Bone-marrow minimal residual disease (MRD) causes relapse after chemotherapy in patients with acute myelogenous leukemia (AML). We postulate that the drug resistance is induced by the attachment of very late antigen (VLA)-4 on leukemic cells to fibronectin on bone-marrow stromal cells. We found that VLA-4-positive cells acquired resistance to anoikis (loss of anchorage) or drug-induced apoptosis through the phosphatidylinositol-3-kinase (PI-3K)/AKT/Bcl-2 signaling pathway, which is activated by the interaction of VLA-4 and fibronectin. This resistance was negated by VLA-4-specific antibodies. In a mouse model of MRD, we achieved a 100% survival rate by combining VLA-4-specific antibodies and cytosine arabinoside (AraC), whereas AraC alone prolonged survival only slightly. In addition, overall survival at 5 years was 100% for 10 VLA-4-negative patients and 44.4% for 15 VLA-4-positive patients. Thus, the interaction between VLA-4 on leukemic cells and fibronectin on stromal cells may be crucial in bone marrow MRD and AML prognosis.

Aureobasidin A (AbA) is a novel cyclic depsipeptide antifungal antibiotic. The antifungal activity of AbAwas studied in vitro and in vivo in comparison with clinically effective antifungal agents, amphotericin B and fluconazole. AbAwas highly active in vitro against many pathogenic fungi, including Candida albicans, Cryptococcus neoformans, Blastomyces dermatitidis and Histoplasma capsulatum. The activity was superior to amphotericin B in most cases. AbAexhibited fungicidal action toward growing cultures of C. albicans. It was highly tolerated by mice and showed good efficacy in the treatment of murine systemic candidiasis whengiven orally or subcutaneously. AbA's fungicidal action in mice with candidiasis was more effective than fluconazole and amphotericin B.The incidence of systemic fungal infections are increasing in immunecompromisedpatients with several underlying diseases, such as leukemia and acquired immunodeficiency syndrome (AIDS), and in patients receiving anti-neoplastic agents, immunosuppressive agents or broad spectrum antibacterial antibiotics. Amphotericin B, flucytosine, and two imidazole drugs, miconazole and ketoconazole, have been the drugs of choice for systemic antifungal chemotherapy. Recently, two neworal triazoles, fluconazole and itraconazole,1) have been successfully developed and are now available for the treatment of some systemic fungal infections. However, clinical usefulness of all of these drugs is limited to insufficient therapeutic efficacy and/or toxicity. Thus there is a need for novel antifungal agents with a greater clinical efficacy.Aureobasidin A (AbA) is a new antifungal cyclic depsipeptide antibiotic (Fig. 1) produced by Aureobasidium pullulans R106.2~4) The characteristic of the structure of AbAis that of a peptide composed of eight L-form amino acids linked through one hydroxy acid to form a ring structure. There are some cyclic peptide antibiotics with antifungal activity in vitro, including valinomycin,5) syringomycin,6'7) calophycin8) and aculeacin/echinocandin family.9~1 1} Manyof them effect cell membrane permeability and have toxicity to eukaryotic cells. Several antifungal cyclic peptides with a long-chain fatty acid, such as aculeacin A, echinocandin B and their analogs, inhibit fungal cell wall synthesis with low acute toxicity. 9' 1 0) However, they show a narrow spectrum antifungal activity, ineffectiveness to murine candidiasis when given orally, and hemolytic effect. On the other hand, AbAhas a broader spectrum and higher

Russet spotting (RS), consisting of numerous small brown spots on the midrib of head lettuce (Lactuca sativa), is a physiological disorder induced by exposure to ethylene. In leaves suffering RS, the increase in spotting was accompanied by a parallel increase in the amount of phenolic compounds. Of these, chlorogenic acid and isochlorogenic acid were identified. Ethylene induced high phenylalanine ammonia-lyase (PAL) activity and RS formation in the susceptible cultivar Salinas, but not in the resistant cultivar Calmar. In the absence of ethylene neither significant PAL induction nor RS occurred. No correlation was found between the increase in polyphenol oxidase or peroxidase and the development of RS. The increase in PAL activity, however, was closely correlated with the development of RS. The increase in PAL activity preceded the development of RS, and the extent of RS was directly related to the level of PAL. Three temperatures (0.5, 5.5, and 12.5 C) were compared on the basis of their influence on both RS and PAL induction. At the lowest temperature (0.5 C) neither PAL induction nor RS occurred to a significant extent. At the highest temperature (12.5 C) an initial rapid increase in PAL activity and an earlier development of spotting were observed, but subsequently there was a decrease in both PAL activity and the rate of development of RS. At the medium temperature (5.5 C) both PAL activity and RS increased progressively with time. The decline of PAL activity at a higher temperature might be attributed to inactivation of the enzyme. Thus, a temperature favorable for induction of PAL activity by ethylene was also favorable for RS. These observations indicate a close interrelationship between the induction of PAL activity and the development of RS in response to ethylene, and suggest a causal relationship between the two events. PAL serves as a useful biochemical marker for the RS reaction.Russet spotting is one of the most common commercially important disorders of postharvest lettuce (Lactuca sativa). It is observed as numerous small brown spots along both sides of the midrib, and may spread over the leaf blade during senescence (16,18 Although RS has been the subject of detailed examination in respect to the symptomology and the various factors which influence the development (16)(17)(18)(19)25), no biochemical studies have been reported. Since the metabolism of phenolic compounds has often been thought to be involved in necrogensis, we have examined activities of five enzymes (PAL, CAH, OMT, PPO, and peroxidase) involved in phenol metabolism as possible biochemical markers, and have investigated the relationship between the activation of these enzymes and the development of RS caused by ethylene. MATERIALS AND METHODS"Crisphead"-type lettuce was used for all experiments. Cultivar Salinas was harvested at Salinas, California, and cv. Calmar was obtained at a local wholesale market. Harvested lettuce heads were stored at 0.5 C until used. Wrapper and cap leaves were removed and the next six to seve...

Mantle cell lymphomas (MCLs) are frequently associated with the overexpression of PRAD1/cyclin D1, activated by 11q13 translocation and its molecular counterpart BCL-1 gene rearrangement. We recently described the correlation of positive nuclear staining using monoclonal antibody against a PRAD1/cyclin D1 product with mRNA overexpression in MCLs. In the present study, we immunohistochemically investigated the PRAD1/cyclin D1 protein in a large series of 334 lymphoproliferative disorders, including 39 cases of MCLs on paraffin sections. Based on the cyclin D1 positivity, CD5 expression, and the morphologic features of the tumor tissue, four groups of MCL-related lesions were identified among the B-cell lymphomas examined: 36 cases with cyclin D1 overexpression, 35 (95%) of which exhibited CD5-positivity and MCL-morphology (Group 1); four cases of lymphomas with MCL morphology and CD5 expression but lacking cyclin D1 overexpression (Group II); four cases of lymphomas without cyclin D1 overexpression and surface CD5 but that fall within the morphologic boundaries of MCLs (Group III); and 11 cases of CD5-positive diffuse large cell lymphomas without cyclin D1 overexpression (Group IV). The Group I cases demonstrated quite homogeneous clinicopathologic features identical to those of MCLs. This group showed a poor prognosis (11% had 5-year survival), which is highly contrasted with that of Group II (100%). Although the four groups of MCL-related lesions sometimes overlapped in their histologic or phenotypic spectrums, each appeared to show distinct clinicopathologic and prognostic profiles. Our study provides a basis for further clarification of the nature of the neoplasms of Groups II, III, and IV. Moreover, this comprehensive study may indicate that the overexpression of PRAD1/cyclin D1 is biologically essential to defining MCLs.

Stilbene synthase (STS) and chalcone synthase (CHS) are plantspecific polyketide synthases that play key roles in the stilbenoid and flavonoid biosyntheses, respectively. We have recently isolated from Pinus densiflora three STS cDNAs (PDSTS1, PDSTS2, and PDSTS3) and one CHS cDNA (PDCHSX). We then heterologously expressed these cDNAs in Escherichia coli and characterized their properties. An unusual STS isozyme, PDSTS3, lacks the common C-terminal extension of STS because of a frame-shift mutation and shows the highest pinosylvin-forming activity among the STSs tested. Pinosylvin was shown to be a potent inhibitor of PDCHSX (K i ‫؍‬ 6 M) as well as PDSTS2 (Ki ‫؍‬ 13 M), which presumably maintains the balance between the stilbenoid and flavonoid biosyntheses. PDSTS3 was insensitive to product inhibition. We identified PDSTS3 in the pine seedlings as well as full-length STS. The data provide evidence that PDSTS3 is involved in the potential regulation of the stilbenoid and flavonoid biosynthetic pathways in pine trees.