Animal Structures Commons^™

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 …

Quantal Mechanisms Underlying Stimulation-Induced Augmentation And Potentiation, Hong Cheng

Electronic Theses and Dissertations

Repetitive stimulation of motor nerves causes an increase in the number of packets of transmitter ("quanta") that can be released in the ensuing period. This represents a type of conditioning, in which synaptic transmission may be enhanced by prior activity. Despite many studies of this phenomenon, there have been no investigations of the quantal mechanisms underlying these events, due to the rapid changes in transmitter output and the short time periods involved. To examine this problem, a method was developed in which estimates of the quantal release parameters could be obtained over very brief periods (3 s). Conventional microelectrode techniques …

Interaction Of Acth And Estradiol In The Regulation Of Growth, Differentiation, And Steroidogenic Maturation Of The Baboon Fetal Adrenal Gland, Maria Gomez Leavitt

Theses and Dissertations in Biomedical Sciences

The present study determined whether the growth of, as well as ACTH receptor and P-450 enzyme messenger ribonucleic acid and/or protein levels in the baboon fetal adrenal are dependent upon fetal pituitary ACTH during mid and late gestation and the mechanism by which placental estrogen modulates ACTH actions. Administration of betamethasone (3mg/day) to baboon mothers on days 60-99 of gestation and to the fetus (0.6 mg/, n = 4) or to the fetus (0.6mg) and mother (6 mg/ml; n = 4) every other day between days 150-164 of gestation (term = 184 days) decreased (P $53β-hydroxysteroid dehydrogenase-isomerase (3β-HSD(+)ctochrome P450 17α-hydroxylase, …

Endothelial Nitric Oxide Synthase And Growth Factor Regulation Of Flow-Mediated Vascular Remodeling, David Anthony Tulis

Theses and Dissertations in Biomedical Sciences

This study was designed to characterize structural remodeling of male Wistar rat mesenteric arteries exposed to elevated blood flow in vivo for 1, 3, or 7 days. A series of arterial ligations induced blood flow increases in ileal and second-order branch arteries compared to same animal control vessels. Neither mean carotid nor local mesenteric arterial pressures changed significantly pre- to post-ligation. The primary flow-mediated force in both vessels was shear stress with possible involvement of acute stretch-induced wall stress in the ileal artery. Significant luminal expansion and medial wall hypertrophy occurred in the ileal and second-order arteries in a time-dependent …

Differential Endometrial Responses Of Primates Vs Rodents: Screening For Antiproliferative Effects Of Antiprogestins, David Williams Burleigh

Theses and Dissertations in Biomedical Sciences

The antiprogestin, mifepristone, has previously been shown to noncompetitively inhibit estrogen-induced endometrial proliferation in nonhuman primates (van Uem et al., 1989; Wolf et al., 1989b; Neulen et al., 1990; Neulen et al., 1996). For both economical and ethical reasons, we are encouraged to identify comparative laboratory rodent models which can substitute the need to use primate models. In the following study, we compared capabilities of the rat uterine weight bioassay versus a primate uterine bioassay, to identify the noncompetitive antiestrogenic/antiproliferative effects of mifepristone.

Long-term ovariectomized monkeys were exposed to exogenous 17β-estradiol (E2) and mifepristone in doses and regimes already demonstrated …

Mechanisms Of American English Vowel Production In A Grey Parrot (Psittacus Erithacus), Denice K. Warren, Dianne K. Patterson, Irene M. Pepperberg

Sentience Collection

Parrots are known for their capacity to reproduce the sounds of human speech, but few studies have investigated their mechanisms for producing such vocalizations. Using three methods of noninvasive video imaging (Super VHS video, infrared, X-ray radiography), we examined correlations between several elements of a Grey Parrot's (Psittacus erithacus) vocal-tract configuration and the bird's production of two vowels, /i/ ("eat") and /a/ ("rock"). This parrot uses mechanisms that both resemble and differ from those used by: (a) humans to produce English speech; and (b) some avian species to produce conspecific vocalizations. This Grey Parrot, for example, uses its vocal apparatus …

Cellular Mechanisms Underlying Myogenic Reactivity In Isolated Arterioles, Hui Zou

Theses and Dissertations in Biomedical Sciences

The myogenic reactivity provides one of the principal mechanisms for blood flow autoregulation. The aims of the performed studies described in this dissertation were to test the role of [Ca²⁺]_i and MLC phosphorylation in arteriolar myogenic reactivity and further examine the source(s) of activator Ca²⁺ required to initiate and maintain myogenic vasoconstriction. In addition, the possible underlying mechanism of contractile protein expression was also addressed.

These studies used male Sprague Dawley rats of 200 ~ 350 grams body weight. Experiments were carried out using rat cremaster first order arterioles and mesenteric vessels. Gel electrophoresis and immunoblotting …

Cytokines And Ovulation In The Mouse Ovary, Jong G. Kim

Electronic Theses and Dissertations

Ovulation has been hypothesized as an inflammatory process. Interleukin(IL)-1$\alpha$, IL-1$\beta$ and tumor necrosis factor(TNF)-$\alpha$ are potent cytokines produced from macrophages and various other cell types, and are pivotal components of inflammation. Although previous studies have investigated cytokine activities in the reproductive system, there is little information on their precise localization and activities during the periovulatory period. To investigate the role of cytokines in ovulation, experiments were designed to determine the immunohistochemical localization and time specific production of cytokines IL-1 and TNF-$\alpha$ using a mouse model at 36h, 12h, 6h, 2h before ovulation, and at 6h and 18h after ovulation in …

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 …

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

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 …

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 …

Enhanced Renal Sympathetic And Cardiovascular Responses To Substance P In Hypertension, Gregory W. Lindsay

Electronic Theses and Dissertations

Blood pressure, heart rate, and renal sympathetic nerve responses were measured in 9-13 week old male spontaneously hypertensive rats (SHR) and compared to those in age and sex-matched Wistar-Kyoto (WKY) rats following intravenous injection of the neuropeptide substance P (SP), the nicotinic stimulant 1,1-dimethyl-4-phenylpiperazinium (DMPP), and the adrenoceptor stimulant norepinephrine (NE). Charles River Sprague-Dawley (CD) rats were used in some studies to develop methodologies. Measurements were made in control rats and also following sinoaortic denervation, pithing, ganglion blockade, or adrenoceptor blockade. Responses were evaluated in order to determine if ganglion stimulation by SP was enhanced in SHR compared to WKY …

Evaluation Of The Gross Anatomy Seasonal Changes Function And Histology Of The Perineal Gland In The Hispid Cotton Rat, Sigmodon Hispidus, Julie Anne Winchell

Biological Sciences Theses & Dissertations

The perinea! gland in the hispid cotton rat, Sigmodon hispidus, is a seasonally cyclic, subcutaneously located organ which is associated with the reproductive system. On gross dissection, the gland possesses a strong attachment to the penis with only loose fascia! connections to the rectum and surrounding muscle and skin. Histologic exam confirms this connection to the reproductive tract and shows the organ to be a compound tubuloacinar gland with a projection leading into the penis. The cyclic hypertrophy and regression of the gland closely parallels that of the testes and seminal vesicles indicating that this cyclicity may be under …

Changes In Intracellular Chloride During Osmotic Stress And L-Alanine Uptake In Mouse Hepatocytes, Kening Wang

Electronic Theses and Dissertations

A stable intracellular ionic environment is necessary for hepatocytes to function normally. Thus, during hypotonic shock or L-alanine uptake, hepatocytes swell and then exhibit a regulatory volume decrease (RVD), which comprises an increase in K$\sp+$ conductance (G$\sb{\rm K}$), an increased K$\sp+$ efflux, and a hyperpolarization of transmembrane potential (V$\sb{\rm m}$). Since hepatocyte intracellular Cl$\sp-$ has been demonstrated to distribute passively with V$\sb{\rm m}$, this study is designed to test the hypothesis that the hypotonic shock- or L-alanine uptake-induced hyperpolarization of V$\sb{\rm m}$ might provide an electromotive force for the efflux of hepatocyte intracellular Cl$\sp-$, which in turn would contribute osmotically …

Plasticity Of The Gnrh Neuronal System During Sexual Maturation Of The Male Djungarian Hamster, Kevin L. Buchanan

Loma Linda University Electronic Theses, Dissertations & Projects

Onset of puberty in male Djungarian hamsters is characterized by increased pituitary gonadotropin secretion and testes maturation, and is controlled by neurons within the brain which secrete gonadotropin-releasing hormone (GnRH). Puberty is associated with increased numbers of morphologically unipolar, but not bipolar, GnRH neurons in the medial preoptic area (MPOA) and diagonal band of Broca (DBB). To test the hypothesis that delayed sexual maturation arrests this increase, males were exposed to short days or administered melatonin. Males with delayed puberty had significantly fewer unipolar GnRH neuron numbers in the MPOA and DBB comparable to pubertal controls in long days. Unipolar …

Social Deprivation Of Infant Rhesus Monkeys Alters The Chemoarchitecture Of The Brain: I. Subcortical Regions, Lee J. Martin, Dawn M. Spicer, Mark H. Lewis, John P. Gluck, Linda C. Cork

Veterinary Science and Medicine Collection

Rhesus monkeys (Macaca mulatta) reared during the first year of life without social contact develop persistent stereotyped movements, self-directed behaviors, and psychosocial abnormalities, but neurobiological mechanisms underlying the behaviors of socially deprived (SD) monkeys are unknown. Monkeys were reared in total social deprivation for the first 9 months of life; control monkeys were reared socially (SR) with mothers and peers. Subjects were killed at 19-24 yr of age. Because the behaviors of SD monkeys are reminiscent of changes in striatal or amygdalar function, we used immunocytochemistry for substance P (SP), leutine-enkephalin (LENK), somatostatin, calbindin, and tyrosine hydroxylase (TH) to evaluate …

Electrophysiology, Cell Calcium, And Mechanisms Of Hepatocyte Volume Regulation, Walid E. Khalbuss

Electronic Theses and Dissertations

The electrophysiologic technique (Reuss, L., Proc. Natl. Acad. Sci. USA 82:6014, 1985) was modified to measure changes in steady-state hepatocyte volume during osmotic stress. Hepatocytes in mouse liver slices were loaded with tetramethylammonium ion (TMA$\sp{+}$) during transient exposure of cells to nystatin. Intracellular TMA$\sp{+}$ activity (a$\sp{\rm i}\sb{\rm TMA}$) was measured with TMA$\sp{+}$-sensitive, double-barreled microelectrodes. Loading hepatocytes with TMA$\sp{+}$ did not change their membrane potential (V$\sb{\rm m}$), and under steady-state conditions a$\sp{\rm i}\sb{\rm TMA}$ remained constant over 4 min in single impalements. Hyperosmotic solutions (50, 100, & 150 mM sucrose added to media) and hyposmotic solutions (sucrose in media reduced by …

Embryonic Chicken Fibroblast Collagen Binding Proteins: Distribution, Role In Substratum Adhesion, And Relationship To Integrins, Roy C. Ogle, A. Jeannette Potts, Marchall Yacoe, Charles D. Little

School of Medical Diagnostics & Translational Sciences Publications

Collagen binding proteins (CBP) are hydrophobic, cell surface polypeptides, isolated by collagen affinity chromatography. Antibodies to CBPs inhibit the attachment of embryonic chicken heart fibroblasts to native type I collagen fibrils in a dose-dependent manner. The CBP antibodies also induce rounding and detachment of cells adherent to a planar substratum. This process of antibody-mediated substratum detachment resulted in a clustering of CBP and cell-associated extracellular matrix at the cell surface, and the rearrangement of filamentous actin. Other functional studies showed that cells grown within a three-dimensional gel of type I collagen cannot be immunostained at the cell surface with CBP …

Specificity Of The Cardiac Response To Conspecific Vocalizations In Chimpanzees, Gary G. Berntson, Sarah T. Boysen

Sentience Collection

Heart rate measures were used to examine the functional response of young chimpanzees and orangutans to acoustic stimuli, including white noise and chimpanzee vocalizations (threat, stress, and alarm). The initial response of the animals to all stimuli was characterized by a prominent cardiac deceleration and an increase in heart period variability. The deceleratory responses persisted with repeated presentations of the noise, stress, and alarm stimuli. In contrast, the response of chimpanzees to the conspecific threat stimulus reverted over trials to a notable cardiac acceleration. This acceleratory response was not attributable to potential patterns of evoked somatic responses. The features of …

Eavesdropping By Bats: The Influence Of Echolocation Call Design And Foraging Strategy, Jonathan Balcombe, M. Brock Fenton

Sentience Collection

We used playback presentations to free-flying bats of 3 species to assess the influence of echolocation call design and foraging strategy on the role of echolocation calls in communication. Near feeding sites over water, Myotis lucifugus and M. yumanensis responded positively only to echolocation calls of conspecifics. Near roosts, these bats did not respond before young of the year became volant, and after this responded to presentations of echolocation calls of similar and dissimilar design. At feeding sites Lasiurus borealis responded only to echolocation calls of conspecifics and particularly to "feeding buzzes". While Myotis, particularly subadults, appear to use the …

A Stereotaxic Atlas Of The Brain Of The Chick (Gallus Domesticus), Wayne J. Kuenzel, Manju Masson

Poultry Science Faculty Publications and Presentations

Nine brains taken from chicks two weeks of age were used for the development of this atlas. Each chick was first anesthetized with an intravenous (IV) injection of Chloropent2 (1.8 ml/kg). Chicks were then perfused via the heart with 90 ml physiological saline followed by 90 ml Heidenhain's3 solution. Each head was then positioned in a stereotaxic instrument as described in the previous section and three stainless steel (SS) insect pins (#2) were implanted in each brain at known coordinates. In the case of the brains used to construct the cross- sectional atlas plates, two pins were implanted horizontal to …

An Attempt To Estimate Teat Quality Of Sows By Hand Milking During Farrowing, D. Fraser, C. S. Lin

Anatomy Collection

For 21 sows, teats were hand milked individually in a standard way during farrowing in an attempt to produce an index of teat quality. The piglets' teat selection and 14-day weights were then compared with the hand milking results. Of within-litter variation in 14-day weight, 38.67% was explained by 1-day weight, and only 4.6% extra variation by the index derived from hand milking. Use of the index gave no improvement over previous models involving 1-day weight and teat number (anterior to posterior). Hand milking showed a pronounced decline in colostrum yield from the most anterior teat pair (46.8 g) to …

A Light And Electron Microscopic Study Of Visual Neurons In The Medulla Externa Of The Crab Hemigrapsus Nudus, Yu Cheng Liao

Loma Linda University Electronic Theses, Dissertations & Projects

The decapod crustacean with a relatively well-defined visual system have contributed significantly to our understanding of visual neuron morphology and physiology. The general morphology of the optic lobes of several decapods were initially described by Parker (1897) and Hanstrom (1924). In the past few years, several light and electron microscope studies have been made on the lamina ganglionaris: the first optic ganglion, of the lobster (Hamori and Horridge, 1966a); the crayfish (Hafner, 1974; Nassel, 1976a), and the crab (Stowe et al., 1977; Rafuse et al., in preparation). As yet, no adequate description has been made of the visual neurons in …

Studies On The Grooming Behavior And Morphology Of The Freshwater Prawn, Palaemonetes Kadiakensis, Bruce E. Felgenhauer

Masters Theses

No abstract provided.

The Developmental Fine Structure Of Pacinian Corpuscles, Pedro B. Nava

Loma Linda University Electronic Theses, Dissertations & Projects

A preliminary light microscopic study of the mouse hind limb revealed a group of about 20 Pacinian corpuscles extending from the mid-region of the fibula to the tibio-fibular fusion strategically located for the possible sensing of bone-transmitted vibration.

The fine structure of the corpuscles is described in four stages: primordial or prenatal (19 and 20 days); early differentiation (1-8 days postnatal); differentiated corpuscle (9, 10, 12, 14 and 21 days postnatal); and adult (28 days old).

The corpuscles commence development during the 19th prenatal day. The corpuscle then consists of a nerve ending surrounded by sheath-cells which appear to be …

A Study Of Thoracic Skeletomusculature In Peracarida (Crustacea), Donna R. Gill

Masters Theses

Two species of peracarid malacostracans, a mysid, Neomysis americana, and an oniscid isopod, Trachelipus cf. rathkei, were used to study the skeletomusculature system. Serial sections, whole mounts, and gross dissections were made. Coxal promotors and remotors and basal adductors and abductors were the muscle groups examined.

The promotor and remotor muscles of N. americana were found to be numerous, well developed, taking origin primarily from the dorsal thoracic wall, and extending nearly ventrally to insert in the coxa; the adductor muscle and two abductor muscles are weakly developed. The coxa in T. cf. rathkei is incorporated completely …

The Comparative Morphology Of The Female Gonads Of Two Members Of The Nematode Order Tylenchida, Owen G. Coker

Masters Theses

No abstract provided.

Some Aspects Of Cranial Bone Growth In The Puberal Macaca Mulatta Monkey: As Evidenced By Metallic Implants And Cephalometric Roentgenography And The Application Of A Geological Lapidary Technique For The Semi-Serial Thin Sectioning Of Undecalcified Bone, Lee Eugene Olsen

Loma Linda University Electronic Theses, Dissertations & Projects

The purpose of this study was to investigate cranial and facial bone growth in the puberal Macaca mulatta monkey over a six month period utilizing the methods of metallic implantation combined with serial cephalometric roentgenography and a bichromatic vital staining method.

The employment of the vital stains, alizarin Red S and anthracene blue, over the six month period of the study, failed to stain the actively growing bone as evidenced by gross and microscopic analysis of the undecalcified bone preparations.

Interimplant measurements were made across certain bone sutures and the following results were obtained: The zygomaticotemporal sutures showed marked growth …

A Study Of The Renal Vascular Supply In The Domestic Cat, Elizabeth Rosen

Bachelors’ Theses

Studies on the normal and abnormal vascularization of the renal vessels in the domestic cat (felis domestica) indicate the frequency of anomalies that occur, but in most of the studies it is the inferior vena cava that is most often recorded. Among the occasional references to several renal veins or arteries we have Huntington and McClure, Elmer Butler, Gaylord Bates, William Darrach, and C.H. Fortune. Yet no study seems to have been made of individuals of any particular class. A superficial observation seems to indicate a large number of cats used in the laboratory had multiple renal veins. Hence a …