Complications and management of microwave coagulation therapy for primary and metastatic liver tumors

Microwave coagulation therapy (MCT) has been widely used, both percutaneously and directly, as effective minimal invasive therapy for liver tumors. To facilitate the use of MCT, we describe the complications we have encountered, and their possible management and prophylaxis. MCT was performed for 42 patients with hepatocellular carcinoma (HCC) and for 29 with metastatic liver tumors, following which complications developed in 14.2% and 20.6% of the HCC and metastatic groups, respectively. The complications included abscess, biloma, bleeding, hepatic failure, and dissemination of cancer cells. In the HCC group, the mean value of tumor size and the clinical stage of patients with complications were significantly larger (P = 0.006) and higher (P = 0.032), respectively, than those of patients without complications. The incidence of complications increased significantly when the tumor size was more than 4cm (P = 0.008). Abscesses and bleeding were successfully treated using percutaneous drainage and interventional angiography, respectively, but as the other serious complications were not able to be treated effectively once induced, prophylaxis is important to facilitate MCT. Transcatheter cooling of the intrahepatic bile duct during MCT and the administration of an anticancer agent into the abdominal cavity are recommended to prevent biloma and dissemination, respectively. MCT is indicated for tumors less than 4 cm in diameter to reduce the risk of complications. The prophylaxis and treatment of these complications enhance the safety of MCT.

[Efficacy of microwave coagulation therapy (MCT) in patients with liver tumors]

We evaluated the efficacy of microwave coagulation therapy (MCT) in 84 patients with hepatocellular carcinomas (HCC) and 40 with metastatic liver tumors (MLT). The response rates calculated with diagnostic imaging were 92% in HCC and 80% in MLT. The regional recurrence rates were relatively higher in patients with MLT (33%) than in HCC (14%). The average surgical margin in operative MCT group was 11 mm. The cumulative survival rates at three and five years were 63% and 38% in HCC and 43% and 33% in MLT, respectively. The complications were similarly encountered in HCC and MLT (12% versus 13%). When these observations are taken together, MCT is a radical and safe locoregional therapy which can keep an adequate surgical margin and assure long survival.

Effects of hypokalaemia on arrhythmogenic risk of quinidine in rats

Plasma potassium concentration plays an important role in the induction of arrhythmia and is closely related to the arrhythmogenicity of various drugs. We quantitatively analyzed the influence of plasma potassium concentration on QT intervals before drug administration and on drug-induced QT prolongation, to estimate the risk of drug-induced arrhythmia under hypokalaemic conditions. The hypokalaemic models were produced by intraperitoneal administration of furosemide and hydrochlorothiazide in male Sprague-Dawley rats. The relationship between the changes in QT intervals and time profiles of plasma quinidine (QND) concentration were analyzed during constant intravenous infusion of QND (10 or 30 mg/kg/h) and post infusion in normal and hypokalaemic rats. The plasma QND concentration reached the therapeutic range (3-7 microg/ml) at the high infusion rate (30 mg/kg/h). No pharmacokinetic differences between normal and hypokalaemic rats were observed. QND induced QT prolongation in parallel with the plasma concentration without hysteresis. Although the potency of QND for QT prolongation was not affected by hypokalaemia, the QT intervals before drug administration were significantly prolonged in hypokalaemic rats (65.90 +/- 1.40 vs 56.60 +/- 0.748 msec, mean +/- SEM, p < 0.0001). Thus, the prolongation of QT intervals before drug administration may act as a risk factor of arrhythmia under hypokalaemic conditions.

Conservation and continuity of periodic bent DNA in genomic rearrangements between the c-myc and immunoglobulin heavy chain mu loci

Periodic bent DNA was mapped in the human c- myc and immunoglobulin heavy chain mu (Ig mu) loci. A total of 12 DNA bend sites in the c- myc gene and 11 sites in the Ig mu locus were aligned at average intervals of 694.2 +/- 281.4 and 654.5 +/- 222.7 bp respectively. Although some of the bend sites retained the distance of 700 bp, their periodicity was disturbed at several locations, including the exons of the c- myc gene and the enhancer element present in the Ig mu locus. Analysis of rearrangements that resulted in tumorigenesis of lymphocytes showed that the continuity of DNA bend sites was conserved in three lymphoma cell lines, Manca, BL22 and Ramos, suggesting that the genomic rearrangements gain stability by retaining their periodicity. This adds further evidence that the periodic bent DNA plays a crucial role in genomic structure.

[Measurement of fibrinogen binding to platelets by flow cytometry: evaluation method for reflecting platelet activation]

Platelet aggregation, induced by agonist-mediated activation of membrane glycoprotein (GP) IIb/IIIa, and binding of fibrinogen to GPIIb/IIIa, is commonly analyzed using an aggregometer in the clinical laboratories. However, this method has a limitation to get precise results on the samples with small number of platelet (less than 100,000/1) or hyperlipidemia. Recently, flow cytometry has been used to evaluate platelet function due to the detection of fibrinogen binding to activated platelets using fluorescence labeled fibrinogen or anti-fibrinogen antibody. However, the appropriate rule for evaluation of the results has not been established yet. We converted a ratio of fibrinogen binding platelets to a velocity per unit concentration of ADP as follows: a difference of two ratios of fibrinogen binding platelets on neighboring two ADP concentrations was divided by a difference of ADP concentrations. It was considered to be a mean velocity between the two ADP concentrations. We adopted the range of ADP concentration, which gave the maximum velocity, as an index of platelet activation. If the peak of maximum velocity move toward lower or higher ADP concentration, it means hyper- or hypoactivation of the platelets, respectively. The objectivity of this method may make it a useful technique for clinical examination of platelet function.

Determinant analysis of IgE and IgG4 antibodies and T cells specific for bovine alpha(s)1-casein from the same patients allergic to cow's milk: existence of alpha(s)1-casein-specific B cells and T cells characteristic in cow's-milk allergy

In an effort to clarify the etiology of milk allergy from the standpoint of allergen-specific immune reactions, we investigated the determinants of IgE, IgG4, and T cells specific for bovine alpha(s)1-casein from the same individual patients by using its synthetic peptides and cyanogen bromide-digested fragments. Alpha(s)1-casein is a major allergen in cow's milk, and its unique conformation enabled us to investigate the determinants of antibodies without consideration about missing the reactivities because of conformational changes. Nine patients were selected as subjects from among 129 milk-sensitive infants screened by ELISA to assess the anti-alpha(s)1-casein IgE levels in their sera. By using ELISA for epitope mapping, a C-terminal region of alpha(s)1-casein was identified as a common binding site for IgE from all of these patients, whereas those for anti-alpha(s)1-casein IgG4 were located in multiple regions of alpha(s)1-casein. We determined the specificities of seven alpha(s)1-casein-specific T-cell lines established from peripheral blood mononuclear cells of two of the patients. These T cells have been shown to secrete IL-4. All of the T-cell lines had different specificities to alpha(s)1-casein. However, a common amino acid residue use was found among the determinants of various T-cell lines from each patient. The results suggest that patients allergic to cow's milk have characteristic B cells recognizing a limited region of alpha(s)1-casein and secreting alpha(s)1-casein-specific IgE. These B cells may interact particularly with T cells recognizing determinants with a common structure.

Expression of transforming growth factor beta1 (TGFbeta1) and its receptors in pancreatic duct cell carcinoma and in chronic pancreatitis

Transforming growth factor beta1 (TGF beta1) is a multifunctional factor that regulates many aspects of cellular functions such as epithelial cell growth and synthesis of extracellular matrices. TGFbeta transduces signaling through a heterodimeric complex of type I and type II TGFbeta receptors (TbetaRI and TbetaRII). Recently, it has been shown that enhanced expression of TGFbeta1 is associated with the progress of pancreatic duct cell carcinoma (PDC) and chronic pancreatitis (CP). In this study, the expression of TGFbeta1 and its receptors, TbetaRI and TbetaRII, is examined in 21 cases of PDC by immunohistochemistry using specific antibodies, and the results are compared with those for 13 cases of CP. In the epithelial cells of PDC and CP, there are no significant differences in the expression of TGFbeta1, TbetaRI, and TbetaRII. In contrast, stromal expression of this cytokine and its receptors tends to be stronger in PDC than in CP; especially, the expression of TbetaRII is significantly stronger in PDC (p < 0.05). These findings suggest that there are some pathological differences in the properties of stromal reactions between PDC and CP, although the morphologies of their stroma resemble each other.

A new experimental device for the measurement of moisture emission and heat release from respiratory organs and body surface

A new experimental device was developed to investigate respiratory diseases. The moisture and heat released from respiratory organs and the body surface of a rat were determined by means of this device as well as the rectal temperature. The high recovery of results was statistically confirmed, and the measured values at various environmental temperatures were significantly different from each other. Some standard drugs, such as ephedrine, aminophylline and chlorpromazine, were examined. Their stimulant or depressant actions were clearly observed. The results of some traditional medicines for the treatment of rhinitis and bronchial asthma from this measuring system were consistent with their clinical applications. These results suggest that this new experimental system is not only effective in the experimental understanding of cold-hot syndrome, but also contributes to the evaluation of the effects of traditional medicines.

Effect of cholinergic blockade on inhibited GH secretion by feeding and intraruminal SCFA infusion in sheep

The effect of cholinergic blockade on suppressed growth hormone (GH) secretion caused by feeding or the intraruminal infusion of an acetate, propionate, and butyrate mixture (107 and 214 mumol.kg-1.min-1 over 6 h) was examined in ovariectomized ewes. Intraruminal infusion at the rate of 107 mumol.kg-1.min-1 increased peripheral plasma short-chain fatty acid (SCFA) concentrations to approximately the physiological levels noted after feeding. Plasma GH was markedly suppressed by feeding and at both the 107 and 214 mumol.kg-1.min-1 SCFA infusion rates; however, cholinergic blocking agents completely blocked the suppressed GH secretion after feeding and only at the 107 mumol.kg-1.min-1 infusion rate. Plasma glucose increased at both infusion rates, and the plasma free fatty acids decreased after feeding and at both infusion rates. However, both metabolites were unchanged relative to the saline control after the injection of the cholinergic antagonists. It is suggested that the decrease in plasma GH observed after feeding and a near-physiological ruminal SCFA increment is mediated via the parasympathetic nerve and not by pharmacological ruminal SCFA increments attributed to other pathways.

Effects of muscarinic and adrenergic blockade on growth hormone secretion induced by growth hormone-releasing peptide-2 (GHRP-2) in ovariectomized ewes

This study was performed to investigate whether the blockade of cholinergic muscarinic and adrenergic pathways was involved in the GH-releasing effect of GH-releasing peptide-2 (GHRP-2) in ovariectomized ewes. Cholinergic muscarinic antagonist, atropine (0.2 mg/kg, i.v., 15 min before GHRP-2 administration) blunted the GH secretion caused by GHRP-2 (12.5 microg/kgBW). alpha-Adrenergic antagonist phentolamine (15 microg/kgBW x min, infusion from -15 to 30 min) did not affect the GH response to GHRP-2, and beta-adrenergic antagonist propranolol (0.25 mg/kgBW, i.v., 15 min before GHRP-2 administration) did not suppress the GHRP-2-induced GH release. These results showed that cholinergic muscarinic antagonist agent, atropine, exerts an inhibitory effect on GHRP-2-induced GH secretion in ovariectomized ewes.

[Determination of neutrophil function by measuring superoxide production with whole blood flow cytometry]

The function of neutrophil can be evaluated by measuring oxidative metabolism using chemiluminescence, tetrazolium dye reduction or the others. Those results are not always satisfactory which would be caused by subtle difference in each preparation of the reagents and the lack of reproducibility. Recently, flow cytometric procedures for semi-quantitating superoxide production in neutrophils have been developed to evaluate their function. This procedure, which requires only small amount of whole blood, can easily and rapidly yield reproducible and reliable data. In this study, we optimized analytical conditions and then determined reference interval to evaluate neutrophil function of patients with various disorders. Optimal concentrations and incubation times of DCFH-DA and PMA were 5 mumol/l for 15 minutes and 25 micrograms/ml for 20 minutes, respectively. Production of superoxide in neutrophil was represented by relative fluorescence intensity(RFI) with assay coefficient of variance(CV) of 4.0-11.1%. Neutrophils had to be examined within 2 hours after venipuncture to obtain reliable data. Reference interval was determined as 170.4 +/- 58.7(mean +/- SD) RFI. Neutrophil function of patients with neutropenia, paroxysmal nocturnal hemoglobinuria(PNH), renal failure, systemic lupus erythematosus(SLE), myeloperoxidase deficiency, myelodysplastic syndrome(MDS), and diabetes mellitus were within the reference interval as evaluated by this method. Only neutrophils of chronic granulomatous disease, which is known to give clearly low superoxide production, showed actually decreased value. These results indicate that this procedure would be clinically useful for diagnosis of patient with impaired neutrophil function.

Rapid colorectal adenoma formation initiated by conditional targeting of the Apc gene

Familial adenomatous polyposis coli (FAP) is a disease characterized by the development of multiple colorectal adenomas, and affected individuals carry germline mutations in the APC gene. With the use of a conditional gene targeting system, a mouse model of FAP was created that circumvents the embryonic lethality of Apc deficiency and directs Apc inactivation specifically to the colorectal epithelium. loxP sites were inserted into the introns around Apc exon 14, and the resultant mutant allele (Apc580S) was introduced into the mouse germline. Mice homozygous for Apc580S were normal; however, upon infection of the colorectal region with an adenovirus encoding the Cre recombinase, the mice developed adenomas within 4 weeks. The adenomas showed deletion of Apc exon 14, indicating that the loss of Apc function was caused by Cre-loxP-mediated recombination.

Mutational analysis of the 5' noncoding region of human immunodeficiency virus type 1 genome

Retrovirus particles are released by budding from the membranes of infected cells. In the course of virus production, particularly during the late stage, viral genomic RNA is incorporated specifically into virion particles. This specific incorporation of the genomic RNA requires a packaging signal sequence. A region that functions as the packaging signal was mapped to a location upstream of the gag open reading frame on the HIV-1 viral genome. In addition of this packaging signal, other cis-acting elements that are scattered throughout the genome are also required for efficient packaging. The region upstream of the splice donor site is probably important for dimer formation. Therefore, we focused on one region located between the 3' end of the primer binding site and the 5' splice donor site of HIV-1. Experiments were conducted to investigate how deletions or point mutations in this region affect both dimerization in vitro and the production of infectious virus particles. A series of RNAs of varying lengths containing the 5' noncoding region were generated, and genomic dimerization of the altered viral RNA was analyzed in vitro. One RNA construct which consisted of 112 nucleotides (nt) from nt 639 to nt 750 formed a heterodimeric complex with the RNA which consisted of 200 nucleotides from nt 551 to nt 750. We then constructed proviruses with mutations in the 639 to 750 nt region and assayed for virus production. Several mutants that lacked the complementarity necessary to form a possible stem-loop structure in this region showed decreased production of infectious virus particles. Moreover, both deletion of this region and randomization of its nucleotide sequence completely impaired infectious virus production. Thus, the way that this region affects infectious virus production may be through its RNA secondary structure.

Junction of the cystic duct with the left hepatic duct: report of a case discovered during laparoscopic cholecystectomy

We report a case of an anomalous junction of the cystic duct with the left hepatic duct found during laparoscopic cholecystectomy. Only five other patients with this anatomy have been reported. Two of these five patients had left-sided gallbladders, and the remaining patients (including ours) had their gallbladder in its normal location. Although the prevalence of this anomaly associated with left-sided gallbladders is 5.6 to 14.3%, this anomaly appears to be quite rare in patients with gallbladders in the normal position. In four cases, it was accompanied by left-sided gallbladder or low bifurcation of the common hepatic duct. This rare condition may accompany other biliary anomalies and should be kept in mind when performing cholecystectomy.

Site-directed mutagenesis of rat hepatic hydroxysteroid sulfotransferases

Two cDNA clones of rat hepatic hydroxysteroid sulfotransferase (ST) (ST-40 and ST-20) were isolated and expressed in Escherichia coli cells. Several histidine residues in their coding regions are highly conserved in the ST superfamily, and histidine mutants were constructed by site-directed mutagenesis. The substitution of alanine or lysine for the histidine at position 98 in the ST-40 enzyme resulted in a loss of ST activities toward dehydroepiandrosterone (DHEA), androsterone (AD) and cortisol (CS). The mutation of histidine 98 into alanine abolished the specific binding to 3'-phosphoadenosine 5'-phosphate agarose, suggesting that the residue is located at a critical position in the 3'-phosphoadenosine 5'-phosphosulfate (PAPS) binding site. In the ST-20 enzyme, the replacement of histidine 98 with alanine also resulted in the loss of ST activity toward its preferential substrate, CS. In the ST-40 enzyme, the mutation at histidine 256 into alanine markedly reduced CS-ST activity, but DHEA-ST activity was not changed. Furthermore, selective decrease in CS-ST activity was also observed in the alanine mutant at lysine 254 or at asparagine 255 of the ST-40 enzyme. Kinetic analysis on the ST-40 and its mutant at asparagine 255 indicated that the Km value for CS was significantly increased in the mutant without any change in the Km values for 3'-phosphoadenosine 5'-phosphosulfate and DHEA. Inhibition studies demonstrated that DHEA-ST activity was competitively inhibited by AD, but not by CS in the ST-40 enzyme, whereas triethylamine, a noncompetitive inhibitor of hydroxysteroid ST, inhibited DHEA-ST activity in the ST-40 enzyme but did not inhibit CS-ST activity in either ST-40 or ST-20 enzymes. These data provide evidence that DHEA and CS bind to different sites, which probably function in a different manner in the ST-40 enzyme.

Reevaluation of clinical features of ischemic colitis. Analysis of 68 consecutive cases diagnosed by early colonoscopy

BACKGROUND

Ischemic colitis (IC) is generally considered a disease of elderly patients who have associated diseases. The aim of the present study was to reevaluate the clinical features of IC.

METHODS

We retrospectively analyzed the clinical characteristics, background, and endoscopic and histologic changes in 68 consecutive patients (16 men and 52 women) with this disease diagnosed by early colonoscopy.

RESULTS

The patients' age ranged from 22 to 98 years (mean, 55 years). Twenty-three patients (34%, including 19 women) were less than 50 years of age. The classical predisposing factors were not discernible in patients younger than 50. Chronic constipation and prior history of abdominal surgery were common in both young and old patients. Early colonoscopy (especially by the 3rd day from onset) showed endoscopic and histologic findings consistent with the characteristics of IC.

CONCLUSIONS

IC is not limited only to the elderly, and it should be considered in the differential diagnosis of colitis with melena in younger patients, especially females, who do not have any predisposing factors. Chronic constipation and prior history of abdominal surgery were commonly associated in both young and old patients. Early colonoscopy, especially by the 3rd day from the clinical onset, is essential for the accurate diagnosis of IC.

[Immune response induced by surgical trauma]

The non-specific immune response induced by surgical trauma is getting much attention with the concept of systemic inflammatory response syndrome (SIRS). SIRS is recognized as the host response to an inflammatory process independent of its cause, and is characterized by generalized activation of the vascular endothelium and polymorphonuclear leukocyte. It is induced by cytokine production, in which tumor necrosis factor (TNF) and interleukin-1 (IL-1) play a major role. Most of SIRS patients recover from surgical trauma without developing organ dysfunction. However, a new subsequent insult (second attack), such as infection, during SIRS state would lead to amplified tissue response. SIRS should be managed as a warning sign of tissue injury.

[A preliminary study of percutaneous ethanol injection therapy for hepatocellular carcinoma: evaluation of the ethanol diffusion area by the ethanol mixed with gadolinium]

To evaluate the ethanol diffusion area after Lipoidalization in 3 patients with advanced HCC treated by Lipoidalization-PEIT combination therapy, 99.9% ethanol mixed with Gadolinium was used for PEIT (Gd-PEIT). T1-weighted MR images wear obtained 1 hr after Gd-PEIT. The area of homogeneous hyperintense change on T1-weighted MR images was taken to be the ethanol diffusion area. In all 3 patients, homogeneous hyperintensity throughout the tumor over the capsule was recognized on T1-weighted MR images after treatment. The results suggests that T1-weighted MR images after Gd-PEIT provide a valuable tool by which to directly evaluate the ethanol diffusion area for advanced HCC treated by Lipoidalization followed by PEIT.

Development of a de novo tumorous necrotic lesion in the liver after transcatheter arterial embolization combined with iodized oil infusion: report of a case

We report herein the case of a 69-year-old woman in whom a hepatic tumorous necrotic lesion was discovered following transcatheter arterial embolization combined with iodized oil infusion (Lp-TAE) for a hepatoma. The lesion, which had not been evident prior to the Lp-TAE, was resected and analyzed pathologically. The portal area distribution in the necrotic lesion was the same as that in the surrounding hepatic tissue, suggesting that the lesion was derived from the nonneoplastic hepatic tissue. Moreover, extensive wall thickening and obstruction were observed in the intrahepatic portal vein and hepatic artery. These findings suggest that the lesion was a focus of hepatic infarction triggered by Lp-TAE.

Inhibition of hepatitis C virus replication by antisense oligonucleotide in culture cells

Oligonucleotides complementary to the sequences containing the initiator codon, AUG, of the core region of positive-stranded hepatitis C virus (HCV) were tested for their effects on viral translation in a cell-free protein synthesis system and on viral replication in a human T-lymphotropic virus type I infected cell line, MT-2C, which was cloned by the limited dilution method from MT-2 cells and showed more efficient HCV replication than an uncloned population of MT-2 cells. Treatment of HCV-infected MT-2C cells with the antisense oligonucleotide (10 microM) had a dramatic inhibitory effect on viral replication. This result suggests that the antisense oligonucleotide complementary to the sequence close to the initiation codon of the core region might be useful as an antiviral agent against HCV replication.

[Perioperative management of patients with Meigs syndrome]

We report our perioperative management of three cases of Meigs syndrome. The major pre-operative problems in Meigs syndrome are physical trouble caused by giant mass in peritoneal space, respiratory distress, and poor nutrition. These problems must be settled before the operation. The important points in the pre-operative management are 1) respiratory care employing the intermittent positive pressure breathing (IPPB) and the pleural effusion drainage, and 2) the correction of intravascular volume and the concentration of albumin and hemoglobin by transfusion of massive lactated Ringer solution and albumin solution and/or whole blood when they are necessary. During the operation, the epidural anesthesia under spontaneous breathing is the best method of anesthesia. According to circumstances, we adopt the intra-tracheal intubation with continuous positive airway pressure breathing (CPAP). We can generally deal with excessive bleeding by transfusion of lactated Ringer solution and plasma expander, during the first half of operation. By the end of the operation, however, the correction of the concentration of albumin and hemoglobin must be made by the fresh frozen plasma and blood transfusion. After the operation, we use epidural analgesia to control the postoperative pain. We have succeeded in the treatment of three cases of Meigs syndrome owing to our perioperative management as described above.

Expression of pS2 gene in rat brain

We have previously shown that the expression of pS2 mRNA, which encodes a secreted 60-amino acid protein of unknown function, is widely distributed throughout the entire body of the mouse including the brain. We report herein that pS2 mRNA is also expressed in the brain and in peripheral tissues of rats. In adult rat brain, pS2 mRNA was predominantly expressed in hippocampus, followed by the cerebral cortex and cerebellum. The developmental expression of pS2 mRNA in hippocampus, which region is known to mature after birth, showed a clear peak in 1- or 3-day-old rats, then gradually decreased by 7 weeks after birth. In midbrain, the maturation of which occurs at an early developmental stage, pS2 mRNA level was retained at a low level from postnatal 1 day to week 7. These results suggest that pS2 protein plays an important role in the development of central nervous system.

Interferons suppress nerve growth factor synthesis as a result of interference with cell growth in astrocytes cultured from neonatal mouse brain

Interferon (IFN)-beta and IFN-gamma inhibited the DNA synthesis and nerve growth factor (NGF) synthesis in growing astrocytes cultured from neonatal mouse brain, but they did not affect the NGF synthesis in quiescent astrocytes. IFN-beta and IFN-gamma also inhibited the enhanced DNA synthesis and NGF synthesis in growing astrocytes after the administration of basic fibroblast growth factor. These results indicated that NGF synthesis in astrocytes is regulated by IFNs associated with cell growth. The mechanism of IFN action on NGF synthesis/secretion is unknown, but the results that their effects last long after IFN removal from the cultures present the possibility that IFNs destabilize NGF mRNA.

Characterization of cancer cell dissociation factor in a highly invasive pancreatic cancer cell line

BACKGROUND

Two pancreatic cancer cell lines, the highly invasive and metastatic cell line PC-1.0 and the weakly invasive and rarely metastatic cell line PC-1, were established from a pancreatic ductal carcinoma induced by N-nitrosobis (2-oxopropyl) amine in a Syrian golden hamster.

METHODS

The cancer cell dissociation activity in serum-free conditioned medium of PC-1.0 cells was partially purified using a heparin column, a hydroxylapatite column, anion exchange, and gel filtration high-performance liquid chromatography. Several biologic properties of the partially purified activity were evaluated.

RESULTS

Two cell lines exhibited different growth morphologic changes in vitro: the weakly invasive cell line PC-1 formed islandlike colonies, and the highly invasive cell line PC-1.0 grew mainly as single cells. The conditioned medium of PC-1.0 cells induced dissociation of islandlike colonies and morphologic changes of PC-1 cells to elongated cells, with a high frequency of pseudopodia formation similar to the morphologic findings of PC-1.0 cells. The dissociation activity did not bind to the heparin column and had an apparent molecular mass of > 400 kDa, as deduced from gel filtration. Several immunoreactive proteinous bands were observed in immunoblotting analysis using a polyclonal blocking antibody. The partially purified activity enhanced cell motility, chemoinvasion, and cell adhesion to plastic plates and fibronectin.

CONCLUSIONS

Highly invasive and metastatic PC-1.0 cells produce a soluble proteinous factor, called "dissociation factor" (DF), which induces cell dissociation of weakly invasive and rarely metastatic PC-1 cells. It seems likely that DF has a role in tumor invasion and metastasis.