Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0020538 (hypertension)
 170,190 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

An investigation was performed on a new strain of genetically hypertensive mice to study those aspects of the renal glomerulus which have in the past been implicated in the etiology of renal parenchymal hypertension. Morphometric analyses were carried out utilizing a computerized graphic data analysing system on information obtained through transmission electron microscopy. Chronically hypertensive animals exhibited thinner basement membranes with numerous sub-epithelial focal thickenings, which were largely absent from the normotensive controls. No difference was noted in the width of the epithelial slit pores (interpedicelar spaces). The glomerular capillary loops of the hypertensive animals appeared otherwise unremarkable, as did the urinary space and parietal epithelium of Bowman's capsule. No evidence of renal parenchymal pathologies implicated in the etiology of systemic hypertension was observed, therefore, these animals would seem to be suitable models for human essential hypertension.
Anat Rec 1979 Nov
PMID:A morphometric analysis of the glomerular capillary wall of a new strain of genetically hypertensive mice. 50 5

Thrombosis of the cranial vena cava in a cow was followed by the formation of aneurysms in the pulmonary arteries. Embolism, pulmonary hypertension and the development of a collateral venous and lymphatic circulation are the suggested causes of these uncommon arterial lesions.
Vet Rec 1977 Aug 13
PMID:Thrombosis of the cranial vena cava in a cow. 91 1

gamma-Aminobutyric acid (GABA) is a major inhibitory neurotransmitter and has been shown to exert considerable influence on the neural control of the cardiovascular function. It is not clear, however, which GABAergic systems are involved in salt-induced hypertension. This study was designed to investigate the GABAergic neurons in specific regions of the brain possibly linked to salt-induced hypertension. After 4 weeks of deoxycorticosterone acetate (DOCA) and salt treatments, the rats developed cardiac hypertrophy. All of the animals were sacrificed for immunocytochemical localization of GABAergic terminals using specific antibodies to glutamic acid decarboxylase (GAD). GAD-positive GABAergic terminal densities in discrete regions of the brain were determined by using morphometric quantitation. Results showed that GABAergic terminal densities in the medial preoptic nucleus and the area lateral to the paraventricular hypothalamic nucleus were significantly increased in DOCA-salt-treated rats 4 weeks after the experiment as compared with 4 week controls. This study provides new evidence to support further the idea that central GABAergic neurons are closely associated with pathogenesis of salt-induced hypertension. Different hypertensive mechanisms between salt-induced hypertension and genetic hypertension are also discussed.
Anat Rec 1990 Aug
PMID:Increased density of glutamic acid decarboxylase-containing terminals in the medial preoptic nucleus and the area surrounding the paraventricular hypothalamic nucleus is associated with deoxycorticosterone acetate (DOCA)-salt hypertension. 239 3

The cardiac atria are known to play a role in blood volume homeostasis, secreting a peptide that induces a potent natriuresis and diuresis. This peptide is atrial natriuretic factor (ANF), and its primary site of storage is within atria-specific granules found in atrial cardiocytes. Since salt loading results in an increase in circulating levels of ANF, our aim was to determine if the atria-specific granule population in the cardiocytes of Dahl rats would decrease accordingly. To this end, the fractional volume of the atria-specific granules was determined by ultrastructural morphometric analysis in the Dahl salt model of hypertension. This analysis was performed on the right atria of Dahl Salt-resistant (DR) and salt-sensitive (DS) rats fed either a low-salt (0.4%) or high-salt (8%) diet for 12 weeks prior to sacrifice. DR and DS rats fed a low-salt diet had significantly reduced plasma sodium levels and osmolalities, and a significantly lower mean arterial blood pressure than did rats fed a high-salt diet. The fractional volume of atria-specific granules was significantly lower in salt-loaded DR (P less than 0.01) and DS (P less than 0.025) rats than in their respective low-salt controls. This significant decrease in atrial granules corresponds to the reported decrease in the storage of atrial ANF in salt-loaded rats, and provides a morphological verification of the biochemical studies. Moreover, these results, in combination with a growing body of physiological data, lend support to the hypothesized role of ANF in the regulation of water-electrolyte balance, which may play an important role in cardiovascular pathophysiological states related to hypertension.
Anat Rec 1987 Jun
PMID:Effects of salt loading on the fractional volume of atria-specific granules in Dahl salt-sensitive and salt-resistant rats. 295 6

Earlier studies established that stroke-prone spontaneously hypertensive rats (SHRSP) invariably infarct after middle cerebral artery (MCA) occlusion. Normotensive rats are usually protected from infarction after the occlusion. Objectives of this study were to characterize the anastomosing collaterals that may determine the different outcomes to MCA occlusion in SHRSP and Wistar Kyoto rats (WKY). Young (5-10 week) and old (40-69 week) rats of each sex were anesthetized, then administered papaverine to produce maximal vasodilatation of the cerebrovascular bed. Under control conditions latex was injected into the arterial tree to measure the internal diameter of branches of the anterior cerebral artery (ACA), the MCA, and the ACA-MCA anastomosing collaterals. Large diameter ACA and MCA rami in old, but not young, SHRSP were significantly smaller in diameter than the respective ACA and MCA branches in old WKY. The number of ACA-MCA anastomoses was the same for SHRSP and WKY. Mean internal diameter of the ACA-MCA anastomoses was significantly (p less than 0.0001) smaller in SHRSP than WKY in both age groups. There were significant negative correlations between age and 1) the internal diameter of the ACA-MCA anastomoses in WKY but not SHRSP, and 2) the largest diameter ACA and MCA rami in SHRSP but not WKY. The findings suggest that vascular resistance of fully relaxed collaterals is greater in SHRSP than WKY, thereby compromising the dorsal collateral circulation before large diameter vessel changes occur that accompany the established form of hypertension.
Anat Rec 1987 May
PMID:Dorsal cerebral collaterals of stroke-prone spontaneously hypertensive rats (SHRSP) and Wistar Kyoto rats (WKY). 360 59

The morphology of the carotid sinus region of the internal carotid artery was studied in spontaneously hypertensive rats (SHR) at 5, 8, 16, and 24 weeks of age. The carotid sinus region occupied the proximal millimeter of the internal carotid artery, and was easily recognizable by the presence of an extensive adventitial capillary plexus, which was absent on adjacent arteries (e.g., common and external carotid arteries). Methylene blue-stained whole-mount preparations showed the extent of baroreceptor nerves over the sinus. Baroreceptor fibers terminated in distinctive bulbous-like endings, which, at the ultrastructural level, were filled with mitochondria. No differences were noted in the sinus adventitial capillary network or baroreceptor distribution between SHR and age-matched Wistar-Kyoto (WKY) normotensive control animals. With the onset of a significant rise in SHR blood pressure, the carotid sinus wall increased in thickness and total vessel size. The wall/lumen ratios were significantly larger in the SHR than in age-matched WKY ratios in all age groups. SHR carotid sinus vessel enlargement was uniform throughout the vessel tunics, with no significant change in the proportion of the tunica media occupied by smooth muscle cells. The increase in the carotid sinus wall thickness associated with increasing hypertension could affect the ability of the sinus to distend and may play a secondary role in the maintenance of hypertension by compromising baroreceptor nerve ending sensitivity.
Anat Rec 1987 Aug
PMID:Morphology of the carotid sinus wall in normotensive and spontaneously hypertensive rats. 366 43

Central catecholamine (CA) neurons in the nucleus tractus solitarius (NTS) and paraventricular hypothalamic nucleus (PVN) were studied in Wistar rats that had been unilaterally nephrectomized. The experimental animals were then treated with deoxycorticosterone acetate (DOCA) and salt water. The control animals were treated with the vehicle and tap water. Blood pressure of animals 4 weeks after DOCA/salt treatment was significantly elevated when compared to control rats. Morphologically, CA terminals showed no noticeable changes in the DOCA/salt hypertensive rats. Furthermore, the density of CA terminals either in the NTS or in the PVN of the DOCA/salt hypertensive rats was not statistically different from that of normotensive controls, suggesting that salt does not cause lesions or destruction of CA terminals. However, an extensive electron-microscopic morphometric analysis indicated that there was an enhancement of CA synaptogenesis (expressed by increased synaptic frequency among all CA boutons labeled with 5-hydroxydopamine) in the PVN, but not in the NTS of DOCA/salt hypertensive rats. In addition, the high-performance liquid chromatography revealed decreased CA contents in the PVN, but not in the NTS, of DOCA/salt hypertensive animals. Since synapses are primary sites for neurotransmitter release, the above results collectively suggest that more CA synapses formed in the PVN may reflect a net CA release from CA terminals resulting in the decreased CA content in the axonal terminals. Such an increased CA release and enhanced CA synaptogenesis may consequently enhance CA function in the PVN of hypertensive rats 4 weeks after DOCA/salt treatment, and relate to the development and/or maintenance of hypertension in the DOCA/salt rats.
Anat Rec 1984 Aug
PMID:Catecholamine synapses and contents in the paraventricular hypothalamic nucleus and nucleus tractus solitarius of DOCA-salt hypertensive rats. 647 21

The spontaneously hypertensive rat (SHR) is a stress-sensitive animal which exhibits moderate immune dysfunction that has been implicated in the onset of hypertension. In this study, we examined the morphology of SHR thymus and spleen and further characterized the immune deficiency using Wistar-Kyoto (WKY) and Fisher 344 (F-344) rats for comparison. The adult SHR thymus does not display the increase in medullary volume typically noted with aging and the volume density of the marginal zone is decreased in the spleen. In vivo tritiated-thymidine incorporation is also decreased in the spleen of unstimulated SHR. In mixed lymphocyte reactions (MLR), the proliferative response of SHR splenocytes is significantly decreased relative to controls, WKY and F-344. Addition of interleukin-1 (IL-1), interleukin-2 (IL-2), or indomethacin to the MLR cultures does not increase proliferation. The proliferative response to T cell receptor monoclonal antibody (mAb-TCR) or interleukin-2 (IL-2) are similarly impaired in the SHR. The depressed proliferative T cell response is reversed by prolactin. It is suggested that the SHR is a valuable model for the study of immune deficiency.
Anat Rec 1993 Oct
PMID:Immune system of the spontaneously hypertensive rat: II. Morphology and function. 823 75

Maternal health in Latin America and the Caribbean continues to be an important issue, which is significantly affected by access to appropriate health technology and quality care, which in turn may be dependent upon economic conditions. Although contraceptive knowledge was high, only 53% of couples used some method of contraception. About 32% and 37% of maternal mortality in Mexico and Colombia could have been averted if contraception had been used. One study of 240 maternal deaths in Mexico indicated that 85% were potentially preventable, and 70% could have been potentially avoided with better medical and institutional care. The table gave the number and rate of maternal mortality and risk by country. In 23 countries, maternal mortality was one of the ten leading causes of death among women. The five prominent causes tended to be abortion, hemorrhage, toxemia, complications of the puerperium, and indirect causes among women aged 15-49 years. Countries can be grouped by level of maternal mortality: 227/100,000 live births, 133/100,000, and 50/100,000. About 280,000 to 420,000 episodes of severe intercurrent obstetric problems potentially occurred annually among the 12 million women of reproductive age in the region. In the United States about 1 out of every 5 pregnancies involved pregnancy related hospitalization in 1987. In Mexico in 1989, of the 740,000 obstetric related discharges for obstetric reasons, 80.5% were related to delivery and 19.5%, to morbidity during pregnancy. During the prenatal period, the five leading causes of morbidity have been identified as premature rupture of membranes, urinary tract infection, potential premature delivery, pre-eclampsia, and pregnancy induced hypertension. Latin American is also a region with increasing numbers of cesarean section deliveries. Maternal deaths in Latin America and the Caribbean would be reduced 47 times and 85% of deaths could be avoided if the health systems paralleled those in Canada.
Wkly Epidemiol Rec 1993 Oct 15
PMID:Maternal and child health. Maternal mortality in the Americas. 824 Sep 44

The duration of action and cardiopulmonary effects of propofol (6.55 mg/kg intravenously), xylazine (0.8 mg/kg intramuscularly), medetomidine (30 micrograms/kg intramuscularly), xylazine plus propofol (3 mg/kg intravenously) and medetomidine plus propofol (3 mg/kg intravenously) were compared in dogs. A cannula inserted into a raised carotid artery before the drugs were given allowed the continuous recording of blood pressure and heart rate and the measurement of arterial pH, PCO2, PO2, bicarbonate and base balance. Xylazine and medetomidine premedication prolonged propofol anaesthesia in dogs. Propofol alone reduced blood pressure and transiently raised heart rate. The apnoea and hypoxaemia induced by propofol alone also occurred in the premedicated groups with hypoxaemia being most evident in the medetomidine/propofol group. Bradycardia was a common feature in all the dogs given xylazine or medetomidine, but hypertension was consistently recorded in all the dogs given medetomidine.
Vet Rec 1993 Apr 10
PMID:Xylazine or medetomidine premedication before propofol anaesthesia. 848 49


1 2 3 4 5 Next >>