Objectives: To assess the association between serum 25(OH)D and body mass index (BMI) in pre- and early-adolescents and to determine whether this association varies by demographic/clinical characteristics. Methods: Vitamin D status was determined using serum 25(OH)D in healthy pre- and early adolescents in Pittsburgh, PA (deficiency=/mL, insufficiency=12-/mL, sufficiency=≥20 ng/mL). Adiposity was quantified using BMI percentile (normal=<85th, overweight=>85th-95th, obese=>95th). The relationship between serum 25(OH)D and adiposity was assessed in the total population and after stratification by gender, race, Fitzpatrick skin type, age, and Tanner stage. Results: 294 children (mean age 10.2 + 2.1 years; 60% African American; median serum 25(OH)D=27.0 ng/mL) were studied. Serum 25(OH)D was significantly lower in obese (n=72) vs. overweight (n=48) and normal weight (n=171) participants at 23.6, 29.5, and 28.2 ng/mL, respectively; p=0.015. This trend remained significant for early adolescents but did not differ after stratification by other demographic/clinical characteristics. A significant negative correlation was found between BMI and serum 25(OH)D (r = -0.315; p=0.000). Regression analysis predicted that 25% of the variance in serum 25(OH)D levels was attributed to BMI, gender, race, skin type, age, pubertal status, daily vitamin D and calcium intake, sun exposure, and sunscreen use, with Tanner stage being the only significant independent predictor. Conclusions: A significant inverse association between serum 25(OH)D and adiposity was observed in a population of pre- and early adolescents. This relationship was stronger in early adolescents. A meta-analysis to further explore this association in pediatric populations is warranted.

The maximum daily dose of vitamin D currently recommended is 2000 IU. Ergocalciferol (D2) 50,000 IU orally weekly for 8-12 weeks is often used to treat vitamin D deficient patients (25(OH) vitamin D <20 ng/mL). The lack of vitamin D toxicity after massive doses of ergocalciferol has yet to be reported in the literature. We report a case of a 56-year-old woman who received supratherapeutic doses of ergocalciferol (150,000 IU orally daily) for 28 years without toxicity. We discuss the possible mechanisms which may account for a lack of toxicity despite intake of massive daily doses of ergocalciferol in this patient.

Inaug.-diss.--Königsberg. / Lebenslauf. "Literaturnachweis, " p. 1-6.

Une réaction simple de condensation de l'acide thiocyanique avec un cétohexose peut conduire à la formation d’une dizaine de 10 oxazolidinethiones (OZTs) ou oxazolinethiones (OXTs) distinctes. La question que nous nous sommes posée a été “comment gérer une chimie aussi complexe?” Un contrôle attentif des conditions de réaction, associé à des séquences de purification comportant des protections sélectives et diverses fonctionnalisations, peuvent certainement être utiles. Un jeu chimique subtil et stimulant a été développé entre des pré- et post-protections sélectives et des réactions originales de fonctionnalisation. Dans ce travail de thèse, nous avons mis à l’étude de nouvelles tactiques de synthèse et de purification pour accéder à des OZTs et des oxazolidinones (OZOs) ancrées sur des charpentes des cétohexoses. Ces travaux ont été mis en application notamment en série D-fructo et dans les séries épimères D-psico et D-tagato dont la chimie ont été peu explorée en comparaison d’autres séries monosaccharidiques. Nous avons ainsi mieux maîtrisé les approches chimiques permettant d’accéder à ces thionocarbamates saccharidiques et ainsi de valoriser ces molécules dont l’intérêt d’un point de vue biologique et chimique est important. Dans ces études, nous avons élaboré une bibliothèque de formes tautomères fixes de composés hybrides qui ont été soumis à des essais biologiques. Ainsi, ce groupe de composés a fait l’objet de tests antimicrobiens, livrant des résultats très intéressants. Par ailleurs, les meilleurs inhibiteurs de GLUT5 seront utilisés dans le développement de nouveaux outils biochimiques pour une meilleure compréhension des rôles joués par ce transporteur du D-fructose en relation au le diabète de type 2 et de l'obésité. / A simple condensation reaction of thiocyanic acid with a ketohexose can provide a library of up to 10 different molecules composed of oxazolidinethiones (OZTs) or oxazolinethiones (OXTs). The question arising is “how to manage such a complex chemistry?” Careful control of the reaction conditions associated with purification sequences (involving selective protection or functionalization) can certainly help. A subtle and challenging chemical game could be played between selective pre- and post-protections and original functionalizing reactions. In this PhD work, we disclose the development of new chemical and purification tactics to access OZTs and oxazolidinones (OZOs) anchored onto ketohexose scaffolds, namely D-fructo and its epimers D-psico, D-tagato, whose chemistry has been poorly investigated in comparison with other monosaccharidic systems. Furthermore we have improved our understanding about saccharidic thionocarbamates chemistry for a better valorization from both chemical and biological point of view. We have generated a library of fixed tautomeric forms of hybrid compounds to be submitted to biological tests. This panel of compounds was subjected to antimicrobial screening and some molecules have shown very efficient effects. Moreover, the leading inhibitors of GLUT5 will be used in the development of biochemical tools for a better comprehension of the role of this D-fructose transporter in relation to type 2 diabetes and obesity.

A research report submitted to the Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, in partial fulfilment of the requirements for the degree of Master of Medicine in the branch of Anaesthesiology / Background and Objective There has been a recent resurgence of interest in vitamin D and its far-reaching effects in physiology and pathophysiology. Theatre personnel, and all indoor workers, should be cognisant of vitamin D deficiency as a real occupational hazard. Vitamin D deficiency is a global problem that has been studied extensively in colder climates and even been found in warmer climates. No research was identified among medical personnel in South Africa. The primary objective of this study was to describe serum 25-hydroxyvitamin D (25(OH)D) levels of anaesthetists. The secondary objective was to describe and compare factors influencing vitamin D levels in anaesthetists who are vitamin D insufficient to those who are not. These factors included: ethnicity, gender, body mass index (BMI), multivitamin use, calcium or vitamin D supplementation, sun exposure, vitamin D intake from diet alone, vitamin D intake from diet and supplementation and calcium intake (dairy). Methods Data was collected over a period of one month, in winter (mid-July to mid-August 2013). On the morning of sample collection anaesthetists agreeing to participate signed the informed consent (Appendix 2), prior to enrolment in the study. The anaesthetists then completed the questionnaire (Appendix 5). The following data was obtained from the questionnaire: age, gender, ethnic group, dietary supplementation, sun exposure, sunscreen use, BMI and diet. Each participant had 5 ml of blood collected in a standardised manner into a purple top ethylenediaminetetraacetic acid blood specimen tube. The processing of samples was done by qualified laboratory personnel using standard chemical pathology equipment and procedures. High Performance Liquid Chromatography was performed to determine 25(OH)D levels using a Shimadzu® Nexera X2 Ultra performance liquid chromatography system with a photodiode array detector (Shimadzu®, Japan). Results The median 25(OH)D was 43.8 nmol/l (IQR 26-76), with 51 of 89 (57.30 %) anaesthetists being vitamin D insufficient. There was a statistically significant association between ethnicity and vitamin D status (p<0.001). Twenty-one (80.77 %) Indian anaesthetists and 14 (70.00 %) black anaesthetists were vitamin D insufficient, as compared to only 10 (28.57%) white anaesthetists. There was no significant association between the other secondary objectives-gender (p=0.60), sun exposure (p = 0.93), vitamin D intake from diet alone (p= 0.07), vitamin D intake from diet and supplementation (p=0.05) and calcium intake (p=0.55) and vitamin D status. There was no significant difference between BMI and vitamin D status. When a comparison was made between the two groups of BMI <25 and BMI ≥25, using a Mann-Whitney test the two-tailed P value was 0.6791. There was a significant association between multivitamin use (p=0.01) and vitamin D status. Conclusion Vitamin D should no longer be a forgotten vitamin. The insufficient vitamin D levels of anaesthetist in this study, puts them at risk for pathology far beyond bone health. Adequate vitamin D levels should be seen as essential, rather than optional, even in “sunny” climates. / MT2016

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Proefschrift Universiteit van Amsterdam. / Met lit. opg., reg. - Met samenvatting in het Engels.

Thèses (M.A.)--Université de Sherbrooke (Canada), 1997. / Titre de l'écran-titre (visionné le 20 juin 2006). Publié aussi en version papier.

Thesis (M.S.) in Food Science and Human Nutrition--University of Maine, 2003. / Includes vita. Includes bibliographical references (leaves 45-47).