Cardiovascular System Commons^™

Hypoxia And Fetal Programming Of Cardiovascular Dysfunction, Qin Xue

Loma Linda University Electronic Theses, Dissertations & Projects

Human epidemiological studies have shown a clear association of adverse intrauterine environment and an increased risk of ischemic heart disease in later adult life. Of all the stresses to which the fetus is subjected, perhaps the most important and clinically relevant is that of hypoxia. The goal of this project is to test the hypothesis that chronic hypoxia during gestation adversely affects fetal cardiovascular development and impairs cardiac function in offspring. In the first part of project, we tested the hypothesis that chronic hypoxia adversely regulates contractility of fetal pulmonary arteries and veins in sheep residing at high altitude (3,801 …

Fetal Programming By Nicotine Increases Cardiac Susceptibility To Ischemic Injury, Jennifer Charlotte Alexie Lawrence

Loma Linda University Electronic Theses, Dissertations & Projects

Fetal programming is the area of study that focuses on the prenatal origins of adult onset disorders. Previous studies have associated an adverse prenatal environment with the onset of physiologic and metabolic diseases during adulthood. Fetal malnutrition, hypoxia, and exposure to drugs - such as cocaine and nicotine - have been associated with adult disease states. Cigarette smoking is the number one cause of preventable death in the developed world. Among the many dangerous chemicals found in tobacco products is nicotine, the compound responsible for the addictive nature of tobacco use. Nicotine use during pregnancy is a known cause of …

Fetal Cocaine Exposure Causes Epigenetic Changes In The Rat Heart, Kurt D. Meyer

Loma Linda University Electronic Theses, Dissertations & Projects

Cocaine abuse continues to be prevalent in the United States and other industrialized nations, in addition to the negative health effects that cocaine abuse has on the user, a mother who uses cocaine while pregnant also exposes the developing fetus to cocaine. Although there have been many studies of the effects of cocaine on the adult heart, studies of cocaine on the fetal heart and its potential delayed pathophysiological effects on cardiac function in adult offspring are extremely limited. The studies of the present project sought to enhance the understanding of the effect of cocaine exposure on the fetal heart …

Maturational Changes In Cerebrovascular Thick- And Thin-Filament Regulation, Renan Joel Sandoval

Loma Linda University Electronic Theses, Dissertations & Projects

The present study focused on the main hypothesis that age-related changes in myofilament Ca²⁺ sensitivity involve simultaneous changes in the relations between cytosolic Ca²⁺ transients, myosin phosphorylation, and force development. To define the effects of late fetal and early postnatal maturation, parallel experiments were carried out using cerebral arteries from both term lamb fetuses (140-141 days of gestation) and nonpregnant adult sheep. Fetal and adult cerebral arteries were stimulated by either mechanically, electromechanically, and/or pharmacomechanically-induced contractions, and the relations of cytosolic Ca²⁺, MLC phosphorylation, and contractile tensions were measured. These measurements allowed for stimulus and age-dependent …

A Continued Investigation Of Craniofacial Growth In Infant Heart Transplant Recipients Receiving Cyclosporine, Gabriel Enriquez

Loma Linda University Electronic Theses, Dissertations & Projects

Since the mid 1980’s, Cyclosporine has proved to be an effective immunosuppressive drug and now has a widespread application in organ transplantation. Several studies, however, have implicated cyclosporine as adversely affecting craniofacial growth in the pediatric population. ^16,18 The purpose of this follow-up study was to continue to evaluate the possible untoward effects of long-term use of cyclosporine on craniofacial growth in a group of infant heart transplantation recipients by re-evaluating as many subjects as possible from the original study and evaluating new subjects. A pediatric group (N=13) was composed of six Caucasian subjects (4 male and 2 female, ages …

Levels Of Intravenous Enterococcus Faecalis That Cause Heart Colonization, Louis Zane Stromberg

Loma Linda University Electronic Theses, Dissertations & Projects

While previous studies have shown that presence of bacteria in systemic circulation can cause infective endocarditis, there is no information on the specific amount of bacteria necessary to cause this condition. The purpose of this study was to establish the minimum level of circulating bacteria that will cause colonization of damaged heart valves in rats. Fifty-two Sprague-Dawley rats were anesthetized and their heart valves were damaged using an established protocol. A clinical isolate of Enterococcus faecalis was transformed with a plasmid bearing the luxF and Chloramphenicol cassettes to label the bacteria with the light-emitting protein. After four weeks, the rats …

Diabetes: The Interrelationship Between Vascular, Nervous Systems And Avandia, Salameh Bweir

Loma Linda University Electronic Theses, Dissertations & Projects

Diabetes Mellitus has been linked to vascular and neurological impairments. The purpose of this study was to assess the relationship between vascular endothelial dysfunction, autonomic and somatic nervous systems impairment in diabetic patients. These studies also evaluated the effects of rosiglitazone (Avandia) on the vascular, autonomic, and somatic nervous systems.

Fourteen diabetic subjects and fourteen control subjects (age matched) participated in three series of experiments. Using Whitney volume plesythmography to assess post occlusion blood flow in the subject’s forearm did assessment of vascular endothelial function. Evaluating skin blood flow, orthostatic tolerance, heart rate, and thermal responses under thermal and postural …

The Effect Of Chronic Hypoxia On Cardiac Function In The Fetal Ovine Heart, Rodney David Rodrigo

Loma Linda University Electronic Theses, Dissertations & Projects

It has been shown that long-term high altitude hypoxia during pregnancy was associated with a decrease in cardiac contractility in fetal sheep. Given that hypoxia caused apoptotic cell death in fetal and neonatal rat cardiomyocytes, the present study tested the hypothesis that chronic hypoxia during pregnancy increases apoptosis in the fetal sheep heart. Pregnant (d 30) sheep were divided between normoxic control and chronically hypoxic (maintained at high altitude, 3,820 m, PaO₂: 60 Torr for 110 days) groups. Hearts were isolated from near-term (d 140) fetal sheep, and samples from all four chambers, right and left atria, and …

Age Related Changes In Contractile Sensitivity To Cyclic Gmp And Intracellular Calcium Compartmentalization In Ovine Arteries, Surya Margono Nauli

Loma Linda University Electronic Theses, Dissertations & Projects

The study examines the hypothesis that maturation changes the ability of cGMP to produce cerebral vasodilatation and alters the relative intracellular calcium pool sizes in ovine arteries. In ovine basilars taken from near-term fetal and young adult sheep, 8- pCPT-cGMP relaxed potassium- and serotonin-induced tone with pD2 values of 4.4±0.1 and 4.9±0.1 (fetal basilar) and 4.0±0.1 and 4.7±0.1 (adult basilar), respectively. In fura-2 loaded arteries, 8-pCPT-cGMP significantly lowered increases in cytosolic calcium concentration induced by serotonin but not potassium regardless of age. When calcium sensitivity was calculated in the same arteries as the slope of the relation between calcium concentration …

A Continued Investigation Of Craniofacial Growth In Infant Heart Transplant Recipients Receiving Cyclosporine, John Michael Cornali

Loma Linda University Electronic Theses, Dissertations & Projects

Cyclosporine is an effective immunosuppressive drug that has found widespread application in organ transplantation. A couple of studies, however, have implicated cyclosporine as adversely affecting craniofacial growth in the pediatric population. The purpose of this follow-up study was to continue to evaluate the possible untoward effects of long-term use of cyclosporine on craniofacial growth in a group of infant heart transplantation recipients by re-evaluating as many subjects as possible from the original study and evaluating new subjects. A prospective group (N=29) of eighteen Caucasian subjects (7 female and 11 male, ages 6-15 years) and eleven Hispanic subjects (3 female and …

Regulation Of Connexin43 By Phosphorylation, Maithili M. Shah

Loma Linda University Electronic Theses, Dissertations & Projects

Gap junctions play a crucial role in embryogenesis, especially of the heart where connexin43 is thought to be important for its formation as well as synchronized contraction. Several reports have shown that connexin43 protein is phosphorylated on serine residues in vitro and in vivo.

Studies performed in our laboratory have demonstrated that cell-to-cell communication in cells expressing connexin43 can be controlled rapidly and reversibly by microinjection of active protein kinases or phosphatases that target serine or threonine residues. Phosphorylation by cAMP-dependent protein kinase (PKA) seems to favor channel opening, whereas the effect of protein kinase C (PKC) on channel gating …

Regulation Of Connexin43 By Phosphorylation In Heart Development, John C. Duncan

Loma Linda University Electronic Theses, Dissertations & Projects

Serine/threonine protein kinases have been shown to reversibly regulate cell-cell communication through gap junctions formed by connexin 43 (Cx43) (Godwin et al.7 1993). The Cx43 protein expression levels are unclear and what role phosphorylation plays in the regulation of signal transduction through these gap junctions during heart formation. Reportedly, mutations which replace potentially phosphorylatable serines within the Cx43 protein are associated with heart malformations (Britz-Cunningham et al.. 1995), highlighting the importance of determining the levels of Cx43 and the activities of PKA and PKC during heart development.

Western analysis performed on hearts from developmentally significant time points revealed principally high …

A Cytochemical Evaluation Of Blood-Brain Barrier Sodium, Potassium- And Calcium-Adenosine Triphosphatase Polarity, Panya Steve Manoonkitiwongsa

Loma Linda University Electronic Theses, Dissertations & Projects

The blood-brain barrier (BBB) is formed by cerebral vascular endothelial cells. Brain ion and fluid homeotasis essential for proper neural functioning is due to the BBB. Sodium-potassium and calcium-activated adenosine triphosphatase (Na⁺, K⁺-ATPase and Ca²⁺-ATPase) serve as one of the main mechanisms controlling brain Na⁺, K⁺, and Ca²⁺ concentrations. The present accepted concept is that both of these enzymes are localized to the abluminal plasma membrane of endothelial cells although there have been contrary results from some studies. Because of these discrepancies, further work was needed. Various cytochemical procedures …

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 …

The Coronary Distribution Zone : Mathematical Modelling Of The Left Ventricular Epicardial Surface For Area Calculation, Three-Dimensional Rotaton And Display, S. Matts E. Sjölander

Loma Linda University Electronic Theses, Dissertations & Projects

A computer model of the left ventricular (LV) epicardial surface was developed from Jang’s truncated ellipsoidal model, which has a minor to major axis ratio of 6:10. The model was applied in calculating the area of a segment of the myocardium, jeopardized by an impending occlusion of its associated artery. The endangered segment of the LV muscle was also visualized in different projections by rotations in three space and graphical displays simulating the three dimensions.

The area formula for the surface of the ideal model , a truncated prolate spheroid, was derived and used in producing maps for manual calculations …

Some Physiological Effects Of The Bed Bath On The Cardiovascular System Of Acute Myocardial Infarction Patients, Arleen Canfield

Loma Linda University Electronic Theses, Dissertations & Projects

At Loma Linda University, a protocol has been in effect that specifies the kinds and amounts of activity that acute myocardial infarction patients may have. The protocol has described six activity levels with each successive level permitting more activity. The patient must have reached the fourth level of progression before he is permitted to receive a complete bed bath. The problem studied in this research: As the result of receiving a bed bath, what physiological effects will occur in the cardiovascular system of patients with acute myocardial infarction?

The theoretical framework for this study consisted of the following: recommendations for …

The Relationship Of Central Venous Pressure To Hemorrhage In Open Heart Surgery, Mable Reynolds

Loma Linda University Electronic Theses, Dissertations & Projects

The problem of this study was to review 100 open heart surgical cases in a selected hospital to determine the changes occurring in central venous pressure in relation to blood loss.

The review of literature revealed that central venous pressure is an important factor in determining immediate postoperative care of open heart surgical patients. If central venous pressure falls below the normal range of 5 to 10 centimeters of water, hemorrhage is suspected. If central venous pressure is elevated between 15 and 20 centimeters of water, cardiac tamponade is suspected.

The descriptive survey method of research was used. Medical records …

Factors Affecting The Rest Of The Hospitalized Cardiac Patient, Julia M. Bensonhaver

Loma Linda University Electronic Theses, Dissertations & Projects

A study was conducted to determine factors which can promote and prevent the rest of the hospitalized cardiac patient. Literature was reviewed in the areas of patients' opinions about their hospitalization and pertinent concepts in medical and nursing literature regarding cardiac rest. A study was not found which polled cardiac patient specifically regarding their ability to rest. Most authorities in this area strongly advocate rest for the cardiac patient, but there is disagreement of how and how long the patient should rest.

A questionnaire was sent to seventy cardiac patients who had been hospitalized in the nine months prior to …