Physiology Commons^™

Factors That Influence The Blood Flow Response Of Skin To Electrical Stimulation, Abdul-Majeed Raja Al-Malty

Loma Linda University Electronic Theses, Dissertations & Projects

Female reproductive hormones, aging, global heating and local heating are factors affecting skin blood flow (SBF), but their effect on electrical stimulation (ES) has never been examined until the present investigation. To investigate female reproductive hormones, nine women (age= 25.6±3.5 years) with a normal menstrual cycle (MC) underwent ES in thermoneutral (25°±0.5°C) and warm environments (35°±0.5°C). To investigate aging, ES was applied on active young (n=15, age=32.1±8.3 years) and old (n=8, 64.5±6.2 years) groups in thermoneutral and warm environments. To investigate the effect of global and local heating, groups of 15 and 18 subjects (age= 18-40 years) experienced ES under …

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 …

Catecholamines And The Regulation Of Uterine Contractions In The Pregnant Rhesus Macaque, Cahleen Mae Mcnutt

Loma Linda University Electronic Theses, Dissertations & Projects

This study was designed to test the hypothesis that: 1) maternal and/or amniotic fluid catecholamines or prostaglandins display nocturnal activity rhythms similar to those of the myometrial contractility in the pregnant rhesus macaque and, 2) catecholamines stimulate prostaglandin production by fetal membranes. Paired maternal arterial blood and amniotic fluid samples were collected at 0900 h (AM) and 2100 h (PM) from chronically catheterized rhesus macaques until delivery and analyzed for prostaglandin metabolites (PGFM and PGEM-II) and catecholamines (norepinephrine, epinephrine, and dopamine). Uterine activity data was continuously recorded. A rhythm in uterine contractility was observed, with peak activity between 1900 and …

Regulation Of Epidermal Growth Factor Receptor Synthesis By Retinoic Acid And Dexamethasone, Kerby C. Oberg

Loma Linda University Electronic Theses, Dissertations & Projects

Fetal rat lung (FRL) cells incubated in the presence of retinoic acid or dexamethasone exhibit altered ¹²⁵I-epidermal growth factor (EOF) binding capacity. Retinoic acid enhances ¹²⁵I-EGF binding 3-fold following 24 hours of 37° incubation. In contrast, FRL cells incubated in the presence of dexamethasone display a 2-fold reduction in ¹²⁵I-EGF binding capacity. The change in binding capacity, induced by either hormone, was due to alterations in the average number of receptors per cell as determined by Scatchard analysis of ¹²⁵I-EGF binding. In the absence of retinoic acid or dexamethasone, FRL cells were calculated to have approximately …

Fetal Whole-Body Fluid, Cardiovascular And Endocrine Dynamics : Computer Analysis Of Regulatory Mechanisms, Peter Stuart Gold

Loma Linda University Electronic Theses, Dissertations & Projects

The dynamics of transcapillary fluid and protein distribution and endocrine regulation of cardiovascular function were studied in chronically instrumented fetal sheep during the third trimester. Average experimental changes in vascular pressures, blood volume, plasma hormone concentrations, hematocrit and plasma protein concentration were analyzed using mathematical modeling and parameter optimization techniques in order to determine values for the major parameters which regulate fluid, protein and endocrine dynamics and to determine endocrine dose-response relationships to changes in cardiovascular function. The hormones which were considered are arginine vasopressin (AVP), angiotensin II (AII), epinephrine (EPI) and norepinephrine (NE). Vascular disturbances which were considered include …

Isolation And Chemico-Physiologic Characterization Of A Parotid Hormone Activity From Porcine Glands, Jean-Marc Tieche

Loma Linda University Electronic Theses, Dissertations & Projects

For the past decade, evidence has accumulated which suggests that the resistance of the teeth to dental decay is in part under systemic control. It was shown that the resistance is accomplished through the optimal operation of a dentinal fluid transport mechanism which is believed to be hormonally controlled by the hypothalamic-parotid gland endocrine axis. Although circumstantial evidence for such an endocrine function was strong, the isolation of a parotid hormone which stimulates the dentinal fluid transport mechanism remained to be accomplished.

Using modern biochemical techniques, a methodology was designed to isolate and purify the hormone from porcine parotid glands. …

Effects Of Cariogenic And Noncariogenic Diets On The Concentration Of The Parotid Hormone Releasing Factor In Rat Hypothalami, Melva Joan Brown

Loma Linda University Electronic Theses, Dissertations & Projects

Hypothalamic and cortical extracts from various cariogenically grouped rats which had been maintained on either a Purina diet or a high sucrose diet (HSD) for three months were infused intravenously into 28 days old rats to determine if there was a titer of parotid hormone releasing factor (PRF) capable of facilitating fluid movement (FM) in the teeth. The hypothalamic and cortical extracts obtained from Purina-fed rats with 0-caries and the hypothalamic extracts from BSD-fed rats conclusively demonstrated FM stimulatory ability. Other Purina-fed groups were essentially biologically ineffective, however, extracts from HSD-fed caries groups including scores 11-40 demonstrated extremely potent FM …

The Effect Of Insulin, Fluoride And Methyl Xanthines On The Hypothalamic-Parotid Gland Endocrine Axis, Reagan Ondler

Loma Linda University Electronic Theses, Dissertations & Projects

The purpose of this study was to determine the effect of insulin and fluoride on dentinal fluid movement (FM) in high-sucrose fed rats as mediated through the hypothalamic-parotid gland endocrine axis. In conjunction with the fluoride study, the possible involvement of cAMP was examined through the use of several methyl xanthines which are recognized as phosphodiesterase inhibitors.

Twenty-one day old, male Sprague Dawley rats were maintained on a high-sugar diet (62% sucrose) for 8-9 days at which time intravenous or arterial infusions of insulin, fluoride or the methyl xanthines were performed. Additional procedures included collecting plasma from rats which had …