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Biomedical subjects

D Kello

Publications and source records attributed to D Kello.

At least 19 recordsLinked to original sources
PubMed1990

Epidemiological aspects in food safety.

The rapid growth of international trade in food products has resulted in increased hazards from trans-boundary foodborne infections and intoxication. Therefore, the development of multinational surveillance and registration of foodborne diseases or food contamination, of both biological and chemical origin, is of utmost importance for their prevention and control. Recognizing the importance of accurate and adequate epidemiological data for decision making with respect to priorities, resources and management, the World Health Organization (WHO) launched in 1976 the Joint UNEP/FAO/WHO Food Contamination Monitoring Programme (GEMS/Food) and in 1980 the surveillance programme for control of foodborne infections and intoxications in Europe. Although the response of participating countries in both programmes was very positive, many questions have arisen during this period which require further improvements through national and international action. Monitoring and surveillance of food contamination and foodborne infections and intoxications is a multidisciplinary process and requires the active involvement of experts in medical and veterinary food hygiene, food chemistry and epidemiology. Since health risk management with respect to food safety is frequently delegated to different authorities, much better coordination between the sectors is needed in order to improve epidemiological analysis at national and international level. The purpose of this paper is to review the WHO regional programme for prevention and control of foodborne infections and intoxications in the light of accumulated experience and to discuss plans and possibilities for further improvements through national and international action in the 1990s.

Disease Outbreaks↗
PubMed1989

WHO drinking water quality guidelines for selected herbicides.

Following the successful introduction of its Guidelines for Drinking-Water Quality in 1984, the WHO Regional Office for Europe was approached by the Government of Italy to develop, as a matter of urgency, recommendations for guidelines levels of certain herbicides found in drinking water supplies. Realizing the extent of the problem, the Regional Office for Europe organized two consultations to develop drinking water quality guidelines for the following 11 herbicides most commonly used in Italy: alachlor, metolachlor, pyridate, atrazine, molinate, simazine, bentazon, pendimethalin, trifluralin, MCPA and propanil. The presence of these and other herbicides in ground and surface water has been reported in several countries. Although the main purpose of these guidelines is to provide guidance to the Government of Italy in making risk management decisions, the information given was also intended to assist the other countries of the European Region in setting standards or in developing alternative control procedures where the implementation of standards is not feasible. The purpose of this paper is to review the process of health risk assessment used in the development of the WHO drinking water quality guidelines for selected herbicides. It will also reveal the major dilemmas and concerns expressed by the participating experts during the process of scientific deliberations, in the interests of understanding the complex issues involved in reaching the bare figures of the recommended guidelines.

Herbicides↗
PubMed1989

Effect of a metal mixture in diet on the toxicokinetics and toxicity of cadmium, mercury and manganese in rats.

The purpose of this work was to determine whether a metal mixture added to diet influences the toxicokinetics and toxicity of some elements. The metal mixture (MM) used in these experiments was ash (slag) from a coal gasification plant. The effect of this mixture (5 percent in diet) on the toxicokinetic and on the acute or subchronic toxicity of Cd, Hg, Mn was determined in rats of different ages. Rats were exposed for five weeks in toxicokinetic and six weeks in acute toxicity experiments. Sucklings were exposed through their mothers, which received the MM in diet over the pregnancy and lactation period. In toxicokinetic studies, half of the animals additionally received Cd, Hg or Mn (100, 50 or 2000 ppm, respectively) in drinking water. In subchronic experiments, six-week-old albino rats of both sexes were given MM in the diet and Cd, Hg or Mn in drinking water for 16 weeks. In toxicokinetic studies, 115mCd, 203Hg or 54Mn were administered orally or intraperitoneally to mothers and pups. Exposure to MM had no effect on the absorption, retention and organ distribution of these elements determined six days after radioisotope administration. In acute toxicity studies, exposure to MM in diet had no effect on LD50 values obtained eight days after oral administration of Cd, Hg or Mn to rats of different ages. In subchronic experiments, the effect of individual metals (Cd, Hg or Mn) was similar in animals with and without simultaneous exposure to the metal mixture (only a slight potentiation of a few health-effect parameters of cadmium was noticed in some animals). It is concluded that oral exposure to MM in the diet had almost no effect on the toxicokinetics and toxicity of Cd, Hg and Mn. This could be explained by the low level or low bioavailability of elements from MM, by the metal-metal interaction within the mixture or by the choice of health effect indicators determined. These results are presented as one of the potential approaches for studying the health effect of a metal mixture as occurring in the environment.

Aging↗
PubMed1982

Chronic and reproduction studies in rats exposed to gasifier ash leachates.

Ash from the coal gasification process contains a broad spectrum of elements which through leaching (gasifier ash leachates) may enter into the environment. The health effect of such leachates i.e. complex mixtures of inorganic elements is insufficiently known. We investigated the effect of gasifier ash leachates in a chronic-(9-month) and in a three-generation reproduction study. The leachates were prepared weekly by water extraction of ash from a Lurgi coal gasification plant in Yugoslavia, and given to experimental animals instead of drinking water. In the chronic experiment exposed animals showed no changes in mortality rate, haematological findings, concentration of Fe, Zn, Mn in kidneys, liver, testicles and femur, as well as in femur composition and morphometry, gross pathology and organ histology. In the reproduction study the number of pregnancies, weight and number of newborns, and concentration of Fe, Zn, Mn in carcasses of sucklings were the same in control and experimental animals.

Animals↗
PubMed1981

Chronic studies in rats exposed to liquid effluent from coal gasification process.

The health effects of the E-effluent (water for quenching ash) from a coal gasification plant were assayed in a chronic experiment (16 month exposure) and a three generation reproduction study. Animals exposed to 100% E-effluent had an increased daily intake of various inorganic elements (Fe, Cu, K, I, Se, Cd, Hg, Pb, As, F and Cr). In spite of that, the exposed and control animals had the same mortality rate, haematological findings, urinary protein excretion, trace element concentrations in kidneys, liver and femur, bone composition and morphometry, and histological findings. The pre- and post-natal development and growth was unchanged during three generations. It is concluded that the higher intake of various inorganics caused no change in the parameters measured.

Animals↗
PubMed1980

Human health hazards associated with chemical contamination of aquatic environment.

Given the finite supply of water available for human use, continued chemical contamination of the aquatic environment may pose a significant human health hazard. Consequently, an effort must be made to develop ambient water quality criteria to protect human health and preserve the integrity of the aquatic environment. In developing water quality criteria based on human health effects, information on sources of exposure, pharmacokinetics, and adverse effects must be carefully evaluated. Information on sources of exposure is needed to determine the contribution of exposure from water relative to all other sources. Pharmacokinetic data are used in inter- and intraspecies extrapolation and in characterizing the mode of toxic action. Information on toxic effects includes data on acute, subchronic, and chronic toxicity, mutagenicity, teratogenicity, and carcinogenicity. In analyzing such information, a distinction is made between threshold and nonthreshold effects. Currently, carcinogenicity and mutagenicity are considered to be nonthreshold effects. For carcinogens and mutagens, criteria are calculated by postulating an "acceptable" increased level of risk and using extrapolation models to estimate the dose which would result in this increased level of risk. For other chemicals, thresholds are assumed and criteria are calculated by deriving "acceptable daily intakes" for man which would presumably result in no observable adverse effects. Neither process is exact, and attempts must be made to improve and verify risk assessment methodologies.

Animals↗
PubMed1980

Toxicologic studies of emissions from coal gasification process. I. Subchronic feeding studies.

The increasing use of new sources of energy may result in additional contamination of the human environment with inorganic and organic pollutants which are not yet adequately investigated with regard to their potential impact on human health. However, some evidence exists that several trace inorganic and organic contaminants found in coal processing residues may constitute potential health problems. Therefore, the comparative biological hazards of solid wastes and effluents from a Lurgi coal gasification plant were initially evaluated using acute and chronic feeding experiments in male and female rats. In the subchronic experiment, six-week old animals were fed diets wih various levels of ash (slag) additive (0.5%, 1%, and 5%) for period of 16 weeks. Following exposure, blood samples were taken and 22-hour urine samples were collected. Livers and kidneys, and testicles in males, were taken for trace element analysis or histologic examination. The urinary values, erythrocyte and leucocyte count, hemoglobin, packed cell volume, and concentration of trace elements in exposed animals were determined. The addition of ash (slag) to the diet in concentrations much higher than expected in conditions of environmental contamination had no measurable health effects. Although these initial results obtained in relatively short-term experiments cannot be directly extrapolated to human health effects, particularly not for carcinogenic assessment, there is an indication that exposure to solid wastes from the coal gasification plant may not be toxic.

Animals↗
PubMed1979

Bioavailability of lead in rats fed "human" diets.

The bioavailability of lead was studied in rats fed various baby foods (Babymix-turkey, Babymix-vegetables, Frutolino-fruit, Frutamix-bananas, Babyron-S-26, Truefood), cow's milk, bread, liver and standard rat diet. Lead absorption was determined by measuring the whole body retention of 203Pb 6 days after a single oral application. Highest absorption values ranging from 17 to 20% were obtained in animals fed cow's milk and fruit foods. Rats on other "human" diets absorbed between 3 and 8% of the radioactive lead dose. Only in animals on rat diet lead absorption was below 1%. It is concluded that rats fed "human" diets show absorption values similar to those in humans. This might indicate that the bioavailability of lead is primarily dependent on dietary habits. This experimental model, if confirmed by further work, might be useful for obtaining preliminary data on the bioavailability of metals from various foods.

Animals↗
PubMed1979

On the role of metallothionein in cadmium absorption by rat jejunum in situ.

The role of metallothionein (MT) in the mechanism of cadmium absorption from the jejunum was studied in 7--9 week-old-male rats exposed to 50 ppm of cadmium in drinking water for 9 days. Exposed animals contained an average of 144 micrograms MT/g of mucosal tissue, compared to 40 micrograms in control anaimls. During jejunal perfusion in situ with 5 mM glucose-saline containing 10--20 nM CdCl2 the increased MT content of mucosa exerted no effect either on cadmium absorption from the lumen (step I), or on its further transport into the body (step II). Immediately after perfusion, essentially all cadmium removed from the lumen was fully recovered in the intestinal mucosa. About 50% of the mucosal cadmium was found in the sediment after homogenization and centrifugation; a large portion of this cadmium may be assigned to the membrane fraction. The binding of freshly absorbed cadmium in the mucosal cytosol was not restricted to low molecular weight protein, although cadmium binding capacity in the MT fraction of controls as well as of exposed animals greatly exceeded actual binding of newly absorbed cadmium. Our results offer no support for the view that MT in the jejunal mucosa serves as determinant of cadmium absorption.

Animals↗
PubMed1979

Influence of some factors on cadmium pharmacokinetics and toxicity.

Cadmium metabolism in the young and in conditions of dietary contamination with ash from coal gasification were investigated. The experiments were performed in adult rats which received ash in the diet (5%) and/or cadmium in drinking water (100 ppm) over a period of five weeks and in sucklings whose mothers were given the same treatment throughout pregnancy and lactation. In pharmacokinetic studies, (115m)Cd was administered orally or intraperitoneally to determine the intestinal absorption, retention, and distribution. Cadmium toxicity (LD(50)) was determined in different age groups of animals treated with ash for five weeks before a single oral or intraperitoneal administration of cadmium chloride. After intraperitoneal administration, (115m)Cd body retention decreased with age and was independent of the dietary treatment. Sucklings had a higher retention in the blood, carcass, and gut than adults. After oral administration, sucklings had a much higher body retention than adults regardless of the dietary treatment of their mothers. Cadmium toxicity was also independent of the dietary treatment. Most striking was a very high oral toxicity of cadmium in sucklings. It is concluded that the young might be at a special risk at the same level of environmental cadmium exposure because of the high oral cadmium toxicity at this age which is most probably due to a high cadmium retention in the gut. It is also concluded that the mixture of elements contained in ash is not likely to influence cadmium metabolism and toxicity in conditions of dietary exposure.

Age Factors↗
PubMed1978

Lead and cadmium in hair as an indicator of body burden in rats of different age.

The purpose of this work was to evaluate whether hair values of lead and cadmium can be used as an indicator of the body burden of these metals in different age groups. The experiments were performed on rats aged 2 and 18 weeks, which received 203Pb and 115mCd by intraperitoneal injection. The whole body retention and the retention of these radioisotopes in the hair (including the skin) was determined 7 days later. Younger animals showed a higher retention in the whole body and hair of radioactive lead and cadmium. The hair values when expressed as the percentage of the whole body retention were for 203Pb the same in young and adult rats but for 115mCd they were 2 to 3 times higher in young animals than in adults. It is concluded that lead hair values are a good indicator of the total body burden in both age groups. However, the cadmium body burden of young animals would be greatly overestimated if based on hair values only. This findings might be relevant for interpreting results of hair concentrations of lead and cadmium in children.

Aging↗
PubMed1978

Influence of age on metal metabolism and toxicity.

The metabolism and toxicity of lead, cadmium, mercury, and manganese in the postnatal period was studied in rats. Absorption, whole body retention, and organ distribution of 203Pb, 115mCd, 203Hg, and 54Mn were determined after oral and parenteral administration of these radioisotopes. The acute oral toxicity (LD50) was determined after a single application of metal chlorides. The results obtained in sucklings show a very high intestinal absorption of all metals which is partly attributed to milk diet; a higher whole body retention, higher blood levels and a much higher accumulation in the brain; and a higher oral toxicity. These results indicate age specific differences in the pharmacokinetics of metals in sucklings. It seems reasonable to consider the early neonatal age as a critical period for metal accumulation and therefore for metal toxicity. The results are interpreted on the basis of current concepts of developmental physiology and pharmacology and suggestions for future research trends are made.

Aging↗