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1993

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Articles 1 - 20 of 20

Full-Text Articles in Cell and Developmental Biology

The C. Elegans Heterochronic Gene Lin-4 Encodes Small Rnas With Antisense Complementarity To Lin-14, Rosalind Lee, Rhonda Feinbaum, Victor Ambros Dec 1993

The C. Elegans Heterochronic Gene Lin-4 Encodes Small Rnas With Antisense Complementarity To Lin-14, Rosalind Lee, Rhonda Feinbaum, Victor Ambros

Victor R. Ambros

lin-4 is essential for the normal temporal control of diverse postembryonic developmental events in C. elegans. lin-4 acts by negatively regulating the level of LIN-14 protein, creating a temporal decrease in LIN-14 protein starting in the first larval stage (L1). We have cloned the C. elegans lin-4 locus by chromosomal walking and transformation rescue. We used the C. elegans clone to isolate the gene from three other Caenorhabditis species; all four Caenorhabditis clones functionally rescue the lin-4 null allele of C. elegans. Comparison of the lin-4 genomic sequence from these four species and site-directed mutagenesis of potential open reading frames …

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Unusual Structure Of A Human Middle Repetitive Dna, Duminda D. Ratnasinghe Dec 1993

Unusual Structure Of A Human Middle Repetitive Dna, Duminda D. Ratnasinghe

Electronic Theses and Dissertations

The L2Hs sequences are a polymorphic, interspersed, middle repetitive DNA family unique to human genomes. Genomic fingerprinting indicates that these DNAs vary from one individual to another and between tissues of the same individual. Sequence analysis reveals that they are AT-rich (76%) and contain many unusual sequence arrangements (palindromes, inverted and direct repeats). These sequence properties confer on the L2Hs elements the potential to fold into non-B-form structures, a characteristic of recombination hot spots. To test this hypothesis carbodiimide, osmium tetroxide and S$\sb1$ nuclease were used as single-strand specific probes to study a recombinant plasmid, pN6.4.39, containing a single L2Hs …

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Xenopus Laevis As A Model Organism, David C. Cannatella, Rafael O. De Sá Dec 1993

Xenopus Laevis As A Model Organism, David C. Cannatella, Rafael O. De Sá

Biology Faculty Publications

Model organisms are often assumed to be representative of some more inclusive taxon of which the species is a part. This assumption leads to mistaken generalizations about the evolutionary and comparative significance of the data gathered. This paper reviews com? parative and evolutionary studies of Xenopus laevis and its relatives. Phylogenetic analysis of data from DNA sequences and morphology indicate that Xenopus is monophyletic and that Silurana is its sister group. The most basal lineages of Pipidae diverged prior to the breakup of Gondwana. The bizarre morphology of Xenopus is in part due to changes in the mode of meta? …

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Inhibition Of Cytochrome P-450 But Not Neutrophil Depletion Prevents The Pulmonary Toxicity Associated With 1-Nitronaphthalene, Steven Michael Green Aug 1993

Inhibition Of Cytochrome P-450 But Not Neutrophil Depletion Prevents The Pulmonary Toxicity Associated With 1-Nitronaphthalene, Steven Michael Green

Masters Theses

1-Nitronaphthalene (1-NN) is an environmental contaminant that has been shown to cause pulmonary toxicity in rodents. To examine the contribution of cytochrome P-450 to the metabolism and subsequent toxicity of 1-NN, rats were pretreated with chloramphenicol, a suicide substrate of P-450. To determine if inflammation plays a role in 1-NN toxicity, rats were pretreated with cyclophosphamide to deplete neutrophils. In both experiments, morphological analysis of the lower airways was performed with light and electron microscopy. A second group of animals was examined for biochemical indicators of inflammation and cell damage. The parameters examined were cell content, protein content and lactate …

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The Isolation And Identification Of Polyphenolics From Grape Seeds And Their Activity Towards Specific Cell Lines, Joseph A. Reddy Jul 1993

The Isolation And Identification Of Polyphenolics From Grape Seeds And Their Activity Towards Specific Cell Lines, Joseph A. Reddy

Chemistry & Biochemistry Theses & Dissertations

Grape seed extract is being marketed in France for cardiovascular use and skin care. The active constituents of both these drugs are certain polyphenols called procyanidins. A similar seed extract has now been obtained from Virginia Chardonnay grape seeds. Ten of the major components in this extract have been isolated in their pure form by the semi-preparative HPLC separation on a YMC ODS-AQ (Octadecylsilane-AQ) column. The ODS-Aq column has been shown to have a better resolving capacity compared to the Spherisorb ODS (Octadecylsilane) column previously described in the literature. This has been attributed to the ODSAQ support which has both …

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The Cytotoxic Effect Of Tropical Plants On Human And Rat Hepatoma Cells, Mark Tafazoli Jun 1993

The Cytotoxic Effect Of Tropical Plants On Human And Rat Hepatoma Cells, Mark Tafazoli

Honors Capstone Projects and Theses

No abstract provided.

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Analysis Of The Proteoglycan Content In Fresh And Cryopreserved Porcine Cardiovascular Tissues, Yun Hee Shon Apr 1993

Analysis Of The Proteoglycan Content In Fresh And Cryopreserved Porcine Cardiovascular Tissues, Yun Hee Shon

Theses and Dissertations in Biomedical Sciences

The purpose of this research was to study the effects of cryopreservation on the proteoglycan (PG) and mineral content of aorta conduit tissue. Proteoglycans from fresh and cryopreserved porcine aorta conduit tissues were isolated by extraction with 4 M guanidine (Gdn) - hydrochloride (HCl) for 48 hours. Quantitative analysis of extracted proteoglycans revealed that the content of proteoglycan material from cryopreserved tissue, measured as uronate and protein per unit weight of wet tissue, was similar to that from fresh tissue. Gel permeation column chromatography studies suggested that proteoglycans present in three CsCl fractions from cryopreserved tissues had molecular weights similar …

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Ribosomal Dna And The Phylogeny Of Frogs, David M. Hills, Loren K. Ammerman, Michael T. Dixon, Rafael O. De Sá Mar 1993

Ribosomal Dna And The Phylogeny Of Frogs, David M. Hills, Loren K. Ammerman, Michael T. Dixon, Rafael O. De Sá

Biology Faculty Publications

Phylogenetic analysis of 1656 aligned sites in the 28S ribosomal RNA gene of frogs supports some of the recently recognized higher groups of anurans but provides counter-support for others. The 28S rDNA data support the monophyly of the recently recognized Pipanura (me- sobatrachians plus neobatrachians), which in turn indicates paraphyly of archaeobatrachians. Me- sobatrachians (pelobatoids plus pipoids), which are either considered paraphyletic or weakly sup- ported as monophyletic in morphological analyses, also receive support as a monophyletic group from the 28S rDNA data. Hyloidea (=Bufonoidea), which is widely recognized but lacks morphological support, receives some molecular support as being monophyletic. …

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Chronic Estrogen-Induced Alterations In Adrenocorticotropin And Corticosterone Secretion: Relationship To Mineralocorticoid And Glucocorticoid Receptor Regulation In The Female Rat Anterior Pituitary Gland And Brain, Loyd H. Burgess Jan 1993

Chronic Estrogen-Induced Alterations In Adrenocorticotropin And Corticosterone Secretion: Relationship To Mineralocorticoid And Glucocorticoid Receptor Regulation In The Female Rat Anterior Pituitary Gland And Brain, Loyd H. Burgess

Dissertations

No abstract provided.

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Detection Of Serum Antibody Responses In Cattle With Natural Or Experimental Neospora Infections, Patricia Conrad, Karen Sverlow, Mark Anderson, Joan Rowe, Robert Bondurant, Gwen Tuter, Richard Breitmeyer, California Department Of Food And Agriculture, Animal Health Branch, Mark Thurmond, Alex Ardans, J. P. Dubey, Gerarld Duhamel, Bradd Barr Jan 1993

Detection Of Serum Antibody Responses In Cattle With Natural Or Experimental Neospora Infections, Patricia Conrad, Karen Sverlow, Mark Anderson, Joan Rowe, Robert Bondurant, Gwen Tuter, Richard Breitmeyer, California Department Of Food And Agriculture, Animal Health Branch, Mark Thurmond, Alex Ardans, J. P. Dubey, Gerarld Duhamel, Bradd Barr

School of Veterinary and Biomedical Sciences: Faculty Publications

Parasite-specific antibody responses were detected using an indirect fluorescent antibody (IFA) test in cattle that were naturally or experimentally infected with Neospora parasites. The test was developed using Neospora tachyzoites isolated from an aborted bovine fetus and grown in bovine cell cultures (isolate BPA1). In all cases, infections were confirmed by the identification of Neospora tachyzoites and/or bradyzoite cysts in fetal or calf tissues using an immunoperoxidase test procedure. Fifty-five naturally infected cows that aborted Neospora-infected fetuses had titers of 320-5,120 at the time of abortion. The titer of 6 cows that were serologically monitored over a prolonged period decreased …

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Ultrastructure And Mitosis Of Glaucosphaera Vacuolata, Steven Philip Allan Goss Jan 1993

Ultrastructure And Mitosis Of Glaucosphaera Vacuolata, Steven Philip Allan Goss

Dissertations, Theses, and Masters Projects

No abstract provided.

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Burden In Spousal Caregivers: A Correlational Study Of The Effect And Interaction Of Stressors, Vulnerability, Psychological Resources And Social Supports On The Development Of Burden In Spousal Caregivers Of The Chronically Ill, Sheila Marie Crossen-Powell Jan 1993

Burden In Spousal Caregivers: A Correlational Study Of The Effect And Interaction Of Stressors, Vulnerability, Psychological Resources And Social Supports On The Development Of Burden In Spousal Caregivers Of The Chronically Ill, Sheila Marie Crossen-Powell

Dissertations, Theses, and Masters Projects

This study investigated burden in a convenience, nonrandom sample of 120 spousal caregivers of cardiac patients, who resided at home in the Richmond, VA area, had health insurance, and received medical care from private providers. Using Vitaliano's theory that burden is a function of stressors and personal vulnerability moderated by psychological resources and social supports, the study examined the relationships between those five constructs.;Burden was measured by the Brief Symptom Inventory and Montgomery's Scales of Objective and Subjective Burden. The Hassles and Uplifts Scales was used to measure stressors; demographic data and the Self control, Responsibility, Socialization, Psychological Mindedness, Tolerance, …

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Epidermal Mosaicism And Blaschko's Lines, Celia Moss, S. Larkins, Michael W. Stacey, A. Blight, P. A. Farndon, E. V. Davidson Jan 1993

Epidermal Mosaicism And Blaschko's Lines, Celia Moss, S. Larkins, Michael W. Stacey, A. Blight, P. A. Farndon, E. V. Davidson

Bioelectrics Publications

To test the hypothesis that epidermal rather than dermal mosaicism determines Blaschko's lines in hypomelanosis of Ito (HI), we studied the distribution of chromosomal mosaicism in four patients. In two, mosaicism had not been detected in lymphocytes or dermal fibroblasts, but was clearly shown in epidermal keratinocytes; furthermore, the abnormal cell line was confirmed to the hypopigmented epidermis and the normal epidermis contained only normal cells. Negative findings in the other two patients might be because of mosaicism which was undetected either because it was submicroscopic or because it was present in melanocytes, which have not yet been studied. These …

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The Effects Of Teratogens On Serotonin Expression In Drosophila Embryonic Cell Cultures, Keri Joel Hopkins Jan 1993

The Effects Of Teratogens On Serotonin Expression In Drosophila Embryonic Cell Cultures, Keri Joel Hopkins

Theses Digitization Project

No abstract provided.

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Cervical Cancer: A Retrospective Study Of The Dna Ploidy Status Using Flow Cytometry And Its Prognostic Applications, Omar Roberto Fagoaga Jan 1993

Cervical Cancer: A Retrospective Study Of The Dna Ploidy Status Using Flow Cytometry And Its Prognostic Applications, Omar Roberto Fagoaga

Theses Digitization Project

No abstract provided.

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Characterization Of Early B Lymphocyte Activation During Trichinella Spiralis Infection In Rats, Elizabeth Margaret Richards Jan 1993

Characterization Of Early B Lymphocyte Activation During Trichinella Spiralis Infection In Rats, Elizabeth Margaret Richards

Theses Digitization Project

No abstract provided.

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The Relationships Between Retrospective Perceptions Of An Alcoholic Home Environment With Levels Of Differentiation Of Self And Trait Anxiety In Adult Children Of Alcoholics, Barbara Lynn Rojas-Hughes Jan 1993

The Relationships Between Retrospective Perceptions Of An Alcoholic Home Environment With Levels Of Differentiation Of Self And Trait Anxiety In Adult Children Of Alcoholics, Barbara Lynn Rojas-Hughes

Dissertations, Theses, and Masters Projects

The purpose of this study was to investigate the relationships between adult children of alcoholics (ACOA's) recollections of their family of origin home environments, with present day levels of ACOA differentiation of self, and trait anxiety. The author explored the influence of ACOA gender differences and a variety of demographic information.;The ACOA volunteers for this study were recruited from The College of William and Mary in Virginia. to be included in the study, subjects must have met the following criteria: (a) the volunteer's age must have been 18 years or above; (b) subjects met the ACOA criteria by scoring a …

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Book Review: The Baculovirus Expression System: A Laboratory Guide (1992) King, L. A. & Possee, R. D., David D. Dunigan Jan 1993

Book Review: The Baculovirus Expression System: A Laboratory Guide (1992) King, L. A. & Possee, R. D., David D. Dunigan

Nebraska Center for Virology: Faculty Publications

The power of molecular biology is unleashed with the ability to clone and sequence genes, and then express these genes in heterologous systems. This sets the stage for the full analysis of proteins that are otherwise difficult to isolate and/or purify, especially when present at very low copy number per cell or when isolated from relatively precious materials. Overexpression of protein is now possible in a number of systems including prokaryotes (e.g., E. coli) and various eukaryotes (yeast, insects, and plants). The issue then becomes, which system (1) most closely reflects the homologous expression with respect to posttranslational modifications, …

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Do All Programmed Cell Deaths Occur Via Apoptosis?, Sallie Smith Schneider, L.M. Schwartz, M.E.E Jones, B.A. Osborne Dec 1992

Do All Programmed Cell Deaths Occur Via Apoptosis?, Sallie Smith Schneider, L.M. Schwartz, M.E.E Jones, B.A. Osborne

Sallie W Smith Schneider

No abstract provided.

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P53 Is Required For Radiation-Induced Apoptosis In Mouse Thymocytes, Sallie Smith Schneider, S.W. Lowe, E.M. Schmitt, B.A. Osborne Dec 1992

P53 Is Required For Radiation-Induced Apoptosis In Mouse Thymocytes, Sallie Smith Schneider, S.W. Lowe, E.M. Schmitt, B.A. Osborne

Sallie W Smith Schneider

No abstract provided.

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