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Full-Text Articles in Life Sciences

Role Of Mitogen-Activated Kinases In Cd40-Mediated T Cell Activation Of Monocyte/Macrophage And Vascular Smooth Muscle Cell Cytokine/Chemokine Production, Denise M. Milhorn Aug 1999

Role Of Mitogen-Activated Kinases In Cd40-Mediated T Cell Activation Of Monocyte/Macrophage And Vascular Smooth Muscle Cell Cytokine/Chemokine Production, Denise M. Milhorn

Electronic Theses and Dissertations

This dissertation represents efforts to determine the functional consequences acquired by vascular smooth muscle cells (SMC) in response to CD40 ligation by activated CD154+ T cells, and to elucidate components of the signaling pathway(s) activated in response to CD40 signaling in both monocytes and SMC. To study the consequences of CD40 stimulation, primary human monocytes and aortic SMC were treated with plasma membranes purified from CD154 + , CD4+ T cells. The results presented in this dissertation demonstrate that SMC, like monocytes/macrophages, are capable of interacting with T cells in a manner that results in reciprocal activation events. SMC were …


Universal Design And Nature Trails: Balancing Accessibility, Site Integrity, And The Recreation Experience, Steve Kirkindall Aug 1999

Universal Design And Nature Trails: Balancing Accessibility, Site Integrity, And The Recreation Experience, Steve Kirkindall

Electronic Theses and Dissertations

This study addressed the application of Americans With Disabilities Act (ADA) guidelines in outdoor recreation settings. The purpose was three-fold: to develop site- and user-friendly design principles for non-urban, accessible nature trails; to design and construct a trail based on those principles; and to evaluate both principles and trail by surveying trail users. The Delphi Method was employed with a national panel to assess current expert opinion regarding accessibility and trails. Fifty-nine principles were developed from combined results of panel deliberations and applied experience gained constructing a prototype trail utilizing the universal design concept. Trail users rated the importance of …


Strength Properties Of Juvenile And Mature Wood Of Twelve Families Of Loblolly Pine (Pinus Taeda L.), Elizabeth Lynn Forbes Apr 1999

Strength Properties Of Juvenile And Mature Wood Of Twelve Families Of Loblolly Pine (Pinus Taeda L.), Elizabeth Lynn Forbes

Electronic Theses and Dissertations

The wood mechanical properties of progeny from twelve open-pollinated parent trees were examined. Six families were from parents which had high wood specific gravity and six were from parents which had low wood specific gravity. Thirty-two-year-old trees, that had been planted at Many, Louisiana, were sampled and juvenile and mature wood test specimens were prepared. Maximum crushing strength, modulus of rupture, modulus of elasticity and wood specific gravity were determined from compression parallel to the grain tests and static bending tests. Maximum crushing strength, modulus of rupture, modulus of elasticity, and specific gravity were found to vary significantly between family …


Seasonal Investigation Of Native Fishes And Their Habitats In Missouri River And Yellowstone River Backwaters, Shannon J. Fisher Jan 1999

Seasonal Investigation Of Native Fishes And Their Habitats In Missouri River And Yellowstone River Backwaters, Shannon J. Fisher

Electronic Theses and Dissertations

Interactions between the Missouri River and its floodplain have been severely degraded due to channelization and impoundment. Ecologists have assumed that backwaters are a critical habitat component for certain life stages of native fishes; however, documented relationships are limited. During this study, I monitored fishes, invertebrates, and habitats to help determine the importance of backwaters to native fishes of various life stages, and to assess the changes that occur in habitat characteristics and invertebrate densities during periods with differential connectivity. Seven assemblages of fishes, identified with catch-per-unit-effort data, had at least some relationship with the backwaters. The assemblages included two …


Food Habits And Diet Overlap Of Age-1 And Older Walleye And White Bass In Lake Poinsett, South Dakota, Andrew B. Starostka Jan 1999

Food Habits And Diet Overlap Of Age-1 And Older Walleye And White Bass In Lake Poinsett, South Dakota, Andrew B. Starostka

Electronic Theses and Dissertations

White bass Marone chysops and walleye Stizostedion vitreum coexist in several of the large glacial lakes in eastern South Dakota. I collected age-1 and older white bass and walleye in Lake Poinsett, South Dakota during May, July and September, 1998 to determine food habits and diet overlap using percent by weight to describe diets and Schoener's index (Cxy) to determine diet overlap. Macroinvertebrates were common prey items for white bass in all length groups during all sample dates. The primary macroinvertebrates consumed by white bass were corixids, amphipods and dipterans. Fish, as a group, were second in diet importance over …


Biochemistry Of Hemolysin Toxin Activation By Fatty Acylation: Characterization Of An Internal Protein Acyltransferase, Michael S. Trent Dec 1998

Biochemistry Of Hemolysin Toxin Activation By Fatty Acylation: Characterization Of An Internal Protein Acyltransferase, Michael S. Trent

Electronic Theses and Dissertations

Hemolysin toxin produced and secreted by pathogenic Escherichia coli is one of a family of cytolytic, structurally homologous protein toxins known as RTX (repeats in toxin) toxins. RTX toxins are products of a gene cluster, CABD . The A gene product, nontoxic hemolysin (proHlyA) is made toxic by post-translational fatty acylation of two internal lysine residues. HlyC, C gene product, is essential for acylation, and acyl-acyl carrier protein (ACP) is the acyl donor. HlyB and HlyD are involved in secretion of the toxin. HlyC was thought to serve as an internal protein acyltransferase and remained uncharacterized until now. ProHlyA and …


In Vitro Assessment Of The Toxicity Of Cocaine And Its Metabolites In The Human Umbilical Artery, Tessa L. Long Aug 1998

In Vitro Assessment Of The Toxicity Of Cocaine And Its Metabolites In The Human Umbilical Artery, Tessa L. Long

Electronic Theses and Dissertations

An in vitro model was used to assess the effect of cocaine and its metabolites on the umbilical artery. Objectives were to pharmacologically confirm the presence of adrenergic innervation using tyramine, evaluate the ability of cocaine, benzoylecgonine, norcocaine and cocaethylene to potentiate vasoconstriction by serotonin and norepinephrine, examine the ability of ketanserin to block the enhanced vasoconstriction produced by cocaine, and determine displacement of 3 H-ketanserin by serotonin, norepinephrine, tyramine and mianserin. The vasoconstrictive effect of tyramine (100 μM) was enhanced in the presence of cocaine by 257%. Vasoconstrictive effects of serotonin and norepinephrine were significantly enhanced by cocaine by …


Tnf(Alpha)-Dependent And Tnf(Alpha)-Independent Activation Of Macrophage Effector Function, Annette R. Clemons-Miller May 1998

Tnf(Alpha)-Dependent And Tnf(Alpha)-Independent Activation Of Macrophage Effector Function, Annette R. Clemons-Miller

Electronic Theses and Dissertations

Tumor necrosis factor α (TNFα) is a pleiotropic cytokine that is predominantly produced by activated macrophages. The effects of TNFα are as diverse as the cells with which it interacts, e.g., stimulating fibroblast growth, exerting cytotoxic/cytostatic; activity against various human and murine cell lines, promoting inflammation through upregulation of endothelial adhesion molecules and IL-8 production. Yet TNFα is best known, and in fact was originally described, for its role in the bacterial-induced hemorrhagic necrosis of tumors and exacerbation of septic shock in which aberrant TNFα production leads to vascular collapse, cachexia, multiple organ failure, and ultimately death in as many …


The Influence Of A Human Repetitive Dna On Genome Stability, Eugenia L. Posey May 1998

The Influence Of A Human Repetitive Dna On Genome Stability, Eugenia L. Posey

Electronic Theses and Dissertations

A uniquely human interspersed repetitive DNA sequence family, the L2Hs, are highly polymorphic in human genomes. Several features of interspersed repeated DNA may contribute to the instability observed. Certain motifs (direct repeats, palindromes, and inverted repeats) comprising L2Hs elements may adopt unusual secondary structures such as cruciforms or hairpins. These motifs have been associated with features of genome instability in recombination, insertions and deletions. The L2Hs elements also are AT-rich (76%) compared to the bulk of human DNA (52%). That their dynamic nature (i.e. polymorphisms) may arise from recombination, insertions and deletions has led to the hypothesis that the L2Hs …


Pest Management Strategies For Longhorn Army Ammunition Plant And An Assessment Of Aerial Radiography For Hazard Rating Pine Stands For Southern Pine Beetle Infestation, James Matthews May 1998

Pest Management Strategies For Longhorn Army Ammunition Plant And An Assessment Of Aerial Radiography For Hazard Rating Pine Stands For Southern Pine Beetle Infestation, James Matthews

Electronic Theses and Dissertations

Currently, sampling or hazard rating insects at military installations is limited. The use of aerial videography is a relatively new technology and is currently used for aerial surveys and is being developed for hazard rating for southern pine beetle. The purpose of this study was to apply existing sampling methods for various insects and disease at the Longhorn Army Ammunition Plant in Karnak, Texas and to test the effectiveness of aerial videography for hazard rating pine stands for southern pine beetle. Based on field data, stands were generally rated as moderate for southern pine beetle; moderate to high infestations of …


Comparison Of Beta-Adrenoceptor Coupled Camp Production In Cultured Human Mononuclear Leukocytes And Myometrial Cells, Yu-Li Liu Dec 1997

Comparison Of Beta-Adrenoceptor Coupled Camp Production In Cultured Human Mononuclear Leukocytes And Myometrial Cells, Yu-Li Liu

Electronic Theses and Dissertations

$\beta\sb2$-Adrenoceptor ($\beta\sb2$-AR) agonists, such as terbutaline, are used as tocolytic agents in the treatment of preterm labor. $\beta$-Adrenoceptor stimulation relaxes myometrium through specific receptors coupled through Gs to adenylyl cyclase (AC) that catalyzes the conversion of ATP to cAMP. The purpose of this study was to compare $\beta$-adrenoceptors and cAMP production in cultured human leukocytes and myometrial cells, and to determine the importance of $\beta$-adrenoceptors and cAMP production in isoproterenol-induced myometrial relaxation. $\sp{125}$I-iodopindolol was used to assess $\beta$-adrenoceptor affinity and number cAMP levels were analyzed before and after stimulation by isoproterenol, AlF$\sb4\sp-$, forskolin, and PGE$\sb1$. Isometric recording was used to …


Cd40-Mediated Signaling Of Interleukin-1(Beta) Synthesis And Rescue From Apoptosis In Monocytes: Modulation By Il-4 And Il-10, Jonathan C. Poe Dec 1997

Cd40-Mediated Signaling Of Interleukin-1(Beta) Synthesis And Rescue From Apoptosis In Monocytes: Modulation By Il-4 And Il-10, Jonathan C. Poe

Electronic Theses and Dissertations

To date, the cellular mechanisms involved in the progression of diseases characterized by chronic inflammation, such as rheumatoid arthritis (RA), remain largely unknown. However, cell-to-cell contact interactions between CD4+ helper T (Th) cells and monocytes have been implicated in the induction and maintenance of pro-inflammatory cytokine synthesis that is characteristic to the pathogenesis of RA. One such cytokine produced during monocyte-Th cell contact is interleukin (IL)-1 β, a mediator directly involved in the characteristic tissue destruction that occurs in the synovia of individuals with RA. Previous studies in our laboratories have shown that ligation of CD40 on monocytes with CD40 …


Effects Of Oxidized Low Density Lipoprotein On Nitric Oxide Production In Macrophages, Annong Huang Dec 1997

Effects Of Oxidized Low Density Lipoprotein On Nitric Oxide Production In Macrophages, Annong Huang

Electronic Theses and Dissertations

The effects of oxidatively modified low density lipoprotein (oxLDL) on atherogenesis may be partly mediated by alterations in nitric oxide (NO) production by macrophages. A major goal of this study was to identify the lipid components in oxLDL modulating NO production. The effect of a water soluble antioxidants (N-acetylcysteine) and lipid soluble antioxidant (alpha-tocopherol) on NO production in macrophages was also determined. A second goal was to determine if the effects of oxLDL occurred at the transcriptional level. Human LDL was oxidized using an azo-initiator 2,2$\sp\prime$-azobis (2-amidinopropane) HCI (ABAP). OxLDL markedly decreased the production of NO in LPS stimulated RAW264.7 …


Endogenous Alkylglycerol Functions As A Mediator Of Protein Kinase C Activity And Cell Proliferation, Fritz G. Buchanan May 1997

Endogenous Alkylglycerol Functions As A Mediator Of Protein Kinase C Activity And Cell Proliferation, Fritz G. Buchanan

Electronic Theses and Dissertations

To explore the possibility that 1-O-alkyl-sn-glycerol (alkylglycerol) may serve a regulatory role in the control of cell proliferation or PKC activity, we examined the ability of alkylglycerol to influence PKC activity and subcellular distribution as well as the ability of alkylglycerol to effect cell proliferation. MDCK cells grown to confluence show a loss of PKC activity associated with the membrane, as reported in fibroblasts. Preconfluent cultures of MDCK cells have a high level of PKC activity associated with the membrane. However, treatment of preconfluent cultures with alkylglycerol causes a reduction of PKC activity. A similar inhibition was observed with alkylglycerol …


Development Of A Predictive Habitat Evaluation Model For Gaillardia Aestivalis (Walt.) Rock. Var. Winkleri (Cory) Turner Using Gps, Remote Sensing And Gis Techniques, Dasyam Samuel Rajasekhar Mar 1997

Development Of A Predictive Habitat Evaluation Model For Gaillardia Aestivalis (Walt.) Rock. Var. Winkleri (Cory) Turner Using Gps, Remote Sensing And Gis Techniques, Dasyam Samuel Rajasekhar

Electronic Theses and Dissertations

Geographic Information Systems (GIS), Global Positioning Systems (GPS) and remote sensing techniques were utilized to characterize and subsequently predict potential habitat of Gaillardia aestivalis var. Winkleri, occurring in Hardin County, TX. Field investigations along with CIR positive aerial photographs were used to study local distribution and ecological requirements (soil, site, plant associations) of the plant. Data were obtained from paper maps, aerial photographs and a Landsat TM image. Sites occupied by G. aestivalis var. Winkleri were characterized as having highly acidic soils with poor nutrient content, good drainage and rapid permeability. Along with soil types, vegetation also is an important …


Use Of The Relative Dose Response Assay To Determine The Vitamin A Status Of Neonatal Calves: Effects Of Season On Colostrum Quality And Immunological Parameters, Mary Jo Boner Jan 1997

Use Of The Relative Dose Response Assay To Determine The Vitamin A Status Of Neonatal Calves: Effects Of Season On Colostrum Quality And Immunological Parameters, Mary Jo Boner

Electronic Theses and Dissertations

Plasma vitamin A is not a reliable indicator of vitamin A status. Therefore, the feasibility of using the relative dose response (RDR) assay as a method for determining vitamin A status of calves was examined. In addition, effects of colostrum quality and season on vitamin A status and health of calves were determined. Blood was sampled from the jugular vein of 16 newborn calves to establish values over a 24 h period for immunoglobulin M (IgM) concentration, hematocrit, serum protein concentration, and leukocyte differentials. Liver biopsies were performed at birth, and successfully completed for 11 calves. Blood samples were obtained …


Gross And Histological Features Of A Myofascial Trigger Point In The Upper Trapezius, Kathryn E. Levee Dec 1996

Gross And Histological Features Of A Myofascial Trigger Point In The Upper Trapezius, Kathryn E. Levee

Electronic Theses and Dissertations

The purpose of this study was to precisely locate, in living humans, a myofascial trigger point associated with the upper portion of the trapezius muscle (TrP1) that refers pain to the head and neck and to determine if this point is associated with anatomical structures. This study is descriptive and utilizes data from measurements of the location of TrP1 in relation to anatomical landmarks, of pressure sensitivity overlying the trigger point and electromyography recordings in localizing the trigger point. Information obtained from living humans was used to determine anatomical correlation to structures in cadavers. Results indicated there is little variability …


Water Quality Of East Texas Streams: Forested Versus Pastured Watersheds Receiving Poultry Litter Applications, Mark Craig Cochran May 1996

Water Quality Of East Texas Streams: Forested Versus Pastured Watersheds Receiving Poultry Litter Applications, Mark Craig Cochran

Electronic Theses and Dissertations

Water quality and stream discharge were monitored at six sites on two Nacogdoches County, Texas streams over a nine month period (March - November 1995). Three sites were located in forested watersheds and the other three sites were downstream of pastured watersheds surface-applied with poultry litter, a potential nonpoint source of pollution. Stream water samples were analyzed for Ca, K, Mg, Na, 03-N ,TKN, P04-P, TP, TSS, pH, and dissolved oxygen. A rapid bioassessment was conducted to assess aquatic life stream conditions. Half of the 273 stream samples had nitrate-nitrogen concentrations greater than 0.30 mg L-1 high enough to support …


Fertility Effects Of Genes Causing Reproductive Isolation Inferred From Three-Way Hybrids In Phacelia, Helen Zhujun Hou Aug 1995

Fertility Effects Of Genes Causing Reproductive Isolation Inferred From Three-Way Hybrids In Phacelia, Helen Zhujun Hou

Electronic Theses and Dissertations

Prior studies of reproductive isolation among three varieties of Phacelia dubia have found that gene loci encoding isozymes of glutamate oxaloacetate transaminase (GOT) were associated with hybrid sterility. In the first part of this study, I generated three-way hybrids to determine if the genetic or chromosomal region linked to GOT encoding loci has major effects on hybrid sterility and if any observed effects were similar in different genetic backgrounds. In three-way crosses, F1 hybrids of two varieties were crossed to a third variety. Fertilities of three-way hybrids were estimated and their GOT genotypes were ascertained by starch gel electrophoresis. A …


Validation Of An Instrument To Measure The Change In Ecological Vocabulary Of Teachers Attending Texas Environmental Education Advisory Committee Endorsed Programs, James Isleib May 1995

Validation Of An Instrument To Measure The Change In Ecological Vocabulary Of Teachers Attending Texas Environmental Education Advisory Committee Endorsed Programs, James Isleib

Electronic Theses and Dissertations

An instrument was developed and evaluated for measuring the effect of the Texas Environmental Education Advisory Committee (TEEAC) endorsed teacher inservice programs on participants' ecological vocabulary. Principal study objectives were to establish a basic ecological vocabulary essential to environmental education and evaluate the instrument's effectiveness in measuring change in participants' ecological vocabulary resulting from exposure to TEEAC programs. The Ecological Vocabulary Survey (EVS) was developed from 57 ecological terms. A comparison of EVS terms with terms selected by ecological and environmental education organizations indicated the EVS terms were essential to environmental education. A total of 148 matched pairs of pre …


Persistent Oral Dyskinesias Induced By Long-Term Haloperidol Treatment Is Dissociated From Changes In Neostriatal B(Max) And Mrna Content For Dopamine D(2) Receptors, Nuoyu Huang May 1995

Persistent Oral Dyskinesias Induced By Long-Term Haloperidol Treatment Is Dissociated From Changes In Neostriatal B(Max) And Mrna Content For Dopamine D(2) Receptors, Nuoyu Huang

Electronic Theses and Dissertations

Due to the presumed associations of dopamine (DA) receptor supersensitivity phenomena in both long-term neuroleptic-treated tardive dyskinetic rats and neonatal 6-hydroxydopamine (n6-OHDA)-lesioned rats, we studied the influence of haloperidol on n6-OHDA-lesioned rats. At 3 days after birth rats received 6-OHDA-HBr (200 $\mu$g, bilateral intracerebroventricularly; desipramine pretreatment, 20 mg/kg, 1h) or vehicle. Two months later haloperidol (1.5/kg/day $\times$ 2 days/week for 4 weeks, then 1.5 mg/kg/day, every day for 10 months) was added to the drinking water. Spontaneous oral activity of intact and n6-OHDA-lesioned rats receiving haloperidol was reached and maintained at significantly higher levels after 15 weeks of haloperidol treatment. …


Moraxella (Branhamella) Catarrhalis: A Molecular Epidemiology Study, Lyndell R. Gill May 1995

Moraxella (Branhamella) Catarrhalis: A Molecular Epidemiology Study, Lyndell R. Gill

Electronic Theses and Dissertations

Moraxella (Branhamella) catarrhalis is the third-most-frequently isolated microorganism associated with acute exacerbations of chronic bronchitis in patients during their stay at the Mountain Home VA Medical Center (MHVAMC). In order to develop a practical, epidemiologically-meaningful typing method for M. (B.) catarrhalis, we tested two methods based on analysis of chromosomal DNA for typeability, reproducibility, and ability to differentiate between unrelated strains (discriminatory power, D). M. (B.) catarrhalis isolants from MHVAMC from 7/1/87-6/30/88 were grown overnight in broth and embedded in agarose. DNA was isolated by standard methods. The DNA was subjected to: (1) restriction endonuclease digestion (with either Bgl II …


Indomethacin Reduces Splenic Red Pulp Macrophage Populations In Female New Zealand White Rabbits, Thane S. Thurmond May 1995

Indomethacin Reduces Splenic Red Pulp Macrophage Populations In Female New Zealand White Rabbits, Thane S. Thurmond

Electronic Theses and Dissertations

In an effort to elucidate the mechanism by which indomethacin (IN) attenuates the stimulatory effect of estradiol (E$\sb2$) on rabbit splenic red pulp macrophages (RPM), thirty-nine female New Zealand White rabbits were divided into 10 groups: ovariectomized (OVX), OVX/IN at 0.1 and 5.0 mg/kg body weight (bw)/day; sham OVX (SOVX), SOVX/IN at 0.1 and 5.0 mg/kg bw/day; OVX/25 mg E2, OVX/25 mg E$\sb2$/IN at 0.1 and 5.0 mg/kg bw/day; intact Control. Quantitative changes in RPM population in response to the treatments were measured using a 0 to 4 histologic grading scale. Estradiol treatment resulted in increased RPM grade when compared …


Microcirculation: Electrophysiological Basis For The Response Of Endothelial Cells To Inflammatory Mediators-Bradykinin, Kai Miao Dec 1994

Microcirculation: Electrophysiological Basis For The Response Of Endothelial Cells To Inflammatory Mediators-Bradykinin, Kai Miao

Electronic Theses and Dissertations

Using conventional microelectrodes, I studied the electrical basis for determining the resting V$\sb{\rm m}$ in intact EC's from hamsters. The resting V$\sb{\rm m}$ were found to be $-$40 mV for aortic EC's and $-$43 mV for vena caval EC's. The contributions of ions to the resting V$\sb{\rm m}$ of aortic EC's were compared in terms of the transference number (t$\sb{\rm ion}$). To develop a technique for in situ monitoring changes in V$\sb{\rm m}$ of postcapillary venular EC's in the hamster mesentery, a voltage-sensitive fluorescent probe, bisoxonol, was used to load the cells and the fluorescence signals were analyzed under an …


Factors Influencing The Oxidation Of Lipoproteins And Plasma Lipids, Yanshan Ma Dec 1994

Factors Influencing The Oxidation Of Lipoproteins And Plasma Lipids, Yanshan Ma

Electronic Theses and Dissertations

The hypothesis that antioxidant vitamins (ascorbate and tocopherols) along with urate protect blood plasma lipids from oxidation was tested. Dietary fat is also an important factor influencing plasma lipid peroxidation. The purpose of this study was to investigate the role of plasma antioxidants and dietary fat on low density lipoprotein (LDL) and plasma lipid oxidation. In the first part of this study, we compared the ability of urate and ascorbate to protect human LDL from in vitro oxidation. LDL oxidation was initiated by 15 mM of a water soluble azo-initiator in the presence or absence of ascorbate or urate. The …


Role Of The Cd40-Cd40 Ligand Interaction In Cd4(+) T Cell Activation Of Monocyte Interleukin-1 Synthesis, David H. Wagner Dec 1994

Role Of The Cd40-Cd40 Ligand Interaction In Cd4(+) T Cell Activation Of Monocyte Interleukin-1 Synthesis, David H. Wagner

Electronic Theses and Dissertations

Most studies of the induction of cytokine synthesis in monocytes have used an exogenous triggering agent such as Lipolpoysaccharide (LPS). However, during nonseptic chronic inflammatory responses (e.g., rheumatoid arthritis) monocyte activation occurs as a result of T cell generated signals. This report demonstrated that plasma membranes from anti-CD3 activated peripheral CD4$\sp{+}$ T cells (Tm$\sp{\rm A}$) but not from resting CD4$\sp{+}$ cells (Tm$\sp{\rm R}$) induced monocytes to synthesize IL-1 in the absence of costimulatory cytokines. The expression kinetics of the molecule(s) unique to activated T cells which interact with monocyte receptors to induce IL-1 demonstrated that optimal expression occurred at 6h …


The Hydroclimatic Characteristics Of Nacogdoches, Texas With Implications For Water Resources Management, Larry David Clendenen Aug 1994

The Hydroclimatic Characteristics Of Nacogdoches, Texas With Implications For Water Resources Management, Larry David Clendenen

Electronic Theses and Dissertations

Sayok's (1986) study and statistical analysis of the climate at Nacogdoches, Texas covering 1901 to 1980 is updated to include the most recent twelve years (1981-92) of records. Missing data are estimated, all analyses are repeated, and the new 1961-90 normal climate is compared to the 1951-80 and other normals. Results showed that the climate at Nacogdoches during the last decade was about the same as that in other recent decades. Thomthwaite's (1957) climate classification defines Nacogdoches as moist subhumid, third mesothermal, with moderate summer water deficiency, and a temperature effIciency regime equal to a fourth mesothermal climate. There are …


Characterization Of The Vasoactivity Of Tachykinins In Isolated Rat Kidney: Functional Studies And In Vitro Receptor Autoradiography, Yuejin Chen May 1994

Characterization Of The Vasoactivity Of Tachykinins In Isolated Rat Kidney: Functional Studies And In Vitro Receptor Autoradiography, Yuejin Chen

Electronic Theses and Dissertations

Although tachykinins have potent vascular actions, their effect on renal resistance blood vessels is currently unknown. The vasoactive properties of tachykinins and related analogs were assessed in isolated perfused rat kidney. At a basal perfusion pressure (PP) of 75 $\pm$ 6 mm Hg (n = 5), bolus injections of substance P (SP) had no significant vasoactive effect. Following a sustained increase in baseline PP (134 $\pm$ 10 mm Hg) produced by phenylephrine (1 $\mu$M), SP evoked a dose-dependent increase in PP. The largest dose of SP increased PP by 60 $\pm$ 5 mm Hg. The vasoconstrictor response to SP was …


Denervation Supersensitivity Of The Rat Vas Deferens: A Role For Protein Kinase C, Sonny T. Abraham May 1994

Denervation Supersensitivity Of The Rat Vas Deferens: A Role For Protein Kinase C, Sonny T. Abraham

Electronic Theses and Dissertations

A role for protein kinase C (PKC) in the denervation-induced supersensitivity of the rat vas deferens was investigated. Chronic, surgical denervation of the rat vas deferens (up to 8 days) resulted in tissues that produced enhanced contractile responses to norepinephrine (NE) in isolated organ baths. Single challenges of NE (10 $\mu$M) produced 0.6 $\pm$ 0.1 g of maximal tension in the control vas whereas in the paired, denervated tissue 2.2 $\pm$ 0.3 g of tension was recorded (n = 6). Cumulative concentration-effect curves to NE produced in the denervated vas deferens were shifted 18-fold to the left of the control …


Differential Role Of The Endothelium In Regulating Microvascular Blood Flow, Tao Tang May 1994

Differential Role Of The Endothelium In Regulating Microvascular Blood Flow, Tao Tang

Electronic Theses and Dissertations

The vascular endothelial cell (EC) plays an important role in regulating vascular tone and local blood flow by sensing chemical and mechanical stimuli on the vascular wall and releasing a host of vasoactive substances upon activations of endogenous or exogenous vasoactive substances. The central hypothesis is that local control of blood now and autoregulatory behavior in the microcirculation is distinctive at different levels of the vasculature and is dependent on the cellular activities of the EC and its interaction with the local environment. The in vivo as well as the ex vivo, flow-controlled preparations of the hamster cheek pouch were …