Studies on the mechanism controlling generation of superoxide radical in luteinized rat ovaries during regression

The mechanism regulating the luteolytic release of superoxide radical (SOR) was examined in prostaglandin F2 alpha (PGF2 alpha)-treated rats. Tail vein injection of PGF2 alpha caused a rapid increase in SOR in mitochondria and plasma membrane samples prepared from luteinized rat ovaries. The peak in the mitochondria preceded that in the plasma membrane, and both occurred before progesterone concentrations decreased in the blood. The amount of SOR produced was greater when samples from the plasma membrane, mitochondria, and cytosol were combined. In plasma membrane samples, SOR generation was lowered by inhibitors of intracellular signaling pathways, but not by cyanide, which blocks electron transport in respiratory enzymes. In mitochondria samples, however, SOR was blocked by cyanide, but not by inhibitors of intracellular signaling enzymes. The addition of phospholipase-A2, phorbol myristate acetate (protein kinase-C activator), or arachidonic acid stimulated SOR production in plasma membrane samples from ovaries of control rats, and phorbol myristate acetate and arachidonic acid inhibited LH-stimulated progesterone secretion in dispersed rat luteal cells. Also, when mitochondria prepared from ovaries of PGF2 alpha-treated rats were added to dispersed corpus luteum cells, there was an increase in SOR generation and an inhibition of LH-stimulated cAMP formation and progesterone secretion. These results indicate that SOR production in the corpus luteum after PGF2 alpha treatment is generated by several subcellular components. Formation in the plasma membrane may be initiated by SOR generation from the mitochondria and regulated by intracellular signaling pathways. Our results indicate that formation of SOR may lead to the disruption of LH stimulation of progesterone secretion.

Suppression of phagocytosis by adrenocorticotropic hormone in murine peritoneal macrophages

Phagocytosis of latex beads by peritoneal macrophages was examined by means of flow cytometry (FCM). This assay revealed that adrenocorticotropic hormone (ACTH) suppressed phagocytosis in a dose-dependent manner. ACTH (1-24) was more suppressive than ACTH (1-39). Control phagocytosis was partially suppressed in Ca(2+)-free solution. Phagocytosis was suppressed by ACTH in this solution to the same degree as in the normal solution. Suppression by ACTH was reduced in phosphodiesterase inhibitor-containing solution. These results suggest that (1) ACTH suppresses extracellular Ca(2+)-dependent and -independent phagocytosis, (2) the suppression is not mediated by cAMP and (3) the inhibition of macrophage phagocytosis by ACTH is one of the mechanisms that modulate immune responses in stressful situations.

Expression of cytokines during glial differentiation

Astrocytes and microglia produce a variety of cytokines, some of which may have roles in the proliferation and differentiation of glial cells during development in the central nervous system. Cytokine mRNAs and activities were therefore assayed during glial development in mixed glial cell cultures from newborn mouse brain. Cytokine mRNAs were also measured in mouse brain during postnatal development in vivo. Macrophage colony-stimulating factor(M-CSF) mRNA, interleukin-1 beta (IL-1 beta) mRNA and tumor necrosis factor alpha (TNF alpha) mRNA were all detected on the in vitro cultures and each showed a distinct time course of expression. IL-6 and granulocyte-macrophage colony-stimulating factor(GM-CSF) mRNAs were not detected in the cultured cells. Measurements of cytokine activity in culture supernatants as well as cytokine mRNAs in vivo gave similar results. The data suggest that IL-1, TNF alpha and M-CSF are produced in the period of gliogenesis, and that M-CSF rather than GM-CSF may promote the generation and proliferation of microglia. Although IL-6 and GM-CSF exhibit neurotrophic effects, these cytokines may not function as neurotrophic factors during early postnatal development.

[Metastasis of an adenocarcinoma of unknown origin to mediastinal lymph nodes, and transient regression]

A 67-year-old woman was admitted to our hospital because of fever. Chest roentgenogram showed an enlargement of mediastinal lymph nodes. Despite thorough examination, no definite diagnosis could be made. The mediastinal lymph nodes got smaller over the next 3 weeks and a chest roentgenogram taken 4 months later showed no mediastinal lymphadenopathy. The mediastinal lymphadenopathy and fever recurred 5 months later. She underwent thoracotomy and the mediastinal lymph nodes were excised. Microscopic examination of pretracheal lymph node specimens showed invasion of poorly differentiated adenocarcinoma associated with abundant tumor-infiltrating lymphocytes. The other lymph nodes showed sarcoid reaction. Although she has been followed for one year and 11 months, no primary site of the cancer has been found. Metastasis of cancer of unknown origin to mediastinal lymph nodes is extremely rare. It is also interesting that the lymph node swelling diminished spontaneously. The tumor-infiltrating lymphocytes and sarcoid reactions may have been immunological responses to the cancer and may have caused the transient regression.

Interleukin-4 induces proliferation and activation of microglia but suppresses their induction of class II major histocompatibility complex antigen expression

We recently found that microglia, brain macrophages, express interleukin-4 (IL-4) receptor mRNA in vitro. Since IL-4 exhibits a variety of functions on the cells of monocyte-macrophage lineage, we examined the effects of IL-4 on the functions of microglia. Recombinant IL-4 induced the proliferation of microglia in a dose- and time-dependent manner as determined by MTT colorimetric assay, [3H]thymidine uptake and bromodeoxyuridine (BrdU) incorporation. IL-4 also synergistically enhanced the proliferation of microglia with such colony-stimulating factors as IL-3, granulocyte-macrophage colony-stimulating factor (GM-CSF) and macrophage colony-stimulating factor (M-CSF). It also increased acid phosphatase activity and superoxide anion formation by these cells. Despite these positive effects on proliferation and activation, IL-4 suppressed the IFN gamma-induced class II MHC antigen expression in these cells. Since these effects of recombinant IL-4 were inhibited by the addition of monoclonal antibody against IL-4 receptors, the effects of IL-4 on microglia appear to be a specific function via IL-4 receptors. Although microglia and astrocytes produce a variety of immunoregulatory cytokines, neither cell produced IL-4 as determined by bioassay or detection of IL-4 mRNA by RT-PCR method. Thus, the exogenous IL-4 may contribute to the accumulation of microglia in or around inflammatory lesions in the central nervous system, and may be involved in the regulatory mechanisms of microglia.

Alterations in free radical activity in aging Drosophila

Drosophila were examined to see if there is an increase in damage associated with free radical activity in older flies. The levels of superoxide radical and of lipid peroxides were higher in membrane samples from older flies. Also, in older Drosophila there was a significant decrease in membrane fluidity, as determined by fluorescence polarization, and an increase in ATP-dependent calcium uptake. In homogenates from whole flies, the concentration of inorganic peroxides and activity of the proteolytic enzyme, cathepsin B, increased with age. During their lifetime, vestigial wing Drosophila displayed a greater level of free radical activity than wild-type flies and a significantly shorter life span (26.7 +/- 0.7 days vs. 34.4 +/- 1.0, p < 0.01). These results indicate that the level of oxidative stress is closely coupled to cellular damage and to life span, and they indicate that free radicals may play a central role in the aging process in Drosophila.

cDNA cloning of a novel protein tyrosine phosphatase with homology to cytoskeletal protein 4.1 and its expression in T-lineage cells

Reversible tyrosine phosphorylation plays important regulatory roles in various cellular events including the differentiation and function of lymphocytes. Here we report the cDNA cloning of a non-receptor type protein tyrosine phosphatase, PTP36, which is expressed in murine thymus. PTP36 was a new member of a tyrosine phosphatase subfamily defined by MEG-01 and PTPH1, which had a C-terminal phosphatase domain as well as an N-terminal domain with homology to cytoskeletal-associated proteins like band 4.1, ezrin, and talin. In addition, we found a putative SH3-binding motif in PTP36 but not in MEG-01 or PTPH1. PTP36 was expressed in cells of both hematopoietic and non-hematopoietic origins. In thymocytes subpopulations, PTP36 was preferentially expressed in double positive stage cells. The change of PTP36 expression level along with T cell maturation suggests its involvement in the regulation of T cell development.

Clonal analysis of human gynecologic cancers by means of the polymerase chain reaction

Clonality of human gynecologic cancers was analyzed in small DNA samples prepared from cryostat sections, by means of the polymerase chain reaction (PCR). The method used for clonal analysis was based on restriction fragment length polymorphism of the X-chromosome-linked phosphoglycerokinase (PGK) gene and on the differential methylation of the PGK gene due to random inactivation of 1 of 2 X-chromosomes by methylation in females. Among 52 gynecologic cancers tested, 25 were found to be heterozygous for the BstXI polymorphism of the PGK gene. All the 25 gynecologic cancers (4 cervix, 11 endometrium, 7 ovary and 3 fallopian tube) analyzed by the PCR-based method were monoclonal in origin while adjacent normal tissues were polyclonal. When DNA samples were prepared from widely separated sites of tumors and/or metastatic lesions, every sample was found to be monoclonal, and the same allele of the PGK gene was inactivated in each case. These results demonstrate that clonal analysis by PCR offers a good method for studying clonality in small DNA samples prepared from cryostat sections of tumors. This method could be applied to distinguish between benign and malignant gynecologic lesions.

Stable expression of human CYP1A2 and N-acetyltransferases in Chinese hamster CHL cells: mutagenic activation of 2-amino-3-methylimidazo[4,5-f]quinoline and 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline

In order to investigate the metabolic activation pathway of food-derived heterocyclic amines, 2-amino-3-methylimidazo[4,5-f]quinoline (IQ) and 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx), cultured cell lines which stably expressed human cytochrome P4501A2 (CYP1A2) and N-acetyltransferases (NATs) were developed by the method of complementary DNA (cDNA) transfection. First, a cell line expressing CYP1A2, designated A2R-5, was established from the cell line CR-68, which was previously established by introducing NADPH-cytochrome P-450 reductase cDNA into Chinese hamster CHL cells. The expression of CYP1A2 in the transfected cells was confirmed by determining sensitivity to aflatoxin B1. As the next step, the A2R-5 as well as CR-68 cells were further transfected with human monomorphic NAT (NAT1) or polymorphic NAT (NAT2) cDNAs. The expression of NAT in the transfected cells was confirmed using p-aminobenzoic acid and sulfamethazine as substrates, while no activity was seen in parental CR-68 and A2R-5 cells. The cell line, ANP-25, which expressed both CYP1A2 and NAT2, was approximately 370- and 100-fold more sensitive to IQ and MeIQx, respectively, than parental CR-68 cells in cytotoxicity assays. There were no clear differences in sensitivity to both compounds among CR-68, A2R-5, and the cell lines which expressed NAT1 alone, NAT2 alone, and CYP1A2 plus NAT1. Mutagenicity of IQ and MeIQx at the hypoxanthine-guanine phosphoribosyltransferase locus was also detectable only in ANP-25 cells but not in A2R-5 or the cell line expressing CYP1A2 plus NAT1. From these results, it is proposed that both CYP1A2 and NAT2 (but not NAT1) are required for mutagenic activation of these compounds, implying that acetylator polymorphism may be an important risk factor in the carcinogenicity of these compounds.

Establishment and characterization of human vaginal malignant melanoma xenotransplants

Human vaginal malignant melanoma represents rare gynecological malignancies of poor prognosis. We have established a melanoma tumor line in nude mice, designated Mela-1, and have examined the histological and biological characteristics of this tumor. The Mela-1 tumor has preserved the histological, histochemical and biological characteristics of malignant melanoma even after 20 passages. Tumor cells are of epitheloid shape varying in size. An ultrastructural study revealed that the tumor cells were characterized by the presence of cells with deeply indented nuclei, and both types of melanosomes, eumelanosomes and pheomelanosomes, in various stages of maturation with vesiculo-globular bodies in the cytoplasm. Melanin analysis of the tumor indicated the Mela-1 tumor to be pheomelanic. Immunohistochemical examinations revealed that the Mela-1 cells were stained positively by melanoma-associated antibody (NKI/C3) and by antibodies for S-100 protein and vimentin, and negatively for keratin and CEA. The levels of AFP, CA125 and CEA in sera of tumor-bearing mice were within normal range. The 5-S-cysteinyldopa level in sera of tumor-bearing mice correlated well with the size of the tumor. Chromosomal analysis showed the human karyotype with great heterogeneity and a modal number of 102 chromosomes. Thus the Mela-1 tumor will be useful in establishing the biological characteristics in the search for an effective treatment of human malignant melanoma of the vagina.

A flow cytometric assay reveals an enhancement of phagocytosis by platelet activating factor in murine peritoneal macrophages

Phagocytosis of fluorescein isothiocyanate-labeled latex beads by peritoneal macrophages from thioglycollate-stimulated mice was examined in vitro by means of flow cytometry. This assay revealed that platelet activating factor (PAF), a known inflammatory mediator, enhanced the phagocytosis in a dose-dependent manner. The enhancement was completely suppressed by a PAF antagonist, Y-24180, and partly suppressed by another antagonist, CV-3988. The phagocytosis of both nonstimulated and PAF-stimulated macrophages was suppressed in Ca(2+)-free ethylene glycol bis(beta-aminoethyl ether) N,N'-tetraacetic acid-containing solution, but the phagocytosis was enhanced by PAF even in this solution. These results suggest that phagocytosis by macrophages is enhanced by PAF in allergic and inflammatory reactions.

[Qualitative evaluation of 123I-IMP SPECT using a rotating gamma camera in atherosclerotic large-artery disease]

PURPOSE Quantitative measurement of regional cerebral blood flow (rCBF) needs special equipment or invasive blood sampling. Therefore, with a popularly used rotating gamma camera, we tried to establish a convenient modality of qualitative evaluation of hemodynamics in patients with atherosclerotic large-artery disease, according to the distribution pattern of isotope-uptake on SPECT image. PATIENTS AND METHODS Forty-one patients with atherosclerotic large-artery disease [9 internal carotid artery (ICA) stenosis, 17 ICA occlusion, 8 middle cerebral artery (MCA) stenosis, and 7 MCA occlusion] and 32 control patients documented as having small cerebral infarction without atherosclerotic large-artery disease were investigated. Using the rotating gamma camera, they underwent 123I-IMP SPECT at baseline and after acetazolamide loading. According to the distribution pattern of low isotope-uptake, early images were classified into four types: Type I: no low uptake, Type II: low uptake in a single watershed, Type III: low uptake in two watersheds with or without a partial MCA territory, Type IV: low uptake in a whole MCA territory. RESULT In patients with large-artery disease, baseline images presented Type I in 12 cases, Type II in 16, Type III in 9, Type IV in 4, and loading images Type I in 3, Type II in 2, Type III in 8, Type IV in 28. Of 37 patients except for 4 belonging to Type IV at baseline, 32 (86.5%) had a more extensive low isotope-uptake area after acetazolamide loading than at baseline. In control patients, baseline images presented Type I in 25, Type II in 7, and the Type III & IV in 0, and the Type after loading was the same as the Type at baseline. CONCLUSION We established the qualitative evaluation of 123I-IMP SPECT image by detecting the "extent" of the ischemic region, taking notice of watershed. The pathognomonic findings on SPECT image of atherosclerotic large-artery disease showed that low isotope-uptake area at baseline extended into two watersheds or MCA territory by acetazolamide loading. The modality of qualitative evaluation based on these pathognomic findings of SPECT image may be useful for easily assessing patients with atherosclerotic large-artery disease using a rotating gamma camera.

Determination of plasma tissue factor antigen and its clinical significance

To investigate the clinical significance of determination of plasma tissue factor (TF) antigen, we have developed a highly sensitive enzyme-linked immunosorbent assay (ELISA) for plasma TF, using two different monoclonal antibodies against TF apoprotein, 6B4 (catching antibody) and 5G9 (detecting antibody), and tetramethyl benzidine/H2O2 as substrates. Titration curves of recombinant human TF in buffer containing Triton X-100 were linear within the range from 50 to 2000 pg/ml. The total assay time was 3 h. Ultracentrifugation and immunoblot analysis indicated that human plasma and urine contained 50,000 g sedimentable and non-sedimentable forms of TF, both of which were detected by our ELISA method. Plasma and urine concentrations of TF in healthy subjects and patients with various diseases were measured by the ELISA method. In healthy subjects, plasma and urinary TF levels were found to be 149 +/- 72 pg/ml (n = 30) and 175 +/- 60 pg TF/urine creatinine mg (n = 95), respectively. TF was increased in plasma of patients with disseminated intravascular coagulation (DIC), thrombotic thrombocytopenic purpura, vasculitis associated with collagen diseases, diabetic microangiopathy and chronic renal failure receiving haemodialysis, but not in the plasma of endotoxaemic patients without DIC. The plasma TF/serum creatinine ratio did not show a positive correlation. Measurement of TF antigen in plasma may be useful for evaluating the endothelial damage and cell destruction in TF-containing tissues.

Selective uptake of liposomes containing lactose mono-fatty acid derivatives by hepatic parenchymal cells

In this study we investigated the hepatic uptake of liposomes containing a novel synthetic glycolipid, lactose mono-arachidic acid amide (LAA). Liposomes containing LAA were aggregated by Ricinus communis agglutinin from caster bean, while the control liposomes were not, and the results suggested that the galactose residues of LAA were exposed to the outer surface of the liposomes. Next, the blood clearance and hepatic uptake of liposomes containing LAA after intravenous administration were compared with those of the control liposomes in rat. Hepatic uptake of liposomes containing LAA was greater than that of the control liposomes, rising significantly with dose. As a result of separation of the parenchymal and non-parenchymal cells, it was shown that the increase in hepatic uptake was mostly accounted for by a greater uptake by parenchymal cells. The inhibitory activity of asialofetuin on the hepatic uptake of liposomes containing LAA suggested that a galactose-specific recognition is involved in this uptake. These results demonstrate that the lactose mono-fatty acid amides (LFAs) are promising novel compounds for the introduction of carbohydrate residues onto the liposomal surface and that liposomes containing LFAs are potential carriers for the selective delivery of drugs to specific cells.

Monoclonal antibodies to a zinc-binding protein of rat Paneth cells

Paneth cells are morphologically well characterized but their function has been not elucidated. Previously, we identified and purified a 90 KD zinc-binding protein (ZBPP-1) in rat intestine that was localized to Paneth cell granules, consistent with their high zinc content. To further elucidate the structure and function of ZBPP-1, we immunized Balb/c mice with purified ZBPP-1 and identified four independent monoclonal antibodies (MAb) producing MAb ZIP-1 (IgM), ZIP-2 (IgG1), ZIP-3 (IgM), and ZIP-4 (IgM). Immunohistochemistry (IHC) and immunoelectron microscopy (IEM) with these MAb showed positive staining of Paneth cell cytoplasmic granules. MAb ZBPP-1 also stained a population of mononuclear cells in the lamina propria of digestive tract mucosa and a few cells in spleen, presumably a subset of macrophages. These MAb will provide a useful tool to study the function of Paneth cells in human health and disease, since they cross-reacted with human intestinal Paneth cells and mucosal mononuclear cells.

Inhibition of the calcitonin-induced outward current in identified Aplysia neurons by interleukin-1 and interleukin-2

1. The effects of bath-applied recombinant human interleukin-1 (rhIL-1) and interleukin-2 (rhIL-2) on the calcitonin (CT)-induced outward current recorded from identified neurons (R9-R12) of Aplysia kurodai were investigated with conventional voltage-clamp and pressure ejection techniques. 2. Micropressure ejection of CT onto the soma of the neuron induced a slow outward current [Io(CT); 4-6 nA in amplitude, 30-40 sec in duration] associated with a decrease in input membrane conductance. 3. Io(CT) was increased by hyperpolarization. 4. The extrapolated reversal potential was +10 mV. Additionally, Io(CT) was sensitive to changes in (Na+)o but not to changes in (K+)o, (Ca2+)o, and (Cl-)o. 5. Micropressure-ejected forskolin produced a slow outward current similar to that induced by CT. 6. Bath-applied rhIL-1 and rhIL-2 (10-40 U/ml) reduced the CT-induced current in identified Aplysia neurons without affecting the resting membrane conductance or the holding current. 7. The inhibitory effects of both cytokines on the current were completely reversible. Heat-inactivated rhIL-1 and rhIL-2 were without effect. 8. These results suggest that the immunomodulators, IL-1 and IL-2, can modulate the CT-induced outward current associated with a decrease in Na+ conductance in the nervous system of Aplysia. Therefore, the study suggests that these cytokines may also serve as neuromodulators.

Characterization and tissue distribution of liposomes containing lactose mono-fatty acid derivatives

In this study we characterized liposomes containing the synthetic glycolipids, lactose mono-fatty acid esters (LFEs), whose structures were the most simple ones compared to the other synthetic glycolipids. Gel filtration chromatography was used to confirm that 78 per cent of lactose monostearic acid ester (LSE) or 85 per cent of lactose monoarachidic acid ester (LAE) existed in the liposomal fraction. The size distribution of liposomes containing LFEs was similar to that of the control liposomes which did not contain LFEs. Liposomes containing LFEs were aggregated by Ricinus communis agglutinin from caster bean (RCA120) while the control liposomes were not, with the agglutinability of the liposomes containing LAE being greater than that of those containing LSE. These findings therefore suggested that the LFEs were incorporated into the liposomal membrane with the galactose residues exposed to the outer aqueous phase. Next, the tissue distribution of liposomes containing LAE at 30 min after intravenous administration was compared to that of the control liposomes in rats. Hepatic uptake was 2-fold higher than that of the control liposomes. These results thus demonstrate that liposomes containing LFEs represent potential drug carriers to the liver.

Simultaneous determination of human neutrophil elastase inhibitor (ONO-5046) and its metabolite in plasma and urine by direct injection column-switching HPLC

The direct injection method for the simultaneous determination of a human neutrophil elastase inhibitor (ONO-5046) and its metabolite (ONO-EI-601) in plasma and urine has been developed using a column-switching HPLC system. The system was set up with a pre-treatment column, a pre-concentration column and an analytical column which were connected in series via two automatic switching valves. The calibration lines showed a good linearity for concentrations of ONO-5046 and ONO-EI-601 in a range of 156-20000 ng ml-1 in plasma and 1.56-100 micrograms ml-1 in urine, all correlation coefficients being greater than 0.9999. The limit of quantitation of ONO-5046 was 156 ng ml-1 in plasma, that of ONO-EI-601 was 313 ng ml-1 in plasma, and those of ONO-5046 and ONO-EI-601 were 1.56 micrograms ml-1 in urine. The developed method is rapid and sensitive with automated operation, allowing untreated samples to be analysed every 45 min. The application of the present method to the real plasma and urine samples proved to be useful for pharmacokinetic, toxicological and clinical studies.

[A case of crescentic glomerulonephritis associated with anti-myeloperoxidase antibody presenting as alveolar hemorrhage]

A 77-year-old man was admitted because of hemoptysis. Chest roentgenograms initially showed progressive infiltrative shadows, which improved spontaneously in 3 months. Transbronchial lung biopsy specimens obtained during the first admission revealed alveolar hemorrhage with neither granuloma nor vasculitis. Alveolar hemorrhage associated with renal dysfunction recurred 9 months later. Serum creatinine level was elevated to 3.5 mg/dl. No other organ than lungs or kidneys was involved. Renal biopsy was performed to confirm the pathological diagnosis of crescentic glomerulonephritis. Anti-basement-membrane antibody was negative, whereas anti-neutrophil-cytoplasmic antibody was positive for perinuclear pattern (P-ANCA) by indirect immunofluorescent (IF) method. He was diagnosed as having idiopathic crescentic glomerulonephritis complicated with alveolar hemorrhage, and the presence of anti-myeloperoxidase (MPO) antibody in serum was anticipated. Anti-MPO antibody level in his serum evaluated by ELISA was markedly elevated. Although myeloperoxidase has been considered as a common antigen to P-ANCA and anti-MPO antibody, the determination of P-ANCA has been clinically unreliable because of equivocal results. In contrast, the presence of anti-MPO antibody is highly specific for idiopathic crescentic glomerulonephritis complicated with alveolar hemorrhage or its incomplete variant case. Also, it is a better index of disease activity. Therefore, there is a possibility that those patients diagnosed as having idiopathic pulmonary hemosiderosis or pulmonary-renal syndrome may be categorized into the one disease, anti-MPO antibody-associated disease, and the measurement of anti-MPO antibody may lead to prompt treatment prior to the histological diagnosis.

Effect of dibutyryl cyclic AMP on morphologic features and marker production of human cervical argyrophil small-cell carcinoma cell line

The effect of dibutyryl cyclic AMP (dB-cAMP) on the morphologic features and marker production of a human cervical argyrophil small-cell carcinoma (ASCC) cell line was examined. Following 1-5 days' exposure to 5 mM dB-cAMP, morphologic differentiation as defined by the expression of cytoplasmic processes (stellate cells) was observed. The number of stellate cells depended on the dose of dB-cAMP and incubation time. Shortly after removal of dB-cAMP from the culture medium, the treated cells returned to their original spherical shape. dB-cAMP caused a reduction in the growth rate of cells which recovered after removal of the agent. The morphological changes appeared not to be the result of growth inhibition by dB-cAMP, because the cells maintained in a serum-free medium did not show any change in shape. Electron microscopic study revealed the development of intracytoplasmic microtubules, microfilaments, and an increase in the number of neurosecretory granules in the treated cells. The levels of neuron-specific enolase, serotonin and gastrin in treated cells were significantly higher than those in untreated controls. These findings indicate that a reversible differentiation of cultured ASCC cells into neuroendocrine cells occurs in a growth medium containing dB-cAMP.

An experimental model for ovarian tumor invasion of cultured mesothelial cell monolayer

BACKGROUND

Peritoneal spread of tumor cells is one of the characteristic features of biologic behavior of ovarian cancers. To understand the mechanism by which human tumor cell invasion takes place, we have tried to establish an in vitro experimental model for ovarian tumor cell invasion of the mesothelial cell monolayer.

EXPERIMENTAL DESIGN

Mesothelial cells were isolated from normal rat mesentery by trypsin digestion and the cells (1 x 10(5)/dish) were cultured in Eagle's minimum essential medium supplemented with 10% fetal calf serum. Cultured mesothelial cells (M cells) grew forming a pavement-like monolayer. When M cells grew to a confluent state, tumor cells (1 x 10(5)/dish) were seeded on M cell monolayers and cultured. Four tumor cell lines derived from human ovarian cancers were tested for their invasive behaviors. The penetration of M cell monolayers by the tumor cells was confirmed by a perpendicular section of the cell layers. The number of penetrated single tumor cells and colonies/cm2 was counted under a phase contrast microscope after the tumor cell seeding.

RESULTS

Several hours after the tumor cell seeding, the cells adhered to M cell monolayers and started to penetrate by extending pseudopodia-like cytoplasmic processes through junctional margins of neighboring M cells, resulting in the formation of penetrated single tumor cells that then proliferated to form colonies under the monolayer. The number of penetrated single tumor cells and colonies/cm2 increased up to 24 hours after the tumor cell seeding, and thereafter stayed almost constant. The number increased with the number of tumor cells seeded, when counted at 48 hours, and therefore was taken to be the number of tumor cells invaded. The in vitro invasiveness of tumor cells varied with the tumor cell lines examined.

CONCLUSIONS

Application of this system appears to provide rapid determinations of the invasive potential of ovarian tumor cells and to make it easy to screen substances that modify the invasion of mesothelial cells.

[The beneficial effects of PGI2 analogue (OP-41483-alpha-CD) on hepatic dysfunction after warm ischemic damage]

The purpose of the experimental study was to investigate the beneficial effects of aPGI2 analogue (OP-41483-alpha-CD; aPGI2) on hepatic dysfunction after warm ischemia and reperfusion. Hepatic warm ischemia was produced by temporary clamping of the portal vein and hepatic artery. Experimental groups were divided into three groups: Group I; 60-minutes ischemia, Group II; 90-minutes ischemia, Group III; 90-minutes ischemia with intravenous aPGI2 (0.25 microgram/kg/min) infusion. The results were as follows: 1; In groups I and III, hepatic tissue flow showed a marked increase after reperfusion when compared to Group II. 2; Arterial ketone body ratio in Groups I and III recovered significantly faster than those of Group II. 3; The tissue total adenine-nucleotide levels in Groups I and III were significantly higher than those of Group II. 4; In the comparison of the radical intensity which was measured by ESR spectroscopy, the free radical of the hepatic venous blood was markedly generalized after reperfusion in Group II. However, production of free radical has significantly suppressed in Group III when compared to Group II. These results suggest that aPGI2-treatment might improved the ischemic damaged liver and might improve the prognosis of the transplanted patient.