Staff Publications

Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

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    Solving large structured Markov Decision Problems for perishable inventory management and traffic control
    Haijema, R. - \ 2008
    University of Amsterdam (UvA). Promotor(en): J. van der Wal; N.M. van Dijk. - Amsterdam : Thela Thesis - ISBN 9789036101011 - 357
    optimalisatie - markov-processen - dynamisch programmeren - inventarisaties - controle - voorraden - bederfelijke producten - bloed - verkeersgeleiding - optimization - markov processes - dynamic programming - inventories - control - stocks - perishable products - blood - controlled traffic
    Toepassing van uitsluitdiagnostiek voor klassieke varkenspest bij a-specifieke klinische problemen op varkensbedrijven: een enquete onder varkenshouders en dierenartsen.
    Elbers, A.R.W. ; Gorgievski-Duijvesteijn, M.J. ; Velden, P.G. ; Loeffen, W.L.A. - \ 2007
    Tijdschrift voor Diergeneeskunde 132 (2007)9. - ISSN 0040-7453 - p. 340 - 345.
    varkenspest - varkenshouderij - diagnostische technieken - laboratoriumdiagnose - polymerase-kettingreactie - testen - bloedmonsters verzamelen - bloed - klinische aspecten - symptomen - swine fever - pig farming - diagnostic techniques - laboratory diagnosis - polymerase chain reaction - testing - blood specimen collection - blood - clinical aspects - symptoms - epidemic
    Outbreaks (of Classical Swine Fever (CSF) occurred in spring 2006 in Germany close to the Dutch border. On 6th April Dutch pig farmers were given the possibility to submit blood samples directly via their veterinary practitioner to the National Reference Laboratory for CSF if their pigs had nonspecific clinical symptoms or if pigs were being treated with antibiotics. The pig farm was not quarantined and was not visited by the veterinary authorities. Over a period of 9 weeks 156 pig farmers submitted whole blood samples via 50 different veterinary practices. All samples tested negative in the PCR test. These pig farmers and veterinary practitioners were asked to respond to a postal questionnaire with questions regarding their experience with this new diagnostic possibility, the distribution of the costs involved, a comparison official notification or use of with other instruments, such as of a leukocyte count test, and their knowledge of clinical signs of CSF 65 pig farmers (42%) and 33 veterinary practices (66%) returned the questionnaire. The main results indicated that pig farmers (72%) would use this type of exclusion diagnostics sooner than that they would approach the veterinary authorities (practitioners: 86%). Moreover the respondents considered the fact that the farm was not quarantined immediately to be an advantage (pig farmers, 79%; practitioners, 88%). 32 percent of the pig farmers were not aware that they were required to submit blood samples if pigs were being treated with antibiotics (practitioners: 11%). The majority of pig farmers and practitioners were not satisfied with the current distribution of the costs involved: in their opinion the costs of the PCR test, the costs of the veterinary practitioner and the costs for shipping the samples to the reference laboratory should be paid out of the Animal Health Fund (50% government and 50% industry) or by the government. If the current distribution of the costs is not changed, a large proportion of the pig farmers indicated that they would not use this form of exclusion diagnostics for CSF in the future. Pig farmers appeared to have a rather limited knowledge of the clinical signs of CSF: 33% of the pig farmers could mention maximally three clinical signs of CSF and 7% could not mention a single clinical sign of CSF and said they were entirely dependent on the practitioners' ability to judge a CSF-suspect situation.
    Analysis of TBBP-A and HBCD in human blood
    Leslie, H.A. ; Micic, D. ; Brandsma, S.H. ; Hesselingen, J.M. van; Kwadijk, C.J.A.F. ; Leonards, P.E.G. ; Boer, J. de - \ 2004
    IJmuiden : RIVO (RIVO report C009/04) - 13
    analytische methoden - bloed - broomhoudende vlamvertragers - analytische scheikunde - analytical methods - blood - brominated flame retardants - analytical chemistry
    The brominated flame retardants, hexabromocyclododecane (HBCD) and tetrabromobisphenyl-A (TBBP-A) were analysed in samples of human blood from 40 different individuals. In only one individual was HBCD detected. In about half of the individuals, TBBP-A was detected. When they were detected, the amounts of both chemicals were near the limits of quantification. That the chemicals were detected confirms that certain individuals were exposed to sources of these substances. The toxicological implications of these low levels are not well known. Very few studies of the toxicology of these compounds have been performed to date.
    Bedreigen virussen de palingpopulatie?
    Ginneken, V.J.T. van; Thilart, G. van den; Haenen, O.L.M. - \ 2004
    Aquacultuur 19 (2004)5. - ISSN 1382-2764 - p. 26 - 29.
    anguilla - palingen - visziekten - virussen - virusziekten - infectieziekten - infectie - infecties - incidentie - epidemiologie - migratie - ziektedistributie - besmetting - hematologie - bloed - bloedsamenstelling - hematocriet - aspartaat aminotransferase - lactaat dehydrogenase - eiwit - eiwitten - experimenten - anguilla - eels - fish diseases - viruses - viral diseases - infectious diseases - infection - infections - incidence - epidemiology - migration - disease distribution - contamination - haematology - blood - blood composition - haematocrit - aspartate aminotransferase - lactate dehydrogenase - protein - proteins - experiments
    Resultaten van een onderzoek naar het voorkomen van virussen (EVEX, Eel Virus European X; HVA, Herpes Virus Anguillea; EVE, Eel Virus European) bij palingen afkomstig uit diverse landen (zowel wilde paling als paling van kwekerijen) en van een zwemexperiment met geïnfecteerde en niet-geïnfecteerde palingen. Na voltooiing van de zwemreis werd in beide groepen het bloedbeeld onderzocht op diverse parameters (o.a. op hematocriet, het aantal rode bloedcellen). De resultaten zijn zeer verontrustend, omdat ze een aanwijzing vormen dat virus-infectie ertoe leidt dat palingen hun migratie naar de paaigronden niet kunnen voltooien door bloedarmoede, een beschadigde lever en een tekort aan eiwitten. Dit kan mede een oorzaak zijn voor het wereldwijd teruglopen van de palingstand
    The immune response of carp to blood flagellates : a model for studies on disease resistance and stress
    Saeij, J.P.J. - \ 2002
    Wageningen University. Promotor(en): W.B. van Muiswinkel; G.F. Wiegertjes. - S.l. : s.n. - ISBN 9789058086839 - 183
    karper - trypanosoma - flagellaten - bloed - immuniteitsreactie - immuniteit - macrofagen - lymfocyten - dna-sequencing - ziekteresistentie - stress - ziektemodellen - gastheer parasiet relaties - visteelt - immunologie - celbiologie - in vivo experimenten - carp - trypanosoma - flagellates - blood - immune response - immunity - macrophages - lymphocytes - dna sequencing - disease resistance - stress - disease models - host parasite relationships - fish culture - immunology - cellular biology - in vivo experimentation - cum laude

    To date, aquaculture accounts for 25% of the total world supply of (shell)fish for human consumption, a relative contribution that is expected to increase with time. The increased global demand for (shell)fish has lead to a further intensification of aquaculture with the inevitable result that fish become disposed to stress and diseases. An important factor leading to this predisposition is stress induced by aquaculture practices such as crowding, transport, handling and impaired water quality. The World Health Organisation seeks to actively stimulate prophylactic measures such as vaccination, genetic selection and the use of immunomodulation by feed additives to prevent future disease outbreaks in aquaculture. Imperative for these approaches are in vivo infection models that allow reliable, reproducible challenge experiments to monitor efficacy of new treatments. Trypanoplasma borreli and Trypanosoma carassii are both protozoan kinetoplastid extracellular blood parasites of fish. The Kinetoplastida contain a number of parasites of major importance to man, e.g.Trypanosoma brucei (sleeping sickness), Leishmania spp. (leishmaniasis), Trypanosoma cruzi (Chagas' disease). Both T. borreli and T. carassii are transmitted by blood-sucking leeches and infect cyprinids, the dominating species in freshwater aquaculture. Infection of carp with these parasites is an excellent model for comparative studies on host-parasite interactions with clear relevance to the problems faced by present day aquaculture ( chapter one ).

    Genetic selection for disease resistance can provide a major contribution to prophylaxis. One route to identify gene regions that determine susceptibility of fish to pathogens is the candidate gene approach. This approach is making use of known types of responses that have been proven important in the development of innate and acquired protective immunity. In chapter two the sequence of a candidate gene: the carp natural resistance-associated macrophage protein (NRAMP) is described. This protein is a putative metal transporter. Metals such as iron are essential nutrients for pathogens. Therefore, reducing iron availability can be an important part of the host defence strategy. Moreover, iron acts as a catalyst in the production of molecules such as hydroxyl radicals (OH·), which act as toxicants in the defence against intracellular pathogens. In chapter three the sequence of a second candidate gene: carp inducible nitric oxide synthase (iNOS) is described. Not only oxygen but also nitrogen radicals, produced by phagocytes, can act as toxicants, forming an important innate defence mechanism against pathogens. Trypanoplasma borreli or bacterial cell wall products induced iNOS expression in carp head kidney phagocytes leading to the production of high concentrations of the nitric oxide (NO) radical. The NO produced in vitro by head kidney phagocytes was cytostatic to the parasite.

    Carp challenged in vivo with T. borreli produce high amounts of NO ( chapter four ). The production of toxic molecules such as NO is potentially dangerous. In fact NO overproduction can lead to tissue damage in the host. Indeed, in vivo inhibition of NO production led to a higher rather than a lower survival of infected carp. A possible explanation for the harmful effect of NO in vivo could be the observation that, at least in vitro , NO can inhibit the proliferation of carp lymphocytes. Interestingly, in clear contrast with the effect of T. borreli , T. carassii did not induce production of NO.

    Lymphocytes are much more susceptible to the cytostatic effect of NO than phagocytes, which are mainly macrophages and neutrophilic granulocytes ( chapter five ). This difference could be ascribed to the fact that lymphocytes had lower levels of the most important cellular antioxidant glutathione (GSH). Furthermore, lymphocytes had lower levels of key enzymes involved in the maintenance of GSH compared to phagocytes.

    In chapter six we describe two sequences for carp tumour necrosis factor (TNF)a, which can be considered a third candidate gene for resistance to diseases of fish. Indeed, a polymorphism in carp TNFa2 could be associated with trypanotolerance. TNFais a cytokine produced mainly by phagocytes in response to inflammation, infection and other physiological challenges. In vitro , T. borreli could induce expression of TNFa, which mediated the production of NO by phagocytes and the proliferation of leukocytes.

    To study the exact role of phagocytes in the immune defence against T. borreli , we applied a technique to deplete carp of macrophages, in vivo ( chapter seven ). These animals became more susceptible to opportunistic bacterial infections. When infected with blood flagellate parasites, however, there was a moderate increase in parasitaemia only, demonstrating that macrophages do not play a major role in the resistance against T. borreli or T. carassii . Carp surviving an infection with T. borreli are resistant to re-infection for more than 12 months. This acquired resistance was not abrogated when the animals were depleted of macrophages.

    The major immunogenic molecules of T. borreli are proteins (probably membrane glycoproteins) and CpG DNA motifs ( chapter eight ). Carp infected with T. borreli were found to upregulate the expression of the inflammatory cytokines TNFaand interleukin (IL)-1bearly during infection. During a later phase, an upregulation of acute phase proteins (serum amyloid A, complement factor 3 and alpha-2-macroglobulin) was seen. Infection with T. borreli induced a non-specific proliferation of lymphocytes, most probably via the induction of TNFaand IL-1b, leading to the formation of parasite-aspecific antibodies. However, late during infection trypanotolerant carp do produce specific antibodies that act together with complement in lysing T. borreli .

    Stress, imposed by daily handling, severely affected resistance of carp to T. borreli ( chapter 9 ). Most likely, the effect was mediated by increased levels of cortisol. We demonstrated that, in vitro, cortisol inhibited T. borreli -induced expression of IL-1b, TNFa, SAA and iNOS thereby modulating the immune response. Cortisol also induced apoptosis of lymphocytes, but not of phagocytes. One of the first cellular metabolic changes during cortisol-induced apoptosis was a depletion of GSH. As GSH plays a major role in the protection against NO-mediated inhibition of lymphocyte proliferation, cortisol may render stressed animals more susceptible to the immunopathological effects of NO.

    In conclusion, infection of carp with blood flagellates presents an excellent model for comparative studies on host-parasite interactions. Evaluation of the modulating effects of stress on the immune response to this type of pathogens can provide information with clear relevance to the disease problems faced by intensive animal production systems.

    Regulation of feed intake in sheep : the role of hormones and metabolites
    Leuvenink, H. - \ 1998
    Agricultural University. Promotor(en): D. van der Heide; J. van Bruchem. - S.l. : Leuvenink - ISBN 9789054859482 - 164
    schapen - diervoedering - voeropname - infusie - voedingsstoffen - metabolieten - hormonen - bloed - propionzuur - insuline - sheep - animal feeding - feed intake - infusion - nutrients - metabolites - hormones - blood - propionic acid - insulin

    In the search for factors involved in the regulation of feed intake, many experiments have been performed in various species. In ruminants, very little is known about the physiological background of the mechanisms involved in feed intake regulation. In earlier experiments, much attention was paid to physical regulation suggesting that the capacity of the digestive tract is the most important limiting factor in feeding.

    Since ruminants are capable of meeting their energy requirements under a wide range of circumstances and feedstuffs, the concept of physiological regulation was introduced. Physiological regulation (or metabolic regulation) can be defined as feed-back signals arising from sensors in the periphery, which inform the central nervous system about the metabolic status of the individual. In the brain, presumably in the hypothalamus, these signals are integrated and decisions are made whether or not to eat. This thesis focuses on blood-borne factors related to feed intake in sheep. This includes the major energy providing components, metabolic hormones and gastrointestinal hormones.

    The aim of this thesis is:

    • To gain insight in the changes in nutrient and hormone concentrations following meals of different feed qualities.
    • To investigate blood borne nutrients/hormones which may be involved in the regulation of feed intake.

    To study this, experiments were performed in wether sheep provided with mesenteric, portal and jugular catheters.
    To address the effect of feeding and feed quality on nutrients and hormones, animals were fed during 90 minutes. Before, during and after feeding, blood samples were withdrawn from jugular and portal catheters in order to identify candidates for intake regulation. Two experimental pelleted grass diets, qualified as High Quality (HQ) and Low Quality (LQ) based on crude protein and fibre contents were fed according to a cross-over design.

    In chapter 2, short-term effects of feed intake on jugular and portal concentrations of metabolites such as Volatile Fatty Acids (VFA), Beta-hydroxy-butyrate (BHB) and glucose were studied. Rapid changes were observed in both jugular and portal veins due to feeding. Portal vein (PV) concentrations of acetate, propionate, butyrate, iso-butyrate and BHB were increased post-prandially in HQ-fed sheep. Due to consumption of LQ feed, bi-phasic patterns were found in acetate, propionate, butyrate levels, measured in the jugular vein (JV).

    The effect of feeding on nutrient concentration may largely differ as a result of feed quality. The PV-JV difference was used to estimate the release of nutrients into the portal vein. Differences in peripheral concentration of a blood component did not necessarily result from a difference in the release of the component but could also have resulted from a changed uptake by peripheral tissues. In most cases, the observed early changes (until 30 minutes past meal start) were probably due to changes in uptake rather than alterations in release. The changes observed later then 30 minutes were likely due to changes in release.

    In chapter 3, the response of metabolic and gastrointestinal hormones to feeding is described. Rapid fluctuations were shown for insulin, glucagon, Pancreatic Polypeptide (PP) and Cholecystokinin (CCK) levels in HQ-fed sheep. Sustained changes were observed for insulin, glucagon and gastrin levels in HQ-fed sheep. LQ-fed sheep showed rapid alterations in Growth Hormone (GH), gastrin, PP and CCK levels. Sustained changes were observed for insulin, GH, gastrin, PP and CCK levels.

    The rapid changes in hormone concentration may be due to decreased para-sympathetic activity and/or increased sympathetic activity. More sustained changes were likely nutrient induced. Feed quality mainly affected the magnitude of the meal induced changes in hormone levels, with the HQ-fed sheep showing more pronounced differences.

    In chapter 4, the hypothesis that propionate is a short-term feed intake regulating agent is discussed. In the first experiment, sheep were infused over 20 min with Na-propionate into the mesenteric vein, while monitoring feed intake and feeding pattern over 1.5 hours. Feed intake was reduced by infusions at 2 mmol/min which were associated with marked increases in jugular as well as portal concentrations of insulin, glucose and propionate.

    In a second experiment, animals were infused with 2 mmol/min Na-propionate into the portal vein. No decrease in feed intake was observed, though similar increases in insulin, glucose and propionate as found in mesenteric vein infused animals were observed. It was concluded that mesenteric propionate in high doses acted as a satiety factor. Possible explanations for the difference between site of infusion may be a different distribution of the infusate over the liver, and/or the presence of propionate sensitive receptors in the mesenteric/portal vein region.

    In a more extensive experiment, described in chapter 5, sheep were infused via the mesenteric catheter with 0, 1.5 or 6 mmol/min Na-propionate for 20 minutes. Infusion of 6 mmol/min Na-propionate decreased feed intake but also induced discomfort. Portal levels of propionate, glucose and insulin were increased while decreased levels of butyrate, BHB, gastrin, PP and CCK were observed. Jugular levels generally showed similar patterns as portal levels except for butyrate. Jugular butyrate was immediately increased after start of the meal, presumably due to a smaller liver uptake.

    Infusion of 1.5 mmol/min Na-propionate resulted in elevated levels of propionate and insulin while gastrin and PP concentrations were decreased.
    It was concluded that propionate is not a major factor influencing intake, since infusion of a physiological dose did not affect meal size. It is possible that effects found during and after a meal on insulin, gastrin, and PP can be attributed to propionate.

    Since propionate levels, which affected intake were rather high, and VFA's are reported to stimulate release of insulin, an experiment was performed in which sheep received an infusion with insulin. This study described in chapter 6, was designed to investigate the effect of insulin infusion on feed intake, feeding pattern and blood concentrations of metabolites and hormones related to feeding and feed quality. During a 90 minutes feeding period, sheep provided with jugular, portal and mesenteric catheters were infused via the mesenteric catheter with 6.7 mU/min insulin or saline for 20 minutes. Blood was frequently sampled from jugular and portal veins. The study was performed on two diets differing in feed quality.

    Infusion of insulin did not decrease feed intake but decreased feeding time. Portal insulin levels of sheep receiving an insulin infusion were increased in animals fed a low quality diet but not in animals fed a high quality diet. Insulin levels in the jugular vein were not influenced by infusion of insulin compared to saline infusion. No differences due to infusion of insulin were shown on glucose, glucagon, gastrin, and PP levels. Effects of diet composition were reflected by glucagon levels but not by other hormones.

    It was concluded that insulin might be a factor involved in satiety, but not by regulation of meal size. It was also postulated that regulation of endogenous insulin release might be more sensible in animals fed a higher feed quality.

    In chapters 7 and 8, the results are presented of a combined infusion of CCK (two dosages) and Na-propionate. In chapter 7, the effect of the 20 minutes infusion with 0, 1.2 or 2.4 nmol/min CCK-8 is described. Infusion of CCK-8 increased levels of CCK-8 in the portal vein but not in the jugular vein. A very accurate clearance of CCK-8 from the liver may have attributed to the absence of increased jugular levels. Infusion of both 1.2 and 2.4 nmol/min CCK-8 decreased portal and jugular CCK-33 levels, suggesting a decreased endogenous release of CCK. Portal PP levels were decreased as a result of 2.4 nmol/min CCK-8 infusion. This may be due to a decrease in release or an enhanced portal blood flow.

    Cortisol concentrations, as an indicator of stress, were decreased during infusion of saline but increased as a result of CCK-8 infusion. It was concluded that CCK-8 might have induced some discomfort. Despite the increased portal CCK-8 levels and the increased cortisol levels no effect was found on feed intake.

    In chapter 8, the effect of an infusion with 0, or 2.4 nmol/min CCK-8 or 0.5 mmol/min propionate or a combination of CCK and propionate are described.
    Feed intake was only reduced by combined infusion of CCK-8 and propionate but not by separate infusion of CCK-8 or propionate. Increased levels of propionate and insulin were observed following the propionate infusion. Infusion of CCK decreased propionate, acetate, butyrate, and glucose levels while insulin levels were initially increased followed by decreased levels. Combined infusion of CCK and propionate induced similar blood concentration as infusion of CCK solely on acetate, butyrate, glucose, and insulin, while propionate levels were decreased compared to propionate infused animals but increased compared to CCK infused sheep.

    It was postulated that decreased levels of VFA's and insulin may be due to increased portal flow and that mechanisms of induction of insulin secretion by propionate and CCK may be different.
    In chapter 9, some of the observations made in the preceding chapters are analysed using a conceptual model. The model proved very suitable in explaining profiles of hormones and metabolites following feed intake. It also proved useful in interpreting the effects the infusion studies. One of the major observations was that release and uptake are usually very tightly matched even during infusion of large amounts of propionate. It also showed that changed plasma concentration may arise from changed uptake (in case of the early peak in jugular propionate following feeding) or changed release (in case of insulin increase following feeding).

    Finally, in the general discussion (chapter 10) some remarks are made concerning the possible role of hormones and metabolites in the regulation of feed intake.
    In conclusion, as a result of feeding, sheep showed both rapid and more sustained changes in plasma concentration of several metabolites and hormones. Furthermore, differences in feed quality may result in differences in hormone and metabolite concentration but also in differences in plasma profiles.

    The infusion studies with propionate, insulin and CCK indicated that the regulation of intake must be regarded as a multifactorial process. It is therefore necessary to study intake regulation as a multifactorial system bearing in mind that gross manipulations may influence other systems involved in intake regulation. Experiments with low (physiological) dosages of combinations of hormones and metabolites should be performed to elucidate the concerted role of these substances.

    Varkens- en runderplasma en dierlijk en plantaardig eiwit in voer voor gespeende biggen
    Peet-Schwering, C.M.C. van der; Binnendijk, G.P. - \ 1997
    Rosmalen : Praktijkonderzoek varkenshouderij (Proefverslag / Praktijkonderzoek Varkenshouderij P1.185) - 20
    diervoedering - jonge dieren - biggen - voer - eiwitten - mest - bloed - lichaamsvloeistoffen - voer van dierlijke oorsprong - animal feeding - young animals - piglets - feeds - proteins - manures - blood - body fluids - feed of animal origin
    Varkens- en runderplasma en dierlijk en plantaardig eiwit in voer voor gespeende biggen
    Peet-Schwering, C. van der; Binnendijk, G. - \ 1997
    Praktijkonderzoek varkenshouderij 11 (1997)6. - ISSN 1382-0346 - p. 25 - 27.
    diervoedering - jonge dieren - biggen - voer - eiwitten - bloed - lichaamsvloeistoffen - groei - ontwikkeling - animal feeding - young animals - piglets - feeds - proteins - blood - body fluids - growth - development
    Speenvoer met 5% varkens- of runderplasma verbetert de voeropname en de groei van biggen gedurende de eerste veertien dagen van de opfokperiode. Met 5% varkensplasma in speenvoer worden vergelijkbare technische resultaten gehaald als met 5% runderplasma.
    Bloedplasma en bloedcellen in voer voor biggen
    Peet-Schwering, C. van der; Binnendijk, G. - \ 1997
    Praktijkonderzoek varkenshouderij 11 (1997)1. - ISSN 1382-0346 - p. 12 - 13.
    dierhouderij - bloed - bloedcellen - bloedplasma - bloedserum - samenstelling - ontwikkeling - voer - groei - biggen - productiviteit - rentabiliteit - spenen - animal husbandry - blood - blood cells - blood plasma - blood serum - composition - development - feeds - growth - piglets - productivity - profitability - weaning
    Speenvoer met 5% bloedplasma, dat gedurende de eerste acht dagen van de opfokperiode verstrekt wordt, verbetert in die periode de technische resultaten van de biggen.
    Blood cholesterol : a public health perspective
    Verschuren, W.M.M. - \ 1995
    Agricultural University. Promotor(en): D. Kromhout. - S.l. : Verschuren - ISBN 9789054854234 - 169
    vaatziekten - bloedstoornissen - hart- en vaatziekten - hart- en vaatstoornissen - bloed - cholesterol - lipiden - epidemieën - epidemiologie - nederland - vascular diseases - blood disorders - cardiovascular diseases - cardiovascular disorders - blood - cholesterol - lipids - epidemics - epidemiology - netherlands
    Changes in total cholesterol levels (TC) were studied using data from three epidemiological studies: about 30,000 men and women aged 37-43 were examined between 1974 and 1980 (CB Project), about 80,000 men aged 33-37 between 1981 and 1986 (RIFOH Project) and 42,000 men and women aged 20-59 from 1987 to 1992 (Monitoring Project on CVD Risk Factors). In men a decline in TC of 6.5% was observed between 1974 and 1992. However, the largest decrease took place between 1981 and 1986 in men in a limited age range (33-37 years), and there were indications that this decrease was not generalizable to other age groups. From 1987 to 1992, a decrease of 7% in HDL cholesterol levels (HDL-C) was observed in men, leading to an increase in the non-HDL-C/HDL-C ratio. In women, no changes in TC and HDL-C were observed.

    Analyses of data from 36,000 men and women aged 20-59 years showed that between ages 30 and 50 about 19-38% of the gender difference in TC was explained by differences in body mass index (BMI) and cigarette smoking between men and women. After age 50, the higher TC in women compared to men was largely due to the effect of the menopause. The TC increase associated with menopause was 0.45 mmol/l in non-smokers and 0.28 mmol/l in smokers. The difference between a low-risk and a high-risk lifestyle was 0.58 mmol/I for TC and 0.38 mmol/l for HDL-C in men, and 0.40 mmol/l for TC and 0.45 mmol/l for HDL-C in women.

    Twelve year follow-up of 50,000 men and women aged 30-54 (CB Project) showed that the adjusted relative risk for coronary heart disease (CHD) mortality for the highest compared to the lowest cholesterol quintile was 3.0 (95% CI 1.8-5.1) in men and 3.8 (95% Cl 1.1-13.1) in women. It was estimated that a TC reduction of 0.6 mmol/l was associated with a 20% lower CHD mortality. Low TC was not associated with non-cardiovascular mortality. All-cause mortality was positively related to total cholesterol, with a 60% and 46% higher risk in the highest compared to the lowest TC quintile for men and women respectively.

    Twenty-five year follow-up of the Seven Countries Study, in which over 12,000 men aged 40-59 at baseline participated, showed that relative risks for CHD mortality were similar in different cultures, but the absolute risks were strikingly different. At a cholesterol level of about 5.4 mmol/l agestandardized CHD mortality rates varied from 4% to 5% in Japan and Mediterranean Southern Europe to 15% in Northern Europe after adjustment for age, smoking and blood pressure. It was concluded that other factors, such as diet, typical for low-risk countries, modify the effect of TC on CHD mortality. In the Seven Countries Study, in non-smokers no association of TC with cancer mortality was observed, while non-cardiovascular/non-cancer mortality was elevated only at TC below 4.15 mmol/l. In smokers, cancer mortality and non-cardiovascular/non-cancer mortality were inversely associated with TC. All- cause mortality showed a J-shaped association with TC in non-smokers (lowest all-cause mortality for TC between 4.15 and 5.15 mmol/l), while all-cause mortality was unrelated to TC in smokers. Absolute mortality rates were higher in smokers than in non-smokers for all endpoints.

    Lowering the average TC level in the population is concluded to contribute to a reduction in the burden of CHD. Low cholesterol levels are not considered an important public health concern in the Netherlands. Changes in the lipid profile should preferably be achieved by lifestyle interventions such as a diet low in saturated fat and rich in fruits and vegetables, no cigarette smoking, a desirable body mass index (less than 25 kg/m 2) and a physically active lifestyle. Such a lifestyle will not only have a favorable impact on coronary heart disease, but is also compatible with recommendations on the prevention of other chronic diseases such as diabetes and cancer.

    Characterisation of fish leucocytes : an immunocytochemical and functional study in carp (Cyprinus carpio L.)
    Koumans - van Diepen, J.C.E. - \ 1993
    Agricultural University. Promotor(en): W.B. van Muiswinkel, co-promotor(en): J.H.W.M. Rombout. - S.l. : Koumans-van Diepen - ISBN 9789054851110 - 167
    cyprinidae - karper - bloedserum - fibrine - bloedplaatjes - bloed - erytrocyten - leukocyten - bloedplasma - reticulo-endotheliaal systeem - antilichamen - immunoglobulinen - immunocytochemie - cyprinidae - carp - blood serum - fibrin - platelets - blood - erythrocytes - leukocytes - blood plasma - reticuloendothelial system - antibodies - immunoglobulins - immunocytochemistry

    A panel of monoclonal antibodies (MAbs) against carp serum immunoglobulin (Ig), WCIs or carp thymocytes (T), WCTs were used for the characterisation of carp leucocytes. Unfortunately, all WCTs and some WCIs react with common carbohydrate determinants present on all leucocytes and Ig. Most WCIs react specific with protein determinants at the heavy chain of Ig. Consequently, B lymphocyte (sub) populations, plasma cells and Ig-binding cells could be studied. Ig molecules are found in clusters at the cell membrane of B cells and plasma cells, and in contrast to mammalian plasma cells, most carp plasma cells still have Ig at their surface membrane. Mainly the dull surface Ig-positive (sIg +) cells were stimulated by the mammalian B cell mitogen LPS and not by PHA (T cell mitogen) in vitro , whereas the sIg-negative (sIg -) cells were stimulated by PHA and not by LPS. The percentages of B cells and plasma cells showed an increase during ontogeny and reached a plateau at about 3 months and 8 months of age respectively. It is suggested that full development of the carp (humoral) immune system needs at least 8 months (at 21-22 °C). Three different subpopulations of B cells and plasma cells and at least two Ig isotypes can be distinguished based upon their reactivity with WCI 4 arid WCI 12. The distribution of the three B cell subpopulations appeared to be organ and age dependent which indicates functional differences between the Ig isotypes. Fc-like receptors were mainly demonstrated on gut macrophages while pronephros macrophages and neutrophilic granulocytes did not show Ig binding. Consequently, other forms of antigen opsonisation (e.g. complement) may play a role in phagocytosis by these non Ig-binding cells. Several procedures were tested for obtaining MAbs specific for Ig -lymphoid cells. It is concluded that the presence of immunodominant carbohydrate determinants is the major problem for obtaining specific MAbs. Tolerisation of mice against these determinants or the use of isolated membrane lysates from (sIg -) PBL appeared promising but till now only specific thrombocyte markers have been obtained. The use of more purified antigen is recommended in further attempts. The data presented in this thesis can be used for fundamental studies on cell interactions in the immune response, but also for more applied investigations on fish health control.

    De bepaling van sulfadimethoxine, sulfamethoxazol, trimethoprim en hun belangrijkste metabolieten in varkensplasma en -urine m.b.v. HPLC
    Huveneers - Oorsprong, M.B.M. ; Mengelers, M.J.B. ; Kuiper, H.A. - \ 1990
    Wageningen : RIKILT (Rapport / RIKILT 90.22) - 19
    varkens - bloed - urine - hippurinezuur - veterinaire producten - hplc - metabolieten - pigs - blood - urine - hippuric acid - veterinary products - hplc - metabolites
    Een analysemethode is opgezet voor de bepaling van sulfadimethoxine (SDM), sulfamethoxazol (SMX), trimethoprim (TMP) en hun belangrijkste metabolieten, zowel vrij als geconjugeerd, in plasma en urine van behandelde varkens.
    Naturally occurring androgens, estrogens and progestogens in the blood, urine and feces of young cattle : a literature survey
    Berende, P.L.M. ; Ginkel, L.A. van; Schilt, R. ; Arts, C.J.M. ; Stephany, R.W. ; Hartog, J.M.P. den - \ 1988
    Wageningen : RIKILT (Report / RIKILT 88.60) - 38
    kalveren - hormonen - androgenen - oestrogenen - progestogenen - bloed - urine - feces - calves - hormones - androgens - oestrogens - progestogens - blood - urine - faeces
    The sources discussed in this literature study give the level of androgens, estrogens, and progestogens found in the blood, urine and feces of veal calves. Since there were not eneough data available in these three matrices for veal valves, the literature data for male and female breeding calves in the age group of 7-11 months has also been added.
    Changes in blood acid-base characteristics, haemoglobin and lactate concentrations due to increasing moderate stress in pigs
    Wal, P.G. van der; Engel, B. - \ 1985
    Zeist etc. : IVO [etc.] (I.V.O.-report / Instituut voor Veeteeltkundig Onderzoek "Schoonoord" no. B-271) - 19
    bloed - bloedchemie - bloedfysiologie - mentale stress - neurosen - varkens - diergeneeskunde - blood - blood chemistry - blood physiology - mental stress - neuroses - pigs - veterinary science
    Zuur-base waarden en haemoglobine- en melkzuurconcentraties werden bepaald in varkensbloed. De monsters werden verkregen via een permanente catheter in de oorvene die was doorgeschoven tot in de vena cava cranialis. De eerste monsters werden afgenomen van varkens (n = 10) in rust; de volgende monsters werden verkregen na een vijftal opeenvolgende stadia van toenemende middelmatige stress. De stress bestond uit het fixeren van de dieren met een neusklem in combinatie met een elektrische prikkelaar als ernstigste vorm van belasting
    Bepaling van dapson, monoacetyldapson en diacetyldapson in bloed, serum en melk
    Beek, W.M.J. ; Aerts, M.M.L. - \ 1985
    Wageningen : RIKILT (Rapport / RIKILT 85.80) - 7
    dapson - dierbehandelingsmiddelen - hplc - melkproducten - bloed - analytische methoden - dapsone - animal treatments - hplc - milk products - blood - analytical methods
    Er zijn methoden ontwikkeld voor de analyse van dapson, monoacetyldapson en diacetyldapson in bloed en boerderijmelk. Na clean-up met behulp van Extrelutkolommen volgt analyse met isocratische reversed phase HPLC.
    The relationship between environmental lead and blood lead in children : a study in environmental epidemiology
    Brunekreef, B. - \ 1985
    Landbouwhogeschool Wageningen. Promotor(en): K. Biersteker; R.L. Zielhuis; J.P. Vandenbroucke. - Wageningen : Brunekreef - 185
    bloed - chemische eigenschappen - chemicaliën - kinderen - zuigelingen - lood - fysiologie - toxische stoffen - milieuhygiëne - blood - chemical properties - chemicals - children - infants - lead - physiology - toxic substances - environmental hygiene

    This study deals with the relationship between environmental lead and blood lead in children.
    Chapter 1 provides a summary of the environmental health aspects of lead. The occurrence of lead in the environment and in man is described; children are discussed as a population at risk for undue lead absorption, and the exposure-response system is briefly outlined.
    Chapter 2 discusses a number of methodological issues in studies on the relationship between environmental lead and blood lead in children. Lead is present in various environmental media like air, soil and dust. From all these media, lead intake by children may occur, by inhalation or ingestion. The inhalation rate per kg body weight is larger in children than in adults, due to a higher metabolism. The ingestion of dust and dirt cannot be easily quantified; at present, measurement of the lead concentration in dust and dirt usually serves as a surrogate. The concentration of lead in blood has been the major dependent variable in studies on the relationship between environmental lead exposure and internal lead exposure. The concentration of lead in blood does not only depend on intake but also on the fractional absorption of lead from the gut, and on distribution and excretion patterns within the body. All of these vary with age. Nutritional factors are important as well, for example dietary calcium, iron, phosphorus and fat. Lead is not only present in the general environment but also in food and drinking water, both of which may act as predominant sources of lead intake. Lead in food originates in part from environmental pollution, and it is still debated how large this part actually is. Lead in drinking water usually originates from pipes or storage facilities. In the United States especially, lead from crumbling paint is an important source for children; paint lead does not seem to be of general importance in The Netherlands, however.
    The relationship between total lead intake and the concentration of lead in blood is usually given as a curvilinear downward function. The implication of this is that at low levels of exposure, a given increase of intake is expected to result in a stronger increase in blood lead concentrations than at high levels of exposure. In some studies, it has been customary to adjust relationships between air lead and blood lead for lead in other media. As lead in the air and lead in other media like soil and dust often originate from the same source or sources, such a procedure may under-estimate the impact of environmental lead on children's blood lead.
    It is difficult to measure the intake of lead from the environment by children exactly. Instead, the concentration of lead in one or more environmental media is usually measured as an index of exposure.
    Apart from being only approximations of actual lead intake from the environment, these concentrations also tend to have large temporal and spatial variations. A decomposition of total variation into within-subjects and between- subjects variation is a weans to estimate the reliability of exposure indicators. If the within-subjects variation of exposure indicators is large compared to the between- subjects variation, the impact of environmental lead exposure on blood lead will usually be underestimated in a regression analysis.
    Chapter 3 reviews a number of studies from which estimates of relationships between environmental lead and children's blood lead can be obtained. Aggregate relationships are emphasized, i.e. it is not attempted to estimate the separate contributions of inhalation, ingestion of soil, dust etc. as the available data usually do not permit such an analysis. Aggregate relationships are relationships in which different indicators of lead exposure are thought to represent all environmental exposure. When the concentration of lead in air is taken as an indicator, a blood lead/air lead slope of about 3-5 μg/100 ml per μg/m 3 is obtained. When the concentration of lead in soil, street dust or house dust is taken as an indicator, most blood lead/soil (dust) lead slopes are in the order of 5.0 - 10.0 μg/100 ml per g/kg.
    Although the ranges of the different types of estimates are wide, the review suggests that for children, lead intake from the environment constitutes a major part of total lead intake in quite a number of situations.
    Chapter 4 is a description of our study on environmental lead and blood lead in children living in Rotterdam, The Hague and Zoetermeer which was performed in 1981.
    Blood lead concentrations in children were different between city centers and suburbs. After adjustment for a number of confounders, more than half of the difference remained. Most probably, this was caused by differences in environmental lead pollution as most indicators of lead exposure were clearly different between city centers and suburbs. In a multiple regression analysis, most exposure indicators were significantly associated with the concentration of lead in blood, after adjustment for a number of confounders. Further analysis of the origins of lead in the environment suggested that in the area under investigation, vehicular traffic was the main source.
    When our study results were compared with those of others, the estimated impact of environmental lead on children's blood lead was somewhat higher than in most other studies, but the difference was not great, considering the wide range in estimates which was reported in chapter 3. Theoretically, the differences can be explained by the low level of exposure which was studied, and by the use of repeated exposure measurements. As indicated in chapter 2, a given exposure difference is expected to result in a larger blood lead difference at low overall levels of PbB than at a high overall level of PbB. Also, repetition of exposure measurements leads to a more precise estimate of exposure, and can theoretically be expected to result in a higher exposure impact estimate than when exposure is only measured once, as was the case in most studies reviewed in chapter 3.

    Veranderingen in het bloed van varkens ten gevolge van diverse factoren = Changes in porcine blood as a consequence of various factors
    Wal, P.G. van der - \ 1983
    Zeist : I.V.O. (Rapport / Instituut voor Veeteeltkundig Onderzoek "Schoonoord" no. B-225) - 35
    bloed - bloedchemie - bloedfysiologie - karakteristieken - patronen - varkens - variatie - blood - blood chemistry - blood physiology - characteristics - patterns - pigs - variation
    Determinants of total and high density lipoprotein cholesterol in boys and men with special reference to diet
    Knuiman, J.T. - \ 1983
    Landbouwhogeschool Wageningen. Promotor(en): J.G.A.J. Hautvast, co-promotor(en): C.E. West. - Wageningen : Knuiman - 99
    bloed - bloedstoornissen - hart- en vaatziekten - hart- en vaatstoornissen - cholesterol - consumptiepatronen - voedselhygiëne - mannen - voedingstoestand - vaatziekten - blood - blood disorders - cardiovascular diseases - cardiovascular disorders - cholesterol - consumption patterns - food hygiene - men - nutritional state - vascular diseases
    At present it is assumed that atherosclerosis begins in childhood and that this process may ultimately result in the manifestations of coronary heart disease later in life. For this reason it is relevant to study the distribution of risk indicators for coronary heart disease (CHD) in children from different countries and to seek possible determinants of these risk indicators.

    In Chapter 1 a general overview is given of coronary heart disease and its determinants. The reasons and objectives for research on CHD and the risk indicators for CHD are also discussed.

    In Chapter 2 the results are presented of a study on the distributions of mean total and HDL cholesterol concentrations in boys aged 7 and 8 years from urban and rural regions in 16 countries. A standardized protocol was used for the collection of samples with the analyses being carried out in one laboratory. The results of this study showed that the concentrations of total cholesterol in Dutch boys are similar to those of boys from Denmark, Austria, Ireland and Sweden but are lower than those of Finnish boys and higher than those of African and Asian boys. The mean concentrations of HDL cholesterol of the boys appeared to increase linearly with that of total cholesterol. This would indicate that both the concentrations of total and HDL cholesterol increase under the influence of a westernized diet. It would also indicate that the mean concentration of HDL cholesterol would be positively related to the incidence of coronary heart disease when different populations are compared, provided that the findings in boys could be extrapolated to adults.

    Chapter 3 deals with the concentrations of total and HDL cholesterol in two age-categories of adult men from thirteen countries. The concentrations of total and HDL cholesterol were on average higher in the groups of men from the European countries than in those from Asia and Africa. Although the tendency for a concomitant increase of mean HDL cholesterol and total cholesterol concentrations was less clear in the adult men than it was in the boys, there was no tendency for lower HDL cholesterol concentrations in men with higher total cholesterol concentrations. The body mass index appeared to be positively related with the concentrations of total cholesterol and negatively with that of HDL cholesterol.

    Chapter 4 deals with the concentrations of total and HDL cholesterol in macrobiotic, vegetarian and non-vegetarian men and boys. The concentrations of both total and HDL cholesterol were lower in the macrobiotic men and boys than in the other groups except for the concentration of HDL cholesterol in the non-vegetarian men. The variation between groups in the concentration of HDL cholesterol appeared to be largely due to variations in the concentration of cholesterol in the HDL 2 fraction (1.063 < ρ 20 < 1.125).

    In Chapter 5 the results are described of a more in depth study on the determinants of total and HDL cholesterol in boys from Finland, the Netherlands, Italy, the Philippines and Ghana. Positive correlations were found between the intake of fat, saturated fatty acids, monounsaturated fatty acids and dietary cholesterol and the concentrations of total and HDL cholesterol within several groups. Using the regression coefficients from a multiple regression analysis on the pooled data, it could be calculated that on average 24 percent of the inter-country differences in the levels of total cholesterol is explained by differences in the intakes of saturated fatty acids. Differences between the groups of the different countries 'in the intakesof carbohydrate explained on average 29 percent of the differences in the concentrations of HDL cholesterol. The results support the hypothesis that higher concentrations of total and HDL cholesterol are associated with western types of diets which are rich in saturated fatty acids and relatively poor in complex carbohydrates.

    Chapter 6 contains a general discussion of the various studies. The main conclusions were the following:
    - young boys from countries like Finland, the Netherlands, Denmark, Austria and Sweden are likely to be at a higher risk of developing coronary heart disease than boys from Greece or Portugal and boys from Asian and African countries;
    - the negative relationship between HDL cholesterol concentration and mortality or incidence from coronary heart disease as found within populations is not incompatible with the absence of a negative or even the presence of a positive relationship between HDL cholesterol and mortality from coronary heart disease when different countries are compared;
    - the changes induced by diet in the concentrations of total and HDL cholesterol tend to be parallel;
    - high concentrations of HDL cholesterol associated with a high intake of animal fat probably reflect a higher capacity to handle large amounts of dietary fat;
    - low concentrations of HDL cholesterol associated with a high intake of animal fat probably reflect a lower capacity to handle large amounts of dietary fat or when associated with a low intake of fat a normal capacity to handle dietary fat;
    - diets with relatively high proportions of food from vegetable origin, especially those relatively rich in complex carbohydrates and relatively poor in saturated fat, together with a considerable proportion of physical activity and an optimum level of body fatness might be beneficial for the prevention of the development of atherosclerosis in childhood.

    Thus it has been shown that epidemiological studies can play an important role in elucidating the relationship between diet and coronary heart disease. In particular, it has been possible to develop hypotheses on the significance of the concentration of HDL cholesterol as a risk factor for coronary heart disease.

    Gedetailleerde gegevens van normaal bloedgaswaarden, haemoglobine- en melkzuurconcentraties bij varkens
    Wal, P.G. van der; Hulshof, H.G. ; Essen, G. van - \ 1982
    Zeist : I.V.O. (Rapport / Instituut voor Veeteeltkundig Onderzoek "Schoonoord" no. B-188) - 22
    bloed - bloedchemie - bloedfysiologie - elisa - immunologische technieken - nederland - varkens - blood - blood chemistry - blood physiology - immunological techniques - netherlands - pigs
    De actuele pCO2 van veneus bloed : de directe pCO2-meting in vergelijking met een indirecte bepalingsmethode
    Wal, P.G. van der; Hulshof, H.G. ; Essen, G. van - \ 1982
    Zeist : I.V.O. (Rapport / Instituut voor Veeteeltkundig Onderzoek "Schoonoord" no. B-194) - 11
    biologische technieken - bloed - bloedchemie - bloedfysiologie - kooldioxide - rundvee - uitrusting - experimenten - methodologie - nederland - varkens - biological techniques - blood - blood chemistry - blood physiology - carbon dioxide - cattle - equipment - experiments - methodology - netherlands - pigs
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