Biochemistry, Biophysics, and Structural Biology Commons^™

Proliferation Of Schwann Cells Induced By Axolemmal And Myelin Membranes, Michael Paul Dinneen

Theses and Dissertations

Purified Schwann cells were cultured from neonatal rat sciatic nerve using a modification of the method of Brockes (Brockes, J.P. et al, Brain Res. 165(1979) 105-118). Schwann cells and contaminating fibroblasts were unambiguously identified using fluorescent antibodies to 2'3' cyclic nucleotide 3'-phosphodiesterase and the thy 1.1 antigen respectively. The Schwann cells were quiescent unless challenged with mitogens, They proliferated rapidly in response to the soluable mitogen, cholera toxin, or to membrane fractions from rat CNS or PNS, prepared by the method of DeVries (DeVries, G.H., J Neurochem, 40 (1983) 1709-1717). Mitogenic activity was present in both axolemmal and myelin enriched …

Nuclear Envelope Proteins: Chemical Characteristics And Molecular Interactions Of The Lamins, David Lee Cochran

Theses and Dissertations

The lamins are a group of proteins in a residual nuclear envelope fraction derived from the nuclear lamina. The absence of specific functional assays for the two predominant species, lamin A and lamin B, has complicated their biochemical characterization. Initial studies reported in this work involved the enzymic cleavage of isolated lamins A and B and another lamina protein with a molecular weight of 61,000-daltons. The results obtained with each of three enzymes indicated strong similarities between the three nuclear envelope proteins.

Further chemical characterization of the lamins has been achieved. Lamins A, B and C have been separated by …

Effects Of Pulsed Electric Fields On Mammalian Cell Membranes, Guy K. Smith

Theses and Dissertations

The effect of pulsed electric fields on cell membranes were studied to investigate the effects of an electric field, per se, on biological systems, without the densometric and other technical problems associated with other forms of nonionizing radiation. Exposure of mouse splenocytes to a high voltage pulse resulted in an increase in membrane permeability to K⁺ that was dependent on both the electric field strength and the pulse duration. Exposure to a 2 μsec, 3.0 kV/cm pulse elicited a 50% loss of intracellular K⁺ indicating that the critical transmembrane potential (V_m) at breakdown was 1.26 volts …

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 …

Direct Chemical Evidence For A Supramolecular Protein Structure In The Nuclear Envelope, David Lee Cochran

Theses and Dissertations

Protein subunit structure in the nuclear envelope has not been previously described. Covalent crosslinking of polypeptides provides a method for studying the subunit structure of protein-rich systems. In this study, several polypeptide crosslinking methods have been used to determine associations among polypeptides in isolated chicken erythrocyte nuclear envelope. Interchain associations that exist in the isolated membrane were fixed by crosslinking the polypeptides in the isolated nuclear envelope. Crosslinked and uncrosslinked polypeptides were resolved by electrophoresis in a dissociating detergent system. Each agent caused distinctive alterations in the gel pattern. Certain bands diminished and disappeared while new bands of two or …

A Spectrophotofluorometric Analysis Of Serum Vitamin A Levels In A Defined Population, James Ronald Schroeder

Theses and Dissertations

The objectives of this thesis were to examine serum vitamin A levels in two defined populations. The method of analysis was a spectrophotofluorometric technique with a correction formula to account for interfering fluorescence from an identified carotenoid phytofluene (37).

The first population were infants at time of delivery. Infants were divided into two groups depending upon length of gestation. A premature group was identified as having a length of gestation of less than 36 weeks. Term infants were defined as 36 weeks or greater. The mean value of serum vitamin A of eight premature infants was 10.5 μg/100ml (S.E.M.+.78). The …

Hepatic Ornithine Metabolism In Hydrazine-Treated Rats, Van Saxton Hubbard

Theses and Dissertations

Ornithine plays an important role in mammalian intermediary metabolism. Ornithine can be (1) utilized as a component of the urea cycle, (2) decarboxylated to form putrescine, a precursor of the polyamines, spermidine and spermine, and (3) converted metabolically to arginine, proline and glutamate. In prior investigations conducted in our laboratories and others, free endogenous hepatic pools of ornithine were found to be elevated following hydrazine administration. Consequently, time-course alterations of arginase, ornithine δ-transaminase, ornithine transcarbamylase, and ornithine decarboxylase activities were investigated regarding the effect of hydrazine treatment on hepatic ornithine metabolism in the rat. As an outgrowth of these investigations, …

Evaluation Of The Essentiality Of Dextran In The Dental Caries Process, William Redman Grigsby

Theses and Dissertations

In summary, the main points to support the view that dextran synthesis is unessential to the dental caries process are presented below:

1 . Dextran-fed, microbe-bearing rats do not experience dental caries.

2 . Lactobacillus casei 4646 has no extracellular dextransucrase enzyme or other extracellular enzymes which release glucose or fructose from sucrose .

3. L. casei 4646 does not synthesize extracellular polysaccharide of the dextran class when grown on sucrose-containing medium.

4. L. casei 4646 does not exhibit in vitro, adherent growth on stainless-steel wire when grown on sucrose-containing medium .

5. L. casei 4646 does not cause dental …