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Articles 181 - 198 of 198

Full-Text Articles in Pharmacology, Toxicology and Environmental Health

Maturational Changes In Myosin Light Chain Kinase Activity In Ovine Carotids, Elisha Raju Injeti Sep 2008

Maturational Changes In Myosin Light Chain Kinase Activity In Ovine Carotids, Elisha Raju Injeti

Loma Linda University Electronic Theses, Dissertations & Projects

Vascular reactivity changes dramatically during postnatal maturation due in large part to developmental changes in myofilament calcium sensitivity. Recent findings suggest that reactivity of the thick filament component of calcium sensitivity is upregulated in fetal compared to adult arteries. In light of these findings, the present study tests the hypothesis that upregulation of fetal thick filament reactivity is due to upregulation of myosin light chain kinase (MLCK) activity. To test this hypothesis, MLCK abundance and its activity is measured in intact arteries. The results indicate that MLCK abundance is 6.03 ± 0.96 fold greater in adult than in fetal arteries. …

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Maternal Cocaine Administration In Mice Alters Dna Methylation And Gene Expression In Hippocampal Neurons Of Neonatal And Prepubertal Offspring, Svetlana I. Novikova, Fang He, Jie Bai, Nicholas J. Cutrufello, Michael S. Lidow, Ashiwel S. Undieh Apr 2008

Maternal Cocaine Administration In Mice Alters Dna Methylation And Gene Expression In Hippocampal Neurons Of Neonatal And Prepubertal Offspring, Svetlana I. Novikova, Fang He, Jie Bai, Nicholas J. Cutrufello, Michael S. Lidow, Ashiwel S. Undieh

Publications and Research

Previous studies documented significant behavioral changes in the offspring of cocaine-exposed mothers. We now explore the hypothesis that maternal cocaine exposure could alter the fetal epigenetic machinery sufficiently to cause lasting neurochemical and functional changes in the offspring. Pregnant CD1 mice were administered either saline or 20 mg/kg cocaine twice daily on gestational days 8–19. Male pups from each of ten litters of the cocaine and control groups were analyzed at 3 (P3) or 30 (P30) days postnatum. Global DNA methylation, methylated DNA immunoprecipitation followed by CGI2 microarray profiling and bisulfite sequencing, as well as quantitative real-time RT-PCR gene expression …

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Maturational Changes In Cerebrovascular Thick- And Thin-Filament Regulation, Renan Joel Sandoval May 2007

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 …

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Regulation Of Alpha-1-Adrenoceptor-Mediated Contractions Of The Uterine Artery By Pkc, Hongying Zhang May 2007

Regulation Of Alpha-1-Adrenoceptor-Mediated Contractions Of The Uterine Artery By Pkc, Hongying Zhang

Loma Linda University Electronic Theses, Dissertations & Projects

Pregnancy is associated with a significant decrease in uterine vascular tone and a striking increase in uterine blood flow, which ensures normal fetal development. Multiple mechanisms are involved in the adaptation of uterine artery contractility during pregnancy. Both protein kinase C (PKC) and activation of ai-adrenoceptors play important roles in the regulation of uterine artery contractility. In addition, PKC mediates the pregnancyassociated decrease in myogenic tone of the uterine artery, and interacts with ajadrenoceptors leading to modulation of ai-adrenoceptor-mediated contractions of vascular smooth muscle. Yet, whether or to what extent PKC regulates ai-adrenoceptormediated contractions of the uterine artery and their …

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Interaction Between Adrenergic And Nitric Oxide-Releasing Nerves In Cerebral Arteries, Emmanuel Ngu Mbaku Jun 2003

Interaction Between Adrenergic And Nitric Oxide-Releasing Nerves In Cerebral Arteries, Emmanuel Ngu Mbaku

Loma Linda University Electronic Theses, Dissertations & Projects

Of all body tissues, the brain is the least tolerant of ischemia so much that interruption of cerebral blood flow by 5 sec can cause syncope, with irreversible tissue damage if the ischemia last a few minutes. In this respect, the body has an imperative duty of ensuring constant and adequate blood supply to the brain. It does so through a series of intrinsic and extrinsic control factors of which adrenergic and nitric oxide-releasing nerves are components. My research examined the interaction between these two nerve-types with emphasis on the mechanisms involved as well as on changes in their functions …

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Bronchodilator, Spasmolytic And Calcium Antagonist Activities Of Nigella Sativa Seeds (Kalonji): A Traditional Herbal Product With Multiple Medicinal Uses, A H. Gilani, N Aziz, I M. Khurram, K S. Chaudhary, A Iqbal Mar 2001

Bronchodilator, Spasmolytic And Calcium Antagonist Activities Of Nigella Sativa Seeds (Kalonji): A Traditional Herbal Product With Multiple Medicinal Uses, A H. Gilani, N Aziz, I M. Khurram, K S. Chaudhary, A Iqbal

Department of Biological & Biomedical Sciences

Objective: The seeds of Nigella sativa locally known as "Kalonji" has been used in traditional medicine for the treatment of a variety of diseases including diarrhoea and asthma. The crude extract of N. sativa seeds (Ns.Cr) was studied in vitro for its possible spasmolytic and bronchodilator activities to rationalize the folkloric uses.
Methods: Isolated rabbit jejunum and guinea-pig tracheal preparations were set up in Tyrode's and Kreb's solutions respectively and aerated with 5% CO2 in oxygen. Isotonic and isometric responses were measured on Bioscience oscillograph and Grass polygraph respectively.Results: The Ns.Cr caused a dose-dependent (0.1-3.0 mg/ml) relaxation of spontaneous contractions …

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Cholera Toxin Mediated Regulation Of The Expression Of Gq Alpha And G11 Alpha Gtp Binding Proteins, B H. Shah Jun 1999

Cholera Toxin Mediated Regulation Of The Expression Of Gq Alpha And G11 Alpha Gtp Binding Proteins, B H. Shah

Department of Biological & Biomedical Sciences

Previously it has been shown that persistent activation of the stimulatory adenylyl cyclase pathway with cholera toxin (CT) downregulates the Gs alpha polypeptide (80%) in a cAMP-independent manner in C6 glioma cells (Shah, 1997). This study was conducted to examine the short and long term effects of CT on the regulation of pertussis toxin-sensitive and -insensitive G proteins and their transcripts in C6 glioma cells. Treatment of C6 cells with CT (100 ng/ml) up to 16 h had no effect on either Gi or Gq/11 alpha proteins. However, prolonged exposure (24-48 h) caused increased expression of Gi (20-30%) and Gq/11 …

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Co-Activation Of Gi And Gq Proteins Exerts Synergistic Effect On Human Platelet Aggregation Through Activation Of Phospholipase C And Ca2+ Signalling Pathways, B H. Shah, A Siddiqui, K A. Qureshi, M Khan, S Rafi, V A. Ujan, M Y. Yakoob, Y Yaqub, H Rasheed, S A. Saeed Mar 1999

Co-Activation Of Gi And Gq Proteins Exerts Synergistic Effect On Human Platelet Aggregation Through Activation Of Phospholipase C And Ca2+ Signalling Pathways, B H. Shah, A Siddiqui, K A. Qureshi, M Khan, S Rafi, V A. Ujan, M Y. Yakoob, Y Yaqub, H Rasheed, S A. Saeed

Department of Biological & Biomedical Sciences

Our previous studies have shown that subthreshold concentrations of two platelet agonists exert synergistic effects on platelet aggregation. Here we studied the mechanism of synergistic interaction of 5-hydroxytryptamine (5-HT) and epinephrine mediated platelet aggregation. We show that 5-HT had no or little effect on aggregation but it did potentiate the aggregation response of epinephrine. The synergistic interaction of 5-HT (1-5 microM) and epinephrine (0.5-2 microM) was inhibited by alpha2-adrenoceptor blocker (yohimbine; IC50= 0.4 microM), calcium channel blockers (verapamil and diltiazem with IC50 of 10 and 48 mM, respectively), PLC inhibitor (U73122; IC50=6 microM) and nitric oxide (NO) donor, SNAP (IC50=1.6 …

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Atherosclerosis And Plaque Rupture: An Update, M N. Afzal, S A. Saeed, B H. Shah Feb 1999

Atherosclerosis And Plaque Rupture: An Update, M N. Afzal, S A. Saeed, B H. Shah

Department of Biological & Biomedical Sciences

No abstract provided.

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Effect Of Cocaine On Rabbit Renin Angiotensin System: Cocaine Detection In Adult And Fetal Tissue And Adult Plasma Using Ion Mobility Spectrometry, Barbara Belinda Guinn Jul 1997

Effect Of Cocaine On Rabbit Renin Angiotensin System: Cocaine Detection In Adult And Fetal Tissue And Adult Plasma Using Ion Mobility Spectrometry, Barbara Belinda Guinn

Biological Sciences Theses & Dissertations

Ion mobility spectrometry (IMS) was used to detect cocaine and/or the metabolite ecgonine methyl ester (EME) in tissue and plasma samples from male, maternal, and fetal New Zealand White (NZW) rabbits. EME was consistently detected in all adult plasma samples 5 minutes after the injection of cocaine hydrochloride (cocaine•HCI, 2 mg/kg). EME was also in the liver, kidneys, testicles, and ovaries. Five minutes after the injection of cocaine•HCI, the male arterial pressure (MAP) increased from a mean control value of 79 ± 3.2 mmHg to 88 ± 4.1 mmHg, and the pCO2 increased from a control value of28 ± …

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Effects Of Lipoproteins On Cyclo-Oxygenase And Lipoxygenase Pathways In Human Platelets, S A. Saeed, R A. Memon, A H. Gilani, B H. Shah Mar 1997

Effects Of Lipoproteins On Cyclo-Oxygenase And Lipoxygenase Pathways In Human Platelets, S A. Saeed, R A. Memon, A H. Gilani, B H. Shah

Department of Biological & Biomedical Sciences

The products of arachidonic acid (AA) metabolism in platelets play an important role in platelet shape change, adhesion and aggregation which may participate in the pathogenesis of ischemic heart disease and thrombosis. Since lipoproteins are also involved in the pathogenesis of thrombo-embolic disorders, the effect of human lipoproteins (HDL, LDL, VLDL) on AA metabolism in human platelets was investigated. Lipoproteins were separated by density gradient zonal ultracentrifugation. The effects of lipoproteins on production of AA metabolites in human platelets i.e., thromboxane A2 (TXA2) and hydroxy-eicosatetraenoic acids (HETEs) were examined using radiometric thin layer chromatography coupled with automated data integrator system. …

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An Update On Hyperlipidemia And Its Management, R A. Memon, A H. Gilani Oct 1995

An Update On Hyperlipidemia And Its Management, R A. Memon, A H. Gilani

Department of Biological & Biomedical Sciences

No abstract provided.

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Possible Presence Of Calcium Channel Blocker(S) In Rubia Cordifolia: An Indigenous Medicinal Plant, A H. Gilani, K H. Janbaz, M Zaman, A Lateef, A Suria, H R. Ahmed Apr 1994

Possible Presence Of Calcium Channel Blocker(S) In Rubia Cordifolia: An Indigenous Medicinal Plant, A H. Gilani, K H. Janbaz, M Zaman, A Lateef, A Suria, H R. Ahmed

Department of Biological & Biomedical Sciences

Crude extract of Rubia cordifolia (RC) was tested in isolated tissue preparations for its possible calcium channel antagonistic activity. RC suppressed the spontaneous contractions of guinea-pig atria, rabbit jejunum and rat uterus in a concentration dependent manner (0.1-3 mg/ml). In rabbit aorta, it inhibited norepinephrine (10 microM) and KCl (80 mM) induced contractions. Replacement of physiological salt solution with calcium free solution abolished the spontaneous movements of rabbit jejunum. However, addition of calcium (25 micrograms/ml) in the tissue bath restored the spontaneous movements. When the tissues were pretreated with plant extract (1 mg/ml) or verapamil (0.5 microgram/ml), addition of calcium …

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Effects Of Portuguese Man-Of-War (Physalia Physalis) Venom On Isolated Rabbit Atria, Wayne R. Bonlie Aug 1993

Effects Of Portuguese Man-Of-War (Physalia Physalis) Venom On Isolated Rabbit Atria, Wayne R. Bonlie

Loma Linda University Electronic Theses, Dissertations & Projects

The cardiac effects of Portuguese man-of-war venom were studied using isolated atria from rabbits. Venom added (7.1 µg protein/ml) to the bath solution stimulates heart rate 120% (P < 0.01) and increases contraction amplitude 308% (P < 0.001). Both effects are dependent on bath concentrations of venom and calcium. The increase in contraction amplitude is significantly attenuated by diltiazem (0.8 µM) and atenolol (10 µM). Atenolol, a β1-adrenergic antagonist, completely blocks the increase in heart rate. Dantrolene (10 µM) did not significantly block the venom's effects. Ryanodine binding increases in the presence of venom showing that the venom is not in competition for calcium channels on the sarcoplasmic reticulum. These results suggest that the venom acts on the sarcolemma to increase calcium permeability, thereby causing an increase in contraction amplitude and possibly causing β1-adrenergic stimulation.

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Molecular Mechanisms Of Physalia Physalis Venom Modulation Of Cardiac And Vascular Functions, Eva Luo Aug 1990

Molecular Mechanisms Of Physalia Physalis Venom Modulation Of Cardiac And Vascular Functions, Eva Luo

Loma Linda University Electronic Theses, Dissertations & Projects

Portuguese man-of-war (Physalia physalis)venom has profound effects on the cardiovascular system of man and animals. The venom produces vascular relaxation in norepinephrine precontracted, intact rabbit femoral arterial rings by stimulating vasodilatory prostaglandin synthesis in the endothelium. This action does not depend on endotheliumderived relaxing factor (EDRF). P. physalis venom produces a vascular constriction on KC1 depolarized, intact rings. This is completely inhibited by dibenzyline and yohimbine. Increased membrane permeability to calcium may be involved in direct vascular smooth muscle stimulation. The venom has a positive inotropic effect on rat atrial preparations, which is intensified by increased extracellular calcium concentration. …

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Mast Cell Histamine Release Induced By Portuguese Man-Of-War (Physalia) Venom, A. Lester Flowers Jun 1982

Mast Cell Histamine Release Induced By Portuguese Man-Of-War (Physalia) Venom, A. Lester Flowers

Loma Linda University Electronic Theses, Dissertations & Projects

Richet and Portier studied the immunization of dogs against attenuated toxic extracts of the sea anemone and showed that, when given secondary injections of sublethal amounts of native toxic extracts, the dogs experienced severe pruritus and insensitivity followed by death. They called this increased sensitivity to the toxins, anaphylaxis. Richet and Portier, and later Jacques and Schachter, and Uvnäs also studied the direct pruritic and histamine releasing effects of cnidarian (e.g. Physalia, Actinia, Cyanea), toxic extracts. While the anaphylactic effect, discovered by Richet and Portier, has been extended by numerous studies to provide the foundation of our current knowledge of …

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Cerebrospinal Fluid Pressure In Weanling Rabbits With Chronic Plumbism, R.C. Hall Jr., H.I. Frier, R.S. Bartlett, J.E. Rousseau Jr. Dec 1974

Cerebrospinal Fluid Pressure In Weanling Rabbits With Chronic Plumbism, R.C. Hall Jr., H.I. Frier, R.S. Bartlett, J.E. Rousseau Jr.

Storrs Agricultural Experiment Station

No abstract provided.

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The Effect Of Drugs On Experimental Renal Hypertension In The Dog., J. J. Prusmack Jan 1937

The Effect Of Drugs On Experimental Renal Hypertension In The Dog., J. J. Prusmack

Electronic Theses and Dissertations

No abstract provided.

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