HCV liver infection and liver steatosis: evidence for indirect mechanisms in genotype 3?

BACKGROUND

Hepatitis C virus (HCV) infection is associated with the appearance of liver steatosis.

AIM

To search for a correlation between the number of HCV infected hepatocytes and the presence, amount and distribution of steatosis.

METHODS

A total of 124 frozen liver biopsies from HCV patients (genotype 3 = 21) were studied. HCV-antigens were detected on frozen liver sections using a four steps immunoperoxidase technique. Steatosis was graded by haematoxilin-eosin counterstaining on a serial section.

RESULTS

Steatosis was detected in 82 of 124 (66.1%) patients without differences between different genotypes. Uric acid, body mass index, gammaGT levels significantly correlated with steatosis in non-3 (P < 0.01, P < 0.05, P < 0.01, respectively) but not in genotype 3 patients. HCV-antigens were detected in 95 of 124 (76.6%) cases. A positive correlation between steatosis and the number of infected hepatocytes was observed only in genotype 3 patients (P = 0.06). In most cases the number of cells with steatosis greatly outnumbered that of HCV infected cells.

CONCLUSION

We confirm a possible role of the virus in the genesis of steatosis in HCV genotype 3 infected patients; however, as steatosis do not appear to be directly related to the presence of HCV-antigens within single hepatocytes, an indirect, possibly cytokine mediated, mechanism might be operative.

Inhibition of lipoxygenase pathway in macrophages co-cultivated with tumor cells

Although there is a great deal of interest in the role played by tumor-associated macrophages in tumor progression, the knowledge of the biological mediators involved in the interplay between macrophages and tumor cells is still limited. In the present study, we investigated whether the lipoxygenase pathway in resident murine peritoneal macrophages is affected by contact with tumor cells of a different origin, e.g. murine B16 melanoma and L929 fibrosarcoma cells, and human Hs294T melanoma and HT1080 fibrosarcoma cells. Our experiments have been carried out by using macrophages co-cultivated with tumor cells at different ratios, in order to simulate the relative proportions between macrophages and tumor cells during the in vivo development of a tumor. Reverse phase HPLC analyses of the lipoxygenase products of resident peritoneal macrophages revealed a rather complex profile characterized by a high level of 12(S)-hydroxyeicosatetraenoic acid and 15(S)-hydroxyeicosatetraenoic acid followed by leukotriene B(4), 5(S)-hydroxyeicosatetraenoic acid, and lipoxins. Macrophages co-cultivated with tumor cells, both murine and human, showed a marked reduction of lipoxygenase products, mainly in the co-cultures where tumor cells prevailed over macrophages. The characteristic profile of macrophage lipoxygenase products was re-established after removal of tumor cells from the co-cultures. The inhibitory effect on lipoxygenase pathways exerted by tumor cells, was not seen when macrophages were co-cultivated with normal primary murine and human fibroblasts.

Stereochemical assignment, antiinflammatory properties, and receptor for the omega-3 lipid mediator resolvin E1

The essential fatty acid eicosapentaenoic acid (EPA) present in fish oils displays beneficial effects in a range of human disorders associated with inflammation including cardiovascular disease. Resolvin E1 (RvE1), a new bioactive oxygenated product of EPA, was identified in human plasma and prepared by total organic synthesis. Results of bioaction and physical matching studies indicate that the complete structure of RvE1 is 5S,12R,18R-trihydroxy-6Z,8E,10E,14Z,16E-EPA. At nanomolar levels, RvE1 dramatically reduced dermal inflammation, peritonitis, dendritic cell (DC) migration, and interleukin (IL) 12 production. We screened receptors and identified one, denoted earlier as ChemR23, that mediates RvE1 signal to attenuate nuclear factor–κB. Specific binding of RvE1 to this receptor was confirmed using synthetic [³H]-labeled RvE1. Treatment of DCs with small interference RNA specific for ChemR23 sharply reduced RvE1 regulation of IL-12. These results demonstrate novel counterregulatory responses in inflammation initiated via RvE1 receptor activation that provide the first evidence for EPA-derived potent endogenous agonists of antiinflammation.

Wine and resveratrol: mechanisms of cancer prevention?

Low alcohol consumption seems to decrease total mortality and to have beneficial properties on cardiovascular disease; data for cancer are still inconclusive. There is evidence that wine consumption decreases the risk of cancer at several sites, including cancer of upper digestive tract, lung, colon, basal cell carcinoma, and non-Hodgkin lymphoma. The presence of resveratrol, a polyphenol specifically present in red wine, may contribute to these cancer preventive effects. Resveratrol in fact inhibits the metabolic activation of carcinogens, has antioxidant and anti-inflammatory properties, decreases cell proliferation and induces apoptosis. Data on the availability of resveratrol in vivo are however still lacking. Although regular consumption of one or two glasses of wine seems reasonably safe from the health point of view, a recommendation to the general population for low wine consumption is not justified.

Persistent contrast enhancement by sterically stabilized paramagnetic liposomes in murine melanoma

In the present research, we investigated the use of paramagnetic liposomes as contrast agents (CAs) for the detection of solid tumors. The liposomes were sterically stabilized by a polyethylene glycol (PEG) coating, and their size was constrained to approximately 100 nm. Dimyristoyl-sn-glycero-3-phosphoethanolamine-N-diethylene-triaminepentaacetate (DMPE-DTPA) was used as the gadolinium-carrying fatty acid chain. The relaxation properties were characterized through nuclear magnetic relaxation dispersion (NMRD) measurements, and analyzed with the use of theories and computer programs that are adequate for slowly rotating systems. Their relaxivity at 1.5 T was found to be acceptable for in vivo use. We then tested the liposomes against B16-F10 murine melanomas using standard T1-weighted schemes at 1.5 T, and concentrations corresponding to 0.03 mmol/kg of gadolinium (i.e., three to six times lower than the concentration of the small gadolinium complexes in clinical use). The blood half-life was found to be 120 +/- 20 min. The experiments show a good contrast enhancement in the tumor (33% +/- 22%) 2 hr after administration, a further increase (43 +/- 27%) 20 hr after administration, and a decrease (25% +/- 14%) 54 hr after administration. High persistence of the CA was also observed in the liver and intestine, as expected in a hepatobiliar excretion pathway.

IFNgamma and TNFalpha account for a pro-clonogenic activity secreted by activated murine peritoneal macrophages

In the present study, we found that murine peritoneal macrophages elicited by BCG or Listeria monocytogenes release into the media an activity capable of stimulating the lung colonization as well as the expression of MHC class I antigens in B16 melanoma cells. A similar activity has previously been found in media conditioned by Corynebacterium parvum-elicited macrophages. Analysis by gel filtration chromatography of media conditioned by Corynebacterium parvum-, BCG- or Listeria monocytogenes-elicited macrophages revealed that the material responsible for the pro-clonogenic activity concentrated in chromatographic fractions corresponding to molecular weights (25 to 52 kDa) which are characteristic of certain cytokines. Thus, we challenged the various macrophage-conditioned media with polyclonal antibodies against IFNgamma and TNFalpha, and found that the macrophage pro-clonogenic activity was completely abolished in the presence of anti-IFNgamma antibodies, but only partially inhibited by anti-TNFalpha antibodies. This finding suggests a cooperative participation of the two cytokines to the pro-clonogenic activity of the media conditioned by Corynebacterium parvum-, BCG- or Listeria monocytogenes-elicited macrophages.

Evaluation of cancer-preventive agents and strategies a new program at the International Agency for Research on Cancer

About five years ago, the International Agency for Research on Cancer (IARC) initiated a new program, IARC Handbooks of Cancer Prevention, aimed at evaluating the evidence base for the cancer-preventive activity of various agents and strategies. To date (2001) 5 volumes have been published--1. Non-steroidalAnti-inflammatory Drugs, 2. Carotenoids, 3. Vitamin A, 4. Retinoids, and 5. Sunscreens--and volume 6 (Weight Control and Physical Activity) is in press. Future volumes will include evaluations of breast cancer screening (vol. 7) and fruits and vegetables (vol. 8).

Allium vegetables and organosulfur compounds: do they help prevent cancer?

Allium vegetables have been shown to have beneficial effects against several diseases, including cancer. Garlic, onions, leeks, and chives have been reported to protect against stomach and colorectal cancers, although evidence for a protective effect against cancer at other sites, including the breast, is still insufficient. The protective effect appears to be related to the presence of organosulfur compounds and mainly allyl derivatives, which inhibit carcinogenesis in the forestomach, esophagus, colon, mammary gland, and lung of experimental animals. The exact mechanisms of the cancer-preventive effects are not clear, although several hypotheses have been proposed. Organosulfur compounds modulate the activity of several metabolizing enzymes that activate (cytochrome P450s) or detoxify (glutathione S-transferases) carcinogens and inhibit the formation of DNA adducts in several target tissues. Antiproliferative activity has been described in several tumor cell lines, which is possibly mediated by induction of apoptosis and alterations of the cell cycle. Allium vegetables and organosulfur compounds are thus possible cancer-preventive agents. Clinical trials will be required to define the effective dose that has no toxicity in humans.

Comparison of fatty acid profile in plasma phospholipids in women from Granada (southern Spain) and Malmö (southern Sweden)

We conducted a first pilot study on healthy women living in two countries with different dietary habits, Granada in the south of Spain and Malmö in the south of Sweden, in order to compare their levels of plasma phospholipid fatty acids, and to examine the relationship between the differences in food consumption. This study is part of a pilot study which is nested in the European Prospective Investigation into Cancer and Nutrition, a multi-centre prospective cohort study on diet, plasma concentrations of antioxidants and fatty acids, and markers of oxidative stress. Thirty-nine women in Granada and thirty-eight women in Malmö, aged 45-50 years (all pre-menopausal) were selected among the female participants in the cohorts from these two countries. Individual measurements of the women's habitual diet were obtained by a food frequency questionnaire. 24-hour diet recalls were used for the standardised measurement of diet at group level. Plasma phospholipid fatty acid composition was determined by capillary gas chromatography. We found a different fatty acid profile in plasma between the two populations, with higher mean levels of palmitic acid (16:0), palmitoleic acid (16:1) (n-7), oleic acid (18:1), alpha-linolenic acid (18:3) (n-3) and eicosapentaenoic acid (20:5) (n-3), and lower mean levels of stearic acid (18:0) in Malmö compared to Granada. Women in Malmö consumed more meat, alcoholic beverages and sugar, and less fish and shellfish than women in Granada. We conclude that the fatty acid composition in plasma phospholipids is different between women from the two European centres. For polyunsaturated fatty acids, differences were observed for (n-3) fatty acids. In relation to these differences, we observed that specific food intakes, particularly meat and fish, varied between the two centres.

Inverse correlation between alcohol consumption and lymphocyte levels of 8-hydroxydeoxyguanosine in humans

In a cross-sectional study of 115 premenopausal non-smoking women, we examined the relationship between lymphocyte levels of 8-hydroxy-2'-deoxyguanosine (8-oxodGuo) and habitual alcohol consumption. The study was conducted in four different regions of Europe, including Potsdam (Germany), Turin (Italy), Malmö (Sweden) and Granada (Spain). Mean 8-oxodGuo levels differed significantly across study centres (P = 0.001), with the highest levels in Granada [2.17 8-oxodGuox10(-6) 2'-deoxyguanosine (95% confidence interval 1.27-4.40)] and lowest levels in Turin [1.19 (0.36-4.29)]. Mean levels of total alcohol intake and of types of alcoholic beverages consumed (wine, fortified wines, beer and cider) also differed across the study centres (P < 0.05), with the highest total alcohol consumption in Turin, and the lowest intake in GRANADA: When combining all the data, but adjusting for study centre, individual 8-oxodGuo level correlated inversely with alcohol intake. This inverse association remained unaltered after further adjustment for Quetelet Index, fruit and vegetable consumption, and plasma carotenoid levels. Furthermore, the inverse association was also observed for each of the study centres separately, and for different beverage types, with the exception of Granada, where the majority of women were non-drinkers and where alcohol intakes were also very low for the consumers. Finally, on a group level, mean levels of 8-oxodGuo and alcohol intake were also inversely associated between the four study centres. The finding of a relationship between alcohol consumption and 8-oxodGuo in lymphocytes was unexpected and not based on a prior hypothesis. This finding consequently requires confirmation from a randomized intervention study.

Prevention of disease with pharmaceuticals

The idea that diseases such as cardiovascular disease and cancer can be prevented by taking a 'pill' is attractive to many people. Chemoprevention is an established method in the primary and secondary prevention of cardiovascular disease such as myocardial infarct and stroke. Clinical trials have demonstrated beyond reasonable doubt that both fatal and non-fatal coronary events and strokes can be prevented. Antihypertensive drugs have been shown to be effective through clinical trials in preventing myocardial infarctions, stroke and other cardiovascular morbidity and mortality. Statins are commonly used to lower the blood cholesterol concentration, and aspirin is widely used to prevent occlusive vascular disease. Aspirin and other non-steroidal antiinflammatory agents have shown promise in the chemoprevention of colorectal cancer. While observational epidemiological studies have consistently suggested that diets rich in antioxidants such as beta-carotene might be useful in preventing coronary heart disease and cancer, the published reports of randomized trials clearly indicate that beta-carotene supplements are of no value in persons of high risk for such conditions. Although the chemoprevention of cancer is decades behind that of cardiovascular disease, there is no reason to believe that progress in cancer chemoprevention will differ substantially from that in cardiovascular disease. Better understanding of the molecular steps critical to carcinogenesis should open new avenues for cancer chemoprevention.

Plasma carotenoids in relation to food consumption in Granada (southern Spain) and Malmö (southern Sweden)

We conducted a cross-sectional pilot study on healthy pre-menopausal women (aged 45-50 years) living in Granada, in the south of Spain (n = 39) and Malmö, in the south of Sweden (n = 38) in order to compare their plasma carotenoid levels and to investigate the relationship between the differences in food consumption. Plasma concentrations of six carotenoids were measured using high performance liquid chromatography, habitual diet (at individual level) was estimated by food frequency questionnaires and 24-hour diet recalls were used for standardised measurement of diet at group-level. We found that women in Granada consumed more fruit and vegetables than women in Malmö. Plasma concentrations of beta-cryptoxanthin, lycopene, zeaxanthin, total carotenoids and alpha-tocopherol were higher in Granada than in Malmö, although plasma concentrations of alpha-carotene and retinol were higher in Malmö. Both within and between study centres, consumption of fruit and vegetables correlated positively with plasma concentrations of different carotenoids. The study showed that differences in consumption of fruit and vegetables between the two European centres were reflected in plasma carotenoid concentrations.

Biological properties associated with the enhanced lung-colonizing potential in a B16 murine melanoma line grown in a medium conditioned by syngeneic Corynebacterium parvum-elicited macrophages

A previous study by our laboratory showed that the peritoneal murine Corynebacterium parnum-elicited macrophages released into their growth medium an activity which enhanced the ability of B16-F10 melanoma cells to form experimental metastases in the lung of syngeneic mice. In the present study, we used a clone of B16-F10 line (F10-M3 cells) to investigate whether the increase in lung-colonizing potential due to the pro-clonogenic activity released by C. parvum-elicited macrophages was associated with biological properties characteristic of a metastatic phenotype. We have found that the pulmonary retention, growth rate in lung parenchyma, invasiveness through Matrigel, adhesiveness to IL-1-activated endothelium and MHC class I expression were increased in F10-M3 cells stimulated by the macrophage pro-clonogenic activity. By using an in vitro experimental protocol, the enhancement of lung-colonizing potential in the stimulated melanoma cells turned out to be a transient phenomenon as was the increase of invasiveness through Matrigel and the higher expression of MHC class I antigens. In conclusion, the melanoma cells stimulated by the pro-clonogenic activity released by C. parvum-elicited macrophages showed changes in biological parameters which are relevant to metastatic diffusion. These changes appeared as a temporary phenomenon which sustains the view that the metastatic phenotype represents a transient biological character influenced by host factors.

An international evaluation of the cancer-preventive potential of sunscreens

The IARC convened a working group of experts in Lyon, France, on 10-18 April, 2000, to evaluate the cancer-preventive activity of sunscreens and to compile the fifth volume of the IARC Handbooks of Cancer Prevention. The working group concluded that the topical use of sunscreens reduces the risk of sunburn in humans and that sunscreens probably prevent squamous-cell carcinoma of the skin when used mainly during unintentional sun exposure. No conclusion can be drawn about the cancer-preventive activity of topical use of sunscreens against basal-cell carcinoma and cutaneous melanoma. Use of sunscreens can extend the duration of intentional sun exposure, such as sunbathing. Such an extension may increase the risk for cutaneous melanoma. The working group warned against relying solely on sunscreens for protection from UV radiation.

Cancer-preventive effects of sunscreens are uncertain

Provocative findings have been published suggesting that the use of sunscreens may promote skin cancer. A recent meeting of international experts on the use of sunscreens and skin cancer was held at the International Agency for Research on Cancer in Lyon. The workshop concluded that the topical use of sunscreens reduces the risk of sunburn and that sunscreens probably prevent squamous-cell carcinoma of the skin when used mainly during unintentional sun exposure. No conclusion could be drawn about the cancer-preventive activity of topical sunscreens against basal-cell carcinoma and cutaneous melanoma. The use of sunscreens can extend the duration of intentional sun exposure, such as sunbathing. Such an extension may increase the risk for cutaneous melanoma. The workshop warned against relying solely on sunscreens for protection from ultraviolet radiation.

The change in leukotrienes and lipoxins in activated mouse peritoneal macrophages

The aim of this study was to investigate to what extent the generation of leukotrienes (LTs) and lipoxins (LXs) was affected by the expression of definite levels of macrophage activation. We used a system of murine peritoneal macrophages at different states of activation consisting in resident macrophages and FCS-, thioglycollate- or Corynebacterium parvum-elicited macrophages. The profile of lipoxygenase metabolites in resident macrophages was characterized by the presence of high levels of 12-HETE, followed by 15-HETE, 5-HETE, LTB(4) and 6-trans-LTB(4), 6-trans-12-epi-LTB(4). A comparable pattern was also found in FCS-elicited macrophages which appeared not to be responsive to the challenge with interferon gamma plus LPS, as measured by the generation of NO and tumor necrosis factor alpha. Resident as well as FCS-elicited macrophages also generated appreciable quantities of LXs (A(4) and B(4)). Thioglycollate-elicited macrophages, which expressed a state of 'responsive' macrophages, showed a block of the LT and LX synthesis. This block was also present in C. parvum-elicited macrophages which expressed a fully 'activated' phenotype, reflected by their capacity of releasing NO and tumor necrosis factor alpha even though they were not challenged. These results provide the first evidence that the level of 'responsive' as well as 'activated' macrophages was associated with of a simultaneous block of LTB(4) and LXs.

Oxidative DNA damage in human lymphocytes: correlations with plasma levels of alpha-tocopherol and carotenoids

In order to investigate whether oxidative damage is associated with differences in antioxidant intake, we measured the levels of 8-oxo-7, 8-dihydro-2'-deoxyguanosine (8-oxodGuo) in lymphocytes and alpha-tocopherol and several carotenoids in plasma of women with different dietary habits. We found that women from Granada (Spain), a region with a typically Mediterranean diet, had significantly higher levels of 8-oxodGuo compared with Malmö (Sweden), a region with a Northern European dietary intake pattern (2.30 +/- 0.78 versus 1.59 +/- 1.01 8-oxodGuo/10(-6) deoxyguanosine). Levels of plasma alpha-tocopherol and carotenoids were higher in Granada and these values were significantly positively correlated with levels of 8-oxodGuo. Our results do not support the hypothesis that a Mediterranean diet rich in alpha-tocopherol and carotenoids protects cells against oxidative DNA damage. It is possible, however, that consumption of foods other than fruits and vegetables, including fats, are responsible for the higher levels of 8-oxodGuo in Granada. Further studies are warranted to better elucidate the role of antioxidants in the modulation of oxidative stress in vivo.

Cytotoxicity and site-specific DNA damage induced by nitroxyl anion (NO(-)) in the presence of hydrogen peroxide. Implications for various pathophysiological conditions

Nitroxyl anion (NO(-)), the one-electron reduction product of nitric oxide (NO(.)), is formed under various physiological conditions. We have used four different assays (DNA strand breakage, 8-oxo-deoxyguanosine formation in calf thymus DNA, malondialdehyde generation from 2'-deoxyribose, and analysis of site-specific DNA damage using (32)P-5'-end-labeled DNA fragments of the human p53 tumor suppressor gene and the c-Ha-ras-1 protooncogene) to study the effects of NO(-) generated from Angeli's salt on DNA damage. It was found that strong oxidants are generated from NO(-), especially in the presence of H(2)O(2) plus Fe(III)-EDTA or Cu(II). NO(.) released from diethylamine-NONOate had no such effect. Distinct effects of hydroxyl radical (HO(.)) scavengers and patterns of site-specific DNA cleavage caused by Angeli's salt alone or by Angeli's salt, H(2)O(2) plus metal ion suggest that NO(-) acts as a reductant to catalyze the formation of the HO(.) from H(2)O(2) plus Fe(III) and formation of Cu(I)-peroxide complexes with a reactivity similar to HO(.) from H(2)O(2) and Cu(II). Angeli's salt and H(2)O(2) exerted synergistically cytotoxic effects to MCF-7 cells, determined by lactate dehydrogenase release assay. Thus NO(-) may play an important role in the etiology of various pathophysiological conditions such as inflammation and neurodegenerative diseases, especially when H(2)O(2) and transition metallic ions are present.

Induction of DNA strand breakage and base oxidation by nitroxyl anion through hydroxyl radical production

Nitroxyl anion (NO-), the one-electron reduction product of nitric oxide (NO*), has been reported to be formed under various physiological conditions and to be cytotoxic, although the mechanism responsible for the toxic effects has not been identified. We have studied the effects of NO- generated from Angeli's salt (sodium trioxodinitrate) or Piloty's acid (N-hydoxybenzenesulfonamide) on DNA strand breakage and DNA base oxidation in vitro. Induction of strand breakage was dose- and time-dependent upon incubation of plasmid pBR322 with Angeli's salt or Piloty's acid. Similarly, 8-oxo-2'-deoxyguanosine and malondialdehyde were formed when calf-thymus DNA or 2'-deoxyribose, respectively, were incubated with Angeli's salt. Electron acceptors (ferricyanide, 4-hydroxy-TEMPO), that convert NO to NO*, inhibited the reactions, indicating that NO , but not NO*, is responsible for the reactions. Furthermore, the reactions were also inhibited by the presence of hydroxyl radical (HO*) scavengers, antioxidants, metal chelators and superoxide dismutase and catalase, implying involvement of free HO*. These results suggest that NO- is a possible endogenous source of HO*, that may be formed either directly from the reaction product of NO- with NO* (N2O2*-) or indirectly through H2O2 formation. Thus NO may play an important role as a cause of diverse pathophysiological conditions such as inflammation and neurodegenerative diseases.

Urinary excretion of 5-(hydroxymethyl) uracil in healthy volunteers: effect of active and passive tobacco smoke

The urinary excretion of 5-(hydroxymethyl)uracil (5-HMUra), one of the major oxidative modifications of thymine, was investigated in 134 healthy volunteers living in North Italy. Overnight urine was collected, and a questionnaire was completed on smoking habits and exposure to environmental tobacco smoke (ETS). 5-HMUra was analyzed by GC/MS, following urine purification by HPLC. 5-HMUra excretion showed an approximately normal distribution, ranging from 0.08 to 0.84 (mean 0.44) nmoles/kg/8 hr and from 3.2 to 18.7 (mean 8.5) nmoles/mmoles creatinine. 5-HMUra excretion was significantly higher in women than in men and in smokers than in non-smokers when results were expressed as the ratio to creatinine. Slightly higher levels of 5-HMUra excretion, expressed as nmoles/mmoles creatinine, were also found in subjects highly exposed to ETS, monitored either as the number of hours of exposure or as the number of smokers in the workplace and at home. Our results show that the urinary excretion of 5-HMUra is higher than that of other oxidized nucleobases, including 8-oxo-7,8-dihydroguanine, and can be slightly modified by environmental factors such as tobacco smoke. These findings suggest that measurement of urinary excretion of 5-HMUra could be useful as a biomarker of oxidative DNA damage and repair, though further research is needed to support these data.

Observation and prevention of an artefactual formation of oxidized DNA bases and nucleosides in the GC-EIMS method

Gas chromatography coupled to electron impact mass spectrometry (GC-EIMS) analysis following hydrolysis of DNA is a widely used assay for the detection of oxidized nucleobases and nucleosides. However, evidence was recently provided for an oxidation of guanine residues of hydrolysed DNA during the silylation prior to GC-EIMS analysis. This reaction accounts for the overestimation of the yield of 8-oxo-7,8-dihydroguanine by GC-EIMS. In the present work, we showed that adenine, cytosine, thymine and thymidine also give rise to oxidized derivatives during the derivatization. This was inferred from the measurement of the amount of 5-formyluracil, 5-hydroxymethyluracil, 5-hydroxycytosine (5-OHCyt), 8-oxo-7,8-dihydroadenine (8-OxoAde) and 5-hydroxymethyl-2'-deoxyuridine (5-HMdUrd) in a series of experiments based on the use of purified bases and nucleosides. Isotopically labelled oxidized bases and 5-HMdUrd were used as internal standards to control the quantitative aspect of the silylation reaction. Support for an artefactual oxidation of hydrolysed DNA was provided by the comparison of the amount of 8-OxoAde and 5-OHCyt detected within native and gamma-irradiated DNA by HPLC-EC and GC-EIMS. To prevent the artefactual formation of oxidized bases during the silylation, an approach based on an HPLC prepurification was developed to remove the precursors of the oxidized bases measured in the DNA sample. The HPLC/GC-EIMS assay was successfully applied to the quantitation of 8-OxoAde and 5-OHCyt in calf thymus DNA. In addition, the detection of the dose-dependent formation of 5-HMdUrd in isolated DNA exposed to ionizing radiation was achieved using the same approach.

5-Hydroxymethyluracil excretion, plasma TBARS and plasma antioxidant vitamins in adriamycin-treated patients

The thymine oxidative lesion-5-hydroxymethyluracil (HMUra)-was measured in urine collected from cancer patients. These patients all received chemotherapy using Adriamycin. Adriamycin (ADR) intercalates DNA coils and interferes with normal cell metabolism through diverse biochemical mechanisms that may explain its different actions. The anticancer action of ADR could derive from its interaction with topoisomerase II, resulting in DNA nicking followed by DNA fragmentation and apoptosis. Side effects of ADR-mainly its cardiotoxicity-may derive from the fact that ADR generates superoxide and hydroxyl radicals in two ways: redox-cycling and a Haber-Weiss type reaction due to Fe-ADR complexes. The oxygen free radicals, particularly .OH, are thought to be produced by ADR directly in genomic material and attack all its components. 5-Hydroxymethyluracil is a thymine lesion provoked by these attacks, and it has been proposed as a marker of DNA alterations. In this article, we report the results of a study involving 14 cancer patients treated with ADR. We found that urine HMUra is significantly increased by the anticancer therapy (HMUra (nmol/24 h): 74.4 9.46 vs. 96.3 8.74; p < .01), this increase reveals a higher risk of mutagenesis. Our study is the first to show an in vivo alteration of DNA by ADR. Results also show that thiobarbituric acid reactants increase significantly, and that the vitamin levels for retinol and alpha-tocopherol, which are antioxidant vitamins, are lower at the end of chemotherapy. We suggest to supplement these patients with vitamins A and E, and selenium to reduce the side effects of ADR.

Effect of route of administration of environmental methylating agents on 7-methylguanine formation in white blood cells and internal organs: implications for molecular epidemiology

The measurement of 7-methylguanine (7-meG) in white blood cells (WBC) is a promising biomarker of individual human exposure to environmental methylating agents. To test the validity of using WBC as a surrogate dosimeter for internal tissues, levels of 7-meG were measured in rat WBC, liver and target organs for carcinogenesis 16 h after oral administration of several methylating carcinogens (DMN, DMH, NNK, NMBA). 7-MeG was detected in WBC DNA but levels were far lower than in internal organs. While the ratio between 7-meG formation in target organs and WBC was highly variable depending on the carcinogen administered, the ratio between 7-meG in the liver and WBC was in the same order of magnitude for each carcinogen, ranging from 81 to 143. In addition, levels of 7-meG in the liver and WBC within individual animals were highly correlated (r = 0.94, P < 0.0001). These results confirmed our previous observations with the same carcinogens after intraperitoneal injection. In order to assess if the lower level of 7-meG in WBC was a result of a low metabolism of methylating agents in WBC, microsomes were prepared from control rat lymphocytes and DMN demethylase activity was measured. The total amount of microsomal proteins was extremely low, especially in comparison with hepatic cells, and the enzymatic activity was less than 0.48 nmol HCHO/min/mg protein, while an activity of 1.26 nmol HCHO/min/mg protein was measured in liver microsomes. Taken together, these results suggest that the presence of 7-meG in WBC DNA reflects an exposure to methylating agents; the level of 7-meG in WBC seems predictive of the level of adduct in the liver, possibly because active methylating species are formed in the liver and then transferred into the hepatic circulation, where the WBC are exposed. It is now important to examine this relationship in humans where exposures are generally to lower levels of carcinogens over long time periods.

7-Methyldeoxyguanosine as a marker of exposure to environmental methylating agents

7-Methyldeoxyguanosine (7-medG) may be a useful marker of human exposure to methylating agents at the individual level. Methods of detection, including 32P-postlabeling, HPLC with electrochemical or fluorescence detection, and immunoassays, are critically summarized. These methods have been applied to the analysis of 7-medG in human samples, resulting from environmental exposure or endogenous processes. Detectable levels of adduct have been demonstrated in several tissues (liver, lung, bronchial, pancreas) and peripheral white blood cells. Studies are in progress to verify the possible use of white blood cells as a surrogate for internal organs.

Comparison of 7-medG formation in white blood cells, liver and target organs in rats treated with methylating carcinogens

The relationship between 7-methylguanine (7-meG) formation in white blood cells (WBC) and internal organs after treatment with methylating carcinogens has been studied in rats, in order to assess the possible use of WBC as a surrogate for target organs in epidemiological studies. Animals were treated with a single intraperitoneal injection of DMN, DMH or NMBA or with a subcutaneous injection of NNK, at different dose levels, and killed 16 h after treatment. 7-meG, following thermal hydrolysis and immunopurification, was analysed by HPLC with electrochemical detection. Administration of methylating carcinogens resulted in the dose-dependent formation of 7-meG in WBC DNA; the adduct level, however, was markedly lower than in internal organs. The ratio between 7-meG formation in target organ and WBC was a function of the carcinogen administered, varying from 3.6 with NNK to 200 with NMBA. On the other hand, the ratio between 7-meG in the liver and WBC was of the same order of magnitude for each carcinogen, ranging from 35 to 100. These results show that the presence of 7-meG in WBC DNA is indicative of adduct formation in internal organs, particularly in the liver, and suggest that active methylating species may be formed in the liver and then transferred to the WBC where they can methylate DNA.

Rectal proliferation and polyp occurrence in patients with familial adenomatous polyposis after sulindac treatment

BACKGROUND/AIMS

Sulindac, a nonsteroidal anti-inflammatory drug (NSAID), decreases the occurrence of polyps in patients with familial adenomatous polyposis (FAP). The effects of colectomy with ileorectal anastomosis (IRA) and sulindac treatment on rectal mucosa proliferation and polyp occurrence were examined in patients with FAP.

METHODS

The number and size of rectal polyps were measured with colonoscopy. The labeling index, the percentage of labeled cells per crypt compartment, was assessed in rectal biopsy specimens with [3H]thymidine incorporation and autoradiography in 6 non-IRA and 14 IRA patients before and after treatment with 200 mg of sulindac/day for 60 days.

RESULTS

The IRA patients had a lower labeling index and a decrease in the percentage of labeled cells in the upper compartment of the crypt (P < 0.01) relative to non-IRA subjects. Sulindac did not influence the labeling index and the distribution of labeled cells along the crypt. On the contrary, a dramatic decrease in the size and number of polyps was observed after sulindac treatment (P < 0.001).

CONCLUSIONS

The persistence of a abnormal mucosal proliferation after sulindac therapy, in spite of the reduction of polyp number, suggests caution in assuming a lower risk of rectal cancer in patients with FAP.

Quantification of 7-methyldeoxyguanosine using immunoaffinity purification and HPLC with electrochemical detection

7-Methylguanine (7-meG) could be a useful marker of recent past exposure to environmental methylating agents for use in epidemiological studies. A method is described that is appropriate for such an application. 7-meG was released from DNA by thermal hydrolysis under conditions (pH 9, 70 degrees C, 8 h) that preferentially released the base from DNA rather than RNA and, following immunopurification using antibodies specific for this DNA adduct, quantification was achieved either by HPLC with electrochemical detection (ECD) or by ELISA. The detection limits of the two approaches were 0.5 and 2 pmol 7-meG/DNA sample respectively. 7-meG was analysed in DNA samples contaminated with known amounts of RNA to test the possible interference in the analysis by the minor modified nucleoside 7-methylguanine, which is present as a normal component of RNA. 7-meG levels measured in human pancreas and untreated rat liver DNA were between 2 and 7 pmol 7-meG/mumol guanosine and this level could not be explained by RNA contamination. The combination of immunoaffinity purification and HPLC with ECD provides a method that is sensitive and specific for 7-meG and suitable for integration into molecular epidemiological studies.

Rats fed high starch diets have lower colonic proliferation and fecal bile acids than high sucrose-fed controls

We studied the effects of sucrose or starch in the diet (460 g/kg diet) on fecal bile acid concentrations in Sprague Dawley rats after 4 wk of feeding. Total bile acid concentration in the feces was significantly lower in the rats fed the starch diet than in those fed the sucrose diet (4.56 +/- 0.47 mg/g dry weight and 8.03 +/- 0.94, respectively, SEM), due to a reduction of deoxycholic, alpha-muricholic and beta-muricholic acids. Fecal and cecal pH values were significantly lower in the rats fed the starch diet compared to those fed the sucrose diet (6.79 +/- 0.08 and 7.15 +/- 0.09 for fecal pH and 7.02 +/- 0.05 and 7.2 +/- 0.04 for cecal pH in the two diet groups, respectively). Colon proliferation was also significantly lower in the starch-fed rats compared to those fed sucrose (labeling index 3.51 +/- 0.6 and 5.69 +/- 0.74, respectively), and the reduction was apparent in the middle and upper compartments of the colon crypts. The mucosal proliferation, expressed as percentage of labeled cells in the upper compartment of the colon crypts, was positively correlated with the concentration of deoxycholic, lithocholic, alpha-muricholic, beta-muricholic, cholic and total bile acids in the feces (per gram wet weight). The results indicate a protective effect of starch versus sucrose diets on colon mucosa.

Mitotic activity in colorectal mucosa of healthy subjects in two Italian areas with different dietary habits

The proliferative activity was evaluated in colorectal biopsies of 39 healthy subjects living in two distinct geographical areas, Trieste in northern and Florence in central Italy. Subjects living in Trieste had a significantly higher mitotic activity compared with subjects living in Florence (mitoses/cells counted x 100 were 0.17 +/- 0.04 in Trieste and 0.089 +/- 0.02 in Florence). The results of a dietary questionnaire also showed that subjects in Trieste consumed significantly fewer starches, fibers, nitrites, and proteins. However, no correlation was evident between the consumption of these nutrients and intestinal proliferation.

The growth of preneoplastic lesions by 1,2-dimethylhydrazine in rat colon is inhibited by dietary starch

The effect of dietary starch and sucrose on colon proliferation and the growth of foci of dysplastic crypts in the colon (FDC) were studied in female Sprague-Dawley rats, treated p.o. with 1,2-dimethylhydrazine (DMH). The animals were fed for 30 and 105 days with high fat (23% w/w corn oil) diets in which carbohydrates were represented by corn starch (starch diet) or sucrose (sucrose diet) (46% w/w). After 105 days of feeding, proliferation was markedly reduced in animals fed the starch diet. The number of FDC was not significantly affected by dietary treatments. However, after 30 and 105 days the percent of small FDC (formed by one-two dysplastic crypts) was higher in the animals fed the starch diet when compared to the sucrose diet. In the cecum of the animals fed the starch diet the percent of butyrate, propionic, isovaleric, and valeric over total short-chain fatty acids (SCFA) was increased, whereas the percent of acetic acid was decreased. Cecal pH was also decreased in the animals fed starch. The results suggest that starch diets have a protective role against DMH-colon carcinogenesis in the rat, mediated by a drop in cecal pH and an increased concentration of some SCFA.

Profile of short-chain fatty acids and rectal proliferation in rats fed sucrose or cornstarch diets

Rats were fed high fat (231 g/kg diet), low calcium (1.3 g/kg diet), low cellulose (20 g/kg diet) diets in which carbohydrates were represented by sucrose or starch (460 g/kg diet). A subgroup of animals was treated with 1,2-dimethylhydrazine (DMH) twice, 4 and 8 d before the beginning of the dietary treatments. Animals fed the starch diet, compared with those fed the sucrose diet, had higher concentrations of cecal and fecal short-chain fatty acids and a significantly lower acetic acid:butyric acid ratio in the cecal contents at d 105. Ratios were 14.7 +/- 1.7 and 6.8 +/- 0.4 for rats fed the sucrose and starch diets, respectively (P less than 0.01). Cecal pH was significantly lower in animals fed the starch diet for 105 d. At d 105, rectal proliferation was lower in rats fed the starch diet (labeled cells/crypt were 7.89 +/- 0.56 and 3.57 +/- 0.40 for rats fed the sucrose and starch diets, respectively, P less than 0.01); at d 30 the effect of starch on proliferation was evident in controls but not in DMH-treated rats. Rectal proliferation data were negatively correlated with the concentration and percentage of butyric acid and positively correlated with the percentage of acetic acid, the acetic acid:butyric acid ratio and cecal pH. These results suggest that low rectal proliferation in animals fed a high fat, high starch diet might be associated with a lower relative concentration of butyric acid in the cecal contents.

Gastric hyperplastic changes and thymidine uptake after partial gastrectomy in rats

Foveolar hyperplastic changes have been recently considered to be the most distinctive histological findings following partial gastrectomy, and their relationship to bile reflux has been proven. The present study was undertaken in order to determine whether an increase in 3H-thymidine uptake, which is an expression of increased gastric mucosal proliferative activity, might correspond to these hyperplastic changes. Histology and thymidine uptake values were assessed and compared in nineteen rats operated upon either with a Polya gastrectomy (11) or with a Roux-en-Y biliary diversion (8). Thymidine uptake values and the extent of gastric hyperplastic changes were greater in the Polya than in the Roux-en-Y group. Moreover, a significant correlation was found between thymidine uptake values and the extent of hyperplastic changes. Therefore, the relationship between hyperplastic changes and increased mucosal proliferative activity post-gastrectomy would seem to have been proven. Since bile acids have been shown to be able to stimulate cell proliferation in ileal and colonic mucosa, a role for bile reflux in the increased cell proliferation activity in the gastric stump can be hypothesized.

Effect of dietary carbohydrates on the growth of dysplastic crypt foci in the colon of rats treated with 1,2-dimethylhydrazine

The effect of dietary starch and sucrose on the growth of foci of dysplastic crypts in the colon (FDC) was studied in female Sprague Dawley rats treated twice p.o. with 25 mg/kg of 1,2-dimethylhydrazine (DMH). After DMH administration, the animals were fed high-fat (23% corn oil, w/w)/low-calcium (0.1%, w/w)/low-cellulose (2%, w/w) diets in which carbohydrates were represented by corn starch (starch diet) or sucrose (sucrose diet) (46%, w/w). The animals were fed for either 30 or 105 days with the experimental diets. The number of FDC was not significantly affected by diet. However, after 30 days the percentage of small FDC (formed by 1-2 dysplastic crypts) was higher in the animals fed the starch diet compared to the animals fed the sucrose diet [90.3 +/- 1.1% (SE) and 82.6 +/- 3.1%, respectively; P less than 0.05]. In contrast, foci formed by 3-4 dysplastic crypts were decreased by the starch diet (P less than 0.05). After 105 days of feeding, the starch diet induced a number of dysplastic crypts/focus lower than that induced by the sucrose diet (2.6 +/- 0.1 and 2.9 +/- 0.1, respectively; P less than 0.05). The percentage of small FDC was also higher in the animals fed the starch diet compared to animals fed the sucrose diet (P less than 0.01). After 30 days of feeding, DMH treatment increased colon proliferative activity in both dietary groups (P less than 0.05). But after 105 days of feeding, proliferation was similar in controls and DMH-treated rats and markedly reduced in animals fed the starch diet (mean labeling index values for both controls and DMH-treated rats were 10.4 +/- 0.8 and 4.4 +/- 0.5 in the sucrose and starch diets, respectively; P less than 0.001). The overall results suggest that starch in high-fat/low-calcium/low-cellulose diets has a protective role against DMH-colon carcinogensis in the rat.

Mucosal cell proliferation of the rectal stump in ulcerative colitis patients after ileorectal anastomosis

The proliferative activity and polyamine levels of the rectal epithelium in unoperated ulcerative colitis patients and in ulcerative colitis patients after total colectomy and ileorectal anastomosis were determined and compared with control subjects. Cell proliferation was evaluated in rectal biopsies by in vitro 3H thymidine incorporation by measuring the labeling index and the position of labeled cells along the crypt; polyamines were determined with a chromatographic method. In ulcerative colitis patients the labeling index was significantly increased, and labeled cells were shifted toward the upper part of the crypt when compared with controls. Ileorectal anastomosis patients showed a normalization of the labeling index and a distribution of labeled cells similar to controls. Polyamine levels were also increased in ulcerative colitis patients; in ileorectal anastomosis patients, the level of polyamines was decreased in respect to unoperated patients and return to normal values except for spermine. Because the increased proliferation and higher polyamine levels are related to increased colon cancer risk, our results confirm that ulcerative colitis is a risk factor for the development of carcinoma. Ileorectal anastomosis may reduce this risk through a normalization of mucosal cell proliferative activity and of some polyamine levels.

Starchy foods and colon proliferation in mice

The effect of starch contained in different foods on colonic proliferation was studied in C57BL/6N mice after four weeks of feeding with 20% fat diets containing cornstarch, white bread, pasta, and rice; an equicaloric amount of sucrose was used in a control diet. Cell proliferation was evaluated in different subsites of the colon (rectal end, mid colon and cecal end) by colchicine arrest and [3H]thymidine incorporation. The following parameters were analyzed: mitotic index (MI), labeling index (LI), and the distribution of labeled cells along the crypt. Different results were obtained in the different subsites. At the rectal end of the colon, all diets containing starch lowered cell proliferation compared with the sucrose diet. The values for MI in the different diets were 2.56 +/- 0.22, 1.73 +/- 0.30, 1.37 +/- 0.19, 1.61 +/- 0.29, and 1.29 +/- 0.31 for control, cornstarch, white bread, pasta, and rice, respectively. Values are means +/- SE (n = 10). The values for LI showed a similar pattern. In the mid colon, the MI was significantly lowered only by the diet containing rice, whereas the DNA synthetic activity (LI) was lowered by cornstarch, pasta, and rice. Toward the cecal end, we observed a significant reduction in MI with diets containing pasta and rice and in the LI with diets containing pasta. The distribution of the LI along the crypt in the different subsites was not significantly affected by experimental dietary variations. The results suggest that starch from different dietary sources might reduce colon proliferation in the mouse.

Effect of dietary lipids on hepatic and intestinal monooxygenases in mice

The effect of dietary lipids on hepatic and intestinal monooxygenases was studied by feeding C57BL/6N mice (for 2 wks) diets containing 5% and 23.5% (wt/wt) olive oil or corn oil. At the end of the feeding period, we measured arylhydrocarbon hydroxylase (AHH) activity in S9 preparations from liver, small intestine, and colon; and, using the same S9 preparations from the liver, we observed the activation of the following three dietary promutagens: 2-amino-3-methylimidazo(4,5-f)quinoline, 2-amino-3,8-dimethylimidazo(4,5-f) quinoxaline, and 2-amino-6-methyldipyrido(1,2-a:3',2'-d)imidazole. The results showed that high-fat diets increased hepatic AHH activity both in corn oil and olive oil diets compared with the low-fat diets; also, a 5% corn oil diet had significantly higher AHH activity compared with the 5% olive oil diet. AHH activity was, respectively, 48.6 +/- 5.1 and 79.5 +/- 11.4 pmol 3OH-benzo[a]pyrene formed/mg/min in the 5% and 23.5% olive oil diets and 66.1 +/- 5.1 and 83.9 +/- 12.2 in the 5% and 23.5% corn oil diets; values are means +/- SE, n = 16. The results also showed a significant increase in the ability of hepatic S9 fractions from animals on high-fat diets to activate promutagens in the Salmonella/plate test. On the contrary, AHH activity in the small intestine and colon was not affected by the fat content of the diet.

Effect of dietary fat, starch and cellulose on fecal bile acids in mice

The effect of dietary fat, starch and cellulose on individual and total fecal bile acids was studied in mice after 4 wk of feeding diets containing different levels of fat (5 and 29%), starch (3, 36 and 57-65%) and cellulose (2 and 10%). Diet affected the fecal concentration of deoxycholic acid, beta-muricholic acid and total bile acids. Increasing dietary fat from 5 to 29% significantly increased the level of deoxycholic acid and total bile acids. An increase in dietary cellulose from 2 to 10% significantly decreased the level of deoxycholic acid, beta-muricholic acid and total bile acids. High levels of dietary starch (36 and 57-65%) did not significantly affect the excretion of deoxycholic, beta-muricholic and total fecal bile acids. Starch was able to bind bile acids in vitro and to affect the level of fecal free bile acids. In high fat diets, the level of free bile acids was lower in the feces of animals fed 36% starch diets than in those fed 3% starch diets. This reduction of free bile acids was accompanied by a reduction in colon proliferative activity. We suggest that free, rather than total, bile acids are the effective damaging agents for colon mucosa, and may represent a risk factor in the development of cancer.

Proliferative activity in the colon of the mouse and its modulation by dietary starch, fat, and cellulose

The effect of dietary starch, fat, and cellulose on colonic proliferation was studied in female C57Bl/6J mice after 4 weeks of feeding with diets containing various levels of starch (3, 36, and 57-65%), various levels of fat (corn oil, 5 and 29%) and various levels of cellulose (2 and 10%). Cell proliferation was measured by colchicine arrest and [3H]thymidine incorporation. The following parameters were analyzed: mitotic index, labeling index, and position of labelled cells along the crypt. Increasing starch content from 3 to 36% decreased cell proliferation both in low (5%) and high (29%) fat diets. By estimating simultaneously the effects of starch and fat with a single multiple regression model, we observed a decrease of mitotic index from 3.04 +/- 0.34 to 2.04 +/- 0.43 (means +/- SE) (P less than 0.05) when starch was increased from 3 to 36% regardless of the level of fat. Other proliferation parameters showed a similar pattern. Changes in dietary fat alone did not affect significantly cell proliferation. We also investigated the effect of starch at high levels (57-65%) and its interactions with cellulose. High starch (57-65%) increased the labeling index from 7.70 +/- 0.58 to 9.65 +/- 0.88 (P less than 0.05), when also considering the effect of cellulose in the multiple regression model. Cellulose by itself did not change the labeling index. Varying starch from 36 to 57-65% increased the number of cells/crypt column from 22.20 +/- 0.82 to 25.87 +/- 1.21 (P less than 0.05) and varying cellulose from 2 to 10% increased the number of cells/crypt column from 22.20 +/- 0.82 to 27.25 +/- 0.97 (P less than 0.01). The results indicate that either high or low fat diets, containing 36% starch, have the minimum proliferative effects in the mouse colon. However, diets containing high levels of both starch (57%) and cellulose (10%) may induce an increase in proliferation. These data suggest a potential beneficial effect of starch on colon proliferation.

Nuclear aberrations and micronuclei induction in the digestive tract of mice treated with different iron salts

Toxic effects of ferrous sulfate and of ferric chloride were determined in the gastrointestinal tract by measuring the induction of nuclear aberrations and micronuclei. In fasting animals ferric chloride induced a dose-related increase of nuclear aberrations in the stomach, whereas ferrous sulfate was not active. In normally feeding animals no increase of nuclear aberrations was observed. The effects of the iron compounds on the duodenum were minimal. In fasting animals a dose-related increase of nuclear aberrations was observed at the level of the colon, with no clear difference between ferrous and ferric compounds. A modest increase of nuclear aberrations of the colon was seen in feeding animals only with ferrous sulphate. By intrarectal administration, nuclear aberrations were induced especially by ferric chloride. An increase of the frequency of micronuclei was not observed at the level of the stomach, duodenum and colon, with the exception of ferric chloride, that induces a significant, although small increase of colon micronuclei when administered intra-rectally. The data demonstrate that iron compounds have an intrinsic cellular toxicity when not administered with food, but do not seem to carry any genotoxic potential for the gastrointestinal tract.

Nuclear damage of colon epithelial cells by the food carcinogen 2-amino-3-methylimidazo[4,5-f]quinoline (IQ) is modulated by dietary lipids

Intestinal damage in C57BL/6J female mice was quantified by measuring the frequency of nuclear aberrations in colonic crypts. The animals were maintained on the following diets: standard (5% lipids, 5% cellulose); low- and high-cellulose (0-20% cellulose); high lipids (20% maize oil or 20% olive oil). All groups of animals were treated by gavage either with saline or 250 mg/kg of the dietary carcinogen 2-amino-3-methylimidazo[4,5-f]quinoline (IQ). After 24 h their colons were removed and stained and the nuclear aberrations scored under the microscope. The administration of IQ markedly increased the number of colon aberrations in all of the treated animals. Variations in dietary fiber did not modify the colon-damaging activity of this compound. Maize oil slightly increased the colon-damaging activity, whereas significant protection was observed in the animals on a high-lipid olive-oil diet. These results show that composition of the diet may vary the genotoxic effect of this dietary carcinogen.

Pharmacological activity of FPP028 (2-phenylpyrazolo-4-ethyl-4,7-dihydro [1,5a]pyrimidin-7-one) a new non-steroid anti-inflammatory agent

The activity of 2-phenylpyrazolo-4-ethyl-4,7-dihydro [1,5a]pyrimidin-7-one (FPP028), a non-acidic, analgesic, antipyretic, and anti-inflammatory compound, was investigated in a number of pharmacological tests performed in rats. The anti-inflammatory properties of FPP028 were evaluated through the carrageenan induced paw edema and the cotton pellet induced granuloma and compared with the activity of indomethacin, phenylbutazone, and isoxicam; as a result, the activity of FPP028 was shown to be similar to that of the latter compounds. To assess the analgesic properties of FPP028 in comparison with indomethacin and phenylbutazone, the Randall and Sellitto and the mouse-writhing tests were used; in both tests, FPP028 demonstrated a significant analgesic activity. FPP028 was shown to possess antipyretic properties in the test of yeast-induced pyrexia. The gastro-erosive activity of phenylbutazone and FPP028 was studied in restraint-stressed rats; in such test the ulcerogenic activity of phenylbutazone appeared to be dose-related; conversely, FPP028 demonstrated a gastro-protective effect since the number of gastric lesions induced either by stress or phenylbutazone treatment was decreased bu FPP028. Our data show that FPP028 is endowed with most of the pharmacological properties of the classic antiinflammatory drugs. Further studies are however needed to more fully elucidate its mechanism of action because our in-vivo data indicate that FPP028 is not an inhibitor of prostaglandin biosynthesis.

Inhibition of the mutagenic activity of some heterocyclic dietary carcinogens and other mutagenic/carcinogenic compounds by rat organ preparations

The mutagenic activity of some dietary mutagens, 2-amino-3-methylimidazo[4,5-f]quinoline (IQ), 2-amino-6-methyldipyrido[1,2-a:3',2'-d]imidazole (Glu-P-1) and 2-amino-dipyrido[1,2-a:3',2'-d]imidazole (Glu-P-2), was inhibited in the Salmonella-plate test preincubated with heat-inactivated rat intestinal preparations. A similar inhibition was observed by preincubating intestinal preparations with 2-acetylaminofluorene (AAF) and benzo[a]pyrene (B[a]P). The effect was not specific for small intestine and was also obtained with spleen, liver, lung, colon and stomach preparations. Mutagenic activity was not inhibited by beef muscle proteins. Lipids extracted from intestinal mucosa preparations were equally effective as inhibitors of the mutagenic activity. Lipid fractions from intestinal mucosa were capable of inhibiting the formation of activated IQ by mammalian S9, and other components of the intestinal preparations were able to bind the promutagens and their active metabolites. The mutagenic activity of 1-(2-hydroxyethyl)-2-methyl-5-nitroimidazole (metronidazole) and of N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) was also inhibited by intestinal preparations, but not by their lipid fractions. A binding of IQ to intestinal preparations was also demonstrated with HPLC techniques. The data indicate that tissue components may reduce the mutagenic activity of chemicals by interfering with the activation process and by reducing the concentration of the promutagens and their active metabolites at target sites.

Glycosyl albumin and diabetic microalbuminuria: demonstration of an altered renal handling

In attempt to elucidate the link between the nonenzymatic glycosylation of proteins and the diabetic functional nephropathy, renal handling of glycosyl albumin has been evaluated in 15 normal subjects and 29 insulin-dependent diabetic patients divided in three groups according to their urinary excretion rates of albumin (Ualb): (group A) ten diabetic patients with Ualb less than 10 micrograms/m', (group B) 12 patients with Ualb between 10 and 100 micrograms/m', and (group C) seven patients with Ualb greater than 100 micrograms/m'. Albumin was purified with Blue-Sepharose CL-6B. The carbohydrate bound to albumin was determined chemically with thiobarbituric acid after the acid hydrolysis of the protein. Serum glycosyl albumin concentration in normal subjects was 0.1256 +/- 0.009 nmoles of hydroxymethylfurfural per nanomole of albumin, in group A, 0.1900 +/- 0.0124; in group B, 0.2199 +/- 0.0177; and in group C, 0.2224 +/- 0.02732. Urinary glycosyl albumin concentration was 1.8467 + 0.2132 in normal subjects, 1.4369 +/- 0.3355 in group A, 1.008 +/- 0.1584 in group B, and 0.2614 + 0.0295 in group C. In normal subjects and patients without apparent nephropathy (groups A and B), the clearance of albumin correlated with the serum concentration of glycosyl albumin. In all patients (groups A, B, and C) the urinary-serum glycosyl albumin concentration ratio was correlated inversely with albumin clearance. These data show that in normal subjects and diabetic patients with normal excretion rates of albumin and microalbuminuric diabetic patients the passage of glycosyl albumin through the glomerular wall is facilitated in contrast to normal albumin and that glycosyl albumin plays an important role in the pathogenesis of diabetic functional nephropathy.

[Emergency surgical treatment of infectious endocarditis. Experience developed on 19 consecutive cases]

Our experience with the emergency surgical treatment of 19 consecutive cases of infective endocarditis (IE) is reported. The aortic valve was always affected, either alone (n = 16) or together with the mitral valve (n = 3). All patients were male. In 10 cases it was possible to identify the infecting agent (a staphylococcus was found in 6). Congestive heart failure (CHF) was the principal indication for surgery in 14 cases (in 6 active IE was associated). Five patients (1 with CHF) underwent operative treatment because of systemic emboli. Fifteen patients were in New York Heart Association (NYHA) functional class IV, 3 in class III and 1 was in class II. Two patients (10.5%), both operated on for CHF, died in the early postoperative period. Early prosthetic valve dehiscence occurred in 2 cases, reoperation was successful in both. Follow-up of operative survivors ranges between 7 and 108 months (mean = 53.24 +/- 41.89). One patients died 10 months after operation with CHF following late prosthetic dehiscence. Out of 16 currently surviving patients 14 are in NHYA functional class I, 1 is in class II and 1 in class III. No one of them has had relapse of IE.