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Articles 12901 - 12930 of 13223

Full-Text Articles in Life Sciences

Effects Of Glucocorticoid Treatment On The Properties Of Single Notor Units In Cat Hindlinb Huscles, Andrew James Robinson Jan 1981

Effects Of Glucocorticoid Treatment On The Properties Of Single Notor Units In Cat Hindlinb Huscles, Andrew James Robinson

Theses and Dissertations

The administration of glucocorticoids has been shown to induce atrophy and weakness in whole skeletal muscle. These effects frequently appear to be more pronounced in pale muscle than in red muscle. The present study was undertaken to examine the effects of steroid treatment on the contractile, electrical, and fatigue properties of single meter units in pale and red cat hindlimb muscles. Single motor units in the medial gastrocnemius (MG) and soleus muscles were isolated using techniques developed by McPhedran, et al., (1965). The properties of a large number of motor units were examined in normal animals and were compared to …


Thermodynamics Of Association And Catalysis Of N-Acyl-Peptidyl-Phenylalanine Amide Substrates By Chymotrypsin, John Paul Huff Jan 1981

Thermodynamics Of Association And Catalysis Of N-Acyl-Peptidyl-Phenylalanine Amide Substrates By Chymotrypsin, John Paul Huff

Dissertations

No abstract provided.


The Role Of Suppressor T Lymphocytes In Renal Allograft Rejection, Fred Barry Pearlman Jan 1981

The Role Of Suppressor T Lymphocytes In Renal Allograft Rejection, Fred Barry Pearlman

Master's Theses

No abstract provided.


Electron Spin Resonance Studies Of Membrane Fluidity Of Normal And Malignant Human Neural Tissues, Robert P. Wersto Jan 1981

Electron Spin Resonance Studies Of Membrane Fluidity Of Normal And Malignant Human Neural Tissues, Robert P. Wersto

Dissertations

No abstract provided.


Methods For Biological, Chemical, And Physical Analyses In Reservoirs, Penelope E. Kellar, Sherell A. Paulson, Larry J. Paulson Dec 1980

Methods For Biological, Chemical, And Physical Analyses In Reservoirs, Penelope E. Kellar, Sherell A. Paulson, Larry J. Paulson

Publications (WR)

This manual contains detailed descriptions of biological, chemical and physical sampling and analytical procedures used at the Lake Mead Limnological Research Center. The manual was prepared in response to requests made by numerous individuals involved in the Las Vegas Valley Water Quality Program. This manual represents what we consider to be a reasonably complete compilation of methods useful in studying both general and specific limnological questions. While each section is sufficiently detailed to be of use to investigators with little experience in limnological methodology, the methods can be used on a wide variety of lakes and reservoirs, with relatively little …


Physical Properties Of Dna From Synchronously Grown Mesophilic And Thermophilic Bacteria, Carol A. Cox Dec 1980

Physical Properties Of Dna From Synchronously Grown Mesophilic And Thermophilic Bacteria, Carol A. Cox

Masters Theses

No abstract provided.


The Effect Of Lead On Developing Rat Brain Lipids, Larry J. Stegink Dec 1980

The Effect Of Lead On Developing Rat Brain Lipids, Larry J. Stegink

Masters Theses

The objective of this study was to determine the effect of lead on the brain lipids of developing rats.

Lead acetate was added to the drinking water of two pregnant rats. A' control dam was maintained on the same diet without the lead. Following birth and weaning the lead concentration was reduced and an equal number of pups from each litter were sacrificed on days 19, 22, 26, 30, and 35 after birth. The brain lipids were isolated and fatty acid distribution analyzed by gas-liquid chromatography.

Variations in fatty acid distribution between the control and experimental pups were noted for …


The Synthesis And Biochemical Evaluation Of Potential Acetylcholinesterase Reactivators, Andrea Mcdearmid Lunsford Oct 1980

The Synthesis And Biochemical Evaluation Of Potential Acetylcholinesterase Reactivators, Andrea Mcdearmid Lunsford

Chemistry & Biochemistry Theses & Dissertations

Objectives of this research were to (1) synthesize, and (2) evaluate new compounds which would be potential reactivators of organophosphate-inhibited acetylcholinesterase.

A series of 1,8-diazafluorenone and 2,2'bipyridylketone oximes and oxime methiodides were synthesized (11, 13, 14, 22, 24). These compounds were developed as structural analogs of 2-PAM (2-Pyridinealdoxime methiodide) and TMB-4 (1,1Trimethylene-Bis(4-formylpyridinium bromide)dioxime), the current drugs of choice for treatment of organophosphorous poisoning.

Acetylcholinesterase from electric eel was inhibited with DFP (diisopropylfluorophosphate), an irreversible-type inhibitor, and the inhibited enzyme was treated with the various reactivator compounds. The reactivation assays were monitored with pH stat apparatus, and the data were evaluated …


Functions Of Deadenylation Factors In Mrna Decay And Mrna Processing Body Formation, Dinghai Zheng Sep 1980

Functions Of Deadenylation Factors In Mrna Decay And Mrna Processing Body Formation, Dinghai Zheng

Dissertations and Theses (Open Access)

Most newly synthesized messenger RNAs possess a 5’ cap and a 3’ poly(A) tail. The process of poly(A) tail shortening, also termed deadenylation, is important for post-transcriptional gene regulation, because deadenylation not only leads to mRNA translational inhibition but also is the first step of major mRNA degradation. Translationally inhibited mRNAs can be stored and/or degraded in dynamic cytoplasmic foci termed mRNA processing bodies, or P bodies, which are conserved in eukaryotes.

To shed new light on the mechanisms of P body formation and P body functions, I focused on the link between deadenylation factors and P bodies. I found …


Multiple Forms Of Nicotinamide Adenine Dinucleotide Glycohydrolase From Bull Semen, Stanley D. Yeatts Ii Jul 1980

Multiple Forms Of Nicotinamide Adenine Dinucleotide Glycohydrolase From Bull Semen, Stanley D. Yeatts Ii

Chemistry & Biochemistry Theses & Dissertations

Nicotinamide adenine dinucleotide glycohydrolase (NADase) of bull semen is an extracellular, soluble enzyme capable of catalyzing the hydrolysis of the nicotinamide N-ribosidic linkage of NAD+. In search for a rapid, simple procedure for the preparation of this enzyme, it was found that Matrex Gel Red A (Amicon) column packing served very well as an affinity gel for NADase. The enzyme was applied to the Matrex Red A column (21 cm x 1.5 cm) in 10 mM sodium phosphate buffer, pH 6.0. Surprisingly, two fractions of NADase activity were obtained when the column was eluted with a sodium chloride …


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 …


High Resolution Two-Dimensional Electrophoretic Study Of Human Seminal Plasma Proteins, Edward E. Gaunt Jul 1980

High Resolution Two-Dimensional Electrophoretic Study Of Human Seminal Plasma Proteins, Edward E. Gaunt

Chemistry & Biochemistry Theses & Dissertations

A comprehensive biochemical screening procedure for the evaluation of seminal plasma constituents is needed which, when used in conjunction with semen analysis, can provide the physician with both qualitative and quantitative information regarding the fertility status of an individual.

High resolution two-dimensional electrophoresis is a technique whereby proteins in a complex mixture such as a biological fluid are separated in one dimension by molecular charge and in the second dimension by molecular mass. It has been the purpose of this investigation to adapt and evaluate this technique for the analysis of human seminal plasma.

Our efforts have shown that this …


Nutrient Interactions Among Reservoirs On The Colorado River, Larry J. Paulson, John R. Baker Jun 1980

Nutrient Interactions Among Reservoirs On The Colorado River, Larry J. Paulson, John R. Baker

Publications (WR)

Interactions among physical, chemical and biological processes in reservoirs can significantly alter the characteristics of the discharge (Neel 1963, Wright 1967, Hannan 1979) that, in turn, can influence the ecology of the river downstream .(Ward and Stanford 1979). Investigations of the Colorado River, system reveal that reservoir-induced changes in the river can also affect downstream reservoirs. The formation of Lake Powell, in 1963 was accompanied by reductions in suspended sediment and nutrient loading and changes in the seasonal temperature and discharge cycles of the Colorado River. In this paper, we evaluate how these changes have influenced the nutrient and trophic …


Studies Of The Reorientational Relaxation Of Pyridine In Water By Depolarized Rayleigh Light Scattering, C. H. Wang, Scott L. Whittenburg, P. A. Lund, D. H. Christensen Apr 1980

Studies Of The Reorientational Relaxation Of Pyridine In Water By Depolarized Rayleigh Light Scattering, C. H. Wang, Scott L. Whittenburg, P. A. Lund, D. H. Christensen

Chemistry and Biochemistry Faculty Publications

The depolarized Rayleigh spectra of aqueous solutions of pyridine have been studied using a high‐finesse Fabry–Perot interferometer as a function of temperature and concentration. The Rayleigh relaxation times are found to have a complex concentration and viscosity dependence. The classical Stokes–Einstein–Debye equation for molecular reorientation breaks down in this system. The Rayleigh relaxation time of pyridine molecules is not determined by the macroscopic shear viscosity of the solution. The specific interaction due to the formation of hydrogen bonds between pyridine and water molecules plays a very important role in affecting the relaxation time. At a fixed temperature the plot of …


Sulfatides As Opiate Receptors: An Evaluation Of The Opiate Binding Potential Of Sulfogalactosylgylcerolipid, Darby Geoghegan Hand Apr 1980

Sulfatides As Opiate Receptors: An Evaluation Of The Opiate Binding Potential Of Sulfogalactosylgylcerolipid, Darby Geoghegan Hand

Chemistry & Biochemistry Theses & Dissertations

Cerebroside sulfate (CS) has recently been shown to bind opiate drugs in a pharmacologically relevent manner and therefore satisfy the structural requirements of an opiate receptor. Seminolipid (SGG), a novel sulfated galactosyl. glycerolipid that has been isolated from the testes of a variety of mammals, may be viewed as a structural analog of CS. In view of this structural similarity, it is reasonable to presume that SGG may also bind opiate drugs. The isolation of SGG from boar testes was accomplished using silica gel dry column chromotography with a chloroform: methanol water solvent system. The structure and purity of the …


Structural Studies Of Preimplantation Rabbit Embryos Using Ftir Atr, Amy R. Moler-Booth Apr 1980

Structural Studies Of Preimplantation Rabbit Embryos Using Ftir Atr, Amy R. Moler-Booth

Chemistry & Biochemistry Theses & Dissertations

FTIR was used in conjunction with a surface selective technique, known as attenuated total reflectance (ATR), to study the infrared spectra of preimplantation rabbit embryos. The rabbit embryos ranged in aged from 3 to 6 days. Since an embryo is mostly water, deuteration of the embryo was necessary to eliminate the intense water background present in the mid-infrared region. A set of spectral standards were tested, in order to identify the bands seen in embryo spectra. By analyzing and comparing the spectra from 3, 4, 5 and 6 day embryos, differences could be noted. In particular, bands defined as Amide …


Oxidative Metabolism Of 4-Aminobutyrate By Rat Brain Mitochondria: Inhibition By Branched-Chain Fatty Acid / J. Cunningham, D. D. Clarke, And W.J. Nicklas, J. Cunningham, Donald Dudley Clarke Phd, William J. Nicklas Jan 1980

Oxidative Metabolism Of 4-Aminobutyrate By Rat Brain Mitochondria: Inhibition By Branched-Chain Fatty Acid / J. Cunningham, D. D. Clarke, And W.J. Nicklas, J. Cunningham, Donald Dudley Clarke Phd, William J. Nicklas

Chemistry Faculty Publications

The oxidation of 4-aminobutyric acid (GABA) by nonsynaptosomal mitochondria isolated from rat forebrain and the inhibition of this metabolism by the branched-chain fatty acids 2-methyl-2-ethyl caproate (MEC) and 2,2- dimethyl valerate (DMV) were studied. The rate of GABA oxidation, as measured by 02 uptake, was determined in medium containing either 5 or 100 mM-[K+]. The apparent Km for GABA was 1.16 ± 0.19 mM and the Vmax in state 3 was 23.8 + 5.5 ng-atoms O2 ·min-1.mg protein-1 in 5 mM-[K+]. In a medium with 100 mM-[K+] the apparent K111 was 1.11 + 0.17 mM and V max was 47.4 …


Adaptative Alteration In Phospholipid Composition Of Plasma Membranes From A Somatic Cell Mutant Defective In The Regulation Of Cholesterol Biosynthesis, Michael Sinensky Jan 1980

Adaptative Alteration In Phospholipid Composition Of Plasma Membranes From A Somatic Cell Mutant Defective In The Regulation Of Cholesterol Biosynthesis, Michael Sinensky

Faculty Publications, Biological Sciences

A somatic cell mutant (CR1) of a Chinese hamster ovary cell (CHO-K1) which has previously been shown to be defective in the regulation of cholesterol biosynthesis accumulates more cholesterol than the parental cell line in plasma membranes. Although such an increase in membrane cholesterol should lead to an increase in the order parameter of these membranes, as measured with an electron spin resonance spin probe, the order parameters of mutant and wild-type plasma membranes are identical--apparently because of an adaptive alteration in membrane phospholipid composition. The phospholipid compositions of mutant and wild-type cell plasma membranes are compared and the mutant …


Anti-Neoplastic Actions In Vivo And In Vitro By Non-Toxic Natural Products From Chara Globularis, A Multicellular Green Alga, Abdessalam Sherif Jan 1980

Anti-Neoplastic Actions In Vivo And In Vitro By Non-Toxic Natural Products From Chara Globularis, A Multicellular Green Alga, Abdessalam Sherif

Theses Digitization Project

No abstract provided.


Immuno- And Bioassayable Extrapituitary Growth Hormone And Thyroid Stimulating Hormone From Discrete Areas Of The Central Nervous System, Sally Ann Hojvat Jan 1980

Immuno- And Bioassayable Extrapituitary Growth Hormone And Thyroid Stimulating Hormone From Discrete Areas Of The Central Nervous System, Sally Ann Hojvat

Dissertations

No abstract provided.


Studies On The Mechanism Of Reaction Of Papain With N-Acetyl-L-Phenylalanyl Glycinal, A Model For An Elementary Step In Catalysis, Thresiamma Kuppy Jan 1980

Studies On The Mechanism Of Reaction Of Papain With N-Acetyl-L-Phenylalanyl Glycinal, A Model For An Elementary Step In Catalysis, Thresiamma Kuppy

Master's Theses

No abstract provided.


Aspects Of Larval Ecology Of Squilla Empusa (Crustacea, Stomatopoda) In Chesapeake Bay, Steven G. Morgan Jan 1980

Aspects Of Larval Ecology Of Squilla Empusa (Crustacea, Stomatopoda) In Chesapeake Bay, Steven G. Morgan

OES Faculty Publications

Larvae of Squilla empusa were collected from the plankton and were laboratory-reared in 16 combinations of temperature and salinity to determine their tolerances. Larvae survived longer and molted more frequently when reared at 25%, and 20° or 25° C, which corresponds to the natural conditions of Chesapeake Bay when the larvae were collected.

A 2 year planktonic survey conducted in the lower region of the bay by the Virginia Institute of Marine Sciences was compared with a survey made at the bay mouth in 1976. The seasonal occurrence of Squilla empusa larvae extended from the last week of July until …


The Association Of 5.8 S With 28s Ribosomal Rna, Nandita Banerjee Jan 1980

The Association Of 5.8 S With 28s Ribosomal Rna, Nandita Banerjee

Chemistry & Biochemistry Theses & Dissertations

5.8S rRNA is a low molecular weight ribosomal RNA which is noncovalently bonded to the larger ribosomal subunit 28S rRNA; through its 3' end and through its 5' end. This interaction is an integral part of the ribosome, and plays an important role in the ribosome structure and function.

There is a high degree of homology between the 5.8S rRNA primary structures of rat, turtle and chicken. The base sequence of rat 5.8S rRNA differs only in one position from that of turtle and in three positions fr.om that of cl1.icken. Tl1ere is a single purine substitution at the 5' …


Multiple Methods Of Analysis Of 2'-O-Methylation In 5.8s Rrna, Sharon H. Ryan Jan 1980

Multiple Methods Of Analysis Of 2'-O-Methylation In 5.8s Rrna, Sharon H. Ryan

Chemistry & Biochemistry Theses & Dissertations

5.8S rRNA is a low molecular weight ribosomal RNA which is found hydrogen bonded to 28S rRNA in the eucaryotic cell. There are two nucleotides which have 2'-0-methylations; a guanine residue at position 77 is fully methylated and a uridine residue at position 14 which is partially methylated. This partial 2'-0-methylation of the uridine residue has been found to vary with the tissue source, with the highest level in normal tissue and the lowest level in neoplastic tissue. In order to study the significance of this site-specific methylation, a reliable and convenient method of analysis was needed.

Early studies on …


Associations Of N-Acyl Amino Aldehyde Analogs Of Specific Substrates To The Active Site Of Chymotrypsin, William P. Kennedy Jan 1980

Associations Of N-Acyl Amino Aldehyde Analogs Of Specific Substrates To The Active Site Of Chymotrypsin, William P. Kennedy

Dissertations

No abstract provided.


Acetoacetate Decarboxylase Activity Of Fraction V Human Serum Albumin, Robert Richard Rosecrans Jan 1980

Acetoacetate Decarboxylase Activity Of Fraction V Human Serum Albumin, Robert Richard Rosecrans

Dissertations

No abstract provided.


The Role Of Skin Temperature In The Control Of Sweating In Man, Thomas V. Mccaffrey Jan 1980

The Role Of Skin Temperature In The Control Of Sweating In Man, Thomas V. Mccaffrey

Dissertations

No abstract provided.


The Isolation, Purification, And Characterization Of A Bacterial Enzyme Catalyzing The Reductive Cleavage Of Anthracycline Glycosides, Mark W. Collison Dec 1979

The Isolation, Purification, And Characterization Of A Bacterial Enzyme Catalyzing The Reductive Cleavage Of Anthracycline Glycosides, Mark W. Collison

Masters Theses

No abstract provided.


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 …


Heating-Effect Minimization In Dye Lasers, Kenneth Lee Matheson, James M. Thorne Aug 1979

Heating-Effect Minimization In Dye Lasers, Kenneth Lee Matheson, James M. Thorne

Faculty Publications

Optical pumping of dye lasers deposits heat nonuniformly in the active medium. Because the refractive index of a liquid or gas is a function of temperature, gradients are created which refract the laser beam. This effect is sometimes serious enough to quench laser action. In this paper, we evaluate the effects caused by optical pumping with a coaxial flashlamp and suggest ultraviolet absorbers and wavelength shifters as materials for minimizing the problem