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J E Harris

Publications and source records attributed to J E Harris.

At least 73 records · Page 4Linked to original sources
PubMed1995

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.

Amino Acid Sequence↗
PubMed1995

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.

5,8,11,14-Eicosatetraynoic Acid↗
PubMed1995

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.

Administration, Oral↗
PubMed1995

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.

Animals↗
PubMed1994

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.

Apoptosis↗
PubMed1994

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.

5,8,11,14-Eicosatetraynoic Acid↗
PubMed1994

Morphologic changes of apoptosis induced in human chronic myelogenous leukemia "blast" cells by SC41661A (Searle), a selective inhibitor of 5-lipoxygenase.

Several inhibitors of the arachidonic acid-metabolizing enzyme, 5-lipoxygenase reduce proliferation of hematopoietic and non-hematopoietic cells and cell lines and some cells undergo limited differentiation. Cells were cultured from patients with chronic myelogenous leukemia in "blast" crisis with the selective inhibitor of 5-lipoxygenase, SC41661A[3-(3,5-bis(1,1-dimethyl)-4-hydroxyphenyl)hiol]-N-me thyl-N-[2-(2- phridinyl-propanamide)]. Cells cultured for 3 to 5 days with 40 microM SC41661A exhibited reduced cellular numbers along with ultrastructural changes and DNA laddering characteristic of apoptosis. Similar culture conditions reduced proliferation of U937 monoblastoid cells. In U937 cells, the ultrastructural features of apoptosis were not observed at 72 hours, when DNA laddering was present and cell numbers were reduced, but was present after 144 hours of culture. Dissociation between certain morphologic and biochemical sequelae of apoptosis has been described in other systems. These observations are of interest since the induction of apoptosis in dividing chronic myelogenous leukemia (CML) cells by a non-cytotoxic agent suggests paradigmatically new sites for therapeutic intervention.

Amides↗
PubMed1994

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.

5,8,11,14-Eicosatetraynoic Acid↗
PubMed1993

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.

6-Ketoprostaglandin F1 alpha↗
PubMed1993

Suppression of the development of tumoricidal function in gamma interferon-treated human peripheral blood monocytes by lipopolysaccharide: the role of cyclooxygenase metabolites.

Bacterial lipopolysaccharide (LPS) is generally regarded as one of the most potent macrophage activators. Thus, LPS has been used as an obligatory second signal to stimulate macrophage cytotoxic function against a wide array of bacterial and neoplastic targets. In this study, however, we define conditions under which LPS can suppress the development of cytotoxic function in normal human peripheral blood monocytes. When monocytes were treated with a priming dose of gamma interferon (gamma-INF), followed 18-24 hr later by a triggering dose of LPS, significant cytotoxic function developed. However, when monocytes were treated with even minimal amounts of LPS during priming with interferon, the development of cytotoxic function following stimulation with a second, triggering dose of LPS was virtually abolished. This effect could be produced from 0 to 14 hr following the addition of gamma-INF. The inhibition of monocyte cytotoxicity which was produced by LPS treatment during priming was dose dependent and could not be overcome by modifying either the priming dose of gamma-IFN or the triggering dose of LPS. The suppression was largely overcome, however, by treatment with the cyclooxygenase inhibitor, indomethacin. The possibility that LPS-induced suppression of monocyte cytotoxicity was mediated by products of the cyclooxygenase pathway was supported further in this study by demonstrating that LPS stimulated the production of significant amounts of prostaglandin E2 (PGE2) from monocytes and that this was facilitated by gamma-IFN. In kinetics studies, it appeared that LPS suppression of monocyte activation was correlated temporally with a heightened sensitivity to suppression by exogenously added PGE2, a condition which was reduced greatly by the end of the priming phase.(ABSTRACT TRUNCATED AT 250 WORDS)

Cell Death↗
PubMed1993

Normal and aberrant expression of cytokines in neoplastic cells from chronic lymphocytic leukemias.

Molecular expression of cytokines and cytokine receptors associated with B-cell growth and differentiation was examined in cells from B-cell chronic lymphocytic leukemia patients using the PCR. These studies were undertaken in order to determine whether a particular cytokine could be associated with leukemic transformation in this disease. The precursor-lymphoid and pro-B, pre-B-cell growth factor, interleukin-7, was found to be expressed in 30 of 30 patients, whereas, it was not expressed in normal donor peripheral blood lymphocytes (0 of 8) or in purified B-cell subsets from normal individuals. IL-1 beta and IL-2 receptors, on the other hand, were expressed by B cells from both normal and B-CLL patients. Other cytokine and cytokine receptors examined were not consistently expressed by all donors. Thus IL-7 was found to be the only cytokine tested that was expressed in CLL cells and not in normal cells.

Adult↗
PubMed1993

Induction of apoptosis in blood cells from a patient with acute myelogenous leukemia by SC41661A, a selective inhibitor of 5-lipoxygenase.

Participation of leukotriene products in normal ex vivo hematopoiesis is well established. With increasingly specific inhibitors of lipoxygenases, it becomes possible to more closely define any participation of their biosynthetic products in these events. We cultured chronic myelogenous leukemia cells from the peripheral blood of several patients in blast crisis with three inhibitors of lipoxygenases: ETYA, and the more selective A63162 (Abbott) or SC41661A (Searle). All three agents reduced labelling of DNA with H3 thymidine measured at 4 h and reduced cell numbers by 72 h. An antisense deoxyoligonucleotide to the 5-lipoxygenase mRNA 'start' codon inhibited DNA synthesis at 24 h, as did two control oligonucleotides. Marked nuclear ultrastructural changes characteristic of apoptosis were induced by SC41661A in a subset of cells with the ultrastructure of promyelocytes. Whether this response characterizes a common pattern of this subset of leukemic cells to SC41661A, if damage to mitochondria with reduced function of bcl-2 protooncogene product located at that site might have contributed or some other mechanism was responsible, and if inhibition of 5-lipoxygenase activity was involved, are questions to be decided in the future.

5,8,11,14-Eicosatetraynoic Acid↗
PubMed1993

Characterization of a variant of the polysaccharide acetan produced by a mutant of Acetobacter xylinum strain CR1/4.

Acetobacter xylinum NRRL B42 (NCIB 40123) produces both cellulose and a complex anionic branched heteropolysaccharide called acetan. Chemical mutagenesis was used to isolate stable cellulose-minus Acetobacter xylinum mutants. Further chemical mutagenesis of these cellulose-minus A. xylinum bacteria was used to select mutants which secrete polysaccharides which are variants of the acetan structure. Preparation, purification and characterization of these polysaccharides are described. Methylation analysis of the polysaccharide structure CR1/4 suggests that the polysaccharide has an acetan structure with a truncated sidechain terminating in glucuronic acid.

Carbohydrate Conformation↗
PubMed1992

Eicosatetraynoic and arachidonic acid-induced changes in cell membrane fluidity consonant with differences in computer-aided design-structures.

ETYA (5,8,11,14-eicosatetraynoic acid), a competitive analogue of arachidonic acid (AA), inhibits the proliferation of U937 (human monoblastoid) and PC3 (human prostate) cancer cells, without the overt cytotoxicity associated with AA at similar concentrations. The mechanism of inhibition is not established. ETYA at 100 microM acutely increased whole cell and isolated microsomal membrane fluidity of both cell lines to a greater extent than arachidonic acid. PC3 cells incubated with ETYA for 72 h evidenced increased membrane fluidity. This was measured by the fluorescence polarization parameter, R, using the probes TMA-DPH and DPH for whole cell and isolated membrane fractions, respectively. Compared with whole cells, isolated membranes yielded a 10-20-fold increase in fluorescence intensity. The intramolecular conformational profiles of both ETYA and AA were explored using a combination of molecular mechanics energy minimization and molecular dynamics simulation. While it is possible that not all of the low energy conformational states of either molecule were sampled, the large number of low-energy conformers determined for ETYA correspond to kink deformed conformers relative to the family of AA conformers. These kinks make the molecular cross sections of ETYA larger than AA and arise from the four alkyne bond geometries. This structural finding is consistent with ETYA's greater effect on membrane fluidity. Dissociation between the extent of change in membrane fluidity due to ETYA or AA and inhibition of DNA synthesis can suggest that either (A) increased fluidity and inhibition of DNA synthesis are independent, or as we believe more likely, (B) greater membrane fluidity evoked by ETYA is important for inhibiting DNA synthesis, while changes induced by AA are insufficient or differ qualitatively from those required to initiate and sustain these nonlethal events.

Arachidonic Acids↗
PubMed1992

5,8,11,14-eicosatetraynoic acid-induced destruction of mitochondria in human prostate cells (PC-3).

Culturing human prostate PC-3 cells for 4, 24, or 72 h in the presence of 5,8,11,14-eicosatetraynoic acid (ETYA), an inhibitor of arachidonic acid metabolism and cholesterol biosynthesis, markedly altered the morphology and reduced the number of mitochondria in the treated cells. Using quantitative electron microscopic morphometry, we documented changes in the number, form, area, matrix density, and integrity of the cristae and limiting membranes of mitochondria in cells cultured with ETYA. The inhibition of cholesterol synthesis or the substitution of ETYA for polyunsaturated fatty acids in the inner membrane may participate in the disruption of the mitochondria, which resembles the morphologic sequelae of oxidative stress. If sufficiently extensive, these changes could contribute to the inhibition of cellular proliferation by ETYA.

5,8,11,14-Eicosatetraynoic Acid↗
PubMed1992

ETYA, a pleotropic membrane-active arachidonic acid analogue affects multiple signal transduction pathways in cultured transformed mammalian cells.

ETYA (5,8,11,14-eicosatetraynoic acid), an arachidonic acid analogue, inhibited DNA synthesis in human transformed U937 (monoblastoid), PC3 (prostate) and A172 (glioblastoma) cells, and partially differentiated the U937 and A172 lines. The agent is not primarily cytotoxic at the concentrations employed, based upon exclusion of trypan blue, continued attachment of PC3 and A172 cells, unchanged release of Cr51, and reversibility of inhibited thymidine incorporation after removal of ETYA. Leukotriene C4 partially reversed the suppression of U937 DNA synthesis, suggesting its modulation by leukotrienes. U937 and A172 cells partially differentiated, as judged by a number of criteria. ETYA increased whole cell and microsomal membrane fluidity, increased intracellular Ca2+ in PC3 and U937 cells, altered the distribution and activity of protein kinase C in U937 cells, and rapidly downregulated the transcription of U937 c-myc. Evidence from transmission electron microscopy consistent with oxidative stress including putative lipofuscin bodies, myelin figures and disordered mitochondrial cristae and matrices was especially evident in PC3 cells, less so in A172 and essentially absent in U937 cells. A specific 5'-lipoxygenase inhibitor, A63162 inhibited PC3 and U937 proliferation. Some of these events are believed to represent components of "signal" transduction pathways responsible for reversible inhibition of DNA synthesis and the induction of partial phenotypic differentiation in competent cells. Arachidonic acid analogues which exert selective effects on physical and functional properties of cell membranes may represent an additional class of membrane-active agents with potential anticancer activity. A subset of their activities can be duplicated by inhibitors of 5' lipoxygenase.

5,8,11,14-Eicosatetraynoic Acid↗
PubMed1992

Differential effects of ETYA, a PUFA-analogue, on prostate (PC3) and monoblastoid U937 ultrastructure; lack of correlation with reduced proliferation.

ETYA (5,8,11,14-eicosatetraynoic acid), a polyunsaturated fatty acid analogue, inhibits proliferation of PC3 and U937 cells and induces a limited differentiation in U937 cells. Human prostate PC3 cells cultured for 72 h with 40 microM ETYA in fetal calf serum contained putative lipofuscin bodies, myelin figures and mitochondria with damaged cristae and matrices. These changes were absent from human U937 monoblastoid cells incubated with ETYA in CPSR3, a semipurified serum replacement. U937 cells cultured with ETYA in fetal calf serum contained occasional lipofuscin bodies, while PC3 cells cultured in CPSR3 exhibited all of the changes described. ETYA reduced the oxygen consumption of both cell lines. Therefore we conclude: (a) The response to ETYA by cells of dissimilar developmental origin is not identical; (b) unidentified serum components can augment potential ETYA-induced oxidative stress-responses of cells; (c) inhibition of U937 proliferation by ETYA does not depend upon the morphologic changes seen in PC3 cells, which resemble sequelae of oxidative stress with excess free radicals; and (d) rapid ETYA-induced inhibition of oxygen consumption in both cell lines implies a reduced synthesis of ATP that could contribute to the reversible impairment of cellular proliferation.

5,8,11,14-Eicosatetraynoic Acid↗