Biochemistry Commons^™

Regulation Of Queuine Insertion Into Transfer Rna: Effects Of Tumor Promoters, Bonnie Jean Brooks

Chemistry & Biochemistry Theses & Dissertations

The purpose of this study was to treat normal human fibroblasts with known tumor promoters and observe queuine modification of tRNA. The queuine insertion enzyme, tRNAguanine ribosyltransferase, was studied in vivo and in vitro. Tumor promoter-treated human fibroblast cultures exhibited variable queuine-insertion rates with a transient inhibition that correlated with variable levels of queuine modified tRNA over time in culture from passages 3 — 8. In contrast the in vitro studies showed that phorbol cetera and saccharin actually increased insertion with strong evidence indicating phosphorylation as a positive modulating force of the enzyme activity. It is proposed that chronic stimulation …

The Determination Of Tamoxifen Citrate In Human Blood Serum And Semen, Karimdad Tahmoresi

Chemistry & Biochemistry Theses & Dissertations

High performance liquid chromatography (HPLC)methodologies for the determination of tamoxifen and its metabolites 4-hydroxytamoxifen and n-desmethyltamoxifen, and using cis-tamoxifen as an internal standard have been developed.

Clinical analyses of tamoxifen and its metabolites in human serum and semen, were performed as follows: The analytes were extracted from serum and semen with hexane, the hexane evaporated, the dried extract then reconstituted with methanol, followed by reverse phase high performance liquid chromatography.

Between-run coefficients of variation (CV'S) for tamoxifen and n-desmethyltamoxifen for serum sample analyses, (n = 15) were, 4% and 13% at mean (SD) concentration of 140.2 (6.2) and 71.8 (9.8) …

Simultaneous Determination Of 3-Methoxy-4-Hydroxyphenyl-Glycol, Homovanillic Acid, And 5-Hydroxyindoleacetic Acid In Plasma By High Performance Liquid Chromatography, Yung-Te Tseng

Chemistry & Biochemistry Theses & Dissertations

A rapid, reliable, and sensitive method for simultaneous determination of 3-methoxy-4-hydroxyphenylglycol (MHPG), Homovanillic acid (HVA), and 5-hydroxyindoleacetic acid (5- HIAA) in plasma is described. The method is based on high performance liquid chromatography with electrochemical detection. Samples were filtered with Amicon Centrifree micropartition systems and extracted with organic solvent before chromatography. Chromatographic separation of sample components was achieved isocratically in a C18 reverse-phase column. Quantitation was performed by measuring the peak height ratios of the sample components to an internal standard. Analytical recoveries ranged from 50.78 (SD 4.2%) to 67.94 (SD 3.28). Within-run coefficient of variations (CVs) ranged from 3.78 …

Microwell Based Competitive Enzyme Immunoassay For Quantifying Serum Triiodothyronine And Thyroxine Levels, Yiwen Yang

Chemistry & Biochemistry Theses & Dissertations

A microwell based competitive enzyme immunoassay for determination of total thyroxine and triiodothyronine in human serum was developed with use of horseradish peroxidase conjugate. The assay, which can be performed in only 1.5 hours at room temperature, involves simultaneous incubation of T₃- or T₄- HRPO conjugate and serum sample in anti-T₃ or anti-T₄ gamma globulin fraction coated polystyrene microwells.

Isolation of anti-T₃ and anti-T₄ gamma globulin fractions were accomplished from whole antiserum by using DEAE-cellulose chromatograph. A carbodiimide coupling method was described to prepare the T₄- and T₃-HRPO …

Spectroscopic Study Of Decomposition Products Of Gossypol, David Bernard Hankins

Chemistry & Biochemistry Theses & Dissertations

Basic research into reproductive physiology has begun to identify possible new approaches to controlling fertility. Gossypol, a natural polyphenol compound isolated from cottonseed oil, has been shown to be an effective male antifertility agent. The decomposition products of gossypol which are thought to possess more potent antifertility effects than the parent compound gossypol have been studied extensively in more recent research. The purpose of this research is to develop techniques and methods which could be used to identify decomposition products of gossypol. A model decomposition reaction by which a smaller molecule can be isolated in a pure state has been …

Regulation Of Epidermal Growth Factor Receptor Synthesis By Retinoic Acid And Dexamethasone, Kerby C. Oberg

Loma Linda University Electronic Theses, Dissertations & Projects

Fetal rat lung (FRL) cells incubated in the presence of retinoic acid or dexamethasone exhibit altered ¹²⁵I-epidermal growth factor (EOF) binding capacity. Retinoic acid enhances ¹²⁵I-EGF binding 3-fold following 24 hours of 37° incubation. In contrast, FRL cells incubated in the presence of dexamethasone display a 2-fold reduction in ¹²⁵I-EGF binding capacity. The change in binding capacity, induced by either hormone, was due to alterations in the average number of receptors per cell as determined by Scatchard analysis of ¹²⁵I-EGF binding. In the absence of retinoic acid or dexamethasone, FRL cells were calculated to have approximately …

Variants And Polymorphisms Of Three Repetitive Dna Families In The Human Genome, Robert M. Roudabush

Electronic Theses and Dissertations

A novel 0.6 kb LINE family in human DNA, designated L2Hs, has been described (Musich and Dykes 1986). Studies employing clone N6.4, containing three 0.6 kb segments of this family, indicate that these sequences are interspersed and moderately repetitive. Two additional variant sequences of the L2Hs family, N6.1 and N6.3, have been identified. Restriction mapping of each cloned segment indicates similarities among N6.4, N6.3 and N6.1. When the cloned DNAs were cleaved with restriction enzymes and subjected to cross-hybridization, each cloned insert produced a pattern indicating that the sequences contained in N6.1 and N6.3 are represented in at least one …

Platelet Function And Energy Metabolism During Storage In A Well-Defined Experimental Medium, Thais Edwina Ahrendt Keegan

Theses and Dissertations in Biomedical Sciences

The most significant problem in maintaining platelet viability during storage is the decrease in pH resulting from accumulation of lactic acid formed by platelet anaerobic glycolysis. This study investigates nutrient alternatives to glucose for maintenance of morphology and functional integrity during platelet storage in a well-defined synthetic medium and correlates this data with purine nucleotide levels determined by high-performance liquid chromatography (HPLC) and other in vitro measures of platelet quality. Platelets prepared from pooled ABO- and Rh- identical platelet-rich plasma were stored as concentrates in the synthetic medium without added nutrients (control) and with added substrates.

The HPLC procedure developed …

Hypoxanthine-Induced Differentiation Of Cultured Human Leukemia Cells, Gayle Jennette Singleton

Chemistry & Biochemistry Theses & Dissertations

Human cultured leukemia cells appear to have a decreased amount of inosine in their tRNA. When cells with inosine deficient tRNA are placed in a hypoxanthine fortified media, they incorporate hypoxanthine into their tRNA by the action of the enzyme tRNA-hypoxanthine ribosyl transferase. This generates the nucleoside inosine in the tRNA. The cultured human leukemia cell lines, CCRF-CEM, HL-60, and HGPRT(-) HL- 60, incorporate hypoxanthine into their tRNA, as determined by tRNA isolation, hydrolysis, and HPLC analysis. Hypoxanthine treatment dramatically inhibited cell growth in conjunction with partial induction of differentiation in the CCRF-CEM, HL-60, and HGPRT ( - ) HL-60 …

Andrological Methods Of Predicting The Pregnancy Outcome Of An In Vitro Fertilization Program, Mahmood S. Morshedi

Theses and Dissertations in Biomedical Sciences

Current advances in fertility treatment emphasize extracorporeal procedures, such as in vitro fertilization (IVF)/embryo transfer. IVF is now used to treat several types of infertility, including male factor and idiopathic infertility. However, IVF is time consuming, costly, unpredictable, and often yields a low pregnancy rate. Thus, it would be valuable to devise laboratory procedures for better prediction of IVF outcome.

The male infertility rate can be as high as 50%. Since sperm count and percent of motility alone do not appear to be strong predictors of IVF outcome especially when these parameters are not severely abnormal, a multivariable analysis of …

Distribution Of The Heterogeneous Hemocyanin Subunits Of Callinestes Sapidus (Rathbun) Along A Salinity Gradient, Julie Sayre Rainer

Dissertations, Theses, and Masters Projects

No abstract provided.

Biochemical Characterization Of The Axolemmal Mitogen For Cultured Schwann Cells, Mark A. Decoster

Theses and Dissertations

The molecule(s) involved at the axon plasma membrane (axolemma) which causes Schwann cells to proliferate has been investigated by three biochemical techniques: 1) Alkaline extraction of axolemma resulted in recovery of 95% of the mitogenic activity and 50% of the protein in the membrane-bound portion of the axolemma. 2) The axonal mitogen for Schwann cells may be associated with heparan sulfate proteoglycans at the axonal surface. Treatment of axolemma with heparitinase, which cleaves the glycosidic bonds of sulfated glycosaminoglycans, allowed mitogenic activity to be solubilized. 3) Treatment of axolemma with heparin, a highly sulfated glycosaminoglycan analogous to heparan sulfate, resulted …

Effects Of Selected Nitrogen-Containing Aromatic Compounds (Ncacs) On Physiological Properties In Escherichia Coli, W. James Catallo Iii

Dissertations, Theses, and Masters Projects

This research examined the effects of quinoline and 4-azafluorene on respiratory electron transport rate (ET), outer membrane permeability and topology, oxygen consumption, and viable cell density in Escherichia coli cell suspensions. ET was estimated spectrophotometrically using INT (2-(p-iodophenyl)-3-(p-nitrophenyl)-5-(phenyl)-2H-tetrazolium chloride, which is reduced in vivo to a red colored formazan (INTF). Both test compounds caused anomalous dose-response behavior in INT assays: in a defined window of doses, ET rates near or above the controls were observed. These doses showed altered INT reduction kinetics, decreased cellular oxygen demand, and decreased viable cell densities. Experiments with E. coli spheroplast preparations, gram(+) cells, and …

Structure And Function Of Crustacean Hemocyaninis, John Edwin Reese

Dissertations, Theses, and Masters Projects

No abstract provided.

Anion And Urea Sensitivity Of Three Elasmobranch Hemoglobins, David Allen Scholnick

Dissertations, Theses, and Masters Projects

No abstract provided.

The Physiology And Biochemistry Of Isolated Skeletal Muscle Mitochondria : A Comparative Study, Mark Lowell Wagner

Dissertations and Theses

The physiological limit to maximum aerobic capacity (VO₂max) in vertebrates has been attributed to cardiovascular oxygen delivery, to the ability of the muscle cells to consume oxygen, or to a fine-tuned development of all components of the respiratory system such that no single component can be shown to limit VO₂max. The above hypotheses have each been developed using different experiments with different animals. The comparative studies uniting these animals and methods are limited. In order to further our knowledge of the cellular limit to VO₂max, skeletal muscle mitochondria were isolated from species representing four …