A dosagem de gama-glutamil transpeptidase sérica (GGT) tem sido amplamente utilizada como marcador bioquímico do uso de álcool. Sua utilização no rastreamento do consumo de álcool em pacientes com doença hepática diagnosticada necessita ser melhor investigada. Neste estudo foram comparados os níveis séricos de GGT ao padrão de consumo de álcool avaliado por meio do teste de rastreamento AUDIT em 126 indivíduos hepatopatas (94 homens e 32 mulheres), com idade entre 20 a 69 anos. Vinte e dois indivíduos (17,4%) obtiveram pontuação maior ou igual a 8 no AUDIT (casos positivos para suspeição de problemas relacionados ao consumo de álcool nos últimos 12 meses). Este percentual eleva-se a 32,7% nos pacientes com diagnóstico de hepatopatia associada ao uso do álcool. A gravidade da hepatopatia foi avaliada com base na classificação de Child-Pugh: 86 pacientes foram classificados como A (68,2%) e 40 como B ou C (31,8%). Todos os pacientes com pontuação &#8805;8 no AUDIT foram do sexo masculino e 77,3% deles tiveram diagnóstico de doença hepática associada ao uso de álcool (p<0,0001). Pacientes com pontuação &#8805;8 no AUDIT apresentaram valores médios de GGT significantemente maiores quando comparados àqueles menores que 8 (526,9 U/L ± 1006,8 versus 138,7 U/L ± 123, p<0,00001). O teste de correlação de Pearson indicou uma forte associação entre a elevação dos valores de GGT em pacientes hepatopatas que fazem uso de álcool e a pontuação total no AUDIT. Pacientes hepatopatas, apesar de manifestarem valores elevados de GGT, as diferenças não estiveram relacionadas à gravidade da hepatopatia. Não houve diferença estatisticamente significante em relação à pontuação &#8805;8 no AUDIT e idade, estado civil, situação de emprego, escolaridade, renda familiar, cor e religião. Nossos dados sugerem que a utilização combinada do GGT e do AUDIT pode ser útil em discriminar pacientes hepatopatas usuários de álcool, principalmente em países em desenvolvimento como o Brasil, devido ampla disponibilidade e baixo custo. / The gamma glutamyltranspeptidase (GGT) has been widely employed as excessive alcohol use biochemical marker. Its utilization in screening of alcohol consumption in patients with diagnosed liver diseases must be better investigated. In this study, serum levels of GGT were compared to the pattern of alcohol consumption using the AUDIT test as alcohol screening instrument in 126 patients with liver disease (94 men and 32 women), with age ranged from 20 to 69 years old. Twenty two patients (17,4%) scored higher or equal 8 in the AUDIT (positive cases for alcohol related problems suspicion in the last 12 months). This proportion increases to 32,7% in patients with alcohol-associated liver disease. The severity of the liver damage was evaluated by the Child-Pugh classification: 86 patients were classified as A (68,2%) and 40 as B or C (31,8%). All patients who scored 8 or higher in the AUDIT were men and had mean values of GGT significantly higher when compared to those who scored less than 8 (526,9 U/L ± 1006,8 versus 138,7 U/L ± 123, p<0,00001). Among them 77,3% had alcohol-associated liver disease diagnosis (p<0,0001). The Pearson’s correlation test showed a strong association between increase of the GGT values in patients that use alcohol and total score in the AUDIT. No association between increase of GGT values and severity of liver damage was found. No statistically significance was observed also between AUDIT scores 8 or higher to age, civil status, employment situation, education, familiar earnings, race or religion. Our data suggest that the combined use of GGT and AUDIT can be useful in discriminating liver disease patients that use alcohol, particularly in developing countries like Brazil, due to their widely availability and low costs.

A dosagem de gama-glutamil transpeptidase sérica (GGT) tem sido amplamente utilizada como marcador bioquímico do uso de álcool. Sua utilização no rastreamento do consumo de álcool em pacientes com doença hepática diagnosticada necessita ser melhor investigada. Neste estudo foram comparados os níveis séricos de GGT ao padrão de consumo de álcool avaliado por meio do teste de rastreamento AUDIT em 126 indivíduos hepatopatas (94 homens e 32 mulheres), com idade entre 20 a 69 anos. Vinte e dois indivíduos (17,4%) obtiveram pontuação maior ou igual a 8 no AUDIT (casos positivos para suspeição de problemas relacionados ao consumo de álcool nos últimos 12 meses). Este percentual eleva-se a 32,7% nos pacientes com diagnóstico de hepatopatia associada ao uso do álcool. A gravidade da hepatopatia foi avaliada com base na classificação de Child-Pugh: 86 pacientes foram classificados como A (68,2%) e 40 como B ou C (31,8%). Todos os pacientes com pontuação &#8805;8 no AUDIT foram do sexo masculino e 77,3% deles tiveram diagnóstico de doença hepática associada ao uso de álcool (p<0,0001). Pacientes com pontuação &#8805;8 no AUDIT apresentaram valores médios de GGT significantemente maiores quando comparados àqueles menores que 8 (526,9 U/L ± 1006,8 versus 138,7 U/L ± 123, p<0,00001). O teste de correlação de Pearson indicou uma forte associação entre a elevação dos valores de GGT em pacientes hepatopatas que fazem uso de álcool e a pontuação total no AUDIT. Pacientes hepatopatas, apesar de manifestarem valores elevados de GGT, as diferenças não estiveram relacionadas à gravidade da hepatopatia. Não houve diferença estatisticamente significante em relação à pontuação &#8805;8 no AUDIT e idade, estado civil, situação de emprego, escolaridade, renda familiar, cor e religião. Nossos dados sugerem que a utilização combinada do GGT e do AUDIT pode ser útil em discriminar pacientes hepatopatas usuários de álcool, principalmente em países em desenvolvimento como o Brasil, devido ampla disponibilidade e baixo custo. / The gamma glutamyltranspeptidase (GGT) has been widely employed as excessive alcohol use biochemical marker. Its utilization in screening of alcohol consumption in patients with diagnosed liver diseases must be better investigated. In this study, serum levels of GGT were compared to the pattern of alcohol consumption using the AUDIT test as alcohol screening instrument in 126 patients with liver disease (94 men and 32 women), with age ranged from 20 to 69 years old. Twenty two patients (17,4%) scored higher or equal 8 in the AUDIT (positive cases for alcohol related problems suspicion in the last 12 months). This proportion increases to 32,7% in patients with alcohol-associated liver disease. The severity of the liver damage was evaluated by the Child-Pugh classification: 86 patients were classified as A (68,2%) and 40 as B or C (31,8%). All patients who scored 8 or higher in the AUDIT were men and had mean values of GGT significantly higher when compared to those who scored less than 8 (526,9 U/L ± 1006,8 versus 138,7 U/L ± 123, p<0,00001). Among them 77,3% had alcohol-associated liver disease diagnosis (p<0,0001). The Pearson’s correlation test showed a strong association between increase of the GGT values in patients that use alcohol and total score in the AUDIT. No association between increase of GGT values and severity of liver damage was found. No statistically significance was observed also between AUDIT scores 8 or higher to age, civil status, employment situation, education, familiar earnings, race or religion. Our data suggest that the combined use of GGT and AUDIT can be useful in discriminating liver disease patients that use alcohol, particularly in developing countries like Brazil, due to their widely availability and low costs.

The main focus of bone loss and Osteoporosis (OP) research has been limited almost entirely to women, but OP has become increasingly common in older men and the impact of hip fracture on mortality may actually be greater in men. OP is a major cause of morbidity and mortality in developed countries, at a cost that currently exceeds $10 billion per year in the United States (US) alone. Osteoporotic fractures affect 50 % of women and 20-30% of white men and 4% of black men over the age of 50 years. These statistics may even increase because of increasing life expectancy. Few studies focusing on Blacks have been published to date and very little is known regarding the bone health and the aetiology and prevalence of OP and fractures among older South African blacks. From the above information it is clear that OP is of considerable clinical and economic importance. Without information on the patterns and determinants of bone loss, the formulation of rational prevention and treatment strategies in these groups is not possible. The aim of the study described in this thesis was to investigate the influence of the dietary factors (iron, vitamin C, and protein) and lifestyle factors (alcohol and tobacco smoking) on osteoporotic fractures and bone mineral density in older South African black men using a case-control study design. Sixteen black male patients with fractures of the proximal femur, the proximal humerus or the distal radius and who conformed to the inclusion and exclusion criteria were included in the study. An equal amount of age-matched (K? years), apparently healthy black men with no previous fracture (of the proximal femur and humerus and distal radius), were recruited as a control group. Dual energy X-ray absorptiometry (DEXA) was used for the measurement of the lumbar vertebrae and the proximal femur (hip). Questionnaires were used to gather demographic and medical information, data on physical activity and dietary intakes. Anthropometric measurements and blood samples were taken. Appropriate biochemical analyses were done with standard methods. Both the cases and controls were osteoporotic according to the mean lumbar spine BMD determined in both groups. The BMD was only marginally lower in the cases than in the controls and therefore not statistically significant. The mean tobacco pack years of the cases (13.29) [95% CI: 4.44; 22.141 were almost double that of the controls (7.43) [1.83; 13.031 but it was not statistically significant (p=0.55). Tobacco pack years were negatively associated with BMD of the lumbar spine (p=0.008) even after controlling for possible confounding SUMMARY factors (p=0.001). Malnutrition, as indicated by the low dietary intakes of energy, protein, vitamin C, iron and low BMI, could play a role in the lower bone mineral density (BMD) observed in the cases. The mean protein intakes of the cases (56.1 19) [46.49; 65.741 were very low compared to the recommended 639 per day. This low protein intake was also significantly less compared to the controls (739) [58.28; 88.311. lron intake tended to be lower in the cases compared to the controls (p=0.09). lron intake was not associated with BMD, however, in the stepwise regression analysis; iron intake came out as a possible predictor of BMD of both the lumbar spine and hip, although it was not statistically significant. The BMI was c 19 kg/m2 in 50% of the cases and the controls. S-GGT, a marker of alcohol intake, was significantly increased in the cases with a mean value of 65.88ulL opposed to the 36.33UIL in the control group. S-GGT was the most important predictor of BMD in both the hip and the lumbar spine. There was a significant statistical correlation between lumbar spine BMD (p=0.04); hip BMD (p=0.02) and s-GGT. In conclusion it can be said that malnutrition played a vital role in the low BMD aggravated by the use of tobacco from a young age and alcohol in excessive amounts over weekends. From the results of this study it can be recommended that any intervention programme should focus on alcohol abuse, tobacco smoking and improvement in nutritional status. Children should be encouraged not to smoke and be educated on the detrimental effects of alcohol. It is important to address dietary risk factors associated with OP, namely to increase the overall nutrition of the South African black male with low cost protein and calcium products. Vitamin C enhances iron absorption and may be beneficial for bone collagen. The increased intake thereof by using seasonal fruit can therefore be recommended. / Thesis (M.Sc. (Dietetics))--North-West University, Potchefstroom Campus, 2004.

The main focus of bone loss and Osteoporosis (OP) research has been limited almost entirely to women, but OP has become increasingly common in older men and the impact of hip fracture on mortality may actually be greater in men. OP is a major cause of morbidity and mortality in developed countries, at a cost that currently exceeds $10 billion per year in the United States (US) alone. Osteoporotic fractures affect 50 % of women and 20-30% of white men and 4% of black men over the age of 50 years. These statistics may even increase because of increasing life expectancy. Few studies focusing on Blacks have been published to date and very little is known regarding the bone health and the aetiology and prevalence of OP and fractures among older South African blacks. From the above information it is clear that OP is of considerable clinical and economic importance. Without information on the patterns and determinants of bone loss, the formulation of rational prevention and treatment strategies in these groups is not possible. The aim of the study described in this thesis was to investigate the influence of the dietary factors (iron, vitamin C, and protein) and lifestyle factors (alcohol and tobacco smoking) on osteoporotic fractures and bone mineral density in older South African black men using a case-control study design. Sixteen black male patients with fractures of the proximal femur, the proximal humerus or the distal radius and who conformed to the inclusion and exclusion criteria were included in the study. An equal amount of age-matched (K? years), apparently healthy black men with no previous fracture (of the proximal femur and humerus and distal radius), were recruited as a control group. Dual energy X-ray absorptiometry (DEXA) was used for the measurement of the lumbar vertebrae and the proximal femur (hip). Questionnaires were used to gather demographic and medical information, data on physical activity and dietary intakes. Anthropometric measurements and blood samples were taken. Appropriate biochemical analyses were done with standard methods. Both the cases and controls were osteoporotic according to the mean lumbar spine BMD determined in both groups. The BMD was only marginally lower in the cases than in the controls and therefore not statistically significant. The mean tobacco pack years of the cases (13.29) [95% CI: 4.44; 22.141 were almost double that of the controls (7.43) [1.83; 13.031 but it was not statistically significant (p=0.55). Tobacco pack years were negatively associated with BMD of the lumbar spine (p=0.008) even after controlling for possible confounding SUMMARY factors (p=0.001). Malnutrition, as indicated by the low dietary intakes of energy, protein, vitamin C, iron and low BMI, could play a role in the lower bone mineral density (BMD) observed in the cases. The mean protein intakes of the cases (56.1 19) [46.49; 65.741 were very low compared to the recommended 639 per day. This low protein intake was also significantly less compared to the controls (739) [58.28; 88.311. lron intake tended to be lower in the cases compared to the controls (p=0.09). lron intake was not associated with BMD, however, in the stepwise regression analysis; iron intake came out as a possible predictor of BMD of both the lumbar spine and hip, although it was not statistically significant. The BMI was c 19 kg/m2 in 50% of the cases and the controls. S-GGT, a marker of alcohol intake, was significantly increased in the cases with a mean value of 65.88ulL opposed to the 36.33UIL in the control group. S-GGT was the most important predictor of BMD in both the hip and the lumbar spine. There was a significant statistical correlation between lumbar spine BMD (p=0.04); hip BMD (p=0.02) and s-GGT. In conclusion it can be said that malnutrition played a vital role in the low BMD aggravated by the use of tobacco from a young age and alcohol in excessive amounts over weekends. From the results of this study it can be recommended that any intervention programme should focus on alcohol abuse, tobacco smoking and improvement in nutritional status. Children should be encouraged not to smoke and be educated on the detrimental effects of alcohol. It is important to address dietary risk factors associated with OP, namely to increase the overall nutrition of the South African black male with low cost protein and calcium products. Vitamin C enhances iron absorption and may be beneficial for bone collagen. The increased intake thereof by using seasonal fruit can therefore be recommended. / Thesis (M.Sc. (Dietetics))--North-West University, Potchefstroom Campus, 2004.

<i>Gaeumannomyces graminis var. triciti (Ggt)</i>, the causal agent of take-all in wheat, is difficult to detect accurately and rapidly due to its similarity to fungi in the Gaeumannomyces-Phialophora complex. My objectives are to detect the fungus in infested plants and soil, and to predict effective combinations of bacteria as biological control agents. Detection was based on avenacinase-based primers and polymerase chain reaction (PCR) conditions specified by earlier research. PCR conditions were modified to effect detection. The annealing temperature was lowered from 68 to 62°C for plant and soil extracts, and the concentration of Taq polymerase was doubled for soil extracts. The lowest detection limit for plant extraction was with plant grown on 4 g Ggt-infested millet seed per kg soil, and that for soil extraction was 16 <span style="font-family:Symbol">m</span>g of purified Ggt DNA per g soil. Chemical and cultural control methods are currently inadequate. Biological control using bacteria is an alternative. Combinations of several bacterial strains are expected to work better than a single strain, but they may be less effective if bacteria antagonize each other or compete for the same rhizosphere habitat. Antagonism of potential biological control agents were assessed using a Petri plate assay. To estimate possible habitat competition, nutritional profiles of the strains were evaluated using the BIOLOG system. I hypothesized that bacteria not antagonistic to each other and having low coefficients of nutritional similarity would make better biological control combinations. Six bacterial combinations gave better mean root weight in the greenhouse experiment but not in the field. / Master of Science

L'athérosclérose est une maladie chronique à évolution lente caractérisée par la formation de plaques d'athérome, consistant en l’accumulation de lipoprotéines de basse densité (LDL), de leucocytes, de cellules spumeuses, la migration des cellules musculaires lisses (CML) et l’altération des cellules endotheliales (ECs). Ces phénomènes conduisent à la formation d'un noyau nécrotique incluant des régions calcifiées. La genèse de l'athérosclérose et de l’instabilité de la plaque d’athérome sont le résultat d'une synergie entre inflammation et stress oxydant. Les données actuelles identifient plusieurs populations de macrophages dans la plaque d’athérome présentant différents phénotypes en lien avec l’inflammation (pro-inflammatoire: M1, anti-inflammatoire: M2) ou avec des modifications redox de l’environnement (Mox). Stress oxydant et inflammation sont liés et jouent un rôle important dans (i) la dysfonction endothéliale induisant une diminution de la biodisponibilité du monoxyde d’azote (NO), (ii) l'oxydation des LDL, (iii) le remodelage de la lésion (régulation de protéases et d’antiprotéases) et (iv) la prolifération des CML. Les CML sont le deuxième type cellulaire le plus abondant dans la lésion athérosclérotique après les macrophages, leur hyperprolifération est la conséquence d’une dédifférenciation cellulaire d’un phénotype contractile à sécrétoire, augmentant leur capacité proliférative et migratoire. Les donneurs de NO, comme les S-nitrosothiols, connus également pour protéger contre le stress oxydant grâce essentiellement à la S-nitrosation, peuvent contrer la carence en NO. Parmi eux, le S- nitrosoglutathion (GSNO), forme physiologique de stockage de NO dans les tissus, spécifiquement metabolisé par la gamma-glutamyl transférase (GGT) peut être envisagé. La corrélation entre l’augmentation des concentrations sériques de GGT et les facteurs de risque cardiovasculaire a récemment été démontrée. En particulier, seule la b-GGT s'accumule dans les plaques d'athérome, et concorde avec l’apparition d'autres marqueurs histologiques de vulnérabilité de la plaque. Étant donné que, les macrophages et les CML sont les principaux types cellulaires retrouvés dans les lésions athérosclérotiques et semblaient être colocalisés avec la GGT, l'attention de ce travail de thèse a été centrée sur la compréhension de la provenance de la GGT et son rôle dans le métabolisme du GSNO au sein de la plaque d’athérome. Une première partie de ce manuscrit vise à identifier l'origine de la GGT accumulée dans la plaque d’athérome, et à élucider entre le stimulus inflammatoire et oxydant, qui est responsable de l'accumulation de GGT dans la plaque d'athérome. La deuxième partie a été consacrée à la restauration de la biodisponibilité de NO dans les CML en condition de stress oxydant avec un intérêt particulier porté sur l'identification des protéines S-nitrosés / Atherosclerosis is a slowly progressing chronic disease characterized by the formation of atherosclerotic plaques consisting of accumulated low density lipoprotein (LDL), leukocytes, foam cells, migrated smooth muscle cells (SMCs) and altered endothelial cells (ECs), leading to the formation of necrotic cores with calcified regions. Atherosclerosis genesis and subsequent instability of atherosclerotic plaques result from a synergy between inflammation and oxidative stress. Current data identified several macrophage populations within the atherosclerotic plaque showing different inflammatory phenotypes (pro-inflammatory: M1, anti-inflammatory: M2) or functions in response to redox changes in the environment (Mox). The oxidative stress linked to inflammation plays an important role in (i) endothelial dysfunction, with reduced nitric oxide (NO) bioavailability, (ii) LDL oxidation, (iii) lesion remodeling (regulation of proteases and antiproteases) and (iv) SMCs proliferation. Indeed, SMCs are the second more abundant cell type, after macrophages, in the atherosclerotic lesion because their dedifferentiation from contractile to secreting phenotype increased their proliferation and migration capacity. NO donors, like S-nitrosothiols, also known to protect from oxidative stress by S-nitrosation, could counteract this NO deficiency. Among them, the S-nitrosoglutathione (GSNO), a physiological storage form of NO in tissues, specifically catabolized by the gamma-glutamyltransferase (GGT) is considered. Recently, it has been shown that the increased serum level of GGT is an independent risk factor for cardiovascular mortality related to atherosclerotic disease. In particular, only the big fraction (b-GGT) has been detected inside human atherosclerotic plaques associated to CD68+ macrophage-derived foam cells. As macrophages and SMCs are the main cell types found in atherosclerotic lesion and seemed to be colocalized with GGT, the attention of this thesis work was focused on the understanding of GGT provenance and its role in the GSNO metabolism within the atherosclerotic plaque. A first part of the thesis was to identify the origin of GGT accumulating inside atherosclerotic plaques, and to decipher between inflammation and oxidative stress stimuli, which one is responsible of GGT accumulation in atherosclerotic plaques. The second part was dedicated to the restoration of NO bioavailability within SMCs under oxidative stress with a focus on the identification of S-nitrosated proteins

Einleitung: Vitamin B12 hat wichtige Funktionen im Energiestoffwechsel sowie bei der Erythropoese. Beide Funktionskreise werden bei Hochleistungskühen besonders beansprucht und können bei Belastungen und ungenügender Vitamin-B12-Versorgung Ausgangspunkt für klinische Störungen werden. Ziele der Untersuchungen: In den vorliegenden Studien wurde der Fragestellung nachgegangen, wie sich die Vitamin-B12-Konzentration im Blutserum von Milchkühen in der Frühlaktation verhält und welche Zusammenhänge zu Stoffwechselparametern, dem Erythrogramm sowie dem Gesundheitsstatus der Kühe bestehen. Des Weiteren wurde geprüft, inwieweit der postpartale Stoffwechsel und der Gesundheitsstatus durch orale Vitamin-B12-Substitutionen stabilisiert werden können. Material und Methoden: Die Untersuchungen zur Vitamin-B12-Statuserhebung erfolgten an 157 Kühen der Rasse Holstein Friesian. Blutproben zur Stoffwechselanalytik wurden 2-6 Tage p.p. sowie 4-5 Wochen p.p. entnommen. Parallel dazu wurden klinische Daten zu Leistung und Gesundheitsstatus bis 3 Monate p.p. erhoben. In einem zweiten Versuch wurden die Kühe in 2 Gruppen eingeteilt, wobei die Versuchsgruppe (65 Kühe) eine orale Vitamin-B12-Substitution in Höhe von 0,5 g Cyanocobalamin/Kuh/Tag 4-6 Wochen a.p. beginnend bis zur Kalbung erhielt. 71 Kühe, die das stallübliche Mineralfutter erhielten, dienten als Kontrollgruppe. Auch hier erfolgten die Blutkontrollen 2-6 Tage p.p. sowie 4-5 Wochen p.p. Es wurden die Milchleistung sowie auftretende Erkrankungen dokumentiert. Die Blutentnahme erfolgte aus der Vena caudalis mediana. Neben den hämatologischen Untersuchungen wurden folgende Parameter aus dem Serum bestimmt: Freie Fettsäuren (FFS), Betahydroxybutyrat (BHB), Glukose, Bilirubin, Cholesterol, Gamma-Glutamyltransferase (GGT), Creatinkinase (CK), Harnstoff, Calcium, Eisen, anorganisches Phosphat (Pi), Cyanocobalamin und Cobalt. Ergebnisse: Die Vitamin-B12-Konzentration zeigt eine signifikante Laktationsdynamik. Alle untersuchten Kühe hatten 4 Wochen p. p. gegenüber 2–6 Tage p. p. erniedrigte Vitamin-B12-Konzentrationen (p ≤ 0,05). Bei den p.p. kranken Kühen sank gegenüber den gesunden Kühen die Vitamin-B12-Konzentration weniger stark ab (p ≤ 0,05), d.h., höhere Vitamin-B12-Konzentrationen können auf klinische Probleme hinweisen. Gesunde sowie auch p.p. kranke Kühe wiesen 2–6 Tage p. p. höhere Werte für die Parameter Erythrozytenzahl, Hämatokrit und Hämoglobinkonzentration auf als 4 Wochen p. p. Die BHB-, FFS- und Bilirubin-Konzentrationen waren bei allen Kühen 2–6 Tage p. p. infolge der partusbedingten Lipolysesteigerung erhöht (p ≤ 0,05). Bei allen Kühen korrelierte die Aktivität der cholestaseanzeigenden GGT eng mit der Vitamin-B12-Konzentration (p ≤ 0,01). Aufgrund dieser engen Korrelation mit der GGT-Aktivität sowie der Bilirubinkonzentration kann Vitamin B12 bei einer Serumkonzentration ≥ 227 ng/l bei Kühen cholestatische Stoffwechselbelastungen anzeigen. Nach Vitamin-B12-Substitution blieben in der Versuchsgruppe 60 % und in der Kontrollgruppe 47,9 % der Kühe in der Frühlaktation gesund. In der Kontrollgruppe hatten 12,7 % eine Nachgeburtsverhaltung und 40,8 % eine Mastitis, in der Versuchsgruppe betrugen die Anteile 21,5 % sowie 26,2 %. Mit x̃ = 320 pg/ml war die Vitamin-B12-Konzentration 2-6 Tage p.p. in der Vitamin-B12-substituierten Gruppe gegenüber x̃ = 224 pg/ml in der Kontrollgruppe gesichert höher. Auch vier Wochen p.p. war die Differenz noch signifikant. Cobalt, die Parameter des Leber- und Energiestoffwechsels sowie Harnstoff und CK unterschieden sich zwischen der Vitamin-B12-substituierten Gruppe und der Kontrollgruppe nicht gesichert. Die Erythrozytenzahlen sowie die Hämoglobin-Konzentrationen waren in der Vitamin-B12-substituierten Gruppe gesichert höher. Der Milchfettgehalt (%) war bei den Vitamin-B12-substituierten Kühen gegenüber den Kontrollkühen signifikant erhöht (p = 0,022), die Milchleistung unterschied sich unwesentlich. Schlussfolgerungen: Signifikant höhere Vitamin-B12- und Hämoglobin-Konzentrationen, höhere Erythrozytenzahlen sowie geringere Morbidität sprechen für positive Effekte der Vitamin-B12-Substitution. Anhand der Parameter des Leber-Energiestoffwechsels sowie der Milchleistung ließ sich dies nicht bestätigen. Cholestase stört die Vitamin-B12-Bewertung im Blut bzw. ist bei der Interpretation zu beachten. / Introduction: Vitamin B12 has important functions in energy metabolism and erythropoiesis. Both functional groups are particularly stressed in high-yielding dairy cows and can be a starting point for clinical disorders under stress and insufficient vitamin B12 supply. Objective: The studies presented were designed to ascertain the characteristics of the serum vitamin B12 concentration of dairy cows in early lactation and to check the relations with metabolic parameters, the erythrogram as well as the health status of the cows. Furthermore, it was examined to what extent the postpartum metabolism can be stabilized by oral vitamin B12 substitutions. Material and methods: The investigations on vitamin B12 status survey were carried out on 157 cows of the Holstein Friesian breed. Blood samples were taken for metabolic analysis at 2-6 days p.p. and at 4-5 weeks p.p. In parallel, clinical findings on the milk yield and the health status were compiled up to 3 months p.p. In a second trial the cows were divided into 2 groups in which the experimental group (65 cows) received an oral vitamin B12 substitution in the amount of 0.5 g cyanocobalamin/cow/day starting 4-6 weeks a.p. up to calving. 71 cows, which recieved the common mineral feed, served as control group. Again the blood tests were performed at 2-6 days p.p. and at 4-5 weeks p.p. The milk yield and emerging diseases were documented. The blood samples werde taken from the Vena caudalis mediana. In addition to haematological investigations the following parameteres were measured: Non-esterified fatty acids (NEFA), beta-hydroxybutyrate (BHB), glucose, bilirubin, cholesterol, gamma-glutamyl transferase (GGT), creatinkinase (CK), urea, calcium, ferric, anorganic phosphor, cyanocobalamin and cobalt. Results: The vitamin B12 concentration shows a significant dynamic in lactation. All examined cows had decreased vitamin B12 concentrations at 4 weeks p. p. compared to 2-6 days p. p. (p ≤ 0.05). In the p.p. morbid cows the vitamin B12 concentration fell less than in the healthy cows (p ≤ 0.05), which means higher vitamin B12 concentrations may indicate clinical problems. Healthy as well as p.p. morbid cows showed higher values for the parameters erythrocyte count, hematocrit and hemoglobin concentration at 2-6 days p.p. than 4 weeks p.p. BHB, FFS, and bilirubin levels were increased in all cows at 2-6 days p.p. as a result of partus related rise in lipolysis (p ≤ 0.05). In all cows, the activity of the GGT, which indicates cholestasis, was closely correlated with the vitamin B12 concentration p ≤ 0.01). Because of this close correlation with GGT activity and bilirubin concentration, vitamin B12 may show cholestatic metabolic stress in cows at a serum concentration ≥ 227 ng/l. After vitamin B12 substitution 60 % of the cows in the experimental group and 47.9 % of the cows in the control group remained healthy during early lactation. In the control group 12.7 % had a Retentio secundinarum and 40.8 % had a mastitis, in the experimental group the proportions were 21.5 % and 26.2 %. At two to six days p.p. the vitamin B12 concentration in the vitamin B12 substituted group was significant higher (x̃ = 320 pg/ml) than in the control group (x̃ = 224 pg/ml). This difference was still significant at four weeks p.p. Cobalt, parameters of liver and energy metabolism as well as urea and CK did not differ significantly between the vitamin B12 substituted group and the control group. Erythrocyte counts and hemoglobin concentrations were significant higher in the vitamin B12 substituted group. Milk fat content (%) was significant higher in the vitamin B12 substituted group compared to the control group (p = 0.022), the milk yield did not differ significantly. Conclusions: Significant higher vitamin B12 and hemoglobin concentrations, higher erythrocyte counts as well as lower morbidity speak for positive effects of vitamin B12 substitution. Based on the parameters of hepatic and energy metabolism as well as milk yield this could not be confirmed. Cholestasis interferes with the evaluation of vitamin B12 in the blood respectively should be considered in the interpretation.

Submitted by Luciana Ferreira (lucgeral@gmail.com) on 2018-03-26T12:09:17Z No. of bitstreams: 2 Tese - Saura Nayane de Souza - 2017.pdf: 4815483 bytes, checksum: a9d3c576d6699488befc8fdde284c795 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2018-03-26T12:11:02Z (GMT) No. of bitstreams: 2 Tese - Saura Nayane de Souza - 2017.pdf: 4815483 bytes, checksum: a9d3c576d6699488befc8fdde284c795 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2018-03-26T12:11:02Z (GMT). No. of bitstreams: 2 Tese - Saura Nayane de Souza - 2017.pdf: 4815483 bytes, checksum: a9d3c576d6699488befc8fdde284c795 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2017-03-06 / The goal of the study was to evaluate cystatin C and other biomarkers as diagnostic tools in canine renal disease. The project was divided in two studies. In the first study renal injury was induced in 6 animals by subcutaneous administration of gentamicin (30mg/kg) for 10 days, and 6 animals were kept as controls. Animals were evaluated for 45 days by the following clinical and laboratorial parameters: physical examination; hemogram and fibrinogen levels; measurement of creatinine, urea, total proteins, albumin, phosphorus, calcium, sodium, potassium, cholesterol levels (biochemical analysis); serum protein electrophoresis; urine sodium, potassium, gamma glutamyl transferase and alkaline phosphatase levels; urinalysis; urine protein / creatinine ratio; hemogasometry and non-invasive systemic arterial pressure. The second study evaluated the level of cystatin C in 58 dogs suffering from different stages (2-4) of chronical renal disease, as defined by International Renal Interest Society (IRIS) guidelines. Six animals presenting acute renal injury induced bygentamicin treatment were also evaluated (for 20 time points upon injury). The results indicated that changes in urine gamma glutamyl transferase and fractional excretion of sodium and potassium were the earliest parameters indicating acute renal injury, even when compared to most common renal disease biomarkers: urea and creatinine. Cystatin C measurement, on the other hand, showed little value for early detection of chronic kidney disease and acute kidney injury in dogs. / O objetivo deste estudo foi avaliar a aplicação dos biomarcadores, em especial da cistatina C, no diagnóstico da doença renal em cães e compreendeu duas etapas. Uma fase constou da avaliação de 12 cães, sendo seis pertencentes ao grupo controle e seis cães pertencentes ao grupo experimental que foram submetidos a um protocolo de indução de injúria renal com 30 mg/kg ao dia de gentamicina, via subcutânea, durante 10 dias. Os cães foram avaliados durante 45 dias por meio de: exame clínico; hemograma e fibrinogênio; bioquímica sérica (ureia, creatinina, proteínas totais, albumina, fósforo, cálcio, sódio, potássio, colesterol e eletroforese das proteínas séricas); bioquímica urinária (sódio, potássio, gama glutamil transferase e fosfatase alcalina); urinálise; determinação da razão proteína/creatinina urinária; hemogasometria e pressão arterial sistólica não- invasiva. A outra fase constou da mensuração da cistatina C sérica em 58 cães com doença renal crônica divididos nos estádios 2, 3 e 4 da IRIS (International Renal Interest Society) e em seis cães com injúria renal aguda induzida por gentamicina, avaliados durante 20 momentos após o início da injúria. Os resultados demonstraram que a enzima gama glutamil transferase urinária e a excreção fracionada de sódio e potássio foram mais precoces em detectar a injúria renal aguda em cães do que outros marcadores mais utilizados na rotina clínica como a creatinina e a ureia. A cistatina C sérica não foi eficiente em detectar de forma precoce a doença renal crônica em cães nos estádios iniciais e a injúria renal aguda, possuindo uma baixa aplicabilidade neste estudo.

Thèse numérisée par la Direction des bibliothèques de l'Université de Montréal.

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