Natural agents in the prevention of cancer, part two: preclinical data and chemoprevention for common cancers.
(41/924)
This paper is the second of a series examining the use of nutritional supplements as chemopreventive agents. The animal and in vitro data are reviewed in support of their use. Human safety data and mechanisms of action are described as well. Many over-the-counter dietary supplements have been shown to have significant chemopreventive activity in preclinical studies. Few side effects are associated with even long-term use of these agents. Along with dietary and lifestyle risk-reducing strategies, nutritional supplementation appears to be a viable intervention for those considered to be at high risk of developing cancer. (+info)
Effects of selenium and zinc supplementation on nutritional status in patients with cancer of digestive tract.
(42/924)
OBJECTIVE: To evaluate the effect of oral administration of selenium and zinc tablets in patients with cancer of the digestive tract during chemotherapy. DESIGN: A case-control, randomized study. SETTING: Medical Oncology, II University of Naples, Naples, Italy. SUBJECTS: A total of 60 patients (median age 55 y, range 46-61 y) with diagnosis of gut cancer were randomized in 1999. Patients were treated for 60 days with chemotherapy. INTERVENTIONS: Trace elements were measured by atomic absorption spectroscopy. The nutritional status of the patients was assessed by biochemical and bio-impedance analysis (BIA) parameters in basal condition and after 60 days of treatment. Oral administration of selenium and zinc in oral tablet form for 50 days was Se 200 microg/day (50 microg/tablet) and Zn 21 mg/day (7 mg/tablet). RESULTS: Both in the basal condition and at 60 days all patients were malnourished. Selenium and zinc concentrations were significantly lower (P < 0.01) whereas copper concentration was significantly higher (P < 0.01) in cancer patients than in control subjects. However, 21/30 (70%) of those treated with Se and Zn did not showed a further worsening of nutritional status and experienced a significant decrease of asthenia with an increase of appetite. On the other hand, 24/30 (80%) untreated patients had a significant decline of all parameters studied after 60 days (prealbumin, cholesterol, transferrin, P < 0.05 vs 0 time; total proteins, albumin/globulin ratio, P < 0.01 vs 0 time; fat-free mass, fat mass, Na+/K+ ratio, body mass index P < 0.05 vs 0 time; fat free mass/fat mass, total body water, extra cellular/intra cellular water, basal metabolic rate: P < 0.01 vs 0 time). CONCLUSIONS: Data indicate that Se and Zn supplementation may improve the clinical course of general conditions in patients with gut cancer. These effects of Se and Zn require confirmation in an independent trial of appropriate design before new public health recommendations regarding Se and Zn supplementation can be made. (+info)
Changes in some blood micronutrients, leukocytes and neutrophil expression of adhesion molecules in periparturient dairy cows.
(43/924)
Dairy cows are highly susceptible to infectious diseases, like mastitis, during the period around calving. Although factors contributing to increased susceptibility to infection have not been fully elucidated, impaired neutrophil recruitment to the site of infection and changes in the concentrations of some micronutrients related with the function of the immune defence has been implicated. Most of the current information is based on studies outside the Nordic countries where the conditions for dairy cows are different. Therefore, the aim of the study was to evaluate changes in blood concentrations of the vitamins A and E, the minerals calcium (Ca), phosphorous (P), and magnesium (Mg), the electrolytes potassium (K) and sodium (Na) and the trace elements selenium (Se), copper (Cu) and zinc (Zn), as well as changes in total and differential white blood cell counts (WBC) and expression of the adhesion molecules CD62L and CD18 on blood neutrophils in Swedish dairy cows during the period around calving. Blood samples were taken from 10 cows one month before expected calving, at calving and one month after calving. The results were mainly in line with reports from other countries. The concentrations of vitamins A and E, and of Zn, Ca and P decreased significantly at calving, while Se, Cu, and Na increased. Leukocytosis was detected at calving, mainly explained by neutrophilia, but also by monocytosis. The numbers of lymphocytes tended to decrease at the same time. The mean fluorescent intensity (MFI) of CD62L and CD18 molecules on blood neutrophils remained constant over time. The proportion of CD62L+ neutrophils decreased significantly at calving. The animals were fed according to, or above, their requirements. Therefore, changes in blood levels of vitamins, minerals and trace elements were mainly in response to colostrum formation, changes in dry matter intake, and ruminal metabolism around calving. Decreased levels of vitamins A and E, and of Zn at calving might have negative implications for the functions of the immune defence. The lower proportion of CD62L+ neutrophils at calving may result in less migration of blood neutrophils into the tissues, and might contribute to the increased susceptibility to infections at this time. (+info)
The EPA National Fuels Surveillance Network. I. Trace constituents in gasoline and commercial gasoline fuel additives.
(44/924)
A National Fuels Surveillance Network has been established to collect gasoline and other fuels through the 10 regional offices of the Environmental Protection Agency. Physical, chemical, and trace element analytical determinations are made on the collected fuel samples to detect components which may present an air pollution hazard or poison exhaust catalytic control devices. A summary of trace elemental constituents in over 50 gasoline samples and 18 commercially marketed consumer purchased gasoline additives is presented. Quantities of Mn, Ni, Cr, Zn, Cu, Fe, Sb, B, Mg, Pb, and S were found in most regular and premium gasoline. Environmental implications of trace constituents in gasoline are discussed. (+info)
A survey of the dietary nutritional composition of centenarians.
(45/924)
OBJECTIVE: To make a survey of the nutritional composition of the diets of centenarians. METHODS: Thirty-four centenarians were selected as subjects. Retrospective surveys were made on the variety and amounts of food consumed and their nutritional composition. Physical examinations with laboratory tests such as cardiograms, ultrasonic B rays, and blood, urine and hair tests were performed. Neutron activation testing was done on hair content. The transmission turbidimetric method was used to measure apolipoprotein content. RESULTS: The main food of the centenarians showed the characteristics of low calories, protein and fat but high fiber and mineral content. Laboratory results showed that the content of the elements of Cu, Se and Mn in hair was higher (P < 0.01). Zn was normal. The apoA1/apoB100 ratio was higher than in the control group (P < 0.01), and total cholesterol (TC) was lower than in the control group (P < 0.01). CONCLUSIONS: The variety of diet and its nutritional composition may be the main factors influencing not only the content of elements in body, but also the levels of apoA1 and apoB100, which may be helpful in preventing arteriosclerosis and forming and maintaining immunity. The diet of these centenarians might aid in preventing cardiovascular and cerebrovascular diseases and malignant tumors. (+info)
Multivitamin-multimineral and iron supplementation did not improve appetite of young stunted and anemic Beninese children.
(46/924)
In developing countries, low food intake is often reported in children < 5 y old. Reduced appetite may be a contributing factor. We investigated whether a combination of a multivitamin-multimineral supplement and additional iron treatment improved appetite and growth of 18- to 30-mo-old stunted and anemic Beninese children. The study was placebo-controlled using VITALIA tablets (11 vitamins and 10 minerals) and ferrous fumarate tablets (66 mg of iron). One hundred fifty stunted (height-for-age Z score < -2) and anemic children (hemoglobin < 110 g/L) were randomly assigned to one of four groups: group 1, multivitamin-multimineral plus iron; group 2, multivitamin-multimineral plus placebo; group 3, placebo plus placebo; and group 4, placebo plus iron. Supplementation was daily and supervised for 6 wk. Appetite, knee-heel length, dietary intakes and morbidity were assessed before and after supplementation. Length, weight, arm circumference and hemoglobin concentration were assessed before, just after supplementation and 4 mo after the intervention. Appetite was assessed by means of an appetite test using a test food, riz-au-gras, eaten ad libitum after an overnight fast. Dietary intakes were assessed during three consecutive days in a subsample by means of the observed weighed record method. Energy intake from the habitual breakfast was significantly correlated with that from the test food (r = 0.49, n = 38, P = 0.002). There were no differences among groups in changes in appetite and growth performance. The habitual diet of the children was monotonous and contained only small amounts of animal products. The morbidity status of the children was comparable in all study groups, before as well as after supplementation. We conclude that the 6-wk multivitamin-multimineral supplementation with additional iron treatment failed to improve the appetite and growth of the children. (+info)
Exposure to metal ions and susceptibility to dental caries.
(47/924)
Results from several epidemiologic studies have shown that there are large differences in the prevalence of dental caries from one region to another within the United States as well as in other countries. It has been postulated that the observed differences may be attributed in part at least to exposure to trace elements such as selenium, vanadium, molybdenum, strontium, and lead. Although data from epidemiologic studies usually support this hypothesis, direct evidence is sparse with the possible exception of exposure to lead. Data from several epidemiologic studies and animal-based research support the concept that lead is a caries-promoting element. Lead mimics calcium in several respects and may affect development of teeth and salivary glands, clearly enhancing susceptibility to dental caries. Elevated blood levels are found most commonly in persons residing in inner cities, particularly among the poor. Many states require blood lead level to be monitored in young children. Where feasible, these records should form part of health history and be available to the treating dental practitioner to ensure that extra preventive procedures may be implemented. (+info)
Trace element analysis in hair: factors determining accuracy, precision, and reliability.
(48/924)
Trace element analysis in biological samples has improved significantly over the last 40 years. Improvements in instrumentation such as inductively coupled plasma-mass spectrometry and microwave digestion have resulted in improved precision, accuracy, reliability, and detection limits. The analysis of human scalp hair has benefited significantly from these improvements. A recent article in the Journal of the American Medical Association found significant inter-laboratory variation amongst several laboratories performing trace metal hair testing. It concluded that standardization was necessary to improve inter-laboratory comparability, and an accompanying commentary described the characteristics of a laboratory that should be used in performing hair analysis. The objective of this study is to demonstrate that good laboratory practices will generate precise, accurate, and reliable results. A method for establishing reference ranges and specific data on an analytical method will also be presented. The use of prescribed clinical quality control, including method validation, proficiency testing, split sampling, and good laboratory practices clearly demonstrates that measuring trace elements in hair can be analytically valid. (+info)