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Results 451 - 500 of 675
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Richards M P - - 1992
Brief hypoxia or hyperoxia has been shown to affect growth and metabolism of chick embryos during the late stages of development. The objective of this study was to alter the availability of oxygen to chick embryos developing in ovo and to determine the effects on tissue zinc, copper, iron and ...
Rosenberg G A - - 1991
Proton nuclear magnetic resonance spectroscopy is a unique method to monitor noninvasively the concentrations of cerebral metabolites. N-Acetyl-L-aspartate, the concentration of which is assumed to be stable during hypoxia, has been used to form ratios with lactate. To determine the stability of the signal from N-acetyl-L-aspartate, we used a model ...
Arieli R - - 1991
1. Two chromosomal species, 2n = 52 and 2n = 60 of the mole rat superspecies (Spalax ehrenbergi), occupy humid (2n = 52) and arid (2n = 60) habitats in Israel. 2. Gas conductivity of the soil of the 2n = 52 mole rat is lower than that of the ...
Shirakami G - - 1991
To investigate the effect of pulmonary alveolar hypoxia on the synthesis and release of endothelin (ET)-1, ET-1-like immunoreactivity (-LI) levels of the lung and plasma were measured in conscious unrestrained rats under hypoxic conditions. Sixty-min exposure to alveolar hypoxia (10% O2 or 5% O2) increased the ET-1-LI level in the ...
Quatrini U - - 1990
1. In our study we followed the growth rate and the haematologic changes occurring in albino rats of Wistar strain when living in a hypoxic environment. Two generations of hypoxic rats were observed for changes in their erythrocytes (RBC), haematocrit (Hct) and haemoglobin (Hb): the first generation (H1) and the ...
Maskrey M - - 1990
During surgery under pentobarbital sodium anesthesia, 20 rats had heat exchange devices implanted into their abdominal cavity. After recovery, 14 rats underwent two sets of trials, one in which body core temperature (Tbc) was lowered to 34.5-35.5 degrees C and another in which Tbc was raised to 40.5-41.5 degrees C. ...
Hampl V - - 1990
The possibility that perinatal exposure to hypoxia influences the pulmonary vasculature in adults was tested. Rats born in a hypoxic environment were kept in hypoxia for an additional week after birth. The rats were then raised in atmospheric air, and when adult, they were compared with the rats born and ...
Maskrey M - - 1990
The respiratory rate (f), tidal volume (VT) and ventilation (V) were measured in 3 groups of rats: 10 rats before and after cutting both recurrent laryngeal nerves (RLNX), 10 rats before and after bilateral phrenicotomy (PNX) and 5 sham transected (SHAMX) rats. All rats were exposed to air and gas ...
Minyailenko T D - - 1990
The level of lipid peroxides, concentration of lactic acid in the blood and brain tissue homogenates were measured in rats under hypoxic hypoxia and hemorrhage. Significant correlation was found between the O2 supply-consumption ratio, the concentration of lactate and the level of lipid peroxides. It is suggested that the peroxidation ...
Russell P C - - 1990
We compared the reactivity of pulmonary vessels to bradykinin (BK) and angiotensin I (AI) in normal and chronically hypoxic rats; the latter have pulmonary hypertension and muscularized pulmonary arterioles. These peptides are respectively inactivated and activated by the angiotensin converting-enzyme (ACE) on pulmonary endothelium. Isolated lungs were perfused at a ...
Culton M - - 1990
Since tissue oxygen levels are believed to play a pivotal role in new vessel growth in several situations, we studied the effect of several oxygen concentrations (0, 10, 21, 50, 75, or 100%) on corneal vascularization induced in the rat by chemical cautery. We achieved this by perfusing known concentrations ...
Raffestin B - - 1990
1. To investigate the mechanisms leading to enhanced synthesis and release of atrial natriuretic factor during chronic hypoxia, we measured immunoreactive plasma atrial natriuretic factor, blood gases, packed cell volume, pulmonary artery pressure and systemic artery pressure in male Sprague-Dawley rats exposed to 1, 2 or 3 weeks of normobaric ...
Swanson M C - - 1990
Concentration of any substance in the air of a room is determined by the ratio between the rates of its production and removal. Thus, high concentrations can result from high production, low removal, or a combination of the two. Air filtration can supplement ventilation in removing allergens from the air. ...
Ricci B - - 1990
Identification of a suitable animal model is essential for the continued study of retinopathy of prematurity (ROP). Since 1984 we have used the newborn rat for the study of oxygen-induced retinopathy (OIR). The rat retina is highly immature at birth. Like those of humans, the retinal vessels arise from mesenchymal ...
Arieli R - - 1990
Rats reacted in immediate escape response to encounters with severe hypoxia. This led to a test of the hypothesis that mammals which live in closed spaces (burrows) should have a hypoxic alarm mechanism. A possible detection of hypoxia was studied. Rats were trained to thrust their heads into a compartment ...
Goshgarian H G - - 1990
The present study was carried out to determine if chronic hypoxia in noninjured rats causes morphological alterations in the phrenic nucleus similar to those caused by spinal cord hemisection rostral to the nucleus. Normal rats were subjected to chronic hypoxia in an atmosphere chamber for 48 h. A Bioquant system ...
Walker B R - - 1990
Experiments were performed to examine the role of the arterial baroreceptors in the cardiovascular responses to acute hypoxia and hypercapnia in conscious rats chronically instrumented to monitor systemic hemodynamics. One group of rats remained intact, whereas a second group was barodenervated. Both groups of rats retained arterial chemoreceptive function as ...
Nacházel J - - 1990
Bilateral paralysis of the diaphragm can result in normo or hypoventilation, according to the species studied. Our aim was to ascertain the results of bilateral phrenicotomy in the rat and, if hypoventilation should be present, to try to identify its pathophysiology. We used 33 male rats under urethane anaesthesia (1.3 ...
Yoshino M - - 1990
1. Metabolic acclimatization by repeated exposure to a simulated altitude of 4000, 5000 and 6000 m for 2 hr per day throughout 2 to 11 days was evaluated by the increased formation of ketone bodies as a marker of fatty acid oxidation and the decreased production of lactate and uric ...
Ohwada A - - 1990
The effect of hypoxia was studied on the ionophore A23187-induced leukotriene production by rat alveolar macrophages. The production of LTB4 and LTC4 decreased with reducing oxygenation without change of cell viability. The synthesis of 5-HETE increased during hypoxia and the total production of LTB4, LTC4 and 5-HETE, the major metabolites ...
Quatrini U - - 1990
Arterial acid-base balance, lactate, pyruvate, lactate dehydrogenase activity (LDH), 2,3-diphosphoglycerate content (2,3-DPG) of normoxic control rats were compared with those of rats exposed to a hypoxic normobaric environment (10% O2 in N2) within a few hours after birth (hypoxic animals of first generation or H1), and with those of rats ...
Lun A - - 1990
Long-lasting alterations of spontaneous motor as well as learning behaviour of rats after an early postnatal mild chronic hypoxia were examined. The exposure to hypoxia was 10 h daily from the 2nd to the 6th day of life. In adulthood these rats were hyperactive and learned the active avoidance response ...
Reed M K - - 1989
The effect of hypoxia on isolated perfused rat mesenteric basal venous prostanoid output was studied. Male rat splanchnic vasculature was removed without (SV) or with its end organ (SV + SI) and perfused with Krebs' buffer with a pO2 of 460 or 60 mm torr. Basal splanchnic venous effluent was ...
de Boer J - - 1989
We investigated the earliest time at which irreversible damage takes place after hypoxia-ischemia in the Levine preparation of rats. In 60 rats anesthetized with chloral hydrate and maintained at one of three body temperatures, we unilaterally ligated the left common carotid artery and placed electrodes in the striatum to measure ...
Cherdrungsi P - - 1989
Experiments were undertaken with rats to determine the effects of chronic exposure to a simulated high altitude of 5,000 m on phagocytic activity of the reticuloendothelial system (RES). Phagocytic index (K) was determined by measuring the rate of blood clearance of colloidal carbon given intravenously. K value of the chronically ...
Okubo S - - 1989
Newborn rats were exposed to 10% O2 from 24 h to 6 days after birth, then returned to normoxia and examined at 50 days of age, i.e., after reaching sexual maturity. Despite the important impairment in somatic growth during hypoxia, at 50 days body weight and nose-tail length were as ...
Mautz W J - - 1989
Breathing pattern (frequency and tidal volume), minute ventilation (VE), oxygen consumption (MO2), and rectal temperature (TR) were measured from rats exposed to 0.8, 0.6, 0.4, and 0.2 ppm O3 to determine the relation between breathing pattern responses to O3 and metabolic rate. In 0.8 ppm O3, rapid-shallow breathing began at ...
Shinozuka T - - 1989
Cerebrovascular dilation over PaO2 ranging from hyperoxia to moderate hypoxia is unexplained. We hypothesize that tissue acidosis is the cause. Local cortical cerebral blood flow (LCBF), tissue hydrogen ion concentration [H+]t, and tissue PO2 (PtO2) were measured with microelectrodes in the parietal cortex of 18 rats during a 30-min steady ...
Dwyer B E - - 1989
Rats aged 7 days were exposed to 3.5 h of cerebral hypoxia-ischemia produced by unilateral common carotid artery ligation combined with hypoxia (8% oxygen). The major inducible heat-shock protein, HSP-68, was synthesized in ipsilateral but not contralateral (control) hippocampus during early recovery (1 and 3 h). HSP-68 synthesis was not ...
Mazmanian G M - - 1989
A bolus injection of methylene blue (1 mg), a guanylate cyclase inhibitor, or aspirin (3 mg) in the isolated rat lung preparation had little or no effect on resting perfusion pressure under normoxic condition. In contrast, methylene blue markedly potentiated hypoxic vasopressor response (4-fold) when injected before or during the ...
Romijn H J - - 1989
We tested whether hypoglycemia, like hypoxia, would preferentially destroy GABAergic nerve cells in the neocortex. To this end, rat neocortex explants dissected from 6-day-old rat pups and cultured up to a developmental stage approximately comparable to that of the newborn human neocortex, were exposed to hypoglycemia for different periods. Quantitative ...
Kissen I - - 1989
This study evaluated the effects of bilateral superior cervical ganglionectomy on cerebral blood flow (CBF) and utilization of brain capillary reserve in conscious rats during normoxia and hypoxia (8% O2 in N2). Regional CBF was determined in sham-lesioned and ganglionectomized rats with [14C]iodoantipyrine. The percentage of the total volume fraction ...
Ribeiro-DaSilva G - - 1989
1. Canatoxin, a protein displaying lipoxygenase-activating properties isolated from Canavalia ensiformis seeds, induces hypoxia and hyperglycemia in male rats. 2. Liver glycogen, blood glucose and lactate levels were measured in male and female rats after canatoxin (50 mU, iv) injection. Increased levels of serum glutamic oxaloacetic transaminase activity were used ...
Wakashiro S - - 1989
The influence of hypoxia on hepatic mitochondrial function and energy status was studied in normal and carbon tetrachloride (CCl4)-induced cirrhotic rats. Under hypoxemia of 50 mm Hg-PaO2, hepatic energy status was suppressed both in normal and cirrhotic rats. After the reversal of hypoxia, it was completely restored in normal rats ...
Davies D G - - 1989
1. Minute ventilation (VE) in the semifossorial ground squirrel (Spermophilus tridecemlineatus) increased with increased levels of hypoxia. 2. The increase in VE was brought about primarily by an increase in breathing frequency (f). There was no significant change in tidal volume (VT). 3. The PiO2 threshold for the ventilatory response ...
Su Y C - - 1989
TXB2 and 6-keto-PGF1 alpha levels in arterial and venous plasma of Wistar and Hilltop rats during hypoxia were measured to investigate the roles of TXA2 and PGI2 in hypoxic pulmonary vasoconstriction (HPV) and responsiveness difference of pulmonary vessels to hypoxia between different strains of rats. The results showed that PGI2 ...
Araki R - - 1989
By measuring precise NIR spectra of anesthetized rat head, we determined principal components included in changes of the NIR spectra caused by acute hypoxia. There was apparent delay in reduction of cyt. aa3 as compared with Hb deoxygenation in the hypoxic period. With regard to the eigenvalues determined by principal ...
Ilkiw R - - 1988
Intralipid (IL) infusion has been associated with pulmonary vasoconstriction and decreased oxygenation and may worsen preexisting pulmonary vascular changes. To investigate this, we infused IL or 0.9% saline for 1 wk in normal Sprague-Dawley rats and in rats with vascular changes induced by a previous 2-wk exposure to chronic hypobaric ...
Ibayashi S - - 1988
Hypocarbia results in an increase in brain adenosine concentrations, presumably because of brain hypoxia associated with hypocarbic vasoconstriction. It was hypothesized that adenosine limits the degree of hypocarbic vasoconstriction. To test this hypothesis, the effects of dipyridamole and theophylline on CO2 reactivity during hypocarbia were investigated in anesthetized rats. Dipyridamole ...
Stefanovich V - - 1988
The purpose of this study was to establish if there are any later changes in the local cerebral energy metabolism after exposing 1-day-old rats for 5 days (10 hr daily) to hypobaric hypoxia (pO2 = 10.5 kPa). For this study the 2-[14C]deoxyglucose method for the determination of the regional utilization ...
Dietz J R - - 1988
The purpose of these studies was to examine the effect of hypophysectomy (HYPOX) on the secretion of atrial natriuretic factor (ANF) and related changes in renal function. Pentobarbital sodium-anesthetized rats received a 20% intravenous blood volume expansion. In intact rats (n = 7), plasma ANF was 39 +/- 3 pg/ml ...
Fedorko L - - 1988
We studied the effect of acute bilateral vagotomy on ventilation and ventilatory pattern in rats. In 1- to 6-day-old unanesthetized rats, vagotomy resulted in a substantial decrease (38%) in ventilation during air breathing. After vagotomy there was a threefold increase in tidal volume (VT), inspiratory time (TI) doubled, and expiratory ...
Jederlinic P - - 1988
The decrease in lung angiotensin converting enzyme (ACE) activity occurring in rats during chronic hypoxia might be related to the pulmonary haemodynamic response or to the hypoxia. A study in rats was carried out to investigate this question. Rats from the Hilltop (H) strain are known to develop more severe ...
Torbati D - - 1988
The CNS tolerance to prolonged normobaric hyperoxia (NH) was investigated using alterations in regional cerebral metabolic rate for glucose (rCMRgl) as a sensitive measure of brain oxygen poisoning. Conscious rats were continuously exposed either to air or to oxygen for 24 h at atmospheric pressure inside a closed and ventilated ...
Yoshimura Y - - 1988
To evaluate the effects of oxygen toxicity in the pregnant rat at high and low concentrations of oxygen, an oxygen-consumption apparatus was devised to measure the consumption of oxygen continuously over long periods. Oxygen consumption, partial oxygen pressure on the skin (tcPo2), and lipid peroxide levels in the serum were ...
Oberpichler H - - 1988
The purpose of the present study was to approach the compound(s) responsible for the beneficial effects of an extract of Ginkgo biloba leaves (EGB) on animals subjected to hypoxia. In this first approach we compared the effects of the flavone and the non-flavone fraction of EGB with those of the ...
Lillo R S - - 1988
No study of decompression sickness has examined both variable gas mixtures and variable time at depth to the point of statistical significance. This investigation examined the effect of N2-He-O2 on decompression outcome in rats after variable time-at-depth dives. Unanesthetized male albino rats were subjected to one of two series of ...
Hakim T S - - 1988
To assess the importance of erythrocyte deformability in the pulmonary hypoxic pressor response (HPR) we examined whether alterations in erythrocyte deformability are related to the differences between the brisk HPR in rats vs the small HPR in hamsters, and between the HPR in low altitude rats vs high altitude rats ...
Fantel A G - - 1988
We report the results of studies on the reductive activation of the schistosomicidal agent, niridazole (NDZ). Intact rat embryos in vitro reduced this compound, generating a stable metabolite in the presence of 5% O2. By contrast, embryo and yolk sac homogenates or liver microsomes appeared to require anaerobiasis. Malformation incidence--specifically, ...
Olson E B EB - - 1988
We determined the effects of carotid body excision (CBX) on eupneic ventilation and the ventilatory responses to acute hypoxia, hyperoxia, and chronic hypoxia in unanesthetized rats. Arterial PCO2 (PaCO2) and calculated minute alveolar ventilation to minute metabolic CO2 production (VA/VCO2) ratio were used to determine the ventilatory responses. The effects ...
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