[The prevention of the myocardial toxicity of doxorubicin with superoxide dismutase]

The production of oxygen free radicals during anthracycline therapy has been proposed as a determinant of the toxicity of anthracyclines. Oxygen radical generation might specifically affect the myocardium because of the low antioxidant defense systems in cardiac tissue. The aim of the present investigations was to evaluate the potential cardioprotective effect of superoxide dismutase (SOD) against the delayed cardiomyopathy induced by doxorubicin (DXR) in a rat model. Female Sprague Dawley rats received 3 mg/kg of DXR intravenously weekly for 4 weeks. SOD was administered intravenously at the dose of 10,000 U/Kg one minute before and 30 minutes after each DXR administration. Cardiac toxicity was monitored in vivo by means of electrocardiography (QaT interval), by determining the contractile properties of isolated atria, and by light and electron microscopy evaluation of left ventricle fragments excised 5 weeks after the last DXR administration. The degree of morphologic lesions was quantitated according to the score system proposed by E. Billingham. DXR treated rats showed, in comparison with control animals treated with saline a decrease of body weight gain, a progressive and irreversible prolongation of QaT, decrease of contractility of isolated atria, and significant morphologic lesions consisting in myocyte vacuolization and myofibrillar loss. SOD significantly prevented the impairment of body weight gain, QaT prolongation and the impairment of myocardial contractility. Moreover morphologic lesions were significantly reduced in rats receiving DXR + SOD. The present data indicate that SOD could represent an important issue in myocardial protection against DXR cardiotoxicity.

Effect of flunarizine on the delayed cardiotoxicity of doxorubicin in rats

The calcium antagonist flunarizine (FLN) was tested for its ability to prevent doxorubicin (DXR)-induced cardiotoxicity in the rat. A cumulative dose of 9.0 mg/kg of DXR was administered i.v. over a period of 1 week. FLN (10 mg/kg/day i.p., 6 days/week) was administered according to two different time schedules, covering respectively the first and last 4 weeks after the beginning of DXR treatment. The two schedules were adopted to assess whether early and/or delayed DXR-induced cardiotoxic effects were affected by FLN. The development of cardiac toxicity was monitored by ECG recordings. The animals were sacrificed 8 weeks after the beginning of DXR treatment. The contractile performance of isolated atria and the morphological pattern of left ventricular fragments were subsequently evaluated. The early administration schedule of FLN was shown to be ineffective in preventing DXR-induced cardiotoxicity and in some cases was actually found to potentiate the effects of DXR. In contrast, the histological evaluation of ventricular preparations from rats treated with DXR and FLN according to the delayed time schedule showed a significant improvement with respect to hearts from animals treated with DXR alone. An inhibition of the delayed calcium overload occurring after DXR administration has been proposed as a possible mechanism for this protective action.

Dietary fiber and cancer prevention

A large body of literature suggests that eating a variety of foods containing high fiber has a protective effect against colon cancer. Evidence also indicates that a high fiber-containing diet may be protective against breast, ovary, endometrial, and gastrointestinal cancer. The focus of this review is the epidemiologic data for an inverse association between a high-fiber diet and risk for the previously mentioned cancers. Epidemiologic studies are categorized as international, within country, metabolic, time trend, case control, and cohort. Since 1980, 32 studies have assessed the role of fiber-containing foods in relation to colon cancer. Among these studies, 25 showed an inverse association. Of the seven case-control studies, which evaluated the relationship between the fiber-rich diet and breast cancer, six demonstrated an inverse association. For cancers of the esophagus, mouth, pharynx, stomach, rectum, endometrium, and ovary, there are only a limited number of studies, most showing a protective effect from eating a diet high in fiber-containing foods. The epidemiologic studies reviewed previously focus on dietary patterns in which fiber-rich foods usually occur as a complex mixture with other foods and food components, thus making it difficult to assess at this time if the protection is clearly from fiber per se or some other dietary component, such as low fat. For cancer prevention, the emphasis for dietary recommendation should be on a dietary pattern rather than on an isolated dietary fiber supplement.

Prevention of doxorubicin-induced cardiomyopathy by reduced glutathione

The aim of the present investigation was to evaluate the potential cardioprotective effect of reduced glutathione (GSH) against the delayed cardiomyopathy induced by doxorubicin (DXR) in a well-documented rat model. DXR was administered i.v. at a weekly dose of 3 mg/kg for a total of 4 doses; 250 or 500 mg/kg of GSH was given i.v. 10 min before and 2 h after each DXR injection, resulting in a total weekly dose of 500 or 1000 mg/kg, respectively. The development of cardiotoxicity was monitored in vivo by means of electrocardiography (QaT duration), and was evaluated by measuring the contractile performance of isolated atria and by light and electron microscopy of left ventricular samples excised 5 weeks after the last DXR administration. DXR was found to impair body weight gain and to produce an irreversible and time-dependent prolongation of QaT, a decrease in myocardial contractility of isolated atria and typical morphologic alterations, including myocyte vacuolization and myofibrillar loss. Pretreatment with GSH at a dose of 500 mg/kg x 2, but not at 250 mg/kg x 2, partially prevented the impairment of body weight gain, QaT prolongation in ECG and the decrease in myocardial contractility of isolated atria induced by DXR. Alterations of the morphologic pattern were also significantly reduced in animals receiving the higher dose of GSH. Determinations of the cardiac non-protein sulfhydryl group content showed that GSH, at doses higher than or equal to 500 mg/kg, significantly increased this parameter, irrespective of the presence of DXR. In conclusion, the present data indirectly support the hypothesis that oxidative damage is involved in DXR cardiotoxicity and indicate that maintenance of the reduced thiol pool could be an important issue in myocardial protection.

Evaluation of the cardiovascular toxic effect of recombinant interleukin-2 in rats

Cardiac and vascular toxicity of recombinant interleukin-2 (rIL-2) was evaluated by in vitro and in vivo experiments in rats. Using isolated spontaneously beating atria, no changes were detected in heart rate or myocardial contractility in response to rIL-2 treatment at concentrations ranging from 0.1-100 U/ml. Daily sc administration of rIL-2 for 7 consecutive days (at doses of 2.3 X 10(4) to 1.15 X 10(6) U/ml) produced a prolongation of the QaT interval and significant modifications in serum electrolyte concentrations. Ex vivo contractility of atria excised at the end of rIL-2 treatment showed no deterioration in myocardial contractility with increasing dosage. rIL-2, at concentrations of 0.1-1000 U/ml, did not induce any modification of perfusion pressure in isolated rat tail artery but produced a significant displacement to the left of the dose-response curves for norepinephrine compared to basal conditions. The relative potencies were not dose-dependent. Our results indicate that rIL-2 does not exert a direct cardiotoxic effect, and suggest an indirect action on vascular smooth muscle, i.e., an aspecific modulation of vascular response to mediators.

Kappa-opioid receptor changes and neurophysiological alterations during cerebral ischemia in rabbits

Endogenous opioids have been shown to produce beneficial effects in experimental stroke. To evaluate both neurophysiological and biochemical parameters, we induced massive cerebral ischemia in 11 rabbits according to the method standardized in our laboratory, using microspheres injected through the internal carotid artery. Binding studies were performed in the 11 embolized, in nine control, and in five sham-operated rabbits using the appropriate concentration of [3H]dynorphin A (1-8). Neurophysiological parameters were evaluated under baseline conditions and 1 hour after embolization, surgical preparation, or sham operation in 17 rabbits. Comparison of visual readings of the electroencephalograms and analyses of the quantified electroencephalograms under baseline conditions and after embolization indicated a marked and statistically significant (p less than 0.01) increase in bilateral delta activity; histologic examination confirmed bilateral brain edema. Binding studies on kappa-opioid receptors indicate that 1 hour after embolization there were significantly more (28%) kappa-opioid receptors (Bmax) in six embolized rabbits than in five sham-operated animals. No significant changes were observed in the affinity parameters, particularly in the dissociation constant (Kd). Our results indicate a role for endogenous dynorphin peptides in the pathogenesis of stroke.

Dietary fiber, vegetables, and colon cancer: critical review and meta-analyses of the epidemiologic evidence

Whether colon cancer risk can be modified by a diet rich in vegetables, grains, and fruit, and, if so, whether the protective factor is dietary fiber or other biologically active components correlated with a high-fiber diet are questions of active research interest. Because studies on diet are susceptible to bias from a number of sources, in this review we evaluated the adequacy of study methodology as well as study results to clarify how much protection, if any, is conferred by a high-fiber diet. The review consisted of an aggregate assessment of the strength of evidence from 37 observational epidemiologic studies as well as meta-analyses of data from 16 of the 23 case-control studies. Both types of analyses revealed that the majority of studies gave support for a protective effect associated with fiber-rich diets; an estimated combined odds ratio (OR) of 0.57 (95% confidence interval = 0.50, 0.64) was obtained when the highest and lowest quantiles of intake were compared. Risk estimates based on vegetable consumption (OR = 0.48) were only slightly more convincing than those based on an estimate of fiber intake (OR = 0.58), but the data do not permit discrimination between effects due to fiber and nonfiber effects due to vegetables.

[Changes in the plasma levels of T3-T4 and TSH during surgical stress and anesthesia with isoflurane]

The authors describe the blood level changes of T3, T4 and TSH in 17 patients undergoing urological surgery and isoflurane anaesthesia. The data were statistically processed and showed that isoflurane, used as the only anesthetic agent in 1.5%-2% concentrations, is not sufficient to block hormonal changes of the hypothalamus-hypophysis-thyroid axis caused by surgical stress.

Effect of ICRF-187 pretreatment against doxorubicin-induced delayed cardiotoxicity in the rat

Doxorubicin (DXR), administered iv in rats at the weekly dose of 3 mg/kg for 5 weeks, significantly impaired body weight gain and induced irreversible ECG alterations, mainly consisting of a progressive prolongation of ST and QT intervals. Five weeks after the last DXR administration, the contractile performance of atria isolated from treated animals was significantly reduced. At the same time, relevant morphologic lesions, consisting of myocyte vacuolization and myofibrillar loss, were also present in the myocardium of the same rats. The study showed that ICRF-187, administered ip at a dose of 125 mg/kg, significantly prevented body weight loss. QT and ST prolongation, and the decreased contractile force induced by DXR. In addition, ICRF-187 caused a significant reduction in incidence and severity of myocardial lesions. The cardioprotective effect of ICRF-187 is not mediated by a modification in DXR pharmacokinetics in heart, since the drug was actually found to increase DXR uptake in myocardial cells.

The effects of RU-38486 on cervical ripening. Clinical studies

One hundred eighty pregnant patients, 17 to 39 years old (mean (+)/- SEM: 25.1 (+)/- 0.39), with an amenorrhea of 7 to 12 weeks (mean (+)/- SEM: 9.4 (+)/- 0.10), and requesting a therapeutic abortion, were selected according to general good health and gave their informed consent to the study. Mifepristone (RU-486; Roussel UCLAF, Paris, France) an antiprogestin steroid, was administered at random in doses of 0, 50, 100, 200, 400, or 600 mg. Clinical evaluations and measurements of cervical dilatation were done before the study and repeated at 24 hours after administration of Mifepristone and at 48 hours, at which time the aspiration was performed. Significant increases in cervical dilatation were observed at 48 hours with all doses of Mifepristone above 50 mg. The increases were significantly greater in patients with a gestational age greater than 10 weeks than in those less than 10 weeks' gestational age. Parity had no influence on cervical dilatation at 48 hours. Bleeding was observed significantly more often with 100 to 600 mg doses of Mifepristone than with 0 to 50 mg. No influence of gestational age or parity on bleeding could be detected. Abdominal cramps were reported more frequently with 200, 400, and 600 mg of Mifepristone at 48 hours and their occurrence appeared to parallel cervical dilatation.

Effect of glutathione and N-acetylcysteine on in vitro and in vivo cardiac toxicity of doxorubicin

The effects of two sulfhydryl compounds, glutathione (GSH) and N-acetylcysteine (NAC), on the cardiotoxicity of doxorubicin (DXR) were tested on in vitro and in vivo models. DXR was administered to rats as 4 weekly i.v. doses of 3 mg/kg. GSH (1.5 mmoles/kg), given i.v. 10 min before and 1 hr after DXR, was found to prevent the development of the delayed cardiotoxic effects of DXR, as assessed by electrocardiographic and mechanical parameters, as well as by histological examination of left ventricular preparations. In contrast, equimolar oral doses of NAC (1 hr before and 2 hrs after DXR) were found to be ineffective. Both GSH and NAC prevented the negative inotropic effect produced by DXR on isolated rat atria. A good correlation exists between the cardioprotective effects of the two agents and their ability to enhance the non-protein sulfhydryl group content of the myocardium. Differences observed in vivo between GSH and NAC might be accounted for by pharmacokinetic factors.

Evaluation of cardiotoxicity of a new anthracycline derivative: 4'-deoxy-4'-iodo-doxorubicin

The present study in rats was performed to evaluate the cardiotoxic activity of 4'-deoxy-4'-iodo-doxorubicin (4'-deoxy-4'-I-DXR), a new anthracycline derivative with interesting antineoplastic properties and possible lower cardiotoxicity than doxorubicin (DXR). DXR produced ECG alterations consisting of a progressive and irreversible prolongation of SaT and QaT. In contrast, in 4'-deoxy-4'-I-DXR-treated rats the increase in SaT and QaT duration was significantly lower than that observed in DXR-treated rats and slightly increased over controls. DXR produced significant histologic changes in myocardium consisting of myocyte vacuolization and myofibrillar loss. No significant modifications were observed in mitochondria. In contrast, no significant cardiac lesions were observed in 4'-deoxy-4'-I-DXR-treated rats. These results suggest that this new anthracycline derivative has a significantly lower degree of cardiotoxic activity than DXR.

NCI dietary guidelines: rationale

The National Cancer Institute (NCI) believes that the potential for dietary changes to reduce the risk of cancer is considerable and that the existing scientific data provide evidence that is sufficiently consistent to warrant prudent interim dietary guidelines that will promote good health and reduce the risk of some types of cancer. Six interim dietary guidelines and their scientific rationale are discussed herein. The evidence presented for the scientific rationale is based on the 1982 National Academy of Sciences Committee report Diet, Nutrition and Cancer and NCI's own scientific reviews that link long-term dietary patterns with cancer risk. These guidelines to the American public are consistent with other dietary recommendations from the US departments of Agriculture and Health and Human Services, the American Cancer Society, and the American Heart Association.

Trifluoperazine does not affect doxorubicin cardiotoxicity in the rat

Sprague Dawley rats received doxorubicin (DXR) at a dose of 3 mg/kg i.v. every third day for a total of three administrations, according to an acute and delayed cardiotoxicity experimental model previously described. DXR was found to induce significant ECG alterations (Qat and Sat prolongation) and typical morphologic lesions in the left ventricle. Trifluoperazine (TFP), administered at the doses of 0.2 of 2 mg/kg i.p., 5 days a week for 4 weeks, starting 1 day before DXR, was ineffective in preventing the electrocardiographic and morphologic alterations induced by DXR.

Effect of adriamycin on myocardial contractility and on the action of antibiotic ionophores

In the isolated guinea pig atria adriamycin exerted a negative inotropic effect; calcium ionophores A23187 and X537A increased the force of contraction. In the presence of adriamycin only the positive inotropic effect of ionophore A23187 was significantly reduced. It may be deduced that adriamycin shows its negative inotropic effect by inhibiting the entry of extracellular Ca++ into the myocardial cells and the release of Ca++ from intracellular stores.

Cheek cell fatty acids as indicators of dietary lipids in humans

Analysis of cheek cell lipids has been suggested as a noninvasive method for monitoring the fatty acid composition of diets in humans. In a pilot study conducted to determine the validity of the method, cheek cell samples were collected from subjects consuming a low fat (20% of calories) diet consisting of fatty acids with either a 1.0 or 0.3 P/S ratio. Neither total lipid nor polar lipid fatty acids in cheek cells consistently reflected the P/S ratio of the diets. However, there were trends, particularly in the nonpolar lipids, suggesting that cheek cell fatty acid ratios might be useful for monitoring the fatty acid composition of the diets. The diet with the higher P/S ratio (1.0 vs 0.3) consistently resulted in cheek cell lipids with lower ratios of 18:1/saturated fatty acids and greater 18:2/20:4, 18:2/18:1 and 18:2/18:0 fatty acid ratios.

Alpha-fetoprotein Monoclonal Assay: Preliminary Clinical Findings in a High Risk Population

A two-site solid phase immunoradiometric assay was developed for measurement of human alpha-fetoprotein, utilizing two high-affinity monoclonal antibodies directed against distinct and separate epitopes on the proteic structure. The analytical sensitivity of the assay is 0.5 ng/ml. The clinical sensitivity was evaluated by comparison of patients with cirrhosis and patients with hepatocellular carcinoma with cirrhosis. This assay gave good diagnostic discrimination. In a preliminary clinical trial, the specificity of the assay was 92.3%, the clinical sensitivity 88.2%. and predictive values were 78.9% in the clinically positive stage and 96.0% in the negative stage. The diagnostic efficacy of the assay was 91.3%.

[Course of the serum determination of 4 tumor markers in viral hepatitis]

The radioimmunological method was used to measure the serum levels of 4 tumour markers--CEA, TPA, Ca 19-9 and Ferritin--in 20 hepatitis patients. Blood levels of bilirubin and transaminase were assayed at the same time. Patients with high levels of bilirubin and transaminase also revealed pathological levels of all 4 markers, especially TPA and ferritin which fell towards normal levels once the acute attack was over.

Dietary fiber intake in the US population

Twenty-four hour recall data from adults interviewed in the Second National Health and Nutrition Examination Survey, NHANES II, were used as the basis to estimate total dietary fiber intake in the United States. Food fiber values were calculated for the 2500 foods in NHANES II in two ways: 1) using fiber values compiled from the literature by NCI and 2) values based on the Southgate methodology. Mean dietary fiber intake in the US adult population (greater than 19 y of age) is 11.1 g/d using the first set of values and 13.3 g/d according to Southgate values. On a per 1000 kcal basis, women consume more dietary fiber (6.5 g/1000 kcal) than men (5.5 g/1000 kcal) at every age. Fiber intake by geographic region, age, race, and sex is discussed. Our study indicates that dietary fiber intake in the United States is considerably lower than that previously reported.

Dietary fiber in the reduction of colon cancer risk

The evidence for an inverse association between a diet of foods high in fiber and colon cancer risk is reviewed in the context of the epidemiological criteria for causality. Five criteria are assessed: consistency of the association, strength of the association, specificity of the hypothesis, temporal relationship of the association, and coherence of the association. Forty epidemiological studies, described in 55 original reports, are analyzed in terms of an association between fiber intake and colon cancer. This evaluation clearly suggests a relationship between colon cancer and diet low in fiber. The epidemiological studies focus on dietary patterns in which fiber usually occurs as a complex mixture with other foods. At present, information on the chemistry and function of various types of fiber as well as the mechanisms of cancer inhibition still is quite limited. As dietary fiber may interact with or be linked to other dietary factors, the impact of total diet and dietary interactions should be considered in studies of colon cancer risk and in dietary counseling.