for TAE therapy was prepared by using a two-step pumping emulsification procedure. The procedure is so easy that the emulsion could be prepared even during the surgical operation. The deposition after hepatic arterial administration of the emulsion was detected by an X-ray CT scanner. The concentration of epirubicin hydrochloride (EPI) in liver was increased and its residence was prolonged by encapsulating it in the w/o/w emulsion. The toxic effects of EPI and lipiodol on the normal hepatic cells were reduced. The w/o/w emulsion prepared by us is a suitable formulation for the TAE therapy.

Matrix metalloproteinases and tissue inhibitors of metalloproteinases of fibrous humans lens capsules with intraocular lenses

PURPOSE

We located immunohistochemically the matrix metalloproteinases (MMP) -1, -2, -3 and -9 and the tissue inhibitors of matrix metalloproteinases (TIMP) -1 and -2 in the fibrous capsule of patients with intraocular lenses (IOLs).

METHODS

During vitreoretinal surgery in 10 patients we obtained post-cataract surgery lens capsules with or without an IOL. The mean interval between the previous cataract operation and the extraction of the specimens was 35.2 months (range: 2-120 months). Circular sections of the anterior capsule with lens epithelial cells (LECs) were also obtained during cataract surgery. Specimens were processed for immunohistochemical identification of MMPs and TIMPs by light microscopy.

RESULTS

While all the members of MMPs and TIMPs were not detected in the normal anterior capsules, they were detected in the ECM and/or LECs on the lens capsules extracted within 18 months after IOL implantations in all of the 4 patients, but were not observed in specimens obtained 18 months or longer postoperatively. In LECs of 1 capsule specimen 10 years postoperatively, MMP-1, but not other MMPs and TIMPs, was detected.

CONCLUSIONS

MMPs and TIMPs were detected in the ECM and/or LECs on post-cataract surgery capsules. These proteins may be remodeling the newly deposited ECM and regulating LEC behavior on residual lens capsules in the early phase of healing after cataract surgery.

Expression of involucrin by ocular surface epithelia of patients with benign and malignant disorders

PURPOSE

Keratinization of the ocular surface epithelium is associated with various disorders impairing vision. We immunohistochemically determined whether the ocular surface epithelia express involucrin, and whether its expression pattern may differ in benign vs. malignant disorders. Expression of cytokeratins was also examined to provide further information relative to the epithelial differentiation.

METHODS

We evaluated 17 specimens; 6 specimens of the normal ocular surface epithelia, 3 specimens from cases of conjunctival intraepithelial neoplasia (CIN), 6 of conjunctival squamous cell carcinoma (SCC) and 2 of conjunctivae from cases of superior limbic keratoconjunctivitis (SLK).

RESULTS

Corneal epithelium exhibited intracellular immunoreactivity for involucrin. Four of the 6 specimens of bulbar conjunctival epithelium showed involucrin immunoreactivity in the perimembranous region, whereas the fornical conjunctiva was negative. Cornified envelope in SLK specimens was positive for involucrin. The CIN showed its immunoreactivity in the perimembranous region in all levels of the hyperproliferative epithelium without keratinization, i.e., similar to the bulbar conjunctiva. The neoplastic cells of well-differentiated SCC showed involucrin in the perimembranous region, and those of moderately- to poorly-differentiated SCC have involucrin in their cytoplasm. The expression pattern of cytokeratins was unrelated to grade of malignancy in ocular SCC.

CONCLUSION

The epithelia of normal subjects and of CIN expresses involucrin without keratinization. In contrary, the keratinized SLK epithelium markedly expresses involucrin in the cornified envelope. The subcellular immunolocalization of involucrin in the ocular SCC may help in evaluating the differentiation, i.e., malignancy, of neoplastic cells.

[Anesthetic management for MIDCAB using the target controlled infusion and the bispectral index]

We report our experience in using the target controlled infusion (TCI) of propofol combined with the bispectral index (BIS) monitoring for anesthetic management of minimally invasive direct coronary artery bypass (MIDCAB) in a 43-year-old-male patient with angina pectoris. After premedication, the patient was connected to the monitor with electrodes for BIS monitor. Then, anesthesia was induced with fentanyl and propofol using TCI technique. When blood concentration of propofol reached 4 micrograms.ml-1, the trachea was intubated. Before starting the operation, we evaluated the relationship between blood concentration of propofol and the value of BIS, and the standard maintenance concentration of propofol was set at 3 micrograms.ml-1. When the concentration of propofol was 3 micrograms.ml-1, the value of BIS was about 60. Anesthesia was maintained with nitrous oxide and oxygen and continuous infusion of propofol using TCI technique. When necessary, we gave additional injection of fentanyl and vecuronium bromide. Furthermore, diltiazem was infused continuously for cardiac rate control, as well as infusion of nicorandil, nitroglycerine for prevention of coronary artery spasms, and prostaglandin. After the operation, the patient was alert in 8 minutes and we could extubate in 12 minutes. The use of TCI combined with BIS monitoring for maintenance of anesthesia for MIDCAB is useful and safe.

Alterations in ultrastructure and c-met expression in a case of ocular epithelial dysplasia following topical mitomycin C treatment

PURPOSE

Topical mitomycin C (MMC) administration is reportedly effective in treating ocular surface neoplasms such as squamous cell carcinoma. We treated a case of ocular epithelial dysplasia that had spread too diffusely to be completely removed. We examined the ultrastructure of and c-met (hepatocyte growth factor receptor) expression in dysplastic epithelial cells from this case to evaluate the efficacy of MMC treatment.

METHODS

Specimens of dysplastic epithelial tissue from the corneo-limbal region of a 62-year-old man were obtained before and after topical application of MMC. Specimens were examined ultrastructurally and immunohistochemically with an antibody against human c-met.

RESULTS

Following topical application of MMC, the dysplastic epithelium exhibited multilayered epithelial cells similar to those seen before treatment. However, ultrastructural examination showed tight interdigitation between neighboring cells, with no intercellular spaces. Also, the marked immunoreactivity to c-met in the dysplastic epithelial cells before MMC treatment was decreased after treatment.

CONCLUSIONS

Ultrastructural observations indicated a restoration of epithelial cellular differentiation following MMC application. The expression of c-met protein was also reduced. Thus, topical MMC was effective in treating epithelial dysplasia of the ocular surface, with no recurrence 15 months post-therapy.

Contribution of ecto-5'-nucleotidase to the inhibition of platelet aggregation by human endothelial cells

We studied the role of adenosine (Ado), which is generated from adenine nucleotides via the activity of ecto-5'-nucleotidase (ecto-5'-NT), in the inhibition of platelet aggregation by endothelial cells (ECs). The enzymatic activity of nucleotidases on human umbilical vein endothelial cells (HUVECs) was examined with regard to (1) the inhibition of adenosine diphosphate (ADP)-induced platelet aggregation and (2) the liberation of inorganic phosphate from adenine nucleotides. Adenosine 5'-monophosphate (AMP) preincubated with HUVECs significantly inhibited ADP-induced platelet aggregation. This was completely blocked by the treatment of HUVECs with a specific inhibitor of ecto-5'-NT, 5'-[alphabeta-methylene] diphosphate (APCP), or by the addition of an A(2a) receptor antagonist. Neither nitric oxide nor prostacyclin was involved in this inhibitory activity, suggesting that Ado generated in the incubation medium by the activity of 5'-NT on HUVECs inhibited platelet aggregation. When ADP was incubated on HUVECs, it lost most of its agonistic activity for platelets. Pretreatment of HUVECs with APCP at a concentration that abolished ecto-5'-NT activity partially restored ADP-induced platelet aggregation. Ecto-5'-NT contributes to EC function by inhibiting platelet aggregation in cooperation with ATP diphosphohydrolase, which degrades ADP to AMP.

Omentoplasty for cervical esophagogastrostomy following radical esophagectomy with three-field dissection

BACKGROUND/AIMS

Anastomotic leakage is the main cause of postoperative mortality and incidence of which, following three-field lymph node dissection, is around 30%. The study was undertaken to investigate the role of omentoplasty to reinforce cervical esophagogastrostomy with the expectation of lowering the rate of anastomotic leakage after radical esophagectomy with three-field lymph node dissection.

METHODOLOGY

Between July 1995 and Dec 1997, a total of 32 patients underwent total thoracic esophagectomy with three-field lymph node dissection and cervical esophagogastrostomy. Eleven patients were stage IIA, 3 stage IIB, 5 stage III and 13 stage IV. After radical esophagectomy and lymph node dissection, several omental branches of the gastroepiploic vessels remained to supply a gastric tube. An end-to-side cervical esophagogastrostomy was performed on the posterior wall of the gastric tube using a circular stapler. The omentoplasty--wrapping the esophagogastrostomy--was performed. A retrosternal route for reconstruction was used in 23 patients and a posterior mediastinal route in 9 patients.

RESULTS

Esophageal anastomotic leakage occurred in only 1 patient, 3.1% overall. There was neither pyothorax nor mediastinitis. There was no lethal anastomotic leakage. Later, 2 patients (6.2%) developed an anastomotic stricture that required balloon dilatation.

CONCLUSIONS

Omentoplasty to reinforce cervical esophagogastrostomy decreases anastomotic failure following radical esophagectomy with three-field lymph node dissection.

Prevalence of anorexia nervosa and bulimia nervosa in a geographically defined area in Japan

OBJECTIVE

Little has been understood regarding the frequency of eating disorders in Japan. This study was designed to identify the prevalence of anorexia nervosa (AN) and bulimia nervosa (BN) in Japan.

METHOD

We asked doctors in all of the relevant medical facilities (130 hospitals and 1,326 clinics) in Niigata Prefecture to report patients with DSM-IV-diagnosed eating disorders who appeared or were admitted between 20-24 October 1997. The response rate was 94.4%.

RESULTS

The estimated point prevalences of AN and BN were 4.79 and 1.02, respectively, per 100,000 females. Specifically for the age group of 15-29 years, the prevalence of AN was 17.10 and that of BN 5.79.

DISCUSSION

The prevalence of AN and BN in Japan is lower than that for European Caucasian populations. This result may be due to cultural and ethnic differences and/or it may be a transient phenomenon.

The resection of non-hepatic intraabdominal recurrence of gastric cancer

BACKGROUND/AIMS

Surgical resection of hepatic or pulmonary metastases from gastrointestinal cancer has been recognized as a curative modality in some patients. However, the role and outcome of the surgical management of a non-hepatic intraabdominal recurrence of gastrointestinal cancer have not been clearly delineated.

METHODOLOGY

We treated 5 patients for non-hepatic intraabdominal recurrence of gastric carcinoma surgically. All the resected specimens were microscopically identified as recurrent gastric cancer. Three of 5 patients received postoperative chemotherapy. The clinicopathological findings were analyzed according to the general rules for gastric cancer study.

RESULTS

The lymph nodes were dissected for lymph node metastases. Surgical resection of the tumors combined with total gastrectomy, esophagectomy, or colectomy was performed for the local and peritoneal recurrences. All of the recurrent tumors were macroscopically resected with curative states. One patient died of sepsis 54 days after surgery. Three patients died of recurrent gastric cancer: 2 within 1 year of surgery and 1 after 3 years. One patient still survives disease free 3 years and 6 months after the 2nd operation.

CONCLUSIONS

Surgical resection for non-hepatic intraabdominal recurrence of gastric cancer is the treatment of choice for selected patients. Surgical resection followed by adjuvant chemotherapy may improve the outcome of these patients.

Optimal end point of FR167653 administration and expression of interleukin-8 messenger RNA on extended liver resection with ischemia in dogs

BACKGROUND

FR167653 is a potent suppressant of interleukin-1 and tumor necrosis factor production. We previously reported that FR167653 inhibited the expression of interleukin-1 messenger RNA (mRNA) after ischemia-reperfusion and provided a protective effect against ischemia-reperfusion injury after extended liver resection. In this study we investigated the optimal end point of FR167653 administration and the inhibition of interleukin-8 (IL-8) mRNA expression caused by the administration of FR167653 during extended liver resection with ischemia in a dog model.

STUDY DESIGN

The right portal pedicle was clamped for 60 minutes but the left portal vein was left patent to avoid portal congestion. After reperfusion 75% of the liver was resected. EXPERIMENT I: Adult mongrel dogs were divided into three groups: the control group (n = 9); the FR-2 group (n = 6), which received FR167653 through the portal vein starting 30 minutes before the onset of ischemia until 2 hours after reperfusion; and the FR-6 group (n = 6), which received FR167653 starting 30 minutes before ischemia until 6 hours after reperfusion. Hepatic venous blood was collected to measure liver enzymes. Liver specimens were harvested for histologic study 6 hours after reperfusion and polymorphonuclear neutrophils were counted. EXPERIMENT II: The expression of IL-8 was measured by reverse-transcriptase polymerase chain reaction.

RESULTS

Aspartate aminotransferase and alanine aminotransferase levels after reperfusion and hyaluronic acid levels 6 hours after reperfusion were significantly (p < 0.05) lower in the FR-2 and FR-6 groups than in the control group. There were no significant differences between the FR-2 and FR-6 groups after reperfusion. Histologically liver tissue damage was mild in the FR-2 and FR-6 groups, and polymorphonuclear neutrophil infiltration was significantly lower in the FR-2 and FR-6 groups than in the control group. The 3-day survival rate was statistically (p < 0.05) better in the FR-2 and FR-6 groups than in the control group. IL-8 mRNA expression was inhibited in the FR-treated group.

CONCLUSIONS

FR167653 should be administered until shortly after reperfusion and need not be administered for many hours after reperfusion. FR167653 inhibits IL-8 mRNA production and inhibits polymorphonuclear neutrophil infiltration.

Polymer coating of liposomes with a modified polyvinyl alcohol and their systemic circulation and RES uptake in rats

The objective of this study was to evaluate the in vivo characteristics of liposomes coated with a polyvinyl alcohol having a long alkyl chain at the end of the molecule (PVA-R) as an injectable drug carrier for passive targeting of drugs. A fluorescence marker, cholesteryl-anthracene-9-carboxylate, was incorporated into the liposomes to detect their concentration in the plasma and organs. The small unilamellar liposomes (100 nm in diameter) with various lipid compositions, such as the different cholesterol contents or the different charges, were prepared by the hydration method followed by sonication and coated with PVA or PVA-R by just mixing the resultant liposomal suspensions with the polymer solutions. The circulation and distribution of the liposomes were tested with their intravenous administration in rats. The PVA-R-coated liposomes showed significantly higher circulation compared to that of non-coated ones in any liposomal formulation tested. The prolonged circulation of PVA-R-coated liposomes was attributed to their fewer uptake in liver and spleen. The extent in improvement in the in vivo characteristics were well interpreted by the hydrophobicity of liposomes and their coating amount of PVA-R. It was also demonstrated that the liposomes having a positive and a negative charge, which showed the completely different circulating profiles, showed almost the same profile by coating with PVA-R. When the liposomes were coated with PVA the improvement in blood circulation was much less in any cases, although coating layer of PVA was detected. These results confirm that not only the hydrophilic property but the sterically stabilizing effect of the coating layer is important to prolong the circulation of the particulate drug carriers with less RES uptake, and the PVA-R having a hydrophobic moiety at the end of the molecule of PVA is a suitable material for the coating of liposomes.

Esophageal anastomosis following gastrectomy for gastric cancer: comparison of hand-sewn and stapling technique

BACKGROUND/AIMS

During the past 4 years, we have experienced a marked reduction in the incidence of esophageal anastomotic leakage and/or stricture coinciding with the use of a mechanical circular stapler for gastric cancer patients.

METHODOLOGY

We reviewed medical records of gastric cancer patients who underwent a total or proximal gastrectomy, and compared the leakage or stricture of stapled anastomosis with the hand-sewn anastomosis technique. A total of 390 esophageal anastomosis were performed between January 1978 and August 1997. Two types of mechanical circular staplers were used (EEA and CDH).

RESULTS

Anastomotic leakage occurred in 13 (3.3%) of 390 cases; three (4.5%) of 66 cases with hand-sewn anastomosis, and 10 (3.1%) of 324 cases with stapled anastomosis (EEA: 4.5%, CDH: 0%). The anastomotic leakage rate was significantly lower in the CDH stapler group than in the EEA stapler group. Anastomotic stricture occurred in one (1.5%) of 66 cases of hand-sewn anastomosis, and 16 (4.9%) of 324 cases of stapled anastomosis (EEA: 5.9%, CDH: 2.9%). There were no significant differences in the stricture rate between the hand-sewn group and the stapler group.

CONCLUSIONS

Stapling anastomosis using a CDH stapler led to a reduction in the incidence of anastomotic leakage. Surgeons must, however, continue to be aware of anastomotic stricture.

Utilization of poly(DL-lactide-co-glycolide) nanoparticles for preparation of mini-depot tablets by direct compression

PURPOSE

The objectives of this study were to prepare the long-acting matrix tablets by direct compression of the mixture of drug and poly(DL-lactide-co-glycolide) (PLGA) nanoparticles and to clarify the effects of such factors as polymer species, mixing ratio of nanoparticles with different molecular weights, and the tablet weight on the drug release and to discuss the mechanism of drug release from matrix tablets. In addition, mini-matrix tablets were prepared to investigate the possibility of application as an implantable dosage form.

METHODS

PLGA nanoparticles were prepared by the modified spontaneous emulsion solvent diffusion method. The matrix tablets were prepared by direct compression of mixtures of drug and nanoparticles, and then the release properties, swelling properties and changes in molecular weight of PLGA during the release test were evaluated.

RESULTS

The drug showed the biphasic release patterns from all matrix tablets; i.e. a portion of the drug was released rapidly (the initial release phase), the release stopped for a long period (the lag time), and then the residual drug was released (the second release phase). Matrix tablets with various biphasic release patterns could be prepared by altering the molecular weight or copolymer ratio of PLGA. The addition of nanoparticles of low molecular weight PLGA to those of high molecular weight reduced the release rate at the initial release phase, but that at the second release phase was almost entirely unaffected by mixing ratio. Also, the release patterns could be changed by altering the tablet weight and size, but the amounts released per unit of surface area were the same. Hydration analysis suggested that the initial release rates were correlated well with the swelling properties of tablets.

CONCLUSION

This system had advantages in terms of simplicity in design and predictability of drug release rate and may be useful as an implantable dosage form.

Inhibition of complement-mediated haemolysis in paroxysmal nocturnal haemoglobinuria by heparin or low-molecular weight heparin

Complement (C')-mediated haemolysis in paroxysmal nocturnal haemoglobinuria (PNH) is mainly due to the deficiency of glycosyl phosphatidylinositol-anchored membrane proteins with C'-regulatory activities CD55 and CD59 in PNH-affected red blood cells (RBCs). Hydrophobic insertion of C5b-7 to RBC membranes, initiating the formation of a membrane attack complex, readily results in lysis of PNH RBCs due to the deficiency of CD59. We studied the significance of the electrostatic interactions between C5b-6 and RBC membranes preceding the insertion of C5b-7. In vitro, C'-mediated lysis of PNH RBCs (assessed by sucrose haemolytic assay) was inhibited by heparin, low-molecular weight heparin (LMWH) or protamine, indicating the significance of the electrostatic interactions between C' components and RBC membranes in the process of C'-mediated haemolysis. Neuraminidase-treated PNH RBCs became resistant to C' activation, suggesting that the sialic acid moieties on RBC membranes are involved in the interactions of RBC with C' components. By using biotin-labelled C7, we demonstrated that LMWH as well as heparin inhibited the insertion of C5b-7 to RBCs, although they did not inhibit the incorporation of C7 into membrane-associated C5b-6. Neither heparin nor LMWH could inhibit the procoagulant alteration of PNH RBC membranes induced by C' activation even at concentrations which inhibited the haemolysis completely. Because LMWH inhibited the C'-mediated lysis of PNH RBCs in vitro at the range which induced a limited prolongation of activated partial thromboplastin time of normal plasma, we consider that LMWH may be useful for both the inhibition of haemolysis and the prevention of thrombosis, which often follow a haemolytic attack in PNH.