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Articles 391 - 401 of 401

Full-Text Articles in Biochemistry, Biophysics, and Structural Biology

The Role Of Small Peptides In Cancer Physiology And Chemotherapy, Bao-Ling Tsay Jan 1990

The Role Of Small Peptides In Cancer Physiology And Chemotherapy, Bao-Ling Tsay

Theses and Dissertations in Biomedical Sciences

The targeting of proven anticancer drugs specifically to cancer cells would provide a unique opportunity to restrict neoplasms without damaging the cancer patient. The present research utilizes the phenomenon of illicit transport, i.e. the coupling of normally impermeant metabolites to permeant metabolites, in targeting the drug melphalan to mouse Ehrlich ascites tumor cells. The dipeptide beta-alanyl-melphalan was synthesized and tested in vitro for toxicity towards mouse Ehrlich ascites tumor cells, mouse liver cells, and mouse 3T3 embryonic cells. The parent compound, melphalan, was used as a control treatment. In addition, both melphalan and beta-alanyl-melphalan were utilized in in vivo chemotherapeutic …


Microwell Based Competitive Enzyme Immunoassay For Quantifying Serum Triiodothyronine And Thyroxine Levels, Yiwen Yang Jul 1989

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 …


Hypoxanthine-Induced Differentiation Of Cultured Human Leukemia Cells, Gayle Jennette Singleton Apr 1989

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 …


Dietary And Hormonal Evaluation Of Men At Risk For Prostate Cancer, Donald J. Pusateri Dec 1988

Dietary And Hormonal Evaluation Of Men At Risk For Prostate Cancer, Donald J. Pusateri

Loma Linda University Electronic Theses, Dissertations & Projects

Relationships between dietary nutrients and plasma and fecal estrone, estradiol-17β, testosterone, and plasma prolactin levels were studied in young Seventh-day Adventist men: 18 nonvegetarians (NV), 20 lacto-ovovegetarians (LOV), and 15 vegans (V). Blood samples and 3 d dietary records were obtained. Contemporaneously collected diet composites and stool samples were analyzed for fiber. The vegetarians consumed significantly more fiber than the omnivores, while NVs and LOVs consumed more saturated fat than the Vs. Although plasma steroid hormone status did not differ, the Vs had significantly higher fecal estrogen levels than the NVs or LOVs. Plasma prolactin levels were significantly higher in …


The Inhibition Of Bone Formation Occurring Under Weightlessness : The Effect Of Skeletal Unloading On Serum Levels Of A Bone-Derived Growth Factor, Jean D. Sibonga Sep 1988

The Inhibition Of Bone Formation Occurring Under Weightlessness : The Effect Of Skeletal Unloading On Serum Levels Of A Bone-Derived Growth Factor, Jean D. Sibonga

Loma Linda University Electronic Theses, Dissertations & Projects

A deleterious effect of spaceflight on human health is the loss of bone associated with the prolonged lack of gravitational stress on the skeleton. A potential for bone loss is indicated by the hypercalciuria and decreased heel bone density determined in Skylab astronauts. Histological studies of juvenile laboratory rats in actual spaceflight and in simulation models document a suppression of bone formation with little alteration of bone resorption. The mechanism for net bone loss needs to be defined in order to develop measures for its prevention or correction.

Skeletal growth factors, which may mediate coupling and locally regulate bone volume …


Decreased Triiodothyronine Binding To The Hepatic Nuclear Thyroid Hormone Receptor In The Diabetic Mouse, Thomas J. Dewind Jun 1988

Decreased Triiodothyronine Binding To The Hepatic Nuclear Thyroid Hormone Receptor In The Diabetic Mouse, Thomas J. Dewind

Loma Linda University Electronic Theses, Dissertations & Projects

The diabetic C57BL/KsJ-db m mouse has abnormal thyroid hormone levels and indications of thyroid hormone resistance. To investigate the basis of these abnormalities, the hepatic nuclear thyroid hormone receptor was extracted with 0.4 M KCl, 1.1 mM MgCl2, 20 mM Tris/HCl, pH 7.9 from hepatocyte nuclei of normal C57BL/KsJ, heterozygous C57BL/KsJ-db m (db/m), and diabetic C57BL/KsJ-db m (db/db) mice. Normal and heterozygous mice were grouped together as the controls. Triiodothyronine (T3) binding studies at 4°C using nitrocellulose filtration to separate free T3 from receptor bound T3 demonstrated an …


Biochemical And Histological Evaluation Of Normal Human Epidermis Vs Cultured Human Epidermis, Ngo Thi Bich Lien Jan 1987

Biochemical And Histological Evaluation Of Normal Human Epidermis Vs Cultured Human Epidermis, Ngo Thi Bich Lien

Biological Sciences Theses & Dissertations

Cultured human keratinocytes were grown in vitro for transplantation purposes in case of severe burns. Single keratinocytes were harvested from human epidermis and grown in culture flasks such that multilayered sheets of keratinocyte cells were harvestable in approximately three weeks. In order to evaluate cultured epidermis for equivalency with normal human epidermis, biochemical and histological studies were performed. Thin sections of cultured epidermis were shown to be composed of cells that had undergone developmental differentiation, but not terminal differentiation. Biochemical analyses of keratin and prekeratin proteins isolated from cultured epidermis indicated that cultured keratinocytes have electrophoretic patterns similar to keratins/prekeratins …


The Effects Of Tri-O-Cresyl Phosphate On 2',3'-Cyclicnucleotide-3'-Phosphohydrolase Activity In Neural And Non-Neural Tissue Of The Rat, Mark K. Schlager Jul 1984

The Effects Of Tri-O-Cresyl Phosphate On 2',3'-Cyclicnucleotide-3'-Phosphohydrolase Activity In Neural And Non-Neural Tissue Of The Rat, Mark K. Schlager

Chemistry & Biochemistry Theses & Dissertations

A total of 44 Long-Evans rats received 5.7 g/kg tri-O-cresyl phosphate (TOCP) orally every 3 days for 6 days. A second group of 13 rats received 4.6 g/kg orally every 3 days for 6 days. Animals were administered atropine sulfate (10 mg/kg) intraperitoneally every 6 hours or as needed to alleviate cholinergic symptoms. Ten control animals were given corn oil orally. Eight rats (18%) survived the 5.7 g/kg dose regimen and 5 rats (38%) survived the 4.6 g/kg dose regimen. Surviving rats were killed at 30-33 days post-dose. Signs of delayed neuropathy included ataxia and motor impairment.

The CNP activity …


The Analysis Of S-Adenosylmethionine And S-Adenosylhomocysteine In Normal And Neoplastic Cells, Kathryn Elizabeth Godburn Jul 1980

The Analysis Of S-Adenosylmethionine And S-Adenosylhomocysteine In Normal And Neoplastic Cells, Kathryn Elizabeth Godburn

Chemistry & Biochemistry Theses & Dissertations

Altered patterns of methylation have been shown in both ribosomal and transfer RNA isolated from cancer cells. In contrast to the elevated activity of the methyltransferases responsible for this modification, hypomethylation appears as a general characteristic. The endogenous levels of S-adenosylmethionine and S-adenosylhomocysteine are important in relationship to their role as substrate and product of the transmethylation reaction. The levels of S-adenosylmethionine and S-adenosylhomocysteine were determined using phosphocellulose cation exchange or high pressure liquid chromatography. High voltage paper electrophoresis was used in a modified procedure to directly resolve (35s) labeled S-adenosylmethionine and S-adenosylhomocysteine in small quantities of cell …


The Synthesis And Evaluation Of The Potential Antineoplastic Activity Of The Semicarbazone And The Thiosemicarbazone Derivatives Of The Di-2-Pyridyl Ketone And The 1,8-Diazafluorenone Ring Systems, Adriene Y. Principe Oct 1979

The Synthesis And Evaluation Of The Potential Antineoplastic Activity Of The Semicarbazone And The Thiosemicarbazone Derivatives Of The Di-2-Pyridyl Ketone And The 1,8-Diazafluorenone Ring Systems, Adriene Y. Principe

Chemistry & Biochemistry Theses & Dissertations

A number of' a-(N)-heterocyclic thiosemicarbazones have been synthesized and evaluated for potential antineoplastic activity since Brockman and colleagues2 reported the antineoplastic activity of' 2-f'ormylpyridine thiosemicarbazone (1). The primary objective of' this research project has been the synthesis and characterization of' the semicarbazone and the thiosemicarbazone derivatives of' the di-2-pyridyl ketone, (9-a) and (9-b), and the 1,8-diazaf'luorenone, (10-a) and (10-b), ring systems, as well as the evaluation of' these compounds for both in vitro and in vivo antineoplastic activity against Ehrlich ascites tumor cells in mice. These studies have suggested that di-2-pyridyl ketone thiosemicarbazone (9-b) is as effective as 2-formylpyridine …


Role Of Membrane-Associated Components Of Mycoplasma Arthritidis On The Biosynthesis Of Humoral Antibodies And Arthritogenic Properties In Experimental Animals, Lois M. Bergquist Jun 1973

Role Of Membrane-Associated Components Of Mycoplasma Arthritidis On The Biosynthesis Of Humoral Antibodies And Arthritogenic Properties In Experimental Animals, Lois M. Bergquist

Loma Linda University Electronic Theses, Dissertations & Projects

The virulence of animal-passaged Mycoplasma arthritidis (158) was demonstrated to be enhanced in rats by growth in oleic acid-enriched broth. The virulence of a laboratory-maintained culture of the same strain was unaffected by similar growth conditions. No differences either in the immune response as measured by complement-fixing (CF) antibodies or in the histogenesis of the disease were detected when rats were injected with animal-passaged M. arthritidis grown either in the presence or in the absence of oleic acid. All tests for metabolism-inhibiting (MI) antibodies in the rat were negative.

A Mycoplasma-associated immunosuppression of the primary and of the secondary hemagglutinin …