Value of laparoscopic microwave coagulation therapy for hepatocellular carcinoma in relation to tumor size and location

BACKGROUND AND STUDY AIMS

The indications for laparoscopic microwave coagulation therapy (LMCT) for hepatocellular carcinoma (HCC) have not yet been adequately evaluated. This study investigated the value of LMCT in the treatment of HCC.

PATIENTS AND METHODS

Forty-three patients with liver cirrhosis (including five patients in Child Pugh grade C), with 56 HCC lesions, were enrolled in the study. When dynamic computed tomography (CT) showed a loss in HCC enhancement characteristics and a low concentration area after LMCT, a lesion was judged to have undergone complete necrosis.

RESULTS

The rate of complete necrosis for lesions measuring 40 mm or less was significantly higher (P<0.01) than for those measuring 41 mm or more. The rate of complete necrosis for lesions located on the liver surface, excluding those located close to the gallbladder or in contact with the diaphragm, was also significantly higher (P<0.01) than for those situated deep within the liver. The outcome for lesions of 40 mm or less was favorable. Intra-abdominal hemorrhage occurred in two patients, pneumothorax in three, and hepatic infarction in one, all associated with LMCT. However, these patients did not suffer any sequelae of clinical significance.

CONCLUSIONS

This study suggests that there is a strong indication for LMCT for HCCs measuring 40 mm or less in diameter and those located on the liver surface even if they are as large as 50 mm, but not for those located close to the gallbladder or in contact with the diaphragm. LMCT appears to be applicable in patients with impaired liver function.

Phosphorylation of Bcl-2 protein by CDC2 kinase during G2/M phases and its role in cell cycle regulation

Although it has been reported that Bcl-2 phosphorylation is associated with certain types of apoptosis, there is much controversy over the functional significance of and the kinases responsible for the phosphorylation. In this study, we examined whether Bcl-2 is phosphorylated by CDC2 kinase, a master regulator of G(2)/M transition in the eukaryotic cell cycle. When CDC2 was activated by okadaic acid in HL-60 cells, Bcl-2 phosphorylation was readily induced. The phosphorylation was correlated with the accumulation of cells in G(2)/M phases, but was not proportional to the level of apoptosis. Furthermore, we found that Bcl-2 was phosphorylated during G(2)/M phases of normal cell cycle. The ability of CDC2 to phosphorylate Bcl-2 was confirmed by in vitro kinase assay with a highly purified CDC2-cyclin B complex. Using synthetic peptides and mutant cell lines, we identified threonine 56, one of two consensus sites for CDC2 within the Bcl-2 sequence, as a residue phosphorylated by CDC2. Mutation at threonine 56 abrogated the cell cycle inhibitory effect of Bcl-2 without affecting anti-apoptotic function. These results suggest that two distinct functions of Bcl-2 (anti-apoptosis and cell cycle inhibition) are differentially regulated by post-translational mechanisms such as phosphorylation. CDC2-mediated phosphorylation of Bcl-2 may play some physiological roles in the negative regulatory events during mitosis.

Clinical implications of TT virus superinfection in patients with chronic hepatitis C

OBJECTIVE

TT virus (TTV) has been identified as a candidate agent of non-A-E hepatitis virus. We investigated superinfection of TTV in patients with chronic hepatitis C and studied the susceptibility to interferon (IFN) treatment and its association with liver disease caused by hepatitis C virus (HCV).

METHODS

TTV DNA was examined using the seminested polymerase chain reaction (PCR), and its virus level was measured by the real-time fluorometric PCR.

RESULTS

TTV DNA was detected in 20 of 102 (19.6%) patients examined. There was no significant difference in the alanine aminotransferase (ALT) level between patients with or without TTV DNA. Quantitative analysis of HCV RNA and TTV DNA revealed no correlation between virus levels in HCV/TTV-coinfected patients. Both TTV and HCV were sensitive to IFN therapy. Complete response to IFN with a sustained loss of viremia for 24 wk after completion of IFN treatment was found in 11 of 20 (55%) patients with respect to TTV DNA and in five of 20 (25%) patients with respect to HCV RNA. The mean pretreatment HCV RNA level was significantly lower in the complete-response cases than in the no-response cases, but there was no significant difference in the pretreatment TTV DNA levels between them. ALT normalization resulting from IFN therapy was not attributable to the eradication of TTV DNA but was attributable to that of HCV RNA. Superinfection by TTV did not influence the effect of IFN against HCV. No specific TTV genotype correlating with IFN sensitivity was found.

CONCLUSIONS

These results suggest that TTV infection stands independent of HCV infection, with no influence on liver injury as a result of HCV infection.

Novel acyl alpha-pyronoids, dictyopyrone A, B, and C, from Dictyostelium cellular slime molds

For the elucidation of the diversity of secondary metabolites of Dictyostelium cellular slime molds, we investigate the constituent of three species of slime molds. From the methanol extract of their fruit bodies, we obtained three novel compounds, dictyopyrone A (1) and B (2) from D. discoideum and D. rhizoposium and dictyopyrone C (3) from D. longosporum. They possess a unique alpha-pyrone moiety with a side chain at the C-3 position. Their relative structures were elucidated by spectral means, and the absolute configuration was confirmed by asymmetric synthesis of 1. Since these compounds were obtained from different species of Dictyostelium slime molds, they may be a type of compound common to this genus.

NH2-terminal pentapeptide of endothelial interleukin 8 is responsible for the induction of apoptosis in leukemic cells and has an antitumor effect in vivo

We have reported that endothelial interleukin 8 (IL-8) induces apoptosis in leukemic cells in vitro and in vivo, and that interaction between endothelial cells and leukemic cells causes induction of apoptosis through the release of endothelial IL-8 (Y. Terui et al., Biochem. Biophys. Res. Commun., 243: 407-411, 1998; Y. Terui et al., Blood, 92: 2672-2680, 1998). Here, we examined whether a pentapeptide corresponding to the NH2-terminal region of endothelial IL-8 can induce apoptosis in leukemic cells. The NH2-terminal pentapeptide Ala-Val-Leu-Pro-Arg (AVLPR) was found to significantly induce apoptosis in the leukemic cell lines K562, HL-60, Jurkat, and Daudi, as compared with the COOH-terminal pentapeptide Arg-Glu-Ala-Asn-Ser (REANS). Moreover, the NH2-terminal pentapeptide AVLPR significantly inhibited growth of i.p. and s.c. tumor masses of K562 cells and induced apoptosis in these cells in vivo. The active site of endothelial IL-8 is the NH2-terminal pentapeptide AVLPR, and this may serve as a new therapy for hematological malignancies.

Beta(2)-microglobulin identified as an apoptosis-inducing factor and its characterization

Major histocompatibility complex (MHC) molecules play an important role in antigen presentation for induction of tumor as well as cellular and humoral immunities. Recent studies using anti-MHC antibodies demonstrated that antibodies specific for HLA class I molecules induced cellular activation and a type of apoptosis that may be distinct from Fas-dependent or TNFR (tumor necrosis factor-alpha receptor)-dependent processes. We purified a previously untested apoptosis-inducing factor from HL-60 human leukemic cell-conditioned media to homogeneity and sequenced it. It was identified as beta(2)-microglobulin (beta(2)m), which has been previously known as thymotaxin and is a part of the HLA class I antigen complex. beta(2)m acts on both T-leukemic cells and myeloid leukemic cells to induce apoptosis, which then activates caspase 1 and 3. Cross-linking studies showed that biotinilated beta(2)m recognized an epitope distinct from those recognized by the anti-HLA class I antibody, as reported previously. We demonstrated that beta(2)m plays a previously unrecognized and important role in regulating the elimination of tumor cells, which occurs as a result of the action of beta(2)m as an apoptosis-inducing factor.

[Moderate aplastic anemia associated with Crohn's disease during antithymocyte globulin treatment]

A 53-year-old woman with moderate aplastic anemia (AA) was treated with antithymocyte globulin (ATG). However, on the 4th day of treatment, ATG was discontinued because of bloody vomiting and melena. The patient improved with conservative treatment but complained of abdominal pain when the prednisolone (PSL) dose was decreased. Crohn's disease was finally diagnosed on the basis of upper and lower gastrointestinal X-ray studies. The patient responded well to ATG with hematologic improvement, and maintained remission with low-dose PSL and nutritional support. Drug-induced AA may occur during treatment for Crohn's diseases. The association of AA and Crohn's disease is rare, and to our knowledge, has not yet been reported in the literature. We discussed the pathogenesis of Crohn's disease during immunotherapy for AA.

A novel variant of translation elongation factor-1beta: isolation and characterization of the rice gene encoding EF-1beta2

A rice gene encoding a novel isoform of translation elongation factor-1beta subunit (termed EF-1beta2) was isolated and characterized. The gene comprises of eight exons, and encodes a 226-amino-acid protein. Expression of EF-1beta2 mRNA is abundant in seeds and cultured cells, but is considerably low in the tissues of the rice seedling. Antiserum raised against an EF-1beta2 synthetic peptide detected a protein with a relative molecular mass of about 32 kDa, indicating the EF-1beta2 gene is actually expressed in rice tissues. EF-1beta2 showed a close similarity to the cognate subunits from plant (beta and beta').

Activated endothelial cells induce apoptosis in leukemic cells by endothelial interleukin-8

Tumor cells are eradicated by several systems, including Fas ligand-Fas and tumor necrosis factor (TNF)-tumor necrosis factor receptor (TNFR). In the previous study, we purified an apoptosis-inducing factor (AIF) to homogeneity from a medium conditioned by PDBu-treated HL-60 cells. N-terminal sequence analysis showed that AIF is identical to endothelial interleukin-8 (IL-8). A novel apoptosis system, in which endothelial cells participate via endothelial IL-8 release, is identified here. Human umbilical vein cells (VE cells) produce and secrete IL-8 by stimulation of IL-1alpha and TNF-alpha. Endothelial IL-8, which is secreted from VE cells by stimulation of IL-1alpha and TNF-alpha , induces apoptosis in myelogenous leukemia cell line K562 cells. Monocyte-derived IL-8 could not induce apoptosis in K562 cells. Moreover, interaction between VE cells and K562 cells induces the release of endothelial IL-8 from VE cells, and the attached K562 cells undergo apoptosis. Moreover, interactions between VE cell and other cell lines, such as HL-60, U937, Jurkat, and Daudi, induce the secretion of endothelial IL-8 and the induction of apoptosis in cell lines. Endothelial IL-8 significantly inhibits tumor growth of intraperitoneal and subcutaneous tumor mass of K562 cells and induces apoptosis in their cells in vivo. Endothelial IL-8 plays an important role in apoptosis involving endothelial cells, which may provide us with a new therapy for hematological malignancies.

[Retrospective analysis of elderly patients > or = 60 years of age with acute leukemia]

A retrospective analysis was performed on 76 consecutive elderly patients with acute leukemia aged 60 years or more (48 men, 28 women). Forty patients were 60-69 years old, 28 were 70-79 years old and 8 were > or = 80 years old. There were 55 patients with acute myelogenous leukemia (AML), 13 acute lymphoblastic leukemia (ALL) and 8 AML from myelodysplastic syndrome (MDS/AML). Patients were treated with the JALSG protocol, CAG regimen, or low-dose Ara-C regimen for AML, and DVP/M-CHOP protocol for ALL. The complete remission (CR) rates were 52.7% (29 of 55) in AML, 61.5% (8 of 13) in ALL, and 0% in MDS/AML. The median CR durations were 226, 85, 0 days, and the median survivals were 204, 177, 99 days, respectively. CR rates were 65.3% for the JALSG protocol, 62.5% for the CAG regimen and 25.0% for low-dose Ara-C regimen. According to age, CR was obtained 62.5% in patients aged 60-69 years and 33.3% in patients over 70 years old. Our results indicated that patients aged 60-69 years should be treated with intensive chemotherapy.

Bcl-x is a regulatory factor of apoptosis and differentiation in megakaryocytic lineage cells

Differentiation- and lineage-related differences in the expression of two anti-apoptotic molecules, bcl-x and bcl-2, were examined using various human hematopoietic cell lines. Bcl-x was strongly expressed in cell lines with erythroid and megakaryocytic properties (K562, HEL, CMK, and Mo7E), and was moderately expressed in immature myeloid cell lines (KG-1 and KCL-22). Bcl-2 expression was relatively weak in these cells. On the other hand, bcl-x was not expressed in more mature myeloid cell lines (HL-60 and PL-21), but bcl-2 was strongly expressed in these cells and in monocytoid cell lines (U937, THP-1, and JOSK-I). We investigated the biological significance of high levels of bcl-x expression in erythroid and megakaryocytic lineage cells. When K562 cells were specifically differentiated into megakaryocytic lineage by phorbol ester, the amounts of bcl-x increased by 10-fold. In contrast, bcl-x was gradually downregulated during erythroid differentiation induced by cytosine arabinoside. Apoptosis was observed following erythroid differentiation of K562 cells, but it was not associated with megakaryocytic differentiation in consistent with the increase in bcl-x. Moreover, phorbol ester-induced megakaryocytic differentiation was facilitated by the overexpression of bcl-x in K562 cells. Finally, in situ hybridization revealed that bcl-x mRNA expression was strongest in megakaryocytes among normal bone marrow cells. These results suggest that bcl-x is a regulatory factor in the apoptosis and differentiation of megakaryocytes.

Identification of a novel apoptosis-inducing factor derived from leukemic cells: endothelial interleukin-8, but not monocyte-derived, induces apoptosis in leukemic cells

The human myelogenous leukemia cell line HL-60, treated with phorbol 12, 13-dibutyrate (PDBu), produces apoptosis-inducing factors (AIFs) in leukemic cells. We have purified AIF against leukemic cell line K562 as target cells, and N-terminal amino acid sequencing analysis revealed that this purified protein is identical to endothelial cell-derived interleukin-8 ([(Ala)-IL-8]77). In Western blot analysis of supernatants of PDBu-treated HL-60 cells, only [(Ala)-IL-8]77 was detected. Moreover, recombinant human [(Ala)-IL-8]77 induced apoptosis in leukemic cell lines such as K562, HL-60, KG-1, U937, THP-1 and Jurkat, but monocyte-derived IL-8 ([(Ser)-IL-8]72) did not. Therefore [(Ala)-IL-8]77 plays an important role in inducing apoptosis against leukemic cells and may lead to a new therapy for leukemia.

Apoptosis-gene expression in hematopoietic system: normal and pathological conditions (Review)

Gene expression involving apoptosis in the hematopoietic system is reviewed. In normal and hematological disorders, Fas-Fas ligand and tumor necrosis factor-alpha-receptor interaction play a major role in enhancing apoptosis. On the other hand, bcl-2 or certain novel proteins (including FADD, RIP, TRADD and sentrin) prevent apoptosis. Apoptosis is involved in myelodysplastic syndrome and pathogenesis of leukemia. Expression of Fas antigen plays a role in negative regulation of hematopoiesis in the bone marrow as does interferon-gamma.

Polyploidization and functional maturation are two distinct processes during megakaryocytic differentiation: involvement of cyclin-dependent kinase inhibitor p21 in polyploidization

The mechanism of megakaryocytic differentiation was investigated using human megakaryocytic leukemia cell line UT-7. Polyploidization of UT-7 cells was induced by the microtubule-depolymerizing agent, nocodazole, and 12-O-tetradecanoylphorbol-13-acetate (TPA), but the effect was much more striking with nocodazole. By contrast, induction of cytoplasmic maturation, as judged by beta-thromboglobulin production and platelet factor 4 expression, was more prominent in TPA-treated cells than in nocodazole-treated cells. Nocodazole and TPA could act synergistically to increase ploidy and to enhance the expression of mature phenotypes. Human thrombopoietin induced functional maturation but not polyploidization in UT-7 cells and also acts synergistically with nocodazole. Cyclin-dependent kinase inhibitor p21 was upregulated at the early stage of megakaryocytic differentiation, and overexpression of p21 resulted in an increase in ploidy of UT-7 cells. This suggests that p21 is implicated in polyploidization via suppression of CDC2 activity at mitosis. UT-7 but not HL-60 cells could incorporate [3H]thymidine in the presence of TPA, indicating the presence of megakaryocyte-specific licensing factor to allow DNA replication during differentiation. Taking these data together, we propose that megakaryocytic differentiation consists of two distinct processes, polyploidization and functional maturation, and that these two processes are independently regulated.

Modulation of E2F activity is linked to interferon-induced growth suppression of hematopoietic cells

E2F is a heterodimeric transcription factor that controls transcription of several growth-regulatory genes including cdc2. To investigate the mechanism of interferon-alpha (IFN-alpha)-mediated growth suppression of hematopoietic cells, we examined the effect of IFN-alpha on the expression and function of E2F using IFN-sensitive Daudi cells. Down-regulation of E2F-1, a subunit of E2F, was observed after 8 h of culture with IFN-alpha; expression of E2F-4, another subunit of E2F, and DP-1, a heterodimeric partner of E2F, was unaffected. Gel shift assays revealed that the DNA binding activity of free E2F, which is composed of E2F-1 and E2F-4, was inhibited by IFN-alpha. In contrast, IFN-alpha did not affect the DNA binding ability of E2F-1 and E2F-4 in a complex with retinoblastoma (RB) susceptibility gene family proteins including pRB, p107, and p130. IFN-alpha could induce dephosphorylation of pRB, thereby turning active E2F-pRB complexes into transcriptional repressors. Transient chloramphenicol acetyltransferase assays revealed that the activity of the E2F-dependent cdc2 promoter was suppressed by IFN-alpha. These results suggest that the antiproliferative action of IFN-alpha is mediated through the modulation of E2F activity in two different ways: down-regulation of transcriptionally active free E2F and conversion of E2F-pRB complexes into transcriptional repressors.

Expression of Src-like adapter protein mRNA is induced by all-trans retinoic acid

By using a differential display method, specific bands were selected from ladder PCR products derived from ATRA-dependent differentiated U937 cells, in comparison with those of untreated U937. By screening the cDNA library of ATRA-dependent differentiated U937 cells with one of the PCR products, we cloned the src-like adapter protein (SLAP). Northern blot analysis of U937 cells with or without ATRA treatment indicated that the SLAP mRNA was clearly induced by ATRA. The induction was inhibited by the addition of cycloheximide, indicating that ATRA acted indirectly through synthesis of other proteins. The SLAP mRNA was induced in HL60 and NB-4 but not in K562 or THP-1. Interestingly, these cells in which SLAP mRNA was induced by ATRA all showed ATRA-dependent cell differentiation. The relationship between SLAP and cell differentiation is unclear, but SLAP may transduce a signal for cell differentiation.

Transcriptional activation of the cdc2 gene is associated with Fas-induced apoptosis of human hematopoietic cells

Apoptosis has recently been hypothesized to be the result of aberrant cell cycle control. In this study, we have investigated the role of cell cycle-regulatory elements in Fas-induced apoptosis of hematopoietic cells. When HL-60 cells were treated with anti-Fas antibody, rapid activation of growth-associated histone H1 kinase was observed without any change in cell cycle distribution. This was accompanied by the increase in cdc2 mRNA expression and Cdc2 kinase activity. Up-regulation of cdc2 mRNA was similarly induced in BCL-2-overexpressing HL-60 subline by anti-Fas treatment independently of the appearance of apoptotic phenotypes. Fas-induced apoptosis was completely inhibited by butyrolactone I, a specific inhibitor of Cdc2 kinase. Moreover, the same phenomenon was observed during Fas-induced but not spontaneous apoptosis of postmitotic granulocytes. Finally, we have found that "Fas-responsive element" was located between nucleotides -730 and -552 of the cdc2 promoter and was responsive for transcriptional activation of the cdc2 gene during Fas-induced apoptosis. These results indicate that aberrant activation of Cdc2 is associated with Fas-induced apoptosis of hematopoietic cells, and that the mechanism of cdc2 transcription during Fas-induced apoptosis is different from that in normal cell cycle control.

Up-regulation of VLA-5 expression during monocytic differentiation and its role in negative control of the survival of peripheral blood monocytes

Interaction between fibronectin (FN) and very late activation Ag-5 (VLA-5) integrin was recently reported to be involved in apoptosis of hematopoietic cells. In an effort to clarify the physiologic role of FN in the regulation of biologic behavior of terminally differentiated hematopoietic cells, we have examined the change of VLA-5 expression during myeloid cell differentiation and its effects on monocytes and granulocytes. VLA-5 alpha mRNA was up-regulated during monocytic differentiation, but not during granulocytic differentiation of HL-60 cells. Flow cytometric and immunocytochemical analysis revealed that surface expression of VLA-5 was selectively increased upon monocytic differentiation and that it was strongly positive on peripheral blood monocytes. Susceptibility to FN-induced apoptosis was greatly increased upon monocytic differentiation, and it was almost completely abrogated by anti-VLA-5 Ab or RGD peptide. Similarly, FN could significantly enhance apoptosis of normal monocytes but not of granulocytes. Finally, we have shown that anti-FN Ab could suppress spontaneous apoptosis of normal monocytes in culture and prolong their survival. These results suggest that FN might play an important role in negative regulation of the survival of monocytes through its interaction with VLA-5, which is selectively up-regulated during monocytic differentiation.

Up-regulation of VLA-5 expression during monocytic differentiation and its role in negative control of the survival of peripheral blood monocytes

Interaction between fibronectin (FN) and very late activation Ag-5 (VLA-5) integrin was recently reported to be involved in apoptosis of hematopoietic cells. In an effort to clarify the physiologic role of FN in the regulation of biologic behavior of terminally differentiated hematopoietic cells, we have examined the change of VLA-5 expression during myeloid cell differentiation and its effects on monocytes and granulocytes. VLA-5 alpha mRNA was up-regulated during monocytic differentiation, but not during granulocytic differentiation of HL-60 cells. Flow cytometric and immunocytochemical analysis revealed that surface expression of VLA-5 was selectively increased upon monocytic differentiation and that it was strongly positive on peripheral blood monocytes. Susceptibility to FN-induced apoptosis was greatly increased upon monocytic differentiation, and it was almost completely abrogated by anti-VLA-5 Ab or RGD peptide. Similarly, FN could significantly enhance apoptosis of normal monocytes but not of granulocytes. Finally, we have shown that anti-FN Ab could suppress spontaneous apoptosis of normal monocytes in culture and prolong their survival. These results suggest that FN might play an important role in negative regulation of the survival of monocytes through its interaction with VLA-5, which is selectively up-regulated during monocytic differentiation.

Endothelin receptor antagonist triterpenoid, myriceric acid A, isolated from Myrica cerifera, and structure activity relationships of its derivatives

As the first non-peptide endothelin receptor antagonist from a higher plant, a new triterpenoid, myriceric acid A (50-235) (1) was isolated from the bayberry, Myrica cerifera. Myriceric acid A (1) inhibited not only an endothelin-1-induced increase in cytosolic free Ca2+ concentration (IC50 = 11 +/- 2 nM) but [125I]endothelin-1 binding in rat aortic smooth muscle cells (Ki = 66 +/- 15 nM). Two new related triterpenoids, myriceric acid C (6), and myriceric acid D (8), were also isolated. Furthermore, the chemical modification of these natural products led to the synthesis of sulfated derivatives (13, 14, 15) which showed 1.5 to 20 times higher affinity for endothelin receptors. The structure activity relationships of myriceric acids and their derivatives are discussed.

Apoptosis during HL-60 cell differentiation is closely related to a G0/G1 cell cycle arrest

The cell cycle-associated differences in the susceptibility to apoptosis were examined in HL-60 cells before and after differentiation with phorbol 12, 13-dibutyrate (PDBu). HL-60 cells in various phases of the cell cycle were separated by the counterflow centrifugal elutriation and the susceptibility to apoptosis was measured by the morphological examination and by DNA fragmentation assay. Undifferentiated HL-60 cells in S phase showed a significantly higher susceptibility to apoptosis than those in G0/G1 or G2/M phase either in the absence or presence of apoptosis-inducing reagents such as A23187, actinomycin D (Act D), and cycloheximide (CHX). In contrast, PDBu-treated HL-60 cells preferentially underwent apoptosis in G0/G1 phase. When untreated HL-60 cells enriched for G0/G1 phase were recultured in a complete medium, the percentage of apoptotic cells increased after 6-12 h in correlation with the increase in S-phase cells. When the same experiment was performed with PBDu-treated cells, spontaneous increase of apoptotic cells was observed while almost all cells remained in G0/G1 phase. Northern blot analysis revealed that undifferentiated cells expressed the same amounts of bcl-2 mRNA in each cell cycle phase, whereas G0/G1-predominant reduction of bcl-2 mRNA was noted in PDBu-treated cells. There was no difference in the amounts of CD11b mRNA between G0/G1 fraction and S+G2/M fraction of differentiated HL-60 cells. BCL-2 overexpression could almost completely abrogate the G0/G1-predominant induction of apoptosis in differentiated HL-60 cells. These results suggest that G0/G1 cell cycle arrest and down-regulation of bcl-2 mRNA in G0/G1 phase might be associated with apoptosis in differentiated HL-60 cells whereas the weakness of chromatin structure in S phase might be related to apoptosis in undifferentiated HL-60 cells.

Salfredins, new aldose reductase inhibitors produced by Crucibulum sp. RF-3817. I. Fermentation, isolation and structures of salfredins

New inhibitors of aldose reductase, designated salfredins A3, A4, A7, C1, C2, C3 and B11, were isolated from the fermentation broth of Crucibulum sp. RF-3817 by successive purification procedures of solvent extraction, silica gel column chromatographies and reverse-phase HPLC. Their structures were established by spectroscopic methods, including UV, SI-MS and NMR. The structures of salfredins A4 and B11 were confirmed by X-ray crystallographic analysis.

Over-expression and amplification of the CDC2 gene in leukaemia cells

The expression and structure of the cdc2 gene, one of the master regulators of the eukaryotic cell cycle, were investigated in fresh leukaemic cells from 51 cases of various types of leukaemia. Cdc2 mRNA transcripts were detectable in approximately 40% (21/51) of cases by Northern blotting. Over-expression of cdc2 mRNA as compared to normal bone marrow cells was noted in 10/21 cases with detectable cdc2 mRNA transcripts. Amplification of the cdc2 gene was found in three cases. Cdc2 mRNA was over-expressed in these three cases, suggesting that gene amplification is a direct cause of mRNA over-expression in a subset of cases. Cell proliferative capacity was well correlated with the amount of cdc2 mRNA transcripts, i.e. 3H-thymidine incorporation was highest in cases with cdc2 mRNA over-expression and was significantly higher in cdc2-positive cases than in cdc2-negative cases. These results suggest that over-expression of CDC2, which is due to the gene amplification in some cases, might play a role in altered growth of leukaemic cells.