Cellular commitment to oncogene-induced transformation or apoptosis is dependent on the transcription factor IRF-1

The transcriptional activator interferon regulatory factor 1 (IRF-1) and its antagonistic repressor IRF-2 are regulators of the interferon (IFN) system and of cell growth. Here we report that embryonic fibroblasts (EFs) from mice with a null mutation in the IRF-1 gene (IRF-1-/- mice) can be transformed by expression of an activated c-Ha-ras oncogene. This property is not observed in EFs from wild-type or IRF-2-/- mice but is still observed in EFs from mice deficient in both genes. The transformed phenotype of ras-expressing IRF-1-/- EFs could be suppressed by the expression of the IRF-1 cDNA. Thus, IRF-1 functions as a tumor suppressor. Furthermore, expression of the c-Ha-ras oncogene causes wild-type but not IRF-1-/- EFs to undergo apoptosis when combined with a block to cell proliferation or treated by anticancer drugs or ionizing radiation. Hence, IRF-1 may be a critical determinant of oncogene-induced cell transformation or apoptosis.

Anti-oncogenic and oncogenic potentials of interferon regulatory factors-1 and -2

Interferon regulatory factor-1 (IRF-1), a transcriptional activator, and IRF-2, its antagonistic repressor, have been identified as regulators of type I interferon and interferon-inducible genes. The IRF-1 gene is itself interferon-inducible and hence may be one of the target genes critical for interferon action. When the IRF-2 gene was overexpressed in NIH 3T3 cells, the cells became transformed and displayed enhanced tumorigenicity in nude mice. This transformed phenotype was reversed by concomitant overexpression of the IRF-1 gene. Thus, restrained cell growth depends on a balance between these two mutually antagonistic transcription factors.

An IRF-1-dependent pathway of DNA damage-induced apoptosis in mitogen-activated T lymphocytes

Lymphocytes are particularly susceptible to DNA damage-induced apoptosis, a response which may serve as a form of 'altruistic suicide' to counter their intrinsic high potential for mutation and clonal expansion. The tumour suppressor p53 has been shown to regulate this type of apoptosis in thymocytes, but an as yet unknown, p53-independent pathway(s) appears to mediate the same event in mitogen-activated mature T lymphocytes. Here we show DNA damage-induced apoptosis in these T lymphocytes is dependent on the antioncogenic transcription factor interferon regulatory factor (IRF)-1. Thus two different anti-onco-genic transcription factors, p53 and IRF-1, are required for distinct apoptotic pathways in T lymphocytes. We also show that mitogen induction of the interleukin-1 beta converting enzyme (ICE) gene, a mammalian homologue of the Caenorhabditis elegans cell death gene ced-3, is IRF-1-dependent. Ectopic overexpression of IRF-1 results in the activation of the endogenous gene for ICE and enhances the sensitivity of cells to radiation-induced apoptosis.

Cooperation of the tumour suppressors IRF-1 and p53 in response to DNA damage

Normally growing cells promptly cease DNA synthesis when exposed to genotoxic stresses, such as radiation, and this cell-cycle arrest prevents the accumulation of mutations. The transcription factor interferon regulatory factor (IRF)-1 is essential for the regulation of the interferon system, inhibits cell growth, and manifests tumour-suppressor activities. Here we show that mouse embryonic fibroblasts (EFs) lacking IRF-1 are deficient in their ability to undergo DNA-damage-induced cell-cycle arrest. A similar phenotype has been observed in EFs lacking the tumour suppressor p53 (refs 8, 9), although the expression of IRF-1 and p53 are independent of one another. Furthermore, we show that transcriptional induction of the gene encoding p21 (WAF1, CIP1), a cell-cycle inhibitor, by gamma-irradiation is dependent on both p53 and IRF-1, and that the p21 promoter is activated, either directly or indirectly, by both in a transient cotransfection assay. These two tumour-suppressor transcription factors therefore converge functionally to regulate the cell cycle through the activation of a common target gene.

Photocrosslinkable chitosan as a biological adhesive

A photocrosslinkable chitosan to which both azide and lactose moieties were introduced (Az-CH-LA) was prepared as a biological adhesive for soft tissues and its effectiveness was compared with that of fibrin glue. Introduction of the lactose moieties resulted in a much more water-soluble chitosan at neutral pH. Application of ultraviolet light (UV) irradiation to photocrosslinkable Az-CH-LA produced an insoluble hydrogel within 60 s. This hydrogel firmly adhered two pieces of sliced ham with each other, depending upon the Az-CH-LA concentration. The binding strength of the chitosan hydrogel prepared from 30-50 mg/mL of Az-CH-LA was similar to that of fibrin glue. Compared to the fibrin glue, the chitosan hydrogel more effectively sealed air leakage from pinholes on isolated small intestine and aorta and from incisions on isolated trachea. Neither Az-CH-LA nor its hydrogel showed any cytotoxicity in cell culture tests of human skin fibroblasts, coronary endothelial cells, and smooth muscle cells. Furthermore, all mice studied survived for at least 1 month after implantation of 200 microL of photocrosslinked chitosan gel and intraperitoneal administration of up to 1 mL of 30 mg/mL of Az-CH-LA solution. These results suggest that the photocrosslinkable chitosan developed here has the potential of serving as a new tissue adhesive in medical use.

Carbohydrate ligands for endothelial-leukocyte adhesion molecule 1

The acute inflammatory response requires that circulating leukocytes bind to and penetrate the vascular wall to access the site of injury. Several receptors have been implicated in this interaction, including a family of putative carbohydrate-binding proteins. We report here the identification of an endogenous carbohydrate ligand for one of these receptors, endothelial-leukocyte adhesion molecule 1 (ELAM-1). Radiolabeled COS cells transfected with a plasmid containing the cDNA for ELAM-1 were used as probes to screen glycolipids extracted from human leukocytes. COS cells transfected with this plasmid adhered to a subset of sialylated glycolipids resolved on TLC plates or adsorbed on polyvinyl chloride microtiter wells. Adhesion to these glycolipids required calcium but was not inhibited by heparin, chondroitin sulfate, keratan sulfate, or yeast phosphomannan. Monosaccharide composition, linkage analysis, and fast atom bombardment mass spectrometry of the glycolipids indicate that the ligands for ELAM-1 are terminally sialylated lactosylceramides with a variable number of N-acetyllactosamine repeats and at least one fucosylated N-acetylglucosamine residue.

Diabetes mellitus prevents ischemic preconditioning in patients with a first acute anterior wall myocardial infarction

OBJECTIVES

This study was undertaken to assess whether prodromal angina could have beneficial effects in diabetic patients with acute myocardial infarction (AMI).

BACKGROUND

Prodromal angina occurring shortly before the onset of AMI is associated with favorable outcomes by the mechanism of ischemic preconditioning. However, little is known about the impact of diabetes on ischemic preconditioning.

METHODS

We studied 611 patients with a first anterior wall AMI who underwent emergency catheterization within 12 h after the onset of chest pain: 490 patients without diabetes and 121 patients with non-insulin treated diabetes. Prodromal angina was defined as angina episode(s) occurring within 24 h before the onset of AMI. Serial contrast left ventriculograms were obtained in 424 patients at the time of acute and predischarge catheterization.

RESULTS

In non-diabetic patients, prodromal angina was associated with lower peak creatine kinase (CK) value (3,068 +/- 2,647 IU/l vs. 3,601 +/- 2,462 IU/l, p = 0.037), larger increase in left ventricular ejection fraction (LVEF) (10.1 +/- 13.0% vs. 5.8 +/- 13.4%, p = 0.004) and lower in-hospital mortality (3.4% vs. 9.3%, p = 0.015). On the contrary, in diabetic patients, there was no significant difference in peak CK value (3,382 +/- 2,520 IU/l vs. 3,233 +/- 2,412 IU/l, p = NS), the change in LVEF (6.7 +/- 13.8% vs. 7.1 +/- 12.4%, p = NS) and in-hospital mortality (8.8% vs. 11.0%, p = NS) between patients with and patients without prodromal angina.

CONCLUSIONS

Prodromal angina limited infarct size, enhanced recovery of LV function and improved survival in non-diabetic patients with AMI. However, such beneficial effects of prodromal angina were not observed in diabetic patients, suggesting that diabetes might prevent ischemic preconditioning.

Implications of prodromal angina pectoris in anterior wall acute myocardial infarction: acute angiographic findings and long-term prognosis

OBJECTIVES

This study was undertaken to assess how prodromal angina affects long-term prognosis after acute myocardial infarction.

BACKGROUND

Although it has been reported that prodromal angina occurring shortly before the onset of acute myocardial infarction has protective effects against ischemia, its implication for long-term prognosis remains unclear.

METHODS

We studied consecutive 350 patients with anterior myocardial infarction who underwent coronary angiography within 24 h after the onset of chest pain. Follow-up was achieved for 340 patients (97%).

RESULTS

Eighty-nine patients had one or more episodes of angina within 24 h before infarction. On initial angiography, patients with prodromal angina in the 24 h before infarction had a patent infarct-related artery more frequently than did those without prodromal angina (34% vs. 22%, p = 0.03). Among 213 patients who underwent thrombolytic therapy for an occluded infarct-related artery, reperfusion was more frequently achieved in patients with prodromal angina in the 24 h before infarction (76% vs. 56%, p = 0.01). Prodromal angina in the 24 h before infarction was associated with a lower in-hospital mortality rate (6% vs. 14%, p = 0.02) and better 5-year survival (p = 0.009). There was no significant difference in survival between patients with previous angina at any time (n = 202) and those without. Multivariate analysis showed that prodromal angina in the 24 h before infarction was an independent factor related to 5-year survival after acute myocardial infarction (odds ratio 0.49, p = 0.04).

CONCLUSIONS

Prodromal angina occurring shortly before the onset of infarction, but not previous angina itself, has a beneficial effect on long-term prognosis after infarction, suggesting a relation to ischemic preconditioning.

Acceleration of wound contraction and healing with a photocrosslinkable chitosan hydrogel

Application of ultraviolet light irradiation to a photocrosslinkable chitosan aqueous solution resulted in an insoluble, flexible hydrogel like soft rubber within 60 seconds. In order to evaluate its accelerating effect on wound healing, full-thickness skin incisions were made on the backs of mice and subsequently a photocrosslinkable chitosan aqueous solution was added into the wound and irradiated with UV light for 90 seconds. Application of the chitosan hydrogel significantly induced wound contraction and accelerated wound closure and healing compared with the untreated controls. Histological examination also showed an advanced contraction rate on the first 2 days and tissue fill rate on days 2 to 4 in the chitosan hydrogel-treated wounds. Furthermore, in cell culture studies, chitosan hydrogel culture medium supplemented with 5% fetal-bovine serum was found to be chemoattractant for human dermal fibroblasts in an invasion chamber assay using filters coated with Matrigel and in a cell migration assay. Due to its ability to accelerate wound contraction and healing, chitosan hydrogel may become accepted as an occlusive dressing for wound management.

Loss of transcription factor IRF-1 affects tumor susceptibility in mice carrying the Ha-ras transgene or nullizygosity for p53

The transcription factor IRF-1 has been implicated in tumor suppression: IRF-1 suppresses cell transformation and mediates apoptosis in vitro. Here we show that the loss of IRF-1 alleles per se has no effect on spontaneous tumor development in the mouse but dramatically exacerbates previous tumor predispositions caused by the c-Ha-ras transgene or by nullizygosity for p53. Grossly altered tumor spectrum, as compared to p53-null mice, was also observed in mice lacking both IRF-1 and p53, and cells from these mice show significantly higher mutation rate. Our results suggest that IRF-1 is a new member of the tumor susceptibility genes.

Suppression of hadrons with large transverse momentum in central Au+Au collisions at root square[s(NN)] = 130 GeV

Transverse momentum spectra for charged hadrons and for neutral pions in the range 1 GeV/c<p(T)<5 GeV/c have been measured by the PHENIX experiment at RHIC in Au+Au collisions at root square[s(NN)] = 130 GeV. At high p(T) the spectra from peripheral nuclear collisions are consistent with scaling the spectra from p+p collisions by the average number of binary nucleon-nucleon collisions. The spectra from central collisions are significantly suppressed when compared to the binary-scaled p+p expectation, and also when compared to similarly binary-scaled peripheral collisions, indicating a novel nuclear-medium effect in central nuclear collisions at RHIC energies.

Experimental evaluation of photocrosslinkable chitosan as a biologic adhesive with surgical applications

BACKGROUND

In various surgical cases, effective tissue adhesives are required for both hemostasis (eg, intraoperative bleeding) and air sealing (eg, thoracic surgery). We have designed a chitosan molecule (Az-CH-LA) that can be photocrosslinked by ultraviolet (UV) light irradiation, thereby forming a hydrogel. The purpose of this work was to evaluate the effectiveness and safety of the photocrosslinkable chitosan hydrogel as an adhesive with surgical applications.

METHODS

The sealing ability of the chitosan hydrogel, determined as a bursting pressure, was assessed with removed thoracic aorta, trachea, and lung of farm pigs and in a rabbit model. The carotid artery and lung of rabbits were punctured with a needle, and the chitosan hydrogel was applied to, respectively, stop the bleeding and the air leakage. In vivo chitosan degradability and biologic responses were histologically assessed in animal models.

RESULTS

The bursting pressure of chitosan hydrogel (30 mg/mL) and fibrin glue, respectively, was 225 +/- 25 mm Hg (mean +/- SD) and 80 +/- 20 mm Hg in the thoracic aorta; 77 +/- 29 mm Hg and 48 +/- 21 mm Hg in the trachea; and in the lung, 51 +/- 11 mm Hg (chitosan hydrogel), 62 +/- 4 mm Hg (fibrin glue, rubbing method), and 12 +/- 2 mm Hg (fibrin glue, layer method). The sealing ability of the chitosan hydrogel was stronger than that of fibrin glue. All rabbits with a carotid artery (n = 8) or lung (n = 8) that was punctured with a needle and then sealed with chitosan hydrogel survived the 1-month observation period without any bleeding or air leakage from the puncture sites. Histologic examinations demonstrated that 30 days after application, a fraction of the chitosan hydrogel was phagocytosed by macrophages, had partially degraded, and had induced the formation of fibrous tissues around the hydrogel.

CONCLUSIONS

A newly developed photocrosslinkable chitosan has demonstrated strong sealing ability and a great potential for use as an adhesive in surgical operations.

Control of cell division in hepatoma cells by exogenous heparan sulfate proteoglycan

The effects of cell surface heparan sulfate proteoglycan (HSPG) prepared from log and confluent monolayers of a rat hepatoma cell line on hepatoma cell growth were studied. When HSPG isolated from confluent cells was added exogenously to log phase cells, it was internalized and free heparan sulfate (HS) chains appeared transiently in the nucleus. Concurrently, the growth of the treated cells was inhibited, but the cells resumed logarithmic growth as the level of nuclear HS fell, and the cells grew to confluence and became contact inhibited. When HSPG prepared from log-phase hepatoma cells was added exogenously to log phase cells, it was internalized but very little of the internalized HS appeared in the nucleus, and there was no change in the rate of cell growth. However, when the rate of cell growth was reduced by culture of the cells in serum- and insulin-deficient medium, HSPG prepared from log-phase cells stimulated the growth rate of these slow-growing cells. The cell cycle dependency of HSPG uptake and growth inhibition was studied in cultures synchronized by a thymidine/aphidicolin double block. When [35SO4]HSPG from confluent cells was added to synchronized cells just as they were released from the second block, a portion of the [35SO4]HSPG was internalized and [35SO4]HS appeared in the nucleus. However, at mitosis the [35SO4]HS disappeared almost completely from all of the cellular pools, and after mitosis, more of the [35SO4]HSPG was taken up and [35SO4]HS reappeared in the nucleus and remained in the nucleus until the cells divided again. When cultures were released from the aphidicolin block, both control and HSPG-treated cells progressed through the S, the G2, and the M phases of the cell cycle. However, the length of the G1 phase of the cycle was increased in the HSPG-treated cells. The treated cultures then progressed through the second S, G2, and M phases. Thus, the inhibition of cell division occurred in the G1 phase of the cell cycle, prior to the G1/S boundary. Addition of the HSPG to the synchronized cultures just after the first mitosis resulted in an immediate arrest of the cell cycle in G1.(ABSTRACT TRUNCATED AT 400 WORDS)

Structural requirements in heparin for binding and activation of FGF-1 and FGF-4 are different from that for FGF-2

Size- and structure-defined oligosaccharides from heparin, 2-O-desulphated (2-O-DS-) heparin, 6-O-desulphated (6-O-DS-) heparin, carboxy-reduced (CR-) heparin, and carboxyamidomethylsulphonated (AMS-) heparin were utilized in characterizing the structural properties of heparin to specifically bind to basic fibroblast growth factor (FGF-2) and to modulate the mitogenic activity of FGF-2 (Ishihara, M. et al., Glycobiology, 4, 451-458, 1994). The previous results showed that both 2-O-sulphate groups and the negative charge of the carboxy group in iduronate residues are required for specific interaction with FGF-2, but the 6-O-sulphate groups in N-sulphated glucosamine (GlcNS) residues do not influence the interaction with FGF-2. In the present study, the same oligosaccharides were fractionated on a FGF-1- or FGF-4-affinity column, and were assessed as promoters of FGF-1- or FGF-4-induced proliferation of adrenocortical endothelial (ACE) cells and chlorate-treated ACE cells. The present results suggest that the smallest heparin-derived oligosaccharide binding to these growth factors with the highest affinity and promoting their mitogenic activities is a fully N-sulphated decasaccharide enriched in 2-O- and 6-O-sulphated disaccharide units. In contrast to our results with FGF-2, a high content of 6-O-sulphate groups in GlcNS residues is required for specific interaction with FGF-1 and FGF-4.

Effect of zeta potential of cationic liposomes containing cationic cholesterol derivatives on gene transfection

Cationic liposomes are known to be useful tools for gene transfection. However, the relation between transfection efficiency and physicochemical properties of liposomes has not been well understood. Here, we synthesized eight cationic derivatives of cholesterol which contain a tertiary amino head group with a different spacer arm. Transfection of plasmid pSV2CAT DNA into cells was done by cationic liposomes made of a mixture of dioleoylphosphatidylethanolamine (DOPE) and each cationic cholesterol derivative. At the same time we measured zeta potential of cationic liposomes by laser Doppler spectroscopy. The present results indicated that zeta potentials of cationic liposomes were well related to transfection activity of pSV2CAT DNA. This suggested that zeta potential of cationic liposomes is one of important factors which control gene transfection.

Structural features in heparin that interact with VEGF165 and modulate its biological activity

The 165 amino acid form of vascular endothelial growth factor (VEGF165) is a heparin-binding growth factor with mitogenic activity for vascular endothelial cells. We examined activities of various heparin derivatives toward their interactions with VEGF165 using an enzyme-linked immunosorbent assay and elucidated the structural features in heparin for the interactions. Native heparin interacted with VEGF165, whereas N-desulfated, N-acetylated (N-DS, N-Ac-) heparin, and 6-O-desulfated (6-O-DS-) heparin did not. The 2-O-desulfated (2-O-DS-) heparin retained the ability for the interaction with VEGF165. In contrast, the 2-O-DS-heparin exhibited no ability for the interaction with FGF-2 and HGF. Thus, structural requirements in heparin for the specific interaction with VEGF165 are distinct from those with FGF-2 and HGF which require a high content of 2-O-sulfate groups. In a cell proliferation assay, native heparin and 2-O-DS-heparin exhibited inhibitory abilities for VEGF165-induced proliferation of human umbilical vein endothelial cells (HUVECs) with their high concentrations (more than 64 microg/ml), while only native heparin could enhance the proliferation of the chlorate-treated cells. These results suggested that a high content of 2-O-sulfate groups is not required for the specific interaction with VEGF165alone, although it is essential for the mitogenic activity of the growth factor.

Synthesis and antifungal activity of cinnamic acid esters

Cinnamic, p-coumaric and ferulic acids were isolated from pineapple stems (Ananas comosus var. Cayenne). Twenty-four kinds of esters were prepared from these acids, alcohols and the components of Alpinia. Isopropyl 4-hydroxycinnamate (11) and butyl 4-hydroxycinnamate (12) were found to have almost the same effectiveness in antifungal activity against Pythium sp. at 10 ppm as that of the commercial fungicide iprobenfos (kitazin P).

Studies on lipoperoxide of normal pregnant women and of patients with toxemia of pregnancy

1. Serum lipoperoxide was determined by the method of Yagi et al. (Yagi, K., Nishigaki, I. and Ohama, H. (1968) Jap. J. Vitamin 37, 105) for 22 cases of non-pregnant women, 24 cases of 1st trimester of pregnancy (1-12 weeks), 39 cases of 2nd trimester of pregnancy (13-26 weeks), 58 cases of 3rd trimester of pregnancy (27-40 weeks), and 30 cases of toxemia of pregnancy (27-40 weeks). Remarkable increases of lipoperoxide were observed at 2nd and 3rd trimester of pregnancy compared with non-pregnant women, and the increase in toxemia of pregnancy was more remarkable than that at 3rd trimester of pregnancy. In umbilical cord blood a higher level of lipoperoxide was observed in patients with toxemia of pregnancy than in normal pregnant women. 2. The total TBA value determined by extracting the serum-lipids with chloroform and methanol solution showed a similar tendency to the above. 3. Those showing TBA-reaction by the analysis of lipids with thin-layer chromatography were the fractions of cholesterol ester, triglyceride and phospholipid. While triglyceride fraction showed a marked increase of TBA value during pregnancy and in toxemia of pregnancy.

Analysis of 1,992 patients with anorectal malformations over the past two decades in Japan. Steering Committee of Japanese Study Group of Anorectal Anomalies

BACKGROUND/PURPOSE

This report describes the results of a group study of the Japanese Study Group of Anorectal Anomolies (JSGA) to determine the relative incidence of specific types of anorectal anomaly in Japan, and includes discussion of rectourethral fistula regarding the relationship between the levels of the fistula and blind end of the rectum, low type deformity, rare types, and associated anomalies.

METHODS

A total of 1,992 patients (1,183 boys and 809 girls) registered from 1976 to 1995 were analyzed.

RESULTS

High-type deformities accounted for 26.0% of cases, intermediate 10.7%, low 57.2%, miscellaneous 4.5% and unclassified 1.8%. The most frequent deformity was male anocutaneous fistula (n = 364), followed by male rectourethral fistula (n = 333), and female anovestibular fistula (n = 241). There were 42 rectovesical fistulas in boys and 93 rectocloacal fistulas in girls. Covered anus complete occurred at the same frequency (10.1% of low deformities) as covered anal stenosis. In rectourethral fistula, the blind end of the rectum lay at or above the level of the P-C line in 40.3% of cases, at or above the M line in 39.6% and at the vicinity of the I line in 20.2%, respectively. There was no parallel relationship between the site of the fistula opening and the level of the rectal pouch. The overall incidence of patients having one or more associated anomalies was 45.2%: 70.6% in high deformity, 60.7% in intermediate, and 31.3% in low. The rate of association of Down's syndrome with deformities without fistula (40.3%) was significantly higher than with deformities with fistula (0.3%).

CONCLUSIONS

Rectovesical fistula and covered anus complete were not infrequent deformities in this series. We consider that at least 20% of rectourethral fistula should be categorized as intermediate or low deformity from the viewpoint of the position of the rectal pouch. A significant preponderance of Down's syndrome in the deformities without fistula suggests that further investigation of associated anomalies in comparision with other congenital diseases may provide insights into the pathogenesis of anorectal malformation in the field of molecular genetics.

Structure of fucose branches in the glycosaminoglycan from the body wall of the sea cucumber Stichopus japonicus

Fucose-branched chondroitin sulfate E was prepared from the body wall of sea cucumber Stichopus japonicus. The purified glycosaminoglycan (GAG) was chemically desulfated, followed by carboxyl reduction. Intact, desulfated, and desulfated/carboxyl-reduced GAG fractions were subjected to per-O-methylation. GC-MS analyses of the resultant partially methylated alditol acetates demonstrated that the fucose branch is formed by two fucopyranosyl residues linked glycosidically through position (1-->3), and that the fucose branch and glucuronic acid are almost equimolar. In addition, it was elucidated that about 20% of the branches stretch from O-3 position of a glucuronic acid moiety of the core chondroitin sulfate polymer, while remaining fucose branches are postulated to protrude from O-4 and/or O-6 position(s) of a N-acetylgalactosamine moiety. This fucose branch was also confirmed to be highly sulfated according to six kinds of substitution pattern in methylation analysis.