An evaluation of the safety of Crodamol PMP

Crodamol PMP (polyoxypropylene (2) myristyl ether propionate) has been extensively employed for many years in a wide variety of human cosmetics in the absence of reported adverse reactions. The compound is being considered for use as a vehicle for veterinary pharmaceuticals in food-producing animals. This paper reviews information on the chemistry, metabolism, and toxicity of this compound, including the details of a recently completed multi-dose study in rats. Based upon this information, it is concluded that Crodamol PMP is a substance of apparently low toxic potential. Potential new uses of this compound must compare the likely exposure to the substance with the available toxicity information.

Five-lipoxygenase inhibitors reduce Panc-1 survival: the mode of cell death and synergism of MK886 with gamma linolenic acid

The 5-lipoxygenase inhibitors ETYA, SC41661A and MK886 reduced the proliferation and viability of Panc-1 human pancreatic cancer cells. The extent of inhibition depended upon drug concentration, and with continued culture, cells detached and stained with trypan blue. Although results from flow cytometry were those associated with programmed cell death, despite repeated attempts, no DNA laddering consistent with its later stages was detected, and studies with the TUNEL assay were negative. Light and electron microscopy of cells cultured with SC41661A provided morphologic evidence of a population of "dark" cells and of an incompletely expressed type 1 programmed cell death including margination of chromatin at the nuclear membrane and by consolidation and degeneration of cytoplasmic organelles, along with extensive vacuolization. Cells cultured with MK886 exhibited compact "dark" cells and an unusual cytoplasmic mode of cell death characterized by vacuolization and widely separated smooth internal membranes without diagnostic nuclear changes. This is in marked contrast to the extensive type 1 PCD induced by 5-lipoxygenase inhibitors cultured with human U937 monoblastoid cells. On balance, the response of Panc-1 cells to MK886 suggests expression of a variant type 2 (autophagic) cellular suicide, although some contribution from components of a "cytoplasmic" (type 3?) form of non-necrotic cell death may also be considered. In a European clinical trial, gamma linolenic acid, a polyunsaturated fatty acid that generates free radicals has been combined with 5-fluorouracil as chemotherapy for pancreatic cancer. Panc-1 cell proliferation was insensitive to inhibition by several chemotherapeutic agents employed clinically, including 5-fluorouracil, cisplatin or gemcitabine and only somewhat sensitive to GLA. When gamma linolenic acid was combined with MK886, the more effective of the two 5-lipoxygenase inhibitors, a synergistic reduction in Panc-1 cell number and viability occurred.

Inhibition of cancer cell proliferation by disruption of interdigitated/concatenated hierarchies of metabolic control/implementation processes: a proposal

With a combination of inhibitors at less than their individual 'therapeutic' concentrations directed against dissimilar cellular hierarchical developmental controls and 'downstream' metabolic pathways, it may be possible to modulate the biologic behavior of malignantly transformed cells synergistically. Ideally the cumulative systemic toxicity of such a 'polytherapy' would be reduced.

Augmentation of impaired tumoricidal function in alveolar macrophages from lung cancer patients by cocultivation with allogeneic, but not autologous lymphocytes

It has been reported that the in vitro development of tumoricidal function in alveolar macrophages from lung cancer patients is reduced significantly when compared to that in peripheral blood monocytes from the same patients or alveolar macrophages from control patients. In the present investigation, a method for potentiating the development of tumoricidal function in alveolar macrophages from lung cancer patients is described. This method, which relies on priming the macrophages with purified, allogeneic peripheral blood lymphocytes from normal donors, could not be demonstrated when autologous lymphocytes from lung cancer patients were used in the priming coculture. The augmentation of tumoricidal function appears to be mediated by one or more soluble factors, since supernatants from cocultures of alveolar macrophages and allogeneic peripheral blood lymphocytes could enhance the cytotoxic function of freshly obtained alveolar macrophages. Furthermore, it appears that NK cells are necessary for this effect, since depletion of CD56+/CD57+ cells from allogeneic lymphocytes eliminated their capacity to enhance alveolar macrophage cytotoxic function. The augmentation of cytotoxic function elicited in alveolar macrophages by this method was not associated with changes in the secretion of tumor necrosis factor alpha, or interleukin 1 beta.

Modulation of tumoricidal function in alveolar macrophages from lung cancer patients by interleukin-6

Previous studies have demonstrated that alveolar macrophages from lung cancer patients are impaired in their ability to develop tumoricidal function when stimulated by activators such as interferon gamma + lipopolysaccharide. However, these same macrophages have been shown to develop significant tumoricidal function when precultured with macrophage-depleted allogeneic peripheral blood lymphocytes from normal donors, an effect that was lost by the elimination of natural killer cells from the allogeneic lymphocyte population. In the present study, the effect of each activation condition on the expression of mRNA for interleukin-1 alpha (IL-1 alpha), IL-1 beta, tumor necrosis factor alpha (TNF alpha) and IL-6 was determined using reverse transcription/polymerase chain reaction. The results show that the non-permissive activation condition is associated with the expression of mRNA for IL-6 while the permissive activation condition is not. Antibodies against IL-6 were subsequently shown to permit the development of tumoricidal function in alveolar macrophages stimulated with interferon gamma + lipopolysaccharide while IL-6 protein was shown to inhibit the stimulatory action of allogeneic lymphocytes on the development of tumoricidal function in the same alveolar macrophages. Neither the permissive (i.e. allogeneic lymphocyte stimulation) nor the non-permissive (i.e. interferon gamma + lipopolysaccharide) activation condition had any effect on the capacity of alveolar macrophages from lung cancer patients to express mRNA for IL-1 alpha, IL-1 beta or TNF alpha. These results show that IL-6 can regulate the ability of alveolar macrophages from lung cancer patients to be stimulated by interferon gamma + lipopolysaccharide to develop significant tumoricidal function. They also show that allogeneic lymphocytes have the capacity to down-regulate IL-6 mRNA synthesis by alveolar macrophages thereby permitting the development and/or expression of macrophage tumoricidal function.

Primary structure and tissue distribution of two novel proline-rich gamma-carboxyglutamic acid proteins

Two human cDNAs that encode novel vitamin K-dependent proteins have been cloned and sequenced. The predicted amino acid sequences suggest that both are single-pass transmembrane proteins with amino-terminal gamma-carboxyglutamic acid-containing domains preceded by the typical propeptide sequences required for posttranslational gamma-carboxylation of glutamic acid residues. The polypeptides, with deduced molecular masses of 23 and 17 kDa, are proline-rich within their putative cytoplasmic domains and contain several copies of the sequences PPXY and PXXP, motifs found in a variety of signaling and cytoskeletal proteins. Accordingly, these two proteins have been called proline-rich Gla proteins (PRGP1 and PRGP2). Unlike the gamma-carboxyglutamic acid domain-containing proteins of the blood coagulation cascade, the two PRGPs are expressed in a variety of extrahepatic tissues, with PRGP1 and PRGP2 most abundantly expressed in the spinal cord and thyroid, respectively, among those tissues tested. Thus, these observations suggest a novel physiological role for these two new members of the vitamin K-dependent family of proteins.

Oral immunization of rainbow trout with antigen microencapsulated in poly(DL-lactide-co-glycolide) microparticles

The model protein antigen, human gamma globulin (HGG) was microencapsulated in poly(DL-lactide-co-glycolide) microparticles and administered orally to rainbow trout. Oncorhynchus mykiss (Walbaum, 1792). Using a Western blotting technique it was demonstrated that the dynamics of passage through the gut were different for the microencapsulated and soluble antigen. The association of HGG with microparticles increased the retention time of the antigen in the stomach and delayed its entry into the intestinal region. After the delivery of microencapsulated HGG, antigen was detected in gut contents in fragmented form which suggested that some of the antigen was present at the particle surface and therefore susceptible to proteolysis. However, a greater amount of intact antigen was detected in the posterior intestine and in the bloodstream of fish, which were administered with microparticle-associated than soluble antigen, indicating that the antigen was partially protected. Immunization with microencapsulated HGG resulted in the detection of specific antibody in the serum but levels were not significantly greater than after the delivery of soluble antigen. However, specific antibody was detected in the intestinal mucus of fish which were administered with the microencapsulated antigen after boosting with soluble HGG but not in fish which were primed with the soluble antigen.

What brings intentions to mind? An in situ study of prospective memory

In a naturalistic study, we aimed to uncover the relationship between thinking about and remembering intentions. Electronic badges allowed us to track the activities of subjects within their work environment. Over two weeks, subjects were asked to respond using a button on their badges (1) every two hours (Time task); (2) whenever they were in a particular room (Place task). In addition, whenever they thought about the task, they were asked to indicate this with their badges. Although subjects thought about the Time task more, they forgot to respond more often than in the Place task. In the Time task, there was a marked absence of thoughts about the task following successful remembering. When subjects remembered the Place task, thoughts increased with proximity to the target location. In both tasks, thoughts about intentions occurred more in places such as stairwells than in locations where people tended to settle. On the basis of these findings, possible mechanisms for prospective memory are discussed.

Hydrosalpinges adversely affect markers of endometrial receptivity

While in-vitro fertilization (IVF) was initially developed in women with tubal factor infertility, recent clinical studies have suggested that the presence of hydrosalpinges lowers implantation and pregnancy rates. We postulated that these hydrosalpinges cause impaired endometrial receptivity. A total of 103 women with hydrosalpinges were prospectively evaluated, and compared with 55 infertile and 44 fertile controls. All women had endometrial biopsies during the window of implantation, analysed by conventional histological criteria, and also stained for three integrin markers of endometrial receptivity (alpha1beta1, alpha4beta1 and alpha vbeta3). Women with hydrosalpinges (cases) expressed significantly less of the alpha vbeta3 integrin compared with controls. There was no difference in expression of alpha1beta1 or alpha4beta1 among groups. A significantly greater number of cases had out of phase histology and missing alpha vbeta3 (type I defects) and absent integrin expression despite normal histological maturation (type II) defects, compared with controls. Of 20 women with impaired endometrial receptivity who were also biopsied after hydrosalpinx surgery, 70% demonstrated increased alpha vbeta3 expression. Seventy-seven percent of type I and 57% of type II defects were corrected postoperatively. Using markers of endometrial receptivity, this study demonstrates that inflammatory hydrosalpinges have an adverse effect on endometrial receptivity, which in some cases may be overcome by surgical treatment of the hydrosalpinx.

A 5-lipoxygenase inhibitor at micromolar concentration raises intracellular calcium in U937 cells prior to their physiologic cell death

Micromolar MK886, a selective inhibitor of 5-lipoxygenase at nanomolar concentration, induces physiologic cell death in U937 and chronic myelogenous leukemia blast cells. When U937 cells were challenged with 10 microM MK886, an acute, biphasic and sustained rise in intracellular Ca2+ occurred, as determined with Fura-2. The initial increase was followed by a transient decline and a larger rise due to an influx of external Ca2+. The first increase and part of the subsequent rise also developed in Ca(2+)-free medium, identifying their origin from intracellular stores. The intracellular Ca2+ concentration of U937 cells that remained after culture for 24 or 48 h with 5 or 10 microM MK886 was not reliably altered from the control values of 130 +/- 8.3 nM. Under similar conditions MK886 did not increase cytosol Ca2+ of a human prostate (PC3) cell line examined in suspension. The increase in intracellular Ca2+ in response to MK886 in calcium-containing medium was confirmed with an ACAS laser spectrometer. U937 cytosol pH was measured with the fluorescent probe BCECF, but not persistent acute or chronic change was induced by MK886. The rapid and sustained rise in Ca2+ induced by MK886 is an early event in U937 cells which subsequently undergo physiologic cell death characterized in many by apoptosis.

American cigarette manufacturers' ability to pay damages: overview and a rough calculation

The American cigarette industry's ability to pay large damage awards and settlement costs is not limited to its current annual profits of $7.6 billion, or $0.31 per pack. Much larger liability payments could be financed through increased wholesale cigarette prices or higher excise taxes. An increase in the federal cigarette excise tax of 50 cents per pack could yield an estimated $10.8 billion annually in net revenues available for liability costs, while the industry would still retain $5.4 billion, or $0.25 per pack, in pre-tax profits. An increase in cigarette price from its current $1.88 per pack to the full, monopoly profit-maximising level of $4.08 per pack would make more than $32 billion available annually for liability payments or pre-taxed profits.

An in vivo inhibitor of 5-lipoxygenase, MK886, at micromolar concentration induces apoptosis in U937 and CML cells

MK886 (Merck Frosst) is a selective in vivo inhibitor of 5-lipoxygenase, active at nanomolar concentrations. At micromolar concentrations, it inhibited the proliferation of U937 monoblastoid cells and of cultured malignant cells from patients with chronic myelogenous leukemia. These cells became morphologically apoptotic, a form of physiologic cell death. U937 cell apoptosis was assessed by flow cytometry, ultrastructure, DNA laddering and immuno-histology for free 3'OH-DNA. MK886-induced apoptosis developed over time as cells were recruited in concert with reduction in their numbers. Some CML cells exhibited cytoplasmic changes of apoptosis without typical nuclear changes. Under conditions used for measuring Ca2+ with Fura 2, 10 micromolar MK886 increased U937 intracellular Ca2+ 4-fold or more over the 8 minute period of measurement. Since MK886 inhibits the association of arachidonic acid with the 5-lipoxygenase activating protein, altered arachidonic acid metabolism may have contributed to these results.

Does an inability to eradicate normal stem cells preclude the cure of some cancers?

Presently, identified signal transduction pathways do not alter normal stem-cell survival. With prostate cancer as a model, the argument is advanced that an inability to eradicate normal androgen-dependent prostate stem-cells precludes successful treatment of transformed, androgen-independent and metastatic progeny. While applying this idea to cancers of non-essential organs or to endocrine cancers seems feasible, the inutility of this approach for most other malignancies appears likely, although not certain.

Renal medullary carcinoma: clinical and therapeutic aspects of a newly described tumor

BACKGROUND

Renal medullary carcinoma is a newly described, aggressive kidney tumor. All patients with the disease have been African-American with sickle cell (SC) trait or hemoglobin SC disease.

METHODS

Patient information was obtained from individual patient records and from the Department of Defense national data bank, The Defense Enrollment and Eligibility Reporting System. Data were obtained from either personal review of the patient's records or from discussion with the patient's physician. Cytogenetic studies were performed on one patient.

RESULTS

Six patients are presented. All had SC trait. Median age was 24.5 years and 1 patient was female. Time from diagnosis to death averaged 3 months (range 1-7 mos). No objective responses were reported to a wide variety of chemo and immunotherapies: cyclophosphamide, doxorubicin, cisplatin; methotrexate, vinblastine, doxorubicin, and cisplatin; single agent interferon; single agent paclitaxel; or single agent vinblastine. Investigational regimens included topotecan, doxorubicin, and filgrastim; alpha-interferon, interleukin-2, and 5-fluorouracil; and single agent paclitaxel. Cytogenetic studies revealed numerous structural, as well as numerical anomalies. Of the cells successfully karyotyped (n=4), 2 contained abnormalities of chromosome 3 and all contained monosomy 11.

CONCLUSIONS

Renal medullary carcinoma is an aggressive, chemoresistant tumor. Time from discovery of tumor to patient death is very short and has been altered by a wide variety of chemotherapies and immunotherapies. An unidentified genetic component is likely present.

Ultrastructural study of the epithelium of the normal human vulva

An ultrastructural study of the pathology of vulvar vestibulitis syndrome (Friedrich, 1987) necessitated a detailed knowledge of the epithelial surface of the vulva. As this has previously been characterised only at the light microscopy level, a comprehensive electron microscopical study of the vulva was considered critical to the study of the pathological tissue. A comparison between vulvar, vaginal and keratinised perineal epithelia, confirmed the resemblance of vulvar epithelium to partially keratinised mucosal-like epithelia. No conclusive evidence of keratinisation was observed and the characteristic granular and spiny cell layers found in skin were absent. The prominent cell type was the glycogenated intermediate cell, which formed a structurally homogeneous layer of cells. Other cell types present were: superficial flattened cells, many having nuclei, traces of organelles and large glycogen deposits; suprabasal cells; and basal cells, some of which appeared mitotically active rich in organelles. All cell layers were characterised by the presence of numerous interdigitating cytoplasmic processes, small numbers of infrequent desmosomal junctions and pale staining cytokeratin filaments.

Luminal and glandular endometrial epithelium express integrins differentially throughout the menstrual cycle: implications for implantation, contraception, and infertility

PROBLEM

Integrins belong to a family of cell adhesion molecules that are present on virtually all cells. The temporal and spatial expression of these important proteins on the human endometrium suggests that certain integrins may participate in the cascade of molecular events leading to successful implantation.

METHODS

Using immunohistochemistry, we studied the expression of 12 different integrins in up to 600 samples of human endometrium throughout the menstrual cycle. Intensity and distribution of staining was determined using the semiquantitative HSCORE, with specific focus on the differences between glandular and luminal expression.

RESULTS

We noted that the glandular and luminal epithelium undergo independent alterations in integrin expression throughout the menstrual cycle. Specifically, glandular epithelium express certain integrins only during the window of implantation, while luminal epithelium down-regulate certain integrins during this time. The expression of one integrin (the alpha v beta 3 vitronectin receptor) on both luminal and glandular epithelium coincides with the time of embryo attachment; aberrant expression of this integrin is associated with infertility.

CONCLUSION

It appears that the endometrium is a unique tissue with regard to the number of integrins that undergo temporal and spatial changes during the menstrual cycle. These data may offer new directions for the development of a novel contraceptive approach targeted to the endometrium as well as a better understanding of occult causes of infertility in women.

Characterization of the 5'-flanking region of the gene for the alpha chain of human fibrinogen

The 5'-flanking region of the gene coding for the alpha chain of human fibrinogen was isolated, sequenced, and characterized. The principal site of transcription initiation was determined by primer extension analysis and the RNase protection assay and shown to be at an adenine residue located 55 nucleotides upstream from the initiator methionine codon, or 13,399 nucleotides down-stream from the polyadenylation site of the gene coding for the gamma chain. Transient expression of constructs containing sequentially deleted 5'-flanking sequences of the alpha chain gene fused to the chloramphenicol acetyltransferase reporter gene showed that the promoter was liver-specific and inducible by interleukin 6 (IL-6). The shortest DNA fragment with significant promoter activity and full response to IL-6 stimulation encompassed the region from -217 to +1 base pairs (bp). Although six potential IL-6 responsive sequences homologous to the type II IL-6 responsive element were present, a single sequence of CTGGGA localized from -122 to -127 bp was shown to be a functional element in IL-6 induction. A hepatocyte nuclear factor 1 (HNF-1) binding site, present from -47 to -59 bp, in combination with other upstream elements, was essential for liver-specific expression of the gene. A functional CCAAT/enhancer binding protein site (C/EBP, -134 to -142 bp) was also identified within 217 bp from the transcription initiation site. An additional positive element (-1393 to -1133 bp) and a negative element (-1133 to -749 bp) were also found in the upstream region of the alpha-fibrinogen gene.

Selective inhibitors of 5-lipoxygenase reduce CML blast cell proliferation and induce limited differentiation and apoptosis

Inhibitors of the arachidonic acid metabolizing enzyme, 5-lipoxygenase, reduce the rate of proliferation of chronic myelogenous leukemia blast cells. The inhibitory agents studied were ETYA, A63162 and SC41661A. These reagents induced differentiation of cultured chronic myelogenous leukemia cells from blast to promyelocytic morphology. Promyelocytic cells then underwent apoptosis, which was identified by nuclear and cytoplasmic morphological features and by DNA laddering. Proliferation of monoblastoid U937 and myelomonocytic HL60 cell lines, known to contain 5-lipoxygenase and synthesize leukotrienes, was reduced by these inhibitors. U937 cells cultured with ETYA, A63162 or SC41661A for 48 h exhibited apoptosis as assessed by DNA laddering and morphology. Characteristic ultrastructural changes of apoptosis were seen at 120 h. MK886, an inhibitor of 5-lipoxygenase with a mechanism of action distinct from oxidation/reduction reagents, at 20-40 microM also inhibited CML and U937 cell proliferation and induced apoptosis, as shown by DNA laddering and ultrastructure.

Drug resistance and biochemical characteristics of Salmonella from turkeys

A study was conducted to determine the antibiotic resistance and biochemical characteristics of 2690 Salmonella strains belonging to 52 serovars and isolated from environmental and feed samples from 270 turkey flocks in Canada. Resistance of the Salmonella strains to the aminoglycoside antibiotics varied widely; none of the strains were resistant to amikacin, 14.2% were resistant to neomycin, 25.8% were resistant to gentamicin, and 27.7% of the strains were resistant to kanamycin. Most strains (97.6%) were resistant to the aminocyclitol, spectinomycin. Regarding resistance to the beta-lactam antibiotics, 14.3% and 14.4% of the strains were resistant to ampicillin and carbenicillin, respectively, whereas only 5 (0.2%) of the strains were resistant to cephalothin. None of the strains were resistant to the fluoroquinolone ciprofloxacin or to polymyxin B. Resistance to chloramphenicol and nitrofurantoin was found in 2.4% and 7% of the strains, respectively. Only 1.7% of the strains were resistant to the trimethoprimsulfamethoxazole combination, whereas 58.1% were resistant to sulfisoxazole. Thirty-eight percent of the strains were resistant to tetracycline. Salmonella serovars differed markedly in their drug resistance profiles. Biochemical characterization of the Salmonella showed that the S. anatum, S. saintpaul and S. reading serovars could be divided into distinct biotypes.

Interaction of dietary factors with oral anticoagulants: review and applications

This article reviews the published original sources of information on interactions of oral anticoagulants with dietary factors, points out deficiencies in our knowledge of these interactions, and suggests applications for this information in the clinical setting. As with many drug-nutrient interactions, the original references include a few experimental studies and many case reports. Deciding which interactions of oral anticoagulants with dietary factors are clinically relevant and determining the appropriate dietary prescription concerning each interaction involves, in most cases, an educated opinion rather than a conclusion based on extensive research. Enough information exists on the vitamin K content of foods and the quantity of vitamin K that alters coagulation status from the therapeutic range to provide the patient with advice concerning a group of foods to avoid and a group of foods to limit to one serving per day. With respect to other dietary factors that may interact with oral anticoagulants, the patient should be cautioned concerning supplements of vitamins A, E, and C and alcohol used chronically or ingested in large quantities.

Reduced drug resistance in a multidrug resistant cell line by 5,8,11,14-eicosatetraynoic acid

We examined whether the arachidonic acid competitive antagonist, ETYA (5,8,11,14-eicosatetraynoic acid), modulated drug sensitivity in a cell line that over-expresses the multiple drug resistance protein, MDR1. ETYA was nontoxic to drug-sensitive parental KB3-1 cells or drug-resistant MDR KB8-5-11 cells, with an IC50 of 190 microM for both lines. ETYA (20 microM) increased rhodamine 123 accumulation in KB8-5-11 MDR cells but not in KB3-1 sensitive cells. Arachidonic acid at 20 microM did not alter rhodamine accumulation in either cell line. Increasing the concentration of ETYA from 40 to 160 microM or incubation beyond 30 min did not increase KB8-5-11 dye retention. Forty microM or more ETYA increased KB3-11 dye retention. In a 6 day proliferation assay of KB8-5-11 cells, a nontoxic (40 microM) concentration of ETYA reduced the IC50 for doxorubicin 4-fold, the IC50 for colchicine 2-fold, but had no effect on the IC50 for vinblastine. ETYA at 40 microM did not alter the IC50 for any drug tested with KB3-1 cells. Therefore: (a) ETYA (20 or 40 microM) modulated resistance of KB8-5-11 cells to several drugs to a limited extent, without potentiating toxicity in the parental line, while arachidonic acid did not. (b) Since cationic rhodamine 123 is concentrated in mitochondria, the extent is dependent upon the transmembrane potential, and increased dye retention due to ETYA may in part be related to altered ETYA-induced cell membrane potential.

Potential applications of apoptosis in modifying the biological behavior of therapeutically refractory cancers

Recent information about apoptosis or programmed cell death, the anti-apoptotic gene, BCL2, its interaction with reactive oxygen species and the role of these agents in senescence and apoptosis, suggests a discussion of their relationships could be of interest. Such information may eventually provide alternative approaches to modifying the biological behavior of therapeutically resistant cancers. Some of these comments probably are self-evident, others may be less so and provide ideas for further studies.

Spontaneous chemiluminescence of ETYA (5,8,11,14-eicosatetraynoic acid) is inhibited by catalase or peroxidase

5,8,11,14-eicosatetraynoic acid (ETYA), an isomorphic competitive analogue of arachidonic acid, spontaneously generates a chemiluminescence signal detected with a liquid scintillation spectrometer operated at ambient temperature in the out-of-coincidence mode. The intensity of the signal was 10- or more-fold above background, required oxygen for its generation, was inhibited by antioxidants, and approximately doubled in D2O. Arachidonic acid, which contains 4-alkene rather than alkyne bonds did no more than double the chemiluminescent signal above background. When examined at 37 degrees C in a Berthold AutoLumat 958 luminometer, DBA (lucigenin) was required to detect a signal above background. Catalase or peroxidase, and to a lesser extent mannitol or histidine but not superoxide dismutase, strongly diminished the signal intensity. These observations provide a baseline for interpreting the functional and electron microscopic changes produced by ETYA in PC3 prostate and A172 glioblastoma cell lines, consistent with a contribution from oxidative stress associated with free radicals, and the absence of these morphological changes in U937 monoblastoid cells.

The selective 5-lipoxygenase inhibitor A63162 reduces PC3 proliferation and initiates morphologic changes consistent with secretion

We examined the effect of A63162 (Abbott), a selective inhibitor of 5-lipoxygenase on human prostate (PC3) cell proliferation. Within 5 min DNA synthesis was reversibly inhibited by 40 microM A63162, without altered cellular attachment or uptake of trypan blue. After 72 Hr, cells continued to be attached and exclude dye, were reduced in number and their histology was altered. Many treated cells were larger, more pleomorphic, with nuclear and cytoplasmic ultrastructural changes consistent with preparation for secretion. Some cells contained moderately swollen, distorted mitochondria. ETYA, a less selective inhibitor of 5-lipoxygenase that also inhibits cell replication, acutely reduced O2 uptake by 40%, but A63162 did not. The retention of the supravital mitochondrial dye, rhodamine 123 was increased by ETYA at 4 hr, but not after 24 hr; retention was not altered by A63162. Although the mechanism by which A63162 reversibly inhibits PC3 proliferation and initiates preparation for secretion is not identified, additional studies should further define its role in these events.

Sensitivity of tumoricidal function in macrophages from different anatomical sites of cancer patients to modulation of arachidonic acid metabolism

The sensitivity of cancer patient macrophages from different anatomical sites to arachidonic acid metabolism was investigated in tumor cell cytotoxicity assays. Alveolar macrophages and peripheral blood monocytes from 13 non-small cell lung cancer patients, peritoneal macrophages and peripheral blood monocytes from 13 ovarian cancer patients, and comparable macrophages from control patients with nonmalignant lung or gynecological diseases were tested. Inhibitors of either the cyclooxygenase pathway or the lipoxygenase pathway together with specific metabolites of each pathway were used to evaluate how these different macrophage populations are regulated by eicosanoids. In addition, metabolic studies were performed to compare directly the arachidonic acid metabolism of macrophages obtained from these different anatomical locations. The results demonstrate that the peripheral blood monocytes from lung cancer and ovarian cancer patients and the peritoneal macrophages from ovarian cancer patients are sensitive to cyclooxygenase inhibition; this was not seen with comparable macrophages from the relevant control patients. Sensitivity to modulation by cyclooxygenase inhibition correlated with increased cyclooxygenase metabolism and with the capacity of prostaglandin to mediate suppression of tumoricidal function in these populations of cancer patient macrophages. In contrast, alveolar macrophages from cancer patients were not sensitive to either cyclooxygenase inhibition or to prostaglandin-mediated suppression. No such differential influences were revealed for the lipoxygenase pathway of arachidonic acid metabolism in any macrophage population tested. Thus, eicosanoids, particularly those of the cyclooxygenase pathway, can be a critical immunoregulatory feature of certain tumor microenvironments.