Procedures of simultaneous radical resection indicated for primary synchronous esophageal and liver cancers--from the personal experience of three cases

Primary double cancers of the liver and esophagus are extremely rare. Only 7 cases, both cancers resected, were reported. A 2 stage surgical procedure has been recommended for such a case. We experienced 3 consecutive patients who underwent successful simultaneous radical resection with a good outcome. Case 1 with an advanced esophageal cancer (EC) and hepatocellular carcinoma (HCC) without liver dysfunction received subtotal esophagectomy and posterior segmentectomy of the liver under a thoraco-laparotomy. Case 2, with an early stage EC and HCC with Child A cirrhosis, received the same surgical procedures as case 1 to complete stanching under good visibility for esophagectomy, because of his bleeding tendency due to liver dysfunction. But post operative bleeding from the thoracic cavity continued for 5 consecutive postoperative days. Case 3, with an early stage EC and cholangiocellular carcinoma (CCC), underwent transhiatal esophagectomy and right hepatic lobectomy under laparotomy. All cases received active enteral nutritional (EN) support from the early postoperative day with good outcomes. In conclusion, simultaneous radical resection for synchronous cancers of the esophagus and liver might be a possible indication for patients who have little or slight liver dysfunction. In the case with liver dysfunction, esophagectomy should be performed under thoracotomy, but transhiatal resection, for complete stanching, even in the early stage EC. Post-operative EN support is essential for these patients to obtain a good outcome.

[Role of peritoneal lavage smears and gastric wall brushing smears in gastric cancer surgery]

Examinations of peritoneal lavage smears (LC) and gastric wall brushing smear cytology (BC) appear to be important for determining accurately the stage of gastric cancer. We have been carrying out such examinations during gastric cancer surgery for 7 years. In the present study, we evaluated the results obtained from 287 patients with gastric cancer. Tumor invasion and peritoneal dissemination were correlated with a positive incidence of cancer cells in LC and/or BC. Gastric cancer showing serosal invasion was classified into positive for LC and/or BC and negative for LC and/or BC. Patients positive for LC and/or BC had a poorer prognosis. For future gastric cancer treatment, patients positive for peritoneal cytology are expected to be targeted for intensive treatment during or before surgery.

[Immediate surgical treatment for the traumatic pulmonary pseudocyst: a case report]

Nonpenetrating blunt trauma causing pulmonary pseudocyst is very rare. A 25-year-old young male suffered from motor vehicle accident. He was transferred to our hospital with severe hemoptysis. Immediately he was intubated and kept under mechanical ventilation. A chest X-ray film and CT-scan revealed a marked cavity lesion surrounded by an extensive infiltrate and alveolar air consolidation. Ordinary, it has benign clinical courses by conservative management. However, he was suffered massive and continuous bleeding from endobronchial tube. Therefore, one lung ventilation using a uni-vent tube blocker was performed. After twelve hours blockade, the cavity lesion was enlarged and trans-bronchial bleeding was continued severely. Emergency right lower lobectomy was carried out successfully.

Formobactin, a novel free radical scavenging and neuronal cell protecting substance from Nocardia sp

Formobactin, a new free radical scavenger, was isolated from the culture of Nocardia sp. strain ND20. The structure of formobactin was determined to be a member of the nocobactin group antibiotics. Formobactin inhibited lipid peroxidation in rat brain homogenate. Formobactin also showed the activity to suppress L-glutamate toxicity in neuronal hybridoma N18-RE-105 cells.

Cloning and expression of cDNA encoding a human ubiquitin-conjugating enzyme similar to the Drosophila bendless gene product

cDNA encoding a novel human ubiquitin-conjugating enzyme has been cloned from an epidermoid carcinoma KB cDNA library. This clone encodes a protein of 152 amino acids with a calculated M(r) of 17,137. The amino acid sequence showed 80% identity with the Drosophila's bendless gene product (ubiquitin-conjugating enzyme E2). The corresponding transcripts are highly expressed in heart, skeletal muscle, and testis. The product expressed in Escherichia coli exhibited the ability to form a thiol ester linkage with ubiquitin in a ubiquitin-activating enzyme E1-dependent manner. These results suggest that the obtained cDNA encodes a novel human E2 which may be involved in protein degradation mainly in the muscles and testis.

Functional coupling of the delta-, mu-, and kappa-opioid receptors to mitogen-activated protein kinase and arachidonate release in Chinese hamster ovary cells

To examine whether the mitogen-activated protein kinase (MAPK) cascade and phospholipase A2 (PLA2) are involved in the signal transduction mechanism of the opioid receptor, the delta-, mu-, and kappa-opioid receptors were stably expressed from cDNA in Chinese hamster ovary cells. Activation of the delta-, mu-, and kappa-receptors by agonists induced a rapid and transient increase in MAPK activity accompanied by reduced electrophoretic mobility of the 42-kDa isoform of MAPK (p42), probably owing to phosphorylation. The opioid receptor-mediated increase in MAPK activity was suppressed not only by pretreatment with genistein, a tyrosine protein kinase inhibitor, but also by prolonged exposure to phorbol 12-myristate 13-acetate and pretreatment with GF 109203X, a selective protein kinase C (PKC) inhibitor, suggesting the involvement of PKC as well as tyrosine protein kinase. Furthermore, stimulation of the delta-, mu-, and kappa-receptors with opioid agonists in the presence of A23187, a calcium ionophore, resulted in an increase in arachidonate release, suggesting that PLA2 is activated by the opioid receptors when the intracellular Ca2+ concentration is elevated. Both MAPK activation and increase in arachidonate release mediated by the opioid receptors were abolished by pretreatment with pertussis toxin, suggesting that these responses are mediated by Gi or Go types of GTP-binding regulatory proteins.

Use of a split dura for revascularization of ischemic hemispheres in moyamoya disease

A new technique of indirect revascularization using the dural arterial supply to provide donor vessels is presented together with the results of an assay performed to determine the angiogenic activity of the dura. At surgery, a portion of the dura near the branches of the middle meningeal artery was split into outer and inner layers, and the split surface of the outer layer was attached to the cortical surface. This procedure, combined a with standard encephaloduroarteriosynangiosis, was applied to 25 hemispheres in 18 patients with pediatric moyamoya disease (mean age 6 years). All of the patients were symptom free by 1.5 years after surgery. The follow-up period ranged from 1 to 12 years (mean 6.5 years). Thirteen (81%) of 16 patients were able to lead normal lives and three were mildly handicapped due to mental retardation that existed preoperatively. Postoperative superselective angiograms demonstrated effective cortical revascularization through the dural arteries as well as from the scalp arteries. A histological study of the dura in cases of moyamoya disease showed an increased number of blood vessels in the outer layer. Angiogenic activity determined by chorioallantoic membrane assay was higher in the split surface of the dura than in the internal surface of the dura (the natural interface between the dura and cortex). The split duroencephalosynangiosis described in this report is a useful addition to indirect revascularization techniques, allowing extension of the area of revascularization in the ischemic hemispheres of patients with moyamoya disease.

Giant intracranial aneurysms in two sisters: case report

BACKGROUND

It is rare for intracranial aneurysms to present with cranial nerve palsy caused by the space-occupying effect of the lesion. Herein we discuss two sisters with familial intracranial aneurysms, both of whom presented with cranial nerve palsy.

CASE DESCRIPTION

Two female siblings presented with ocular movement and facial sensory disturbances caused by the space-occupying effect of giant aneurysms at the cavernous portion of the internal carotid arteries. The aneurysms were located at the identical site in both patients. Proximal occlusion of the internal carotid artery was effective in both cases, resulting in the promotion of thrombosis within the aneurysms in order to reduce their space-occupying effect.

CONCLUSION

This is considered to be the first known case of siblings, both suffering from giant internal carotid artery aneurysms.

Ca(2+)-dependent activation of the 33-kDa protein kinase transmits thrombin receptor signals in human platelets

Thrombin stimulation induces a dramatic increase in the activity of the 33-kDa serine/threonine kinase (PK33) in human platelets (10). The Arg-Gly-Asp (RGD) peptide, an inhibitor of the thrombin-mediated aggregation of platelets, did not affect the PK33 activation induced by thrombin suggesting that the activation of this kinase occurs independently from platelet aggregation. To identify a potential role of Ca2+ and calmodulin in the regulation of PK33, the effect of several Ca2+/calmodulin inhibitors on the thrombin-induced activation of PK33 was assessed using denaturation/renaturation method. Pretreatment of platelets with EGTA decreased the maximum PK33 activity induced by thrombin. The chelation of both the extra- and the intracellular Ca2+ by EGTA and by acetoxymethyl ester of 5,5'-dimethyl-bis-(0-aminophenoxy) ethane-N,N,N',N'-tetraacetic acid (BAPTA-AM) decreased further the PK33 activation by thrombin. Preincubation of platelets with the anticalmodulin agent, N-(4-aminobutyl)-5-chloro-2-naphthalenesulfonamide (W13), inhibited markedly the activation of PK33 by thrombin, whereas the inactive structural analog N-(4-aminobutyl)-2-naphthalenesulfonamide (W12) and the myosin light chain kinase inhibitor 1-(5-chloronaphthalene-1-sulfonyl)-1H-hexahydro-1,4-diazepine (ML9) showed very weak inhibitory effects. Treatment of resting platelets with the calcium ionophore, A23187, activated PK33 in a dose-dependent manner; phorbol 12-myristate 13-acetate enhanced this effect. However, the two foregoing agents did not induce similar degree of PK33 activities as thrombin. These results indicate that the activation of PK33 is independent of the formation of the GPIIb/IIIa-fibrinogen complex and that it might be regulated by a Ca(2+)-dependent pathway.

Ability to culture dermal papilla cells from red deer (Cervus elaphus) hair follicles with differing hormonal responses in vivo offers a new model for studying the control of hair follicle biology

Red deer stags annually grow two distinct seasonal coats, a winter coat and a summer coat; in addition, they produce a mane during the breeding season when plasma testosterone levels are high, which is replaced by the short neck hairs of the summer coat when testosterone levels are low. As two very different hair types are produced from the same follicle under hormonal regulation, they offer an interesting model for studying the effects of hormones, particularly androgens, on mammalian hair growth. Since the dermal papilla of the hair follicle has a regulatory function and is probably the site of androgen action, we have investigated whether cells from the dermal papilla can be readily cultured from various types of red deer follicles; as the follicular connective tissue sheath may regenerate a new papilla in vivo, this was also examined. Individual dermal papillae and lower portions of the connective tissue sheath were microdissected from mane and flank follicles of red deer stags during the winter breeding season and from the summer coat during the nonbreeding season. Primary cultures were established from isolated dermal papillae, connective tissue sheath and dermal explants, subcultured and reestablished after freezing. Deer dermal papilla cells resembled sheep cells; they displayed a polygonal shape and irregular organisation, but did not form aggregates in contrast to human and rat vibrissa cells. Connective tissue sheath cell morphology was intermediate between that of dermal papilla cells and dermal fibroblasts. However, all three cell types derived during the breeding season grew at a much faster rate than the same cells derived during the nonbreeding season. Therefore, primary cell lines can be fairly readily derived from deer hair follicles. Since the red deer stag offers both androgen-dependent neck (mane) and control flank follicles in the breeding season, plus control nonbreeding season neck follicles, this means that stag follicular cells, particularly the dermal papilla cells, appear to offer a unique novel model system for the study of the hormonal regulation of hair growth.

Serum stimulation, cell-cell interactions, and extracellular matrix independently influence smooth muscle cell phenotype in vitro

Vascular injury profoundly alters the vessel wall microenvironment, and smooth muscle cells respond with cell cycle re-entry, loss of contractile elements, extracellular matrix remodeling, and altered signaling by endogenous growth factors and their receptors. Environmental cues include stimulation by exogenous mitogens and both cell-cell and cell-matrix interactions. Modeling this process in smooth muscle cells in vitro, these environmental determinants were varied independently and the phenotypic consequences assessed. Mitogenic stimulation with serum promoted the synthesis of collagen and fibronectin and the expression of fibroblast growth factor receptor-1 and suppressed the content of smooth muscle alpha-actin, myosin heavy chain, and basic fibroblast growth factor. Low cell density (reduced cell-cell contact) was also associated with enhanced extracellular matrix protein production, increased fibroblast growth factor receptor-1 expression, and reduced contractile protein and basic fibroblast growth factor content. The influence of serum stimulation and reduced cell-cell contact were independent and additive. Provision of a type I collagen matrix blunted the influence of serum and cell-cell contact on collagen synthesis but had minor effects on other measures of phenotype. Environmental factors thus independently influence smooth muscle cell phenotype, including endogenous growth factor expression and responsiveness, which can in turn influence the microenvironment of the vessel wall after injury.

Familial occurrence of electrocardiographic abnormalities of the Brugada-type

Electrocardiographic abnormalities were pointed out in a 51-year-old Japanese male whose major complaint was dizziness. His electrocardiogram showed a complete right bundle branch block, and a prolonged His bundle-ventricle (HV) interval of 100 msec. Two members of his family died of heart disease and 3 members, including a case of sudden death, presented an abnormal electrocardiogram of the Brugada-type with persistent ST segment elevation in the right precordial leads and right bundle branch block. The signal-averaged examination was made in the children of cases that died with the diagnosis of sudden death. Four cases showed a tendency of delay in the HV interval and a positive finding in the late potential. Further studies are necessary to clarify the relationship between electrocardiographic abnormalities of the Brugada-type and atrioventricular conduction disorder as well as to clarify the genetic basis of this disorder.

Amyotrophic lateral sclerosis with hypertensive attacks: blood pressure changes in response to drug administration

Blood pressure changes in response to intravenous drug administration were examined in a respirator-dependent 49-year-old patient with sporadic amyotrophic lateral sclerosis (ALS) who developed severe hypertensive attacks. She showed severe hypertension and tachycardia during the daytime and nocturnal hypotension without compensatory tachycardia, which were consistent with the autonomic phenomenon reported in ALS patients. Infusion of phenotolamine (2.5 mg) induced an abrupt 90 mmHg decrease in systolic pressure and slight increase in heart rate. Propranolol (1 mg) infusion induced decreases in both systolic pressure (36 mmHg) and heart rate (17 beats/min), although the pressure decrease was transient while the heart rate remained at the decreased level Infusion of diazepam (10 mg) induced a 47 mmHg decrease in systolic pressure and a 23 beats/min increase in heart rate. These vasomotor responses indicate the distinct participation of abnormally augmented sympathetic tone, and especially of alpha-sympathetic hyperactivity rather than of beta-sympathetic hyperactivity, in the hypertensive attacks occurring in this ALS patient.

Tumour necrosis factor receptor gene expression and shedding in human whole lung tissue and pulmonary epithelium

This study aimed to investigate the expression of tumour necrosis factor receptor (TNF-R) at the gene and surface level, and its shedding in human lung tissue and a pulmonary epithelial cell line, A549. Levels of gene expression of TNF-R were evaluated by Northern blot analysis. Human lung tissue expressed both type I and type II TNF-R gene, while A549 cells expressed only type I TNF-R gene. Phorbol ester upregulated and TNF-alpha down-regulated the TNF-R gene expression in A549 cells. Consistent with these modulations of TNF-R gene expression, 125I-TNF binding capacities were increased with phorbol ester stimulation and decreased with TNF stimulation after 24 h in A549 cells. The shedding of TNF-R from A549 cells was investigated using enzyme-linked immunosorbent assay (ELISA) for soluble type I TNF-R. Not only lung tissues but also A549 cells spontaneously released soluble type I TNF-R into the culture medium. Both phorbol ester and TNF stimulation accelerated the shedding of soluble TNF-R from A549 cells. These results suggest that type I TNF-R gene expression and shedding of soluble TNF-R are differentially regulated in A549 cells. We conclude that tumour necrosis factor receptor surface expression is regulated, at least in part, at the gene expression level and shedding of soluble tumour necrosis factor receptor is modulated by inflammatory mediators, such as tumour necrosis factor in A549 cells.

Synthesis and biological activity of 4-amino-5-chloro-2-ethoxy-3-hydroxybenzamides, metabolites of a new gastroprokinetic agent, mosapride

To confirm the proposed structures of the minor metabolites of a potential gastroprokinetic agent, mosapride, 4-amino-5-chloro-2-ethoxy-3-hydroxy-N-(2-morpholinylmethyl)benzamide (3) and the N-(5-oxo-2-morpholinyl)-methyl analogue 4 were prepared. As the common intermediate, 2-ethoxy-3-hydroxy-4-nitrobenzoic acid (15) was prepared via the regioselective ethylation of 2,3-dihydroxybenzaldehyde (10) and subsequent nitration of the resultant 2-ethoxy-3-hydroxybenzaldehyde (11). The key intermediate 15 was converted into the benzamides 3 and 4. After enzymatic treatment of the isolated metabolites, their structures were identified by comparison with the synthetic compounds. Serotonin-4 receptor binding affinity of these metabolites was found to be lower than that of mosapride.

Bacterially expressed rat retinol-binding protein is functional for retinol and transthyretin bindings

Retinol-binding protein (RBP) was expressed in Escherichia coli using the cDNA for rat RBP, and characterized. The expressed RBP was fused to maltose-binding protein (MBP) at the N-terminal end (MBP-RBP), and MBP was enzymatically removed from the MBP-RBP with proteinase factor Xa. The binding of retinol and transthyretin (TTR) to the recombinant RBP was monitored by means of gel filtration. The recombinant RBP specifically bound to retinol with an affinity similar to that of purified RBP from rat serum. Furthermore, the retinol-bound recombinant RBP formed hetero-complexes with TTR similar to RBP. Thus, the results showed that the recombinant RBP expressed in E. coli is as functional as serum RBP in terms of retinol and TTR bindings.

cDNA cloning and functional analysis of the p97 subunit of the 26S proteasome, a polypeptide identical to the type-1 tumor-necrosis-factor-receptor-associated protein-2/55.11

Molecular cloning of cDNA for a new regulatory subunit, designated p97, of the human 26S proteasome showed that the polypeptide consists of 908 amino acid residues with a calculated molecular mass of 100184 Da and an isoelectric point of 4.94. Computer analysis showed that p97 is very similar to type-1 tumor-necrosis-factor (TNF)-receptor-associated protein (TRAP)-2 and 55.11, both of which were identified recently as binding proteins of the cytoplasmic domain of type-1 TNF receptor by yeast two-hybrid screening. This finding suggests that the 26S proteasome might serve as a mediator molecule in the TNF signaling pathway in cells. Computer-assisted similarity analysis also revealed the high sequence similarity of p97 with a yeast protein whose function is yet unknown, the gene for which is here termed NAS1 (non-ATPase subunit 1). Disruption of NAS1 resulted in several phenotypes, including lethality and temperature-sensitive growth, depending on the genetic background of the cells used. The human p97 cDNA suppressed the growth defect of nas1 disruptant cells, when expressed from single-copy or multi-copy vectors, indicating that p97 is functionally equivalent to yeast Nas1p. Culturing of the temperature-sensitive nas1 cells at the restrictive temperature promoted the accumulation polyubiquitinated cellular proteins, implying that the 26S proteasome requires a functional Nas1p subunit for ubiquitin-dependent proteolysis. These results indicate that p97/Nas1p plays an important regulatory role in the function of the 26S proteasome.

Squamous cell carcinoma in a Müllerian duct cyst: report of a case

A 36-year-old man presented with a pelvic mass which proved to be a Müllerian duct cyst. The cyst was determined to be squamous cell carcinoma which involved the rectum and the bladder. A total pelvic exenteration was carried out for complete resection.

Electrophoretic characterization of boar epididymal antiagglutinin

Boar epididymal antiagglutinin, previously shown to inhibit sperm head-to-head agglutination, was purified from cauda epididymal plasma by precipitation with ammonium sulfate, anion-exchange chromatography, and reverse-phase HPLC, and was characterized by electrophoretic and membrane blotting techniques. Blotting techniques, using the ECL Glycoprotein Detection System (Amersham Life Science, Buckinghamshire, UK) and wheat germ agglutinin (WGA)-peroxidase, established the presence of sialic acid residues on purified antiagglutinin. Removal of sialic acid residues from antiagglutinin greatly reduced its immunoreactivity with the specific antiserum. Further purification by two-dimensional PAGE established the presence of one major and two minor forms that cross-reacted with the antiserum, with only the major form reacting with WGA-peroxidase. Extracts of washed epididymal spermatozoa contained a polypeptide with the same electrophoretic mobility as the major form. Additionally, the antiserum detected cross-reacting material in seminal plasma and in extracts from ejaculated spermatozoa. When spermatozoa were incubated under conditions shown to promote capacitation, the cross-reacting material could not be detected in sperm extracts. These results are consistent with the following conclusions: 1) antiagglutinin contains sialic acid residues that may be related to its immunoreactivity and molecular heterogeneity, and 2) either sperm-bound antiagglutinin is released or its epitope recognized by the antiserum is altered after ejaculation and in vitro capacitation.

Dopamine transporter gene polymorphism and psychiatric symptoms seen in schizophrenic patients at their first episode

To investigate the possible role of the dopamine transporter (DAT) gene in determining the phenotype in human subjects, allele frequencies for the 40-bp variable number of tandem repeats (VNTR) polymorphism at this site were compared between 117 Japanese normal controls and 118 schizophrenic patients, including six subgroups: early-onset, those with a family history, and those suffering from one of the following psychiatric symptoms at their first episode: delusion and hallucination; disorganization; bizarre behavior; and negative symptoms. No significant differences were observed between the group as a whole or any subgroup of schizophrenic patients and controls. The results indicate that VNTR polymorphism in the DAT gene is unlikely to be a major contributor to any of the psychiatric parameters examined in the present population of schizophrenic subjects.

Evaluation of biological responses to polymeric biomaterials by RT-PCR analysis. I. Study of IL-1 beta mRNA expression

In this study, we introduce a novel research methodology, the evaluation of mRNA expression of cells contacting with polymeric materials using reverse transcription-polymerase chain reaction (RT-PCR) analysis HL-60 was used as a model of the macrophages. The expression of interleukin-1 beta (IL-1 beta) mRNA, a cytokine secreted by macrophages, was selected to estimate the extent of inflammation. The expression of IL-1 beta mRNA in the HL60 cells cultured on various substrates and in various conditions was studied. Expression of IL-1 beta could be successfully determined by RT-PCR analysis. A 48 h incubation period was necessary to clarify the expression of IL-1 beta mRNA. It became clear that lipopolysaccharide stimulation was not necessary in this analysis because of the high sensitivity of RT-PCR analysis. It is concluded that RT-PCR analysis is a powerful tool for studying cell-polymer interaction, and is a complementary method for ELISA.

[Mitomycin C-DNA adduct detection in rat organs and human liver]

Mitomycin C-DNA adduct formation was detected in rat organs and also in human tissues by 32P-postlabeling assay. The adduct levels were 1-4 adduct/ 10(8) nucleotides in the human liver after 20 mg of mitomycin C by intra-artery administration and which level was higher comparing with the levels in the rat liver after 10 times more dosages of mitomycin C administration by intra-venous injection. The levels in the human liver were maintained at least 56 days after administration. Organ-specific differences of adduct levels were observed in rat experiments: the adduct levels of liver, lung and kidney were stable but rapidly decreased in stomach and colon. These results, which were obtained from the experiments using the normal parts of each organs may indicate that the drug effectivity for adduct formation was sufficient with smaller dose in the stomach and colon, but disappeared quickly, mean while, the drug effectivity was undergoing in relatively high levels for longer periods in the liver lung and kidney. The analysis of human liver samples may suggest that the selective intra-artery injection induced stronger drug effectivity for adduct formation in human organs.

Reactive oxygen species involved in the glutamate toxicity of C6 glioma cells via xc antiporter system

We recently demonstrated that continuous L-glutamate exposure led to cell death in C6 glioma cells over a period of 24-36 h, due to inhibition of cystine uptake through the cystine/glutamate (XC) antiporter. The antioxidant vitamin E provided protection against this effect, supporting the hypothesis that depletion of glutathione might be responsible, resulting from insufficient cystine uptake. To clarify the content of oxidative stress after glutathione depletion, the present study was done to investigate accumulation and target molecules of reactive oxygen species induced by glutamate treatment. The accumulation of reactive oxygen species was increased three-fold as compared to a control culture. Membrane oxidation, as judged by lipid peroxidation, was increased two-fold after glutamate treatment. Cellular ATP content was significantly reduced by glutamate exposure. For the two cytosolic enzymes examined, activity of glyceraldehyde 3-phosphate dehydrogenase was slightly enhanced by glutamate treatment, while activity of glutamine synthetase was not changed. Impairment of nuclear DNA after glutamate exposure was also revealed by nuclear chromatin condensation with DNA fragmentation. Thus, the multiple targets (membrane, cytoplasm and nuclei) of oxygen radicals in glutamate toxicity through the xc antiporter system were evaluated for the first time. Furthermore, prevention from cell death and from cellular toxicity induced by oxygen radicals could be seen using three specific oxygen radical scavengers, catalase, 3,3,5,5-tetramethyl-pyrroline N-oxide and alpha-phenyl-N-t-butylnitrone, without restoring the glutathione deficit. This indicates that radical scavengers did not interact with the xc antiporter system, but directly scavenged the oxygen radicals. Taken together, the data strongly suggest that O2-, H2O2 and OH accumulate in response to oxidative stress after glutathione depletion, resulting in glutamate cell death of C6 glioma cells.

Role in nitric oxide in Kupffer cell-mediated hepatoma cell cytotoxicity in vitro and ex vivo

The metabolic change in tumor cells (AH70, a rat hepatoma cell line) cocultured with isolated rat Kupffer cells were visualized and analyzed by a laser scanning confocal imaging system. When AH70 cells were cocultured with Kupffer cells, fluorescence intensity of rhodamine 123 (Rh123) decreased, indicating the reduction of mitochondrial function. The reduction in Rh123 was eliminated by NG-monomethyl-L-arginine (L-NMMA), an analogue of L-arginine, suggesting the involvement of nitric oxide (NO). Two hour after the cells were cocultured, membrane compromised AH70 cells which were observed as propidium from 2.8% to 25%. This increase was also attenuated by L-NMMA, suggesting that Kupffer cell-mediated injury of tumor cells largely depends on NO. The concentrations of NO-2 + NO-3 in the culture medium markedly increased after coculture of AH70 cells with Kupffer cells. Moreover, NO synthase (NOS) activity in Kupffer cells significantly increased after coculture. These in vitro results suggest that NO mediates Kupffer cell-induced tumor cell damage characterized by reduced mitochondrial function and diminished barrier function. In the ex vivo study of the perfused liver to which AH70 cells were injected via the catheter inserted into the portal vein, some AH70 cells were arrested in the upper stream of sinusoid and the fluorescence intensity of Rh123 in adherent AH70 cells decreased in a time-dependent manner within 2 hours. The number of PI-positive AH70 cells also increased 2 hours after the injection of AH70 cells. These changes were inhibited by either administration of N omega-L-nitroarginine-methylester (L-NAME) to perfusate or pretreatment of the rat liver with GdCl3, which is known to deplete Kupffer cell function. Thus, the present study suggests that NO from Kupffer cells induces mitochondrial dysfunction in tumor cells followed by membrane barrier dysfunction in the liver sinusoid.