Biomedical subjects

U Ranft

Publications and source records attributed to U Ranft.

At least 19 recordsLinked to original sources

PubMed2004

Challenges to environmental toxicology and epidemiology: where do we stand and which way do we go?

Modern toxicology investigates a wide array of both old and new health hazards. Priority setting is needed to select agents for research from the plethora of exposure circumstances. The changing societies and a growing fraction of the aged have to be taken into consideration. A precise exposure assessment is of importance for risk estimation and regulation. Toxicology contributes to the exploration of pathomechanisms to specify the exposure metrics for risk estimation. Combined effects of co-existing agents are not yet sufficiently understood. Animal experiments allow a separate administration of agents which can not be disentangled by epidemiological means, but their value is limited for low exposure levels in many of today's settings. As an experimental science, toxicology has to keep pace with the rapidly growing knowledge about the language of the genome and the changing paradigms in cancer development. During the pioneer era of assembling a working draft of the human genome, toxicogenomics has been developed. Gene and pathway complexity have to be considered when investigating gene-environment interactions. For a best conduct of studies, modern toxicology needs a close liaison with many other disciplines like epidemiology and bioinformatics.

Animals↗

PubMed2002

Concentrations of lead in blood, hair and saliva of German children living in three different areas of traffic density.

Lead contents in hair, whole blood and saliva were determined for 245 healthy children (121 male, 124 female, age: 8-10 years) from three residential areas of Düsseldorf (North-Rhine-Westphalia, Germany) with different traffic densities. The geometric mean for the lead content in hair was found to be 0.87 microg/g (range: 0.2-9.9 microg/g) for the entire test group. While the levels of lead in hair in the suburban population were significantly lower than in the two city centre populations, no significant difference concerning the lead content in hair could be detected in the latter. The geometric mean for lead concentration in whole blood amounted to 25.0 microg/l (range: 8.0-154 microg/l). There was no significant difference between the sub-groups. The lead concentrations found in saliva were rather low (range: < 1.5-47.0 microg/l). Of the values, 89% were below the detection limit of 1.5 microg/l. Due to reduced levels of lead in fuel, the present study exposes that the amount of lead in the children examined has further decreased compared to preceding surveys. The correlation between the lead content in hair and the road traffic density was not corroborated by the findings with regard to amounts of lead found in blood, indicating that residual lead from fuel does not result in a substantial burden of lead found in the whole body. In contrast to levels of lead found in blood, levels of lead found in hair may be influenced more by environmental conditions. Saliva is not a suitable material for biological monitoring with respect to lead exposure in children.

Air Pollutants↗

PubMed2002

Assessment of environmental arsenic levels in Prievidza district.

A coal-burning power station in the Nitra Valley in central Slovakia annually emitted large quantities of arsenic (up to 200 tonnes) between 1953 and 1989. Since then, pollution-control measures have reduced arsenic emissions to less than 2 tonnes a year. However, the power station was still a source of airborne arsenic pollution. As part of an EU-funded study on exposure to arsenic and cancer risk in central and Eastern Europe we carried out a study of environmental levels of arsenic in the homes and gardens of residents of the district. Garden soil samples (n=210), house dust samples (n=210) and composite house dust samples (n=109) were collected and analysed using inductively coupled plasma atomic absorption spectroscopy (ICP-AES) at Imperial College. The mean arsenic content of coal and ash in samples taken from the plant was 519 microg/g (n=19) and 863 microg/g (n=22), respectively. The geometric mean (GM) arsenic concentration of garden soils was 26 microg/g (range 8.8-139.0 microg/g), for house dust 11.6 microg/g (range 2.1-170 microg/g) and for composite house dust 9.4 microg/g (range 2.3-61.5 microg/g). The correlation between the arsenic levels in soil and in house dust was 0.3 (P<0.01), in soil and composite house dust 0.4 and house dust and composite house dust 0.4 (P<0.01 for both), i.e., were moderate. Arsenic levels in both house dust and soil decreased with distance from the power station. Overall, levels in both fell by half 5 km from the point source. Weak correlations were seen between the total urinary arsenic concentrations and arsenic concentrations in composite house dust.

Arsenic↗

PubMed2002

Mercury concentrations in urine, scalp hair, and saliva in children from Germany.

Mercury levels measured in urine, hair, and saliva of 245 German children (8-10 years old) are reported. Mercury concentrations in urine ranged between <0.1 and 5.3 microg/l [geometric mean (GM) 0.26 microg/l or 0.25 microg/g creatinine; median for both, 0.22 in microg/l and microg/g, respectively]. Using multiple linear regression analysis, two predictors have been found accounting for 25.3% of the variance of mercury levels in urine: the number of teeth with amalgam fillings (23.2%) and the number of defective amalgam fillings (2.1%). The mercury content in hair ranged from <0.06 to 1.7 microg/g (GM 0.18 microg/g; median 0.18 microg/g). The frequency of fish consumption, the smoking habits of the parents, and the age of the children accounted for 20.4% of the variance of mercury levels in hair. The correlation between the hair mercury content and urine mercury concentration was low (r=0.297). Mercury levels in saliva ranged between <0.32 and 4.5 microg/l (median 0.16 microg/l). The mercury concentration in saliva was below the limit of quantification of 0.32 microg/l in more than 70% of the samples. Mercury analysis in urine is suitable to estimate mercury exposure due to amalgam fillings, whereas hair mercury better reflects mercury intake by fish consumption. Up to now, saliva does not seem to be a suitable tool to monitor the mercury burden, at least not at low exposure levels.

Animals↗

PubMed2002

[Studying school beginners in western and eastern Germany: allergy trends and sensitisations 1991-2000].

AIM: Aim of the study is to examine the hypotheses of a steeper increase in allergies and allergic sensitisations in East than in West German children between 1991 and 2000. METHOD: Between 1991 and 2000 we yearly repeated cross-sectional studies (SAWO: Study on school beginners) and asked 36,645 parents about diagnoses and symptoms of allergies in their six-year old children (response: 79 %). The study was done in Leipzig, Halle, Merseburg, Magdeburg, small towns in the Altmark region, Duisburg, Essen, Köln and Borken during spring. An allergological investigation was included 1991, 1994, 1997 and 2000. Dermatologists diagnosed a prevalent atopic eczema, administered a skin prick test (n = 7,229) and blood was taken for the determination of specific IgE antibodies against common allergens (n = 7,714, RAST). Odds Ratios (OR) for trend were calculated separately for the data from East and West Germany and are given along with their 95% confidence intervals. RESULTS: Allergies and their symptoms (exception: atopic eczema) were less prevalent in East German children born before the reunification than in West German ones. In East as well as in West Germany bronchial asthma was diagnosed more often in 2000 than in 1991 (OR East: 2.42 [1.78-3.28] West: 2.07 [1.43-3.00]). In contrast the prevalence of atopic eczemas was more than halved between 1991 and 2000. Of all symptoms and diagnoses of allergies only hay fever and its symptoms showed an upward trend in East Germany which was steeper than the trend in West Germany (OR East: 4.41 [3.17-6.13] West: 1.74 [1.19-2.57]). This can partly be explained by a parallel trend in sensitisation against grass pollen. CONCLUSION: The spatial and temporal pattern of the allergic diseases bronchial asthma, hay fever and atopic eczema in six-year old children from Germany is different. The expected steeper increase of allergies in East than in West Germany could only be shown for hay fever.

Asthma↗

PubMed2000

Value of acoustic rhinometry in environmental medicine.

It is a weak point of environmental medicine that health disturbances, e.g. functional affections of the upper respiratory tract, cannot be objectively judged by physicians resp. researchers. In this study, the validity of acoustic rhinometry, a method giving information on cross-sectional areas of the upper airways by means of ultrasound probing, was tested in 40 volunteers seven times during one year. Furthermore, using a simplified model of the nose the accuracy of this method to measure the minimal cross-sectional area (MCA) in the nose was tested. The measurements were extremely confounded by the mode of connection to the nose (e.g. selected adapter, direction of application) and by the MCA in the nasal cavity. Statistical analyses showed a good reproducibility of measurements repeated within minutes, but suggested an intrapersonal variability over the analyzed examination phases due to apparatus independent factors. However, this variability could not be explained by influencing and confounding factors obtained by questionnaire, medical history, and physical examination. The test model showed little to great errors (1.5 to 568.5%) between the actual and the measured MCA, depending on the diameter. It is concluded that the method of acoustic rhinometry has to be standardized before it's value for environmental medicine can finally be judged. Further studies are necessary that should focus among others on factors influencing the variability of MCA and the effect of MCA on the measurement of the area behind the MCA. So far, the use of acoustic rhinometry for the evaluation of nasal function cannot be recommended.

Acoustics↗

PubMed2000

Occupational risk factors for urothelial carcinoma: agent-specific results from a case-control study in Germany. MURC Study Group. Multicenter Urothelial and Renal Cancer.

BACKGROUND: This multicentre population-based case-control study was conducted to estimate the urothelial cancer risk for occupational exposure to aromatic amines, polycyclic aromatic hydrocarbons (PAH), and chlorinated hydrocarbons besides other suspected risk factors. METHODS: In a population-based multicentre study, 1035 incident urothelial cancer cases and 4298 controls matched for region, sex, and age were interviewed between 1991 and 1995 for their occupational history and lifestyle habits. Exposure to the agents under study was self-assessed as well as expert-rated with two job-exposure matrices and a job task-exposure matrix. Conditional logistic regression was used to calculate smoking adjusted odds ratios (OR) and to control for study centre and age. RESULTS: Urothelial cancer risk following exposure to aromatic amines was only slightly elevated. Among males, substantial exposures to PAH as well as to chlorinated solvents and their corresponding occupational settings were associated with significantly elevated risks after adjustment for smoking (PAH exposure, assessed with a job-exposure matrix: OR = 1.6, 95% CI: 1.1-2.3, exposure to chlorinated solvents, assessed with a job task-exposure matrix: OR = 1.8, 95% CI: 1.2-2.6). Metal degreasing showed an elevated urothelial cancer risk among males (OR = 2.3, 95% CI: 1.4-3.8). In females also, exposure to chlorinated solvents indicated a urothelial cancer risk. Because of small numbers the risk evaluation for females should be treated with caution. CONCLUSIONS: Occupational exposure to aromatic amines could not be shown to be as strong a risk factor for urothelial carcinomas as in the past. A possible explanation for this finding is the reduction in exposure over the last 50 years. Our results strengthen the evidence that PAH may have a carcinogenic potential for the urothelium. Furthermore, our results indicate a urothelial cancer risk for the use of chlorinated solvents.

Aged↗

PubMed2000

Occupational risk factors for renal cell carcinoma: agent-specific results from a case-control study in Germany. MURC Study Group. Multicenter urothelial and renal cancer study.

BACKGROUND: This case-control study was conducted to estimate the renal cell cancer (RCC) risk for exposure to occupation-related agents, besides other suspected risk factors. METHODS: In a population-based multicentre study, 935 incident RCC cases and 4298 controls matched for region, sex, and age were interviewed between 1991 and 1995 for their occupational history and lifestyle habits. Agent-specific exposure was expert-rated with two job-exposure matrices and a job task-exposure matrix. Conditional logistic regression was used to calculate smoking adjusted odds ratios (OR). RESULTS: Very long exposures in the chemical, rubber, and printing industries were associated with risk for RCC. Males considered as 'substantially exposed to organic solvents' showed a significant excess risk (OR = 1.6, 95% CI : 1.1-2.3). In females substantial exposure to solvents was also a significant risk factor (OR = 2.1, 95% CI : 1.0-4.4). Excess risks were shown for high exposure to cadmium (OR = 1.4, 95% CI : 1.1-1.8, in men, OR = 2.5, 95% CI : 1.2-5.3 in women), for substantial exposure to lead (OR = 1.5, 95% CI : 1.0-2.3, in men, OR = 2.6, 95% CI : 1.2-5.5, in women) and to solder fumes (OR = 1.5, 95% CI : 1.0-2.4, in men). In females, an excess risk for the task 'soldering, welding, milling' was found (OR = 3.0, 95% CI : 1.1-7.8). Exposure to paints, mineral oils, cutting fluids, benzene, polycyclic aromatic hydrocarbons, and asbestos showed an association with RCC development. CONCLUSIONS: Our results indicate that substantial exposure to metals and solvents may be nephrocarcinogenic. There is evidence for a gender-specific susceptibility of the kidneys.

Carcinoma, Renal Cell↗

PubMed2000

Traffic-related air pollution is associated with atopy in children living in urban areas.

Traffic emissions are a major source of air pollution in Western industrialized countries. To investigate the association between traffic-related air pollution and parameters of atopy, we studied 317 children 9 years of age living near major roads in two urban areas and one suburban area of a city in West Germany. Atopic sensitization was analyzed by skin-prick testing and determination of allergen-specific serum immunoglobulin E. Parents recorded allergic symptoms in a symptom diary, and physicians assessed allergic diseases. Personal NO2 exposure and NO2 concentrations in front of each child's home were measured. Outdoor NO2 was a good predictor for traffic exposure but a poor predictor for NO2 exposure at the personal level. Atopy was found to be related to outdoor NO2 (odds ratio for the association between symptoms of allergic rhinitis and outdoor NO2 = 1.81; 95% confidence interval = 1.02-3.21) but not to personal NO2 (odds ratio for the association between symptoms of allergic rhinitis and personal NO2 = 0.99; 95% confidence interval = 0.55-1.79). When the analysis was restricted to urban areas, we found that hay fever, symptoms of allergic rhinitis, wheezing, sensitization against pollen, house dust mites or cats, and milk or eggs were associated with outdoor NO2. The results indicate that traffic-related air pollution leads to increased prevalence of atopic sensitizations, allergic symptoms, and diseases.

Child↗

PubMed1999

Tobacco, occupation and non-transitional-cell carcinoma of the bladder: an international case-control study.

Transitional-cell carcinoma is the dominant histological type of malignant tumors of the urinary bladder. There is limited information on risk factors for non-transitional-cell carcinoma (NTCC) of the bladder. We used data from 9 case-control studies on bladder cancer from 6 European countries to examine the association between NTCC, tobacco smoking and occupation. Information on 146 cases diagnosed with NTCC were matched by age, gender and study center to 727 non-cancer population or hospital controls and also with 722 transitional-cell-bladder-cancer controls. Lifetime smoking and occupational history were evaluated. A statistically significant excess risk for NTCC was observed for current smoking [odds ratio (OR) = 3.61, 95% confidence interval (CI) 2.08-6.28]. The risk increased with higher tobacco consumption (OR for highest tertile of pack-years = 7.01, 95% CI 3.60-13.66). The risks were higher for squamous-cell carcinomas than for other types of NTCC. Among major occupational groups, a significant excess risk was seen for field-crop and vegetable-farm workers (OR = 2.06, 95% CI 1.03-4.10). These results indicate that NTCC of the bladder is associated with smoking and specific occupations. The risk pattern seems to differ, in part, from that observed for transitional-cell carcinoma of the bladder.

Carcinoma, Squamous Cell↗

PubMed1999

Smoking as a confounder in case-control studies of occupational bladder cancer in women.

BACKGROUND: In studies in men, risk estimates on occupation and bladder cancer are distorted by about 10% when not adjusting for smoking. We examined the degree to which occupational risk estimates for bladder cancer in women are confounded by smoking, and the degree of residual confounding by inadequate control of this effect. METHODS: Primary data of 11 case-control studies on occupation and bladder cancer from Denmark, France, Germany, Greece, Italy, and Spain were pooled. Information for smoking and lifetime occupational history for 700 female cases and 2,425 female controls ages 30-79 was abstracted and recoded. Logistic regression was used to calculate odds ratios (OR) by occupation, applying five models which differed in their degree of adjustment for smoking. RESULTS: In major occupational groups, risk estimates were distorted by less than 10% when not adjusting for smoking. A statistically significant excess risk for bladder cancer was found in 13 specific occupations and industries. In most occupations, adjustment for smoking led the ORs towards the null value, but all statistically significant associations were maintained after adjustment. In three occupations (lathe operators, field crop workers, and wood manufacturers), a statistically significant excess risk was masked when not adjusting for smoking. In six occupations, estimates were distorted by more than 10% (-22% up to +40%). In occupations where smoking acted as a positive confounder, the proportion of confounding removed using a dichotomous smoking variable (ever/never) was around 60%. In one occupation (buyers), controlling for smoking status (ever, never) led to over-adjustment, because the percentage of smokers was high but the quantity smoked was low.

Adult↗

PubMed1999

Occupation and bladder cancer in European women.

OBJECTIVES: We examined the importance of occupational exposures for bladder cancer in women. METHODS: We combined data from 11 case-control studies conducted between 1976 and 1996 in six European countries. The pooled data comprised 700 incident female cases and 2425 population or hospital controls, aged 30-79 years. Lifetime occupational and smoking history were examined using common coding. RESULTS: Excess risks were found in only a few of the occupations previously identified at high risk for bladder cancer. Statistically significant excess risks were observed for metal workers, particularly blacksmiths, toolmakers and machine tool operators (OR: 2.0, 95% CI: 1.1-3.6), tobacco workers (OR: 3.1, 95% CI: 1.1-9.3), field crop and vegetable farm workers (OR: 1.8, 95% CI: 1.0-3.1), tailors and dress makers (OR: 1.4, 95% CI: 1.0-2.1), saleswomen (OR: 2.6, 95% CI: 1.0-6.9), and mail sorting clerks (OR: 4.4, 95% CI: 1.0-19.5). About 8% (95% CI: 3.1 19.9) of all bladder cancers in women could be attributed to occupation after adjusting for smoking. The attributable risk was higher in women aged less than 65 years (12%), compared to older women (4%). CONCLUSIONS: The calculation of the attributable risk on the basis of results from this analysis may have caused some overestimation of the proportion of occupational bladder cancer in women. A significant proportion, however, of bladder cancer cases among European women less than 65 years is likely to be attributed to occupation. This link between bladder cancer in women and occupational factors has received little recognition, probably because studies addressing these issues have predominantly been done in men.

Adult↗

PubMed1999

Airway diseases and allergies in East and West German children during the first 5 years after reunification: time trends and the impact of sulphur dioxide and total suspended particles.

BACKGROUND: East-West comparison studies in Europe find higher prevalences of infectious airway diseases and lower prevalences of allergies in eastern areas. Pollution from sulphur dioxide (SO2) or total suspended particles (TSP) are discussed as causes of this difference. METHODS: In four differently polluted areas of East Germany where pollution decreased dramatically between 1989 and 1995 cross-sectional studies in about 7-year-old children were repeated every year between 1991 and 1995. In two differently polluted areas of West Germany studies with the same design were done in 1991 and 1994. In all, 19090 children participated in the study. Thirteen different questions about airway diseases and allergies were evaluated. Logistic regression was used to adjust for confounding. RESULTS: With the exception of pneumonia, all infectious airway diseases and irritations of the airways show a steeper temporal decrease in East than in West Germany or are positively associated with either SO2 or TSP in East Germany. For allergies and related symptoms no differences in time trends could be detected or no association with SO2 or TSP could be seen in East Germany. CONCLUSION: Most airway diseases were more frequent in East than in West Germany in 1991 and were associated with SO2 or TSP. The decrease in these pollutants between 1991 and 1995 has already had a favourable effect. An effect of SO2 or TSP pollution on allergies and related symptoms could not be detected. This pollution does not protect against the development of allergies.

Age Distribution↗

PubMed1999

Inner room-questionnaire for the German-speaking area.

The sick building syndrome (SBS) is well known in Germany, too. Because reliable objective data are missing questionnaires are essential in investigations of SBS. Internationally, different questionnaires are used which often lack thorough validation. Therefore, aim of this study was to combine the development of a questionnaire and the analysis of its sensitivity and reliability. For proofing sensitivity, 40 volunteers kept a Symptom Diary for one week and, for comparison, answered the questionnaire in the following week seven times during one year. For testing reliability, 60 volunteers filled in the questionnaire on Monday and on Friday of the same week. Agreement was tested by statistical measure kappa (kappa). The sensitivity test showed that details obtained by diary occurred less pronounced but similarly distributed in the questionnaire. The reliability test showed stable socio-demographic and work-related variables. Among the symptoms, eye troubles (kappa = 0.88), skin troubles in the face (kappa = 0.77) and on the hands (kappa = 0.75) were stable. Among the indoor complaints unpleasant odors (kappa = 0.68), sounds (kappa = 0.72), bright lighting (kappa = 0.85), and dust (kappa = 0.86) were stable. Our questionnaire recorded principally plausibly indoor complaints and well-being disturbances. A definite judgement of the questionnaire can only be made after its application to a SBS-affected group. Nevertheless, our questionnaire can be introduced into the process of developing a standardised international SBS-questionnaire. Moreover, our results indicate that events asked by questionnaire over a retrospective period of more than one week should be interpreted with caution.

Germany↗

PubMed1999

Soluble tumor necrosis factor receptor (sTNF RII) in sera of children and traffic-derived particulate air pollution.

Tumor necrosis factor receptor (sTNF RII) was determined in sera of 160 healthy schoolchildren of the city of Düsseldorf, Germany, living in areas with different traffic density. According to the frequency distribution a higher prevalence of children with increased sTNF RII values (> 3000 pg/ml) were found for a high traffic area as compared to a low traffic area. Based on sTNF RII values above the 75% percentile of children from the low traffic area, the group of children from the high traffic area revealed a significant increased odds ratio of 2.5. Concerning traffic-derived particulate air pollution an association between the concentration of fine particles (PM2.5) and sTNF RII serum levels could be observed for both areas. Furthermore, sTNF RII values gave a significant positive correlation with C3c, an activation product of the complement component C3. C3c has been shown to be a sensitive indicator of the non-specific humoral defence in response to air pollution. Therefore, the results suggest that traffic-derived fine particles may upon inhalation trigger immune modulation via the activation of macrophages and enhanced cytokine production.

Air Pollutants↗

PubMed1996

Internal and external tetrachloroethene exposure of persons living in differently polluted areas of Northrhine-Westphalia (Germany).

An epidemiological study was performed to measure the internal and external tetrachloroethene exposure of persons living in two differently polluted areas of Northrhine-Westphalia (Germany). Tetrachloroethene concentrations were determined in venous blood samples of 5- to 7-year-old children (n = 81) and 55-year-old women (n = 91) living in Essen, an industrial city located in the Ruhr area. 103 children und 131 women of the same age living in Borken, a small town north of the Ruhr area, served as reference group. Outdoor air samples were collected on passive samplers (sampling period: 4 weeks) from 70 measurement points per study area (about 2 km2, mean distance 100 m). In the course of a year these measurements were repeated three times to cover seasonal variations. Parallel to the outdoor measurement periods, indoor air concentrations were determined in the homes of those women from Essen and Borken, who donored a blood sample. Tetrachloroethene levels in blood were generally low with a geometric mean of 0.05 microgram/L in women and 0.021 microgram/L in children. Nevertheless, children and women living in the industrial area were found to have significantly higher tetrachloroethene levels in blood than those of the reference group. In both study areas blood levels of women exceeded those of children by a factor of 2. Participants living in the neighbourhood of a dry-cleaning shop had distinctly elevated blood levels. The same applied to persons who stored dry-cleaned clothes at home. Like the internal exposure, external exposure was also higher in Essen than in Borken. In both areas tetrachloroethene concentrations indoors exceeded those outdoors. Outdoor tetrachloroethence concentrations were significantly increased during the cold season, while the opposite was true for indoor levels. The correlation between indoor and outdoor exposure was found to be significant, while those between blood levels and outdoor exposure became only significant when people living next to a dry-cleaning shop were excluded. No significant relationship was observed between blood and indoor tetrachlorethene levels. It is concluded that the higher tetrachloroethene blood levels of the urban population result from the higher atmospheric concentrations in industrial areas with tetrachloroethene emitting sources like metal and textile industry. The fact that indoor air tetrachloroethene levels exceeded those outdoors can only be explained by the presence of additional indoor sources. Provided that women spend on average more time indoors than children the higher indoor air concentrations may be the reason for the higher blood tetrachloroethene levels found in women. Persons living near a dry-cleaning shop or storing dry-cleaned clothes at home showed a higher internal and external exposure to tetrachloroethene than other persons. In individual cases it can by far exceed the average exposure of the general population, so that health impairments can not be generally excluded.

Air Pollutants↗

PubMed1992

[Insulin-like growth factor I--a connecting link between nutrition and growth].

The influence of an increasing protein supply in combination with soybean oil upon the IGF-I concentration in the serum in correlation with growth was measured on 8 x 10 male Wistar rats. With a casein content of 0% in the food, the IGF-I level was 0.13 +/- 0.02 rU/ml. An IGF-I plateau of 0.74 +/- 0.07 rU/ml was reached at some 15% casein. The additional application of 3% soybean oil increased the IGF-I concentration significantly (P less than 0.01) up to 0.95 +/- 0.16 rU/ml. The investigations show a specific increase of the IGF-I synthesis by the addition of oil, which is paralleled by a further stimulation of the growth of the rats. The nutrition-dependent IGF production in the peripheral tissues (mainly liver) represents the connection link between the growth hormone axis (genetically potential growth) and the growth realizable depending on the supply with nutrients.

Animal Nutritional Physiological Phenomena↗

PubMed1991

[The regulation of feed intake and selection with special reference to poultry].

Feed intake is regulated in a dialogue between the animal and the feed, which is influenced by numerous factors. The hypothalamus has a central integrative function. Furthermore, caudal brain areas (medulla oblongata, pons) are of importance because these areas are relays of peripheral signals and gustatory afferents. All peripheral informations are integrated by various neurotransmitters and neurohormones. The function of this neuronal system is not exactly known yet. Sensorial informations, mechano-, chemo- and osmoreceptors of the gastrointestinal tract and gastrointestinal hormones are discussed as influences of the periphery. The physiological satiety function of cholecystokinin is questionable in poultry. Hepatic chemoreceptors, which are activated by various metabolites, influence the amount of feed ingested. The feed choice appears to be regulated by the same mechanisms. Our knowledge about the translation of peripheral signals into choice behaviour by changes of neurotransmitter systems is limited.

Animal Feed↗