Research Methods in Life Sciences Commons^™

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 …

Effect Of Glucose Administration On Hamster Liver S9-Mediated Mutagenesis, Metabolism And Dna-Binding Of Benzo[A]Pyrene And Aflatoxin B1, Daniel C. Rubano

Loma Linda University Electronic Theses, Dissertations & Projects

Hamster liver S9 prepared from control animals and animals given 30% glucose in drinking water 48 h before time of sacrifice was used in studies of benzo[a]pyrene (BaP) and aflatoxin (AFB₁)-induced mutagenesis, metabolism of BaP and AFB₁, and metabolite binding to calf thymus DNA. BaP-induced mutagenesis in Salmonella typhimurium TA100 was reduced 38.5% while AFB₁-induced mutagenesis was increased 36% by S9 from glucose-treated hamsters. The reduction of [³H]BaP metabolite binding to calf thymus DNA in incubations with S9 from glucose-treated hamsters correlated with a decrease in unknown BaP metabolite-deoxyribonucleoside adducts isolated by …

Effect Of Photoperiod On Developmental Morphology And Enolase Isoenzyme Immunohistochemistry In Rat And Djungarian Hamster Superficial Pineal Glands, Chalmer D. Mcclure

Loma Linda University Electronic Theses, Dissertations & Projects

The best understood functional activity of the pineal gland is its diurnal production of melatonin in response to environmental lighting cues. Several enzymes of the melatonin pathway respond to daily photoperiod changes, for example hydroxyindole-O-methyltransferase (HIOMT) and serotonin N-acetyltransferase (SNAT). Increased levels of the glycolytic enzyme neuron-specific enolase (NSE) are thought to reflect increased physiological demands placed on neurons and neuroendocrine tissues. Homodimer non-neuronal enolase isoenzyme (NNE) is immunolocalized to cells, and the hybrid enolase (consisting of subunits from NSE and NNE) has been seen in cerebellar stellate and basket cells. Although not rate limiting, concentrations of both NSE and …

Autonomic Nervous System And Cholesterol Transport, Yuan-Line Hung

Loma Linda University Electronic Theses, Dissertations & Projects

The effect of autonomic nervous system on cholesterol transport is of clinical interest because the relationship between lipoprotein metabolism and atherogenesis is expressed in coronary artery disease.

Generally speaking, beta blockers increase serum VLDL level but decrease both HDL and HDL₂ cholesterol levels without affecting the LDL in humans. We are unaware of reports concerning the effects of metoprolol on lipoprotein metabolism nor comparison of the effects of metoprolol and propranolol in the unhandled rat model. In part I we employed the unhandled rats to compared the effects of these 2 drugs administered with the drinking water in order …

Isolation And Partial Characterization Of Basic, Sperm-Specific, Nuclear Proteins In The Dog And Hampster, Richard William Hall

Biological Sciences Theses & Dissertations

The purpose was to determine whether dogs and hamsters contain the same sperm-specific protamine and testis specific proteins (TP) as other eutherian mammals previously studied. The proteins (protamine and TPs) were isolated from spermatids and mature spermatozoa, and were subjected to electrophoresis in an acid-urea, polyacrylamide gel system according to the procedure of Panyim and Chalkley (1962). The results indicated that, regardless of the anatomical location of sperm acquisition, acid precipitation technique, or denaturing agents used, epididymal and testicular samples from both the dog and hamster contained protamine in elongated spermatids and mature spermatozoa. The protamines from dogs and hamsters …

Decreased Triiodothyronine Binding To The Hepatic Nuclear Thyroid Hormone Receptor In The Diabetic Mouse, Thomas J. Dewind

Loma Linda University Electronic Theses, Dissertations & Projects

The diabetic C57BL/KsJ-db m mouse has abnormal thyroid hormone levels and indications of thyroid hormone resistance. To investigate the basis of these abnormalities, the hepatic nuclear thyroid hormone receptor was extracted with 0.4 M KCl, 1.1 mM MgCl₂, 20 mM Tris/HCl, pH 7.9 from hepatocyte nuclei of normal C57BL/KsJ, heterozygous C57BL/KsJ-db m (db/m), and diabetic C57BL/KsJ-db m (db/db) mice. Normal and heterozygous mice were grouped together as the controls. Triiodothyronine (T₃) binding studies at 4°C using nitrocellulose filtration to separate free T₃ from receptor bound T₃ demonstrated an …

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 …

Sprague-Dawley Rats Fed Milk Or Beef Protein : Differences In Response To 1,2-Dimethylhydrazine Carcinogenesis, Stanley W. L. Ng

Loma Linda University Electronic Theses, Dissertations & Projects

Colon cancer is responsible for a high percentage of cancer deaths in developing countries, and there is convincing epidemiological evidence that meat protein and fat in the diet increase the incidence of this form of cancer. An animal tumor model which has been used by many investigators interested in colon cancer is the 1,2-dimethylhydrazine (DMH)-rat or DMH-mouse tumor model. In previous work done in this laboratory the DMH-BALB/c mouse tumor model was used to compare the production of colon tumors in mice fed a diet using non-fat powdered milk as a source of protein with those in mice fed beef …

The Effect Of Dietary Fat Level On Tumor Development And Immunity In Balb/C Mice Fed Casein Of Wheat Gluten As Protein And Challenged With Herpes Type 2-Transformed Cells, Helen Drakou

Loma Linda University Electronic Theses, Dissertations & Projects

A high percentage of fat in the diet has been implicated through epidemiological studies in several human cancers. Studies in experimental animals have produced evidence that increasing the fat in the diet decreases the animal’s ability to restrict tumor development and growth. In previous work done in this laboratory with BALB/c mice injected with herpes simplex Type 2-transformed mouse cells (H238), the effects of a diet which greatly enhanced tumor growth was compared with one which restricted tumor growth. The latter, a low (5%) fat, low protein diet, in which the protein was casein, was also found to produce a …

Interaction Of Putative Estrogens And The Estrogen Receptor System In Leydig Cells In The Balb/C Mouse Testis Resulting In The Initiation Of Dna Synthesis, R. Lloyd Juriansz

Loma Linda University Electronic Theses, Dissertations & Projects

Continuous administration of estrogens for 7-9 months, both steroidal and nonsteroidal, to male BALB/c mice, leads to the formation of testicular Leydig cell tumors. Three days following the subcutaneous implantation of a pellet of estrogen in cholesterol, there is a peak in the incorporation of ³H-tymidine into the DNA of the interstitial cells. These effects are hypothesized to be mediated by the estrogen receptor system in the Leydig cell. Common experimental techniques for the measurement of hormone binding, such as dextran coated charcoal treatment, proved to be impossible to employ in this system, therefore a procedure was developed using …

The Role Of The Salivary Glands In Uptake Of Fluoride In Teeth And Bone, Robin E. Vance

Loma Linda University Electronic Theses, Dissertations & Projects

The cariostatic capability of fluoride is generally recognized, in addition, it may also have a beneficial effect on bone. Fluoride is thought to exercise its cariostasis through a local effect on teeth, however, the possibility exists that fluoride exerts its action through a systemic mechanism. Fluoride uptake by rat teeth and its effectiveness as a cariostatic substance was studied in parotidectomized, submaxillariectomized, and totally sialoadenectomized animals (both parotid and submaxillary glands removed). The uptake of fluoride in bone was also quantitated for comparison purposes.

Rats were injected daily with 15 micromoles of fluoride dissolved in 0.1 ml saline. The rats …

The Effect Of Hypercholesterolemia On The Membrane Lipids, 3-0-[¹⁴C] Methylglucose Transport, And 2,3-Diphosphoglycerate Levels In Rat Erythrocytes, Edwin J. Lester Jr.

Loma Linda University Electronic Theses, Dissertations & Projects

An increase in dietary cholesterol and cholic acid will produce hypercholesterolemia in rats. For ten months, two groups of rats (six in each group) were fed commercial rat pellets (control group) or rat pellets plus cholesterol (1%) and cholic acid (0.25%) (experimental group). A blood sample from each animal was divided into three aliquots for three separate experiments on the erythrocytes: a membrane cholesterol and phospholipid determination, a 3-0-[¹⁴C] methylglucose (30MG) transport determination, and a 2,3-diphosphoglycerate (2,3 DPG) determination. The 30MG transport and 2,3 DPG aliquots were each incubated in the same five concentrations of 30MG and glucose …

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. …

Human Placental Alkaline Phosphatase And Steroid Metabolism By Rat Adrenals, Allen G. Meier

Loma Linda University Electronic Theses, Dissertations & Projects

Human placental alkaline phosphatase was purified by butanol extraction, methanol precipitation and chromatography on DEAE-cellulose. The pH optimum was found to be 10.9. The enzyme was competitively inhibited by di-ethyl-p-nitrobenzyl-phosphonate and copper sulfate. An increase in enzymatic activity occurred in the presence of the phosphate ion (HPO₄) and ATP.

The enzyme was crystallized from a 40% saturated solution of ammonium sulfate and shown to be homogeneous by sedimentation analysis. Homogeneity of the enzyme was also demonstrated using poly-acrylamide-gel-electrophoresis. At a pH of 7.5% the electrophoretic pattern yielded a single band and showed no significant contamination.

The metabolic transformation …

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 …

The Relationship Of Alcohol Consumption In Rats To Morphine And Codeine Intake And The Metabolism Of Dopamine, Hsiu Fen Liu

Loma Linda University Electronic Theses, Dissertations & Projects

The effects of morphine and codeine free-choice alcohol consumption in male Sprague-Dawley rats were studied. Intakes of a 10% alcohol solution in milliliters per 100 gm. of body weight were on recorded weekly. No difference was found in the alcohol intake of rats given either a morphine-supplemented diet (0.01% of the diet) or daily injection of morphine sulfate (2 mg./kg.); however, there was a significant lower intake of water (p < .05) in those rats fed the diet with morphine. Total fluid consumption of both groups given the morphine-supplemented diet and daily injection of morphine sulfate was decreased (p < .05). It was found that morphine did not affect the percentage of total fluid consumed as alcohol or the weight gain.

Two levels of codeine phosphate (10 mg./kg. and 20 mg./kg.) were injected subcutaneously into rats twice a day. It was observed that the codeine significantly decreased alcohol intake in rats …

The Response Of Gingival Tissues To Alterations In Ph, Robert C. Jann

Loma Linda University Electronic Theses, Dissertations & Projects

The purpose of this study was to evaluate the histopathological and clinical changes that occurred when a continuous supply of exogenous acid or base, at varying pH, was delivered adjacent to the gingival crest of the monkey. A related goal was to develop a monkey model system which would deliver test solutions continuously and atraumatically, to the experimental gingival sites.

Two young adult female monkeys had a perfusion apparatus attached to certain maxillary teeth so that test solutions were deposited atraumatically to the marginal gingival tissues. During the experimental periods the animals were kept in primate restraining chairs and fed …

The Transfer Of Hydrogen In The Reduction Of Progesterone, William H. Kersey

Loma Linda University Electronic Theses, Dissertations & Projects

Experimental female rats were given daily injections of synthetic estrogens for six months. The effect on rat ovarian 20α-OH-SDH was not definitive. Diethylstilbestrol and 17α-ethynylestradiol caused a significant drop in activity as compared with controls while mestranol caused a slight increase in activity. A synthetic progestin, medroxyprogesterone, had no apparent effect on the activity of the enzyme.

Rat ovarian 20α-OH-SDH was purified fivefold by ammonium sulfate fractionation and chromatography on DEAE-cellulose.

The homogeneity of the enzyme was checked by means of disc gel electrophoresis. At pH 8.2 no significant contamination appeared in the electrophoretic pattern, but at pH 9.0 five …

The Effect Of Schistosoma Mansoni On Free Amino Acid Levels In Mice, Richard D. Tkachuck

Loma Linda University Electronic Theses, Dissertations & Projects

Free amino acid levels in the blood plasma of mice infected with Schistosoma mansoni Sambon, 1907, were measured at 3, 6, and 9 weeks post-infection with an automatic amino acid analyzer. Significant differences between experimental and control animals occurred at all three time periods. At 3 weeks, asparagine, alanine, citrulline, proline, methionine, and threonine levels all were lower in the infected animals. At 6 weeks, four differences were noted. Alpha-amino-n-butyric acid, ornithine, lysine, and histidine all had lower values in infected animals. At 9 weeks there were 12 differences. Tyrosine, phenylalanine, threonine, serine, proline, citrulline, glycine, alanine, valine, isoleucine, and …

Antibiotics And The Wasting Disease In Neonatally Thymectomized Rats, Douglas M. Grignon

Loma Linda University Electronic Theses, Dissertations & Projects

The administration of the antibiotic, Chloramphenicol, to pregnant rats just prior to, and for four days after delivery, diminishes the incidence of the so-called "Wasting Disease" in neonatally thymectomized rats.

A total of 50 rats were divided into the following groups:

1. Thymectomy only---nonmedicated 17 rats
2. Thymectomy only---medicated 12 rats
3. Thymectomy-adrenalectomy---nonmedicated 5 rats
4. Thymectomy-adrenalectomy---medicated 8 rats
5. Controls---nonmedicated 4 rats
6. Controls---medicated 4 rats

Chloramphenicol was administered in the drinking water to the mothers of groups 2, 4 and 6 for about 2 days prior to delivery and 4 days after. On the day of birth or within three days after birth, the …

The Effect Of Varying Protein Intake On Trichinella Spiralis Infection In Mice, Clare K. Kwan

Loma Linda University Electronic Theses, Dissertations & Projects

Three hundred Swiss Webster albino mice three weeks of age were placed on low (8%), medium (24%), high (48%) protein levels and a commercial laboratory animal feed, Purina Chow for various lengths of time: (1) simultaneously with infection, and four weeks thereafter, (2) three weeks before infection and throughout the four-week infection period, and (3) six weeks prior to infection and during the infection period. The protein source was casein. Sixty of the 300 mice used served as noninfected controls, and the other 240 were each infected with 400 washed, suspended Trichinella spiralis larvae obtained from a rat by the …