The riminophenazine agents clofazimine and B669 inhibit the proliferation of cancer cell lines in vitro by phospholipase A2-mediated oxidative and nonoxidative mechanisms.

Clofazimine, a riminophenazine antimicrobial agent, and its analogue B669 were investigated for their effects on FaDu cells, a human squamous carcinoma cell line. These agents, at concentrations within the therapeutic range (0.25-2 micrograms/ml), caused a dose-dependent tumor cell cytotoxicosis which was greatly enhanced in the presence of human neutrophils. The neutrophil-mediated increment in tumoricidal activity, but not the direct antitumor effects of the drugs per se, was inhibited by catalase. The effects of these drugs on three more cell carcinoma lines as well as on two primary cultures and a noncarcinoma cell line were also investigated and compared with the activity of the standard antitumor chemotherapeutic agents bleomycin, cisplatin, and methotrexate. All seven cultures were sensitive to clofazimine and B669 compared to six that were sensitive to cisplatin, three that were sensitive to bleomycin, and one that was sensitive to methotrexate. The treatment of FaDu cells with clofazimine and B669 was associated with enhanced activity of phospholipase A2, as evidenced by increased release of radiolabeled arachidonate and lysophosphatidylcholine from membrane phospholipids. Inhibitors of arachidonic acid metabolism, protein kinase C inhibitors, as well as water and lipid soluble antioxidants failed to protect the cells against the cytotoxic activity of clofazimine and B669. However, alpha-tocopherol, a lysophospholipid-complexing agent, completely blocked the antiproliferative effects of the riminophenazines and also protected the cells against the direct cytotoxic effect of lysophosphatidylcholine, while the lysophospholipid-neutralizing enzyme lysophospholipase protected against the riminophenazines. These observations demonstrate that the tumoricidal properties of clofazimine and B669 are probably due to increases in the lysophospholipid content of cell membranes.

Inactivation of poly (ADP-ribose) polymerase by hypochlorous acid.

The effects of the phagocyte-derived reactive oxidants hydrogen peroxide (H2O2) and hypochlorous acid (HOC1) on the activity of poly(ADP-ribose) polymerase (pADP RP), an enzyme involved in DNA repair, and on the induction and repair of DNA strand breaks in human mononuclear leukocytes (MNL) have been investigated in vitro. Exposure of MNL to reagent H2O2 was accompanied by DNA damage and activation of pADP RP. Addition of reagent HOCl (25 microM) was not associated with DNA strand breaks. However, when combined with 150 microM H2O2, HOCl potentiated H2O2-mediated DNA damage, and compromised the repair process. Furthermore, HOCl caused a dose-related decrease in the activity of pADP RP in both control and H2O2-exposed MNL. Interactions between the phagocyte-derived reactive oxidants H2O2 and HOCl are probably involved in the etiology of inflammation-related cancer.

Nutritional status of HIV-1 seropositive patients in the Free State Province of South Africa: anthropometric and dietary profile.

OBJECTIVE: To evaluate the nutritional intake and status of HIV-1 seropositive patients, as well as the relationship between malnutrition and disease stage. DESIGN: A cross-sectional study. SETTINGS: The Immunology Clinic at the Pelonomi Hospital in Bloemfontein, South Africa. SUBJECTS: Eighty-one HIV/AIDS patients in different stages of disease were recruited consecutively from January to May 1995. Eleven of these patients were followed in 1997. MAIN OUTCOME MEASURES: Anthropometric data including current weight, height, triceps skinfold thickness, mid-upper-arm circumference, body mass index and bone-free arm muscle area were collected. Nutrient intake was estimated using a diet history in combination with a standardised food frequency questionnaire. The patients were divided into 3 groups according to their CD4+ T cell counts. RESULTS: The men were leaner (BMI = 18.9) than the women (BMI = 22.7) and patients with a CD4+ T cell count < 200 (stage III) tended to have the lowest median values for all anthropometric measurements. More than half the patients had a low intake (< 67% of the recommended dietary allowances) of vitamin C, vitamin B6, vitamin D, vitamin A, calcium, iron and zinc. CONCLUSIONS: The results confirms that HIV/AIDS patients from this population are malnourished. There was, however, no association between disease stage and nutritional status. Nutritional supplementation of HIV/AIDS patients should be considered, as this might lead to improved immune function in these patients.

Vitamin E protects mononuclear leucocyte DNA against damage mediated by phagocyte-derived oxidants.

The protective effects of physiological concentrations (3-12.5 micrograms/ml) of vitamin E (VE, dl-alpha-tocopherol) on the formation of DNA single-strand breaks in mononuclear leukocytes (MNL) in close proximity to activated phagocytes have been investigated in vitro. Human neutrophils, activated by phorbol myristate acetate (PMA), induced DNA-strand breaks in neighbouring lymphocytes. Vitamin E caused dose-related protection of MNL DNA against phagocyte-mediated oxidative damage. This apparently novel protective activity of vitamin E is due primarily to the inhibitory effects of this agent on the generation of reactive oxidants by activated neutrophils and is apparently unrelated to the classical oxidant-scavenging properties of VE.

Hypochlorous acid potentiates hydrogen peroxide-mediated DNA-strand breaks in human mononuclear leucocytes.

In this study the formation of DNA single-strand breaks in MNL in close proximity to activated phagocytes, or in contact with added H2O2 and/or HOCl, were evaluated. Neutrophils activated by phorbol myristate acetate (PMA), induced DNA-strand breaks in neighboring lymphocytes which increased after 1-2 h incubation in a repair medium. These DNA-strand breaks could be prevented by the addition of catalase or substitution of the neutrophils with cells from a patient with chronic granulomatous disease. Inclusion of the myeloperoxidase (MPO) inhibitor, sodium azide (NaN3), to the system was associated with less damage after 1-2 h incubation and a faster repair rate. Exposure of MNL to added reagent H2O2 (12-100 microM) was also accompanied by DNA damage. Addition of reagent HOCl (3-25 microM) did not induce any DNA-strand breaks. However, when combined with H2O2 (12.5 microM), HOCl increased H2O2-mediated DNA damage and compromised the repair process. Interactions between the phagocyte-derived reactive oxidants H2O2 and HOCl are probably involved in the etiology of inflammation-related cancer.

Nutritional status of HIV-1 seropositive patients in the Free State Province of South Africa--laboratory parameters.

OBJECTIVE: To evaluate the nutritional status of HIV-1 seropositive patients with regards to laboratory parameters; the correlation between nutrient intake and actual values of nutrients, as well as the relationship between malnutrition and disease progression. DESIGN: A cross sectional study. SETTING: The Immunology Clinic at the Pelonomi Hospital in Bloemfontein, South Africa. SUBJECTS: 90 HIV/AIDS patients in different stages of disease were recruited consecutively from January to May 1995. Sixteen patients were followed up in 1997. MAIN OUTCOME MEASURES: The patients were divided into three groups according to their CD4+ T-cell counts, and blood levels of protein, albumin, cholesterol, ferritin, vitamin B12, magnesium, and phosphorus, as well as several micronutrients including vitamin E, vitamin C, beta-carotene and retinol which were determined using standard methods. These values were compared with the normal reference values used in the laboratory, and we tried to correlate these parameters with disease stage, as well as recorded nutrient intake in a subgroup of 35 patients. RESULTS: Abnormal values for several parameters, including plasma-retinol and serum-protein were found, but no correlation between more advanced disease and micronutrient deficiencies could be demonstrated. CONCLUSIONS: HIV/AIDS patients from this population are deficient in several micronutrients, and for some patients this is mirrored by a low intake. Multivitamin/anti-oxidant supplementation of HIV/AIDS patients should be considered, as this could lead to improved immune function in these patients.

Sister chromatid exchanges in lymphocyte cultures of patients previously treated with dibromodulcitol.

Acute non-lymphatic leukaemia and myelodysplasia occur in a larger percentage of patients treated with dibromodulcitol (DBD) than in patients treated with other cytostatics. Sister chromatid exchanges (SCE) in the lymphocytes in peripheral blood as well as other haematological parameters were measured in women with breast cancer to investigate whether women who had previously been treated with DBD as a part of their treatment regime had an increased frequency of SCE or another haematological abnormality attributable to DBD. SCE levels were elevated in women treated with DBD as well as in those treated with other cytostatics compared to the untreated control group. All other haematological parameters were normal. There was no significant difference in the number of SCEs between the patients who received DBD and those treated with other cytostatics. The increased frequencies of SCE in the treated patients are attributable to various cytostatic agents, and there is no significant permanent increase in the frequency of SCE after exposure to DBD.