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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
111

CHARACTERIZATION OF RECEPTORS AND BINDING PROTEINS FOR THE ACTIVE METABOLITES OF VITAMINS A AND D IN NORMAL AND RESISTANT CELLS (PRIMATE RESEARCH).

KELLY, MICHAEL ALAN. January 1986 (has links)
Involvement of Cellular Retinoic Acid (CRABP) or Retinol (CRBP) Binding Proteins and 1,25-dihydroxyvitamin D₃ (1,25(OH)₂D₃) receptors in the response of cultured cells to retinoic acid and 1,25(OH)₂D₃ was examined. A new method for saturation analysis of CRABP and CRBP was applied to human tumors, human neuroblastoma cells, which retinoic acid causes to differentiate, and a bioselected subline resistant to retinoic acid. These data suggest that CRABP may not mediate cell differentiation by retinoic acid. In other studies, 1,25(OH)₂D₃ receptors and bioresponses were characterized in cultured primate cells. Rhesus monkey kidney cells (LLC-MK₂) were resistant to 1,25(OH)₂D₃-dependent induction of 25(OH)D-24-hydroxylase enzyme. The ED₅₀ in LLC-MK₂ cells was 10-100 fold higher than in other cultured cells. This resistance resulted from a low affinity receptor. Since the LLC-MK₂ variant receptor did not differ in size from the wild type rhesus 1,25(OH)₂D₃ receptor, (Mᵣ = 52 kDa) a subtle alteration in the receptor likely caused the decreased ligand affinity. Also of interest was the possible cellular resistance to 1,25(OH)₂D₃, in the owl monkey (Aotus trivurgatus), which generally occurs in new world primates. Owl monkey kidney (OMK) cells had the same content of receptors for 1,25(OH)₂D₃ and sensitivity to this hormone as cells from the rhesus monkey (old world primate). The ED₅₀ for induction of 24hydroxylase was 2-3 nM in both the OMK cells and the rhesus monkey fibroblasts. Both cells contained 2300 high affinity receptor molecules per cell, which bound DNA and were characterized by immunoblot as 52 kDa proteins. 1,25(OH)₂D₃ treatment increased the content of 1,25(OH)₂D₃ receptors in OMK cells, by increasing the synthesis of receptor mRNA. These data indicate the owl monkey is not resistant to 1,25(OH)₂D₃, unlike other new world primates. This finding was confirmed independently by demonstration that the owl monkey maintained mean serum 1,25(OH)₂D₃ levels (29 pg/ml) in the range of old world primates (33 pg/ml) and humans, in contrast to the elevated 1,25(OH)₂D₃ in other new world primates (97-129 pg/ml). This result suggests the alteration of 1,25(OH)₂D₃-endocrine dynamics in new world primates occurred subsequent to the evolutionary divergence of the owl monkey.
112

A Pilot Survey to Assess the Vitamin A Status of Children Aged 6-72 months in the Ramu Region of Papua New Guinea

Verma, Nitin January 2000 (has links)
Papua New Guinea has been classified by the World Health Organisation as an area where clinical vitamin A deficiency (VAD) exists. This is at variance with the experience of the local physicians who do not encounter classical VAD in clinical practice. This pilot study was carried out to resolve this contradiction, since many suggestions have been made to fortify foods with Vitamin A. If done in the absence of concrete data to back up this classification, it could take the focus away from the real problem as well as potentially create problems of Vitamin A toxicity. Therefore, answers from this study could have far reaching implications in a country such as PNG, which has high childhood mortality and limited financial and manpower resources. The objective of this study was to determine the vitamin A status and identify risk factors of VAD in children aged 6 months to 6 years in a rural area of Papua New Guinea. The survey was carried out in the Ramu region of Madang province. Households and children were randomly selected and standard questionnaires were used to collect information about diet, previous illnesses and night blindness. The weight and height of all children was recorded and an ocular and physical examination carried out by trained personnel. In addition, haemoglobin estimation and examination of blood films for malaria parasites was carried out in all the children. In a randomly selected number of children, estimations of serum retinol and other micronutrient levels were carried out. Results: A total of 609 children were enrolled in the study. Biochemical parameters were studied in 106 of them .The mean age of the children was 35 months. Possible night blindness was reported in 4 children. No xerophthalmia was seen. The prevalence of serum retinol levels ( 0.7 (mol/L (WHO suggested cut off values for subclinical VAD) was 10.3%. Anthropometric indicators indicated a high proportion of the children had stunting and wasting or both. Analysis of dietary patterns, maternal literacy, food availability and other surrogate indicators indicated that the population is at mild-moderate risk of developing VAD. In conclusion, no evidence of clinical vitamin A deficiency was found. Subclinical vitamin A deficiency seemed to occur in this population at a level of mild-moderate public health importance. Further studies need to be carried out to assess the situation in different areas in PNG before policy decisions can be made with regards to mass vitamin A supplementation.
113

AUTORADIOGRAPHIC LOCALIZATION OF LABELED 1,25-DIHYDROXYVITAMIN-D3 IN TARGET TISSUE OF THE RACHITIC CHICK

Jones, Patricia Gale January 1978 (has links)
No description available.
114

Pharmacokinetics and in vitro stability of retinyl palmitate

Einspahr, Janine Gay January 1981 (has links)
No description available.
115

A measure of the Vitamin A content of Arizona sorghum grains and yellow corn, and of the value of alfalfa as a vitamin A supplement

Lynott, Mable Leavitt January 1929 (has links)
No description available.
116

In vivo and in vitro determination of the bioavailability of vitamin B-6 from plant foods containing pyridoxine glucoside

Bills, Nathan D. 11 June 1990 (has links)
Graduation date: 1991
117

A study of the vitamin G content of Oregon Bosc pears

Douglass, Ruth January 1931 (has links)
Graduation date: 1931
118

The vitamin B₁ content of baking powder bread

Little, Ruth Ramabai 06 1900 (has links)
Graduation date: 1940
119

The utilization of riboflavin by human beings on controlled diets supplemented with meat, milk products and synthetic riboflavin

Prentiss, Marian Gary 06 1900 (has links)
Graduation date: 1946
120

A study of the vitamin B (B₁) content of Oregon Bosc pears

Holloway, Mae Lujeanne 06 1900 (has links)
Graduation date: 1931

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