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Biomedical subjects

J E Harris

Publications and source records attributed to J E Harris.

At least 19 recordsLinked to original sources
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↗
PubMed1991

Impaired tumoricidal function of alveolar macrophages from patients with non-small cell lung cancer.

The capacity of alveolar macrophages and peripheral blood monocytes from patients with non-small cell lung cancer to develop tumoricidal function after in vitro stimulation with different macrophage activators was investigated. Alveolar macrophages were found to be impaired in their ability to develop cytotoxic activity compared with either the peripheral blood monocytes from the same patients or alveolar macrophages from patients with nonmalignant lung disorders. This result was observed consistently under diverse culture conditions and with different macrophage activators including gamma-interferon (gamma-IFN), granulocyte-macrophage colony-stimulating factor (GM-CSF), phorbol myristate acetate, or endotoxin. The impairment in tumoricidal function observed in alveolar macrophages was not associated with reduced target cell binding compared to peripheral blood monocytes. Alveolar macrophages from patients with lung cancer were found to secrete significantly greater amounts of tumor necrosis factor (TNF) and interleukin-1 (IL-1) than either peripheral blood monocytes from the same patients or alveolar macrophages from the patients with nonmalignant disorders. These results are consistent with either different regulatory pathways for cytotoxicity and cytokine secretion in the alveolar macrophages of patients with lung cancer or diversity in the subpopulations of cells responsible for these functions.

Carcinoma, Non-Small-Cell Lung↗
PubMed1991

A pilot study of three sequential chemotherapeutic regimens in metastatic breast cancer.

The aim of this pilot study was to estimate the toxicity and response rate of an alternating chemotherapeutic program in chemotherapy-naive metastatic breast cancer patients. Treatment consisted of regimen A (given days 1-28): cyclophosphamide 100 mg/m2 PO days 1-14, doxorubicin 30 mg/m2 i.v. days 1 and 8, and 5-fluorouracil 500 mg/m2 i.v. days 1 and 8 (CAF regimen); regimen B (given days 29-56): dibromodulcitol 135 mg/m2 p.o. days 30-39, mitoxantrone 9 mg/m2 i.v. day 29, and vincristine 1.2 mg/m2 i.v. (maximum 2.0 mg) day 29 (DMV regimen); and regimen C (given days 57-84): thiotepa 12 mg/m2, doxorubicin 45 mg/m2 and vinblastine 4.5 mg/m2 all i.v. on day 57. There were 27 eligible patients with a median age of 51 years (range 34-78). On 14 episodes the leukocyte count fell to less than 1 X 10(9)/L during the first six cycles of treatment (14% of 99 cycles). There were no treatment-related deaths. Common non-life-threatening toxicities included thrombocytopenia, anemia, vomiting, and alopecia. Despite having no drugs in common, the leukocyte and platelet nadirs after CAF correlated with the nadir counts after DMV (r values of 0.6829 and 0.5892, respectively; p = 0.01). Among the 23 patients with measurable and/or evaluable disease there were five complete responses (22%) and nine partial responses (39%), with a median time to treatment failure of 29 weeks. The overall median survival was 19 months.

Adult↗
PubMed1991

Vinblastine fails to improve response of renal cancer to interferon alfa-n1: high response rate in patients with pulmonary metastases.

One hundred sixty-five patients were randomized to receive either interferon alfa-n1 (Wellferon; Burroughs Wellcome Co, Research Triangle Park, NC) alone or with vinblastine. An initial six-cycle induction treatment consisted of interferon given at daily doses of 3, 5, 20, 20, and 20 x 10(6) U/m2 every 2 weeks. Vinblastine at a dose of 10 mg/m2 (later decreased to 5 mg/m2) was given on day 1 of alternate cycles. Toxicities were generally well tolerated. The overall response rate was 10% with no significant difference between treatment arms. Survival was also not significantly different for the arms. A small subset of patients (16) with metastases only to the lungs had a high complete response (CR) and partial response (PR) rate of 44%. Responses were durable, and overall survival of this group was much better than that of the other patients.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1990

Improved short-term survival of AIDS patients initially diagnosed with Pneumocystis carinii pneumonia, 1984 through 1987.

I analyzed trends in the survival of 36,847 adults who were diagnosed with acquired immunodeficiency syndrome between January 1984 and September 1987 under the pre-1987 surveillance definition of acquired immunodeficiency syndrome. For patients in whom Pneumocystis carinii pneumonia was among the first manifestations of acquired immunodeficiency syndrome, the estimated 1-year survival increased from 42.7% for those diagnosed in 1984 and 1985 (95% confidence interval, 41.5% to 44.3%) to 54.5% for those diagnosed in 1986 and 1987 (95% confidence interval, 53.7% to 55.7%). The gain in survival was observed in homosexual men and intravenous drug users of both sexes, in all age and racial groups, in all geographic regions, and in patients with and without coexisting initial diagnosis. Reduced mortality in the 3-month period immediately following the initial diagnosis of acquired immunodeficiency syndrome contributed little to the overall gain in survival. No gain in survival was seen for patients in whom P carinii pneumonia was not an initial manifestation of acquired immunodeficiency syndrome. It is unlikely that the observed improvements in survival resulted solely from errors in death reporting. Better diagnosis and treatment, particularly the introduction of zidovudine in 1986, may have contributed to the decline in mortality.

Acquired Immunodeficiency Syndrome↗
PubMed1990

The in vitro development of cytotoxicity in response to granulocyte/macrophage-colony-stimulating factor or interferon gamma in the peripheral blood monocytes of patients with solid tumors: modulation by arachidonic acid metabolic inhibitors.

The capacity of granulocyte/macrophage-colony-stimulating factor (GM-CSF) and interferon gamma (IFN gamma) to elicit monocyte cytotoxicity in vitro in the peripheral blood monocytes of patients with solid tumors was investigated. The cytotoxicity elicited by IFN gamma was significantly reduced in cancer patient monocytes compared to normal monocytes. The cytotoxicity elicited by GM-CSF, however, was comparable between cancer patient monocytes and normal monocytes, but was lower than that induced by IFN gamma. Indomethacin, a cyclooxygenase inhibitor, significantly augmented IFN gamma-elicited cytotoxicity in cancer patient monocytes, but not in normal monocytes. In contrast, indomethacin augmented GM-CSF-elicited cytotoxicity in both cancer patient monocytes and normal monocytes. Nordihydroguaiaretic acid (NDGA), a lipoxygenase inhibitor, was found to suppress cytotoxicity in response to IFN gamma and GM-CSF in both cancer patient monocytes and normal monocytes. The addition of leukotrienes to NDGA-treated cultures restored the development of cytotoxicity. Thus there are differences in the in vitro response of cancer patient monocytes and normal monocytes to distinct biological activators. Furthermore, these responses can be manipulated by agents that modulate arachidonic acid metabolism.

Adult↗
PubMed1990

Tumor cell mitochondrial matrix/cristae complexes as potential sites for anticancer therapy with polyunsaturated fatty acid analogues.

The consequences of incubating human cancer cells with ETYA, a competitive analogue of arachidonic acid, and the reported responses of cells cultured with polyunsaturated fatty acids indicate that polyunsaturated fatty acid analogues or their modified congeners could represent potential cytotoxic anticancer agents. The inner mitochondrial membrane and matrix may represent important targets for such agents, since they seem unusually susceptible to ETYA-induced oxidative stress.

5,8,11,14-Eicosatetraynoic Acid↗
PubMed1990

Randomized phase II evaluation of carboplatin and CHIP in advanced transitional cell carcinoma of the urothelium. The Eastern Cooperative Oncology Group.

A total of 83 patients with metastatic transitional cell carcinoma who had previously received no systemic therapy entered a randomized phase II evaluation of carboplatin and cis-dichloro-transdihydroxy-bis-isopropylamine platinum IV (CHIP), administered respectively at 400 and 270 mg./m.2 every 28 days. Among evaluable patients with measurable disease response rates were 3 of 22 (14%, 95% confidence interval 5 to 35%) for carboplatin and 4 of 25 (16%, 95% confidence interval 5 to 36%) for CHIP. Among 17 patients with evaluable but not measurable metastases (10 carboplatin and 7 CHIP recipients) there were no responses. Median survival for 64 evaluable patients was 4.8 months (5.0 months for carboplatin and 4.3 months for CHIP recipients). Independent factors prognostic for survival (p less than 0.01) were performance status (0 or 1 versus 2 or 3), liver metastases, prior radiation therapy and recent weight loss (p = 0.02). Multivariate analysis confirmed that a performance status of 2 or 3 and liver metastases were predictive of shorter survival. A total of 31% of the patients treated with carboplatin and 34% of those who received CHIP experienced severe or life-threatening myelosuppression. While the response rates with carboplatin and CHIP are modest, we believe that the characteristics of these agents indicate that they should be evaluated further.

Aged↗
PubMed1990

A scheme for classifying carcinogens.

We present a scheme for classifying chemical carcinogens according to the weight of the evidence that each substance poses a human cancer hazard. The approach represents a logical extension of and builds upon those previously developed by the International Agency for Research on Cancer, the U.S. Environmental Protection Agency, and the so-called Tripartite Group of industrial scientists. It takes into account new scientific knowledge about chemical carcinogenesis and animal models. Eight categories are presented: known human carcinogen (Category 1), carcinogenic activity in animals, probable human carcinogen (Category 2), possible human carcinogen (Category 3), equivocal evidence for carcinogenic activity (Category 4), evidence inadequate for classification (Category 5), carcinogenic activity in animals; probably not a human cancer hazard (Category 6), carcinogenic activity in animals; considered not a human cancer hazard (Category 7), evidence of noncarcinogenicity (Category 8). Evidence useful for categorization includes human studies, animal bioassays, corroborative evidence from bioassays, and mechanistic studies relevant to determining the predictivity of animal responses for human hazard. Weighing this evidence to derive a conclusion about classification is a process that requires expert judgment; it cannot now be reduced to a simple set of decision rules. However, we identify the kinds of information that can be useful in this process, and indicate how each might most appropriately be used.

Animals↗
PubMed1990

Hepatic glutathione, metallothionein and zinc in the rat on gestational day 19 during chronic ethanol administration.

Ethanol, under certain conditions, alters the metabolism of sulfur amino acids, metallothionein (MT) and zinc. If chronic ethanol administration during pregnancy decreases the availability of sulfur amino acids or Zn, this deficiency could contribute to growth retardation of the fetuses, one of the features of fetal alcohol syndrome. The purpose of this study was to discern whether chronic ethanol administration to pregnant rats alters glutathione (GSH), MT or Zn content of selected tissues of the dams and fetuses. Sprague-Dawley rats were fed from gestational days 5 to 19 either the control diet ad libitum (AF), the ethanol diet ad libitum (EF) or the control diet using the pair-feeding technique (PF). On the 19th day of gestation, total hepatic GSH was significantly lower for the EF and PF dams than for the AF dams. Hepatic MT contents were similar for the AF and EF dams, and hepatic MT content was significantly greater for the PF dams than the AF and EF dams. The three groups did not differ regarding hepatic Zn content of dams or fetuses. In summary, on the 19th day of gestation, chronic ethanol feeding of pregnant rats did not lower the maternal hepatic GSH level below that of PF dams, did not induce hepatic MT in the dams and did not prevent fetuses from achieving body weights and hepatic Zn concentrations equal to those of controls.

Animals↗
PubMed1990

Phase II trial of carboplatin in soft-tissue sarcoma.

As part of the Eastern Cooperative Oncology Group program for the assessment of new drugs in sarcomas, a Phase II trial of carboplatin was performed in patients who had received no more than one prior chemotherapy regimen. A total of 50 patients received either 400 mg/m2 or 320 mg/m2 depending on whether they had received prior radiotherapy. A response rate of 16% (95% confidence interval 6-32%) occurred in the 37 patients who had received doxorubicin as their only prior systemic therapy. Three of the six responses were complete and persisted for 7 to 34 months. In contrast none of the 13 patients who received carboplatin after initial progression on doxorubicin and subsequent progression on interferon alpha responded. The overall response rate was therefore 12% (95% confidence interval 5-24%). Toxicity was primarily hematologic, with 14 patients having Eastern Cooperative Oncology Group (ECOG) grade 3 toxicity and no grade 4 or 5 toxicities. In view of the number of complete responses, carboplatin should be studied further in untreated patients with advanced soft tissue sarcoma.

Adult↗