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Results 401 - 450 of 675
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Spivak J L - - 1993
From the foregoing data, it is clear that erythropoietin production is tightly regulated not only under normal circumstances but also during hypoxia, unless the hypoxia is extreme. Various disease states can have a negative impact on erythropoietin production, but while altering it quantitatively, they do not appear to abrogate basic ...
Quaresima V - - 1993
The effects of fraction of inspired oxygen (FiO2) on the reduction of a nitroxide free radical were studied by X-band electron paramagnetic resonance (EPR) monitoring of circulating rat blood. The decay half-life of the metabolism/elimination phase increased significantly by 24 +/- 8% during hyperoxia and decreased significantly by 16 +/- ...
Hotchkiss R S - - 1993
Neurological abnormalities including agitation, confusion, disorientation, lethargy, and obtundation are early characteristic findings in patients with sepsis. The etiology of the changes in mental status that occur during severe infection is unknown. We investigated the effects of sepsis on intermediary metabolism and bioenergetics in the brain during normoxia and moderate ...
Verna A - - 1993
A group of adult rats was divided into two subgroups: one was submitted to long-term normobaric hypoxia (10% O2, two weeks) while the other (control group) was kept in the same room, breathing air. Animals from each subgroup were used to study either the norepinephrine content of the carotid body ...
Costa L E - - 1993
The spontaneous in situ liver chemiluminescence of female rats submitted to 4,400 m (simulated altitude) for 2 mo and of their corresponding controls at sea level was determined as an approach to the measurement of the intracellular steady-state concentrations of singlet oxygen and oxygen free radicals. Spontaneous liver chemiluminescence was ...
Penn J S - - 1993
Recently a new technique was reported in which examination of the retina of oxygen reared newborn rats was made using indirect fluorescence microscopy (Invest. Ophthal. Vis. Sci. 31:810). We have now improved this technique and systematically employed it as a means of studying oxygen-induced retinopathy in the newborn rat as ...
Froldi G - - 1993
1. The hypoxia-induced changes of contractile force, frequency and diastolic tension in isolated atria from guinea pig, rat and rabbit were studied together with tissue content of adenine nucleotides, creatine phosphate and lactic acid. 2. Increasing hypoxia induced a progressive reduction of contractility in guinea pig, rat and rabbit atria. ...
Barer G - - 1993
1. The effect of blockade of nitric oxide synthesis in pulmonary endothelium by two L-arginine analogues was tested in isolated blood-perfused lungs of normal rats and rats exposed chronically to 10% O2. 2. In both groups of rats the analogues (N-monomethyl-L-arginine (L-NMMA) and N-nitro-L-arginine methyl ester (L-NAME)) enhanced hypoxic vasoconstriction. ...
Palmer C - - 1993
We determined that treatment of immature rats with allopurinol at 15 min after cerebral hypoxia-ischemia reduces brain damage. Seven-d postnatal rats were subjected to right common carotid artery ligation followed by 2.25 h of hypoxia (8% O2). At 15 min of recovery in room air, the rat pups received either ...
Quatrini U - - 1993
1. Albino Wistar rats were raised in a normobaric hypoxic environment (10% O2 in N2). Two generations of hypoxic rats were observed for changes in their haemoglobin-oxygen (Hb-O2) dissociation curves (ODC), 2,3-diphosphoglycerate (2,3-DPG), haemoglobin (Hb), and Hill co-efficients at P50 (n50). The first generation were called (H1) and the second ...
Holland S K - - 1993
19F NMR imaging of the perfluorocarbon emulsion Fluosol has been used to study regional variations in oxygen tension in rat liver and spleen. We have used the linear dependence of spin lattice relaxation rate (1/T1) on the partial oxygen pressure (pO2) of Fluosol to determine the oxygen tension in the ...
Russell-Jones D L - - 1993
Rats were maintained in chambers and breathed air (control, n = 8) or an atmosphere containing 10% oxygen (hypoxic, n = 10) for 35 days. On completion of the experiment the hypoxic animals weighed less than the controls (hypoxic, 290 +/- 11.7g; control, 339 +/- 19.2g; means +/- S.E.M., p ...
Yamamoto C - - 1993
The de-acclimatization process in rats acclimatized to high altitude hypoxia was analyzed according to the changes in the activities of hepatic enzymes. The activities of tryptophan 2,3-dioxygenase and tyrosine aminotransferase in the liver of non-acclimatized rats were increased, whereas those of acclimatized rats were decreased after exposure to a simulated ...
Johnson A C - - 1993
Toluene is a widely used organic solvent causing loss of auditory sensitivity in rats and presumably in humans. Also, the hearing loss in humans occupationally exposed to noise has been reported to be aggravated by simultaneous exposure to solvents. The aim of the present investigation was to study the effects ...
Papa M - - 1993
The effects of exposure to spatial novelty on expression of the immediate early gene (IEG) products c-Fos and c-Jun were mapped in the rat brain by immunohistochemistry. Adult male Sprague-Dawley rats were tested for 10 min in a Làt-maze, and corner-crossings, rearings, and fecal boli were recorded. Rats were sacrificed ...
Vízek M - - 1993
We tested the effect of perinatal (one week prenatal and one week postnatal) normobaric hypoxia on the immune response of rats in their 9th week of life. We found that perinatally hypoxic rats produced less serum antibodies after sequential immunization with ovalbumin and sheep red blood cells. Also phagocytosis of ...
Fowler J C - - 1993
Concentrations of adenosine and inosine in the incubation media of baths containing rat hippocampal slices were measured during graded hypoxia. Slices were exposed to atmospheres containing 95%, 71%, 48%, 24%, or 0% oxygen, with 5% CO2 and a balance of N2. Absorbance HPLC measurements were made with samples drawn from ...
Yamamoto K - - 1992
Participation of hypoxic hypoxia in low COHb (Carboxyhemoglobin) concentrations frequently observed in fire victims was examined using rats and rabbits exposed to low-O2 and CO gas mixtures. Rats exposed to the most hypoxic gas mixture (O2 3%-CO 0.3%) died with COHb value below 40%. Rabbits also died with a low ...
Raneburger J - - 1992
Muscle tissue oxygen pressure (ptO2) was measured in rats employing the microwire platin electrode according to Kessler and Lübbers. In extracellular volume expansion up to 50% above the normal volume the ptO2 histograms are situated within the normal range. Increase of the interstitial space for oxygen diffusion seems to be ...
Zhao L - - 1992
We have studied the acute effect of brain natriuretic peptide (BNP) and atrial natriuretic peptide (ANP) on pulmonary vascular tone in normoxia and acute hypoxia in the absence and presence of a specific inhibitor of neutral endopeptidase 24.11 (NEI, UK 73, 967, candoxatrilat; Pfizer) in the isolated and blood-perfused rat ...
Bee D - - 1992
Chronically hypoxic (CH) and normoxic control rats were used to assess the action of S9581, a water-soluble analogue of almitrine bismesylate. S9581 increased ventilation (Ve) by 34% in control and 20% in CH rats. During acute hypoxia Ve was raised and S9581 caused a further increase of 20% in both ...
Jensen F E - - 1992
We showed that hypoxia is acutely epileptogenic in immature but not in adult rats. In the present study, we evaluated whether hypoxia results in an increase in long-term seizure susceptibility to flurothyl and whether this is associated with impaired performance on behavioral tests. We also determined whether these long-term outcomes ...
McCulloch P F - - 1992
Peripheral chemoreceptors generally play a limited role in the initial development of diving bradycardia in mammals. However, T.F. Huang and Y.I. Peng (Jpn. J. Physiol. 26: 395-401, 1976) reported that peripheral chemoreceptors are very important for manifestation of the diving response in conscious rats. The objectives of this study were ...
Fushiki T - - 1992
The effect of chronic hypoxia on the whole-body insulin action in rats was investigated. Rats were kept in a hypobaric hypoxia chamber maintained at a simulated altitude of 4000 m for 10 weeks. At the end of the experimental period, the mean body weight of the hypoxic rats was significantly ...
Hertzberg T - - 1992
1. The influence of postnatal hypoxia on regulation of breathing and turnover rate of carotid body dopamine was examined in newborn rats. The percentage change in frequency, tidal volume and ventilation elicited by transient hyperoxia was assessed by flow plethysmography in unanaesthetized pups. The alteration in ventilation was taken as ...
Hirofuji C - - 1992
Fibre type composition in the soleus muscle was studied in second generation male and female Sprague-Dawley rats bred at 460 Torr (hypobaric hypoxia). In control male and female rats (bred at sea level atmospheric pressure) the percentage of slow twitch oxidative (SO) fibres increased, and the percentage of fast twitch ...
Wazawa H - - 1992
Fire deaths at low COHb (carboxyhemoglobin) concentrations are frequently observed, but it is difficult to determine the causative factors. Participation of hypoxic hypoxia was examined using rats and rabbits exposed to various low-O2 and CO gas mixtures. The ranges of O2 and CO concentration were 3.0-22.2% and 0.3-2.9%, respectively. The ...
Reuter A - - 1992
The concentrations of reduced (GSH) and oxidized glutathione (glutathione disulfide, GSSG) in lung, liver, brain and plasma of newborn rats were investigated under the condition of reversible hypoxia. Brain and lung of newborn rats seem to be susceptible to reversible hypoxia. We found an increase in GSSG concentration after hypoxia ...
Varela A - - 1992
Isolated rat atria in hypoxia released lactate into the bathing medium and underwent a decline of the contraction frequency which, in some cases led to a complete cessation of the pacemaker activity. A pronounced fall in the peak developed tension and a rise in the resting tension also appeared. The ...
Martin I H - - 1992
Female rats were submitted to 5,500 m simulated altitude (50.7 kPa) for 23 weeks in a hypobaric chamber. In vitro biosynthesis of estradiol from labelled pregnenolone was studied in the ovaries of these rats and of their controls at sea level barometric pressure. The weight of the ovaries expressed as ...
Dürk H - - 1992
1,1,1-Trichloroethane (TCE) is a widely used industrial solvent of low acute toxicity. It is slowly oxidized to trichloroethanol and trichloroacetic acid by cytochrome P-450-dependent mono-oxygenases. Increased inhalative uptake by rats under hypoxia and spin-trapping experiments indicate that TCE is also reductively metabolized to a radical intermediate. Acetylene is formed as ...
Gautier H - - 1992
The effects of hypoxia on thermoregulation and ventilatory control were studied in conscious rats before and after carotid denervation (CD). Measurements of metabolic rate (VO2), ventilation (V), shivering intensity (SI), and colonic temperature (Tc) were made in groups of eight rats subjected to three protocols. In protocols 1 and 2, ...
Papadopoulou M V - - 1992
Two new bioreductive compounds, 9-[3-(2-nitro-1-imidazolyl)propylamino]acridine hydrochloride (NLA-1) and 9-[2-(2-nitro-1-imidazolyl)ethylamino]acridine hydrochloride (NLA-2), which behave as hypoxic cytotoxins and radiosensitizers, have been investigated for potentiation of 1-(2-chloroethyl)-3-cyclohexyl-1-nitrosourea's (CCNU) cytotoxic activity in vitro using V-79 cells. The preincubation effect as well as conditions of coadministration of CCNU with each sensitizer have been examined. ...
Cheng J T - - 1992
In an attempt to understand the changes of circulating neuropeptide Y (NPY) during hypoxia, the plasma level of NPY was investigated by radioimmunoassay. Exposure of rats to hypobaric hypoxia at an altitude of 18,000 ft for 4 weeks causes an increase of pulmonary pressure and an elevation of plasma NPY-like ...
Ou L C - - 1992
Hilltop (H) and Madison (M) strains of Sprague-Dawley rats exhibit strikingly different susceptibilities to the effects of chronic altitude exposure. The H rats develop greater polycythemia, hypoxemia, and pulmonary hypertension. We studied ventilation, pulmonary gas exchange, tissue oxygenation, and hematologic adaptations in the two rat strains during a 50-day exposure ...
Bômont L - - 1992
The quantitative autoradiographic 2-[14C]-deoxyglucose technique (2-DG) was applied to measure the effects of an acute hypoxic exposure on local cerebral metabolic rates for glucose (LCMRglcs) in the 10 (P10)-, 14 (P14)-, and 21 (P21)-day-old rat. The animals were exposed to hypoxic (7% O2/93% N2) or control gas mixture (21% O2/79% ...
Tenney S M - - 1992
A disturbed water and electrolyte homeostasis is not generally held to be a primary mechanism in the pathogenesis of acute mountain sickness (AMS) and high altitude pulmonary edema (HAPE), but the association of oliguria and weight gain with AMS and HAPE has led to the hypothesis that water retention may ...
Zhou Z Y - - 1992
Replantation of amputated rat feet utilizing an efferent arteriovenous shunt constructed between the distal posterior tibial artery and the proximal posterior tibial vein, in the absence of all other venous drainage, provides an alternative pathway to the normal venous drainage in a replanted rat foot. However, this substitute venous drainage ...
Wang D X - - 1992
The alteration in hypoxic pulmonary vasoconstriction (HPV) induced by cigarette smoking was studied in Wistar rats, piglets and in humans. The percentage change of pulmonary vascular resistance (delta PVR%) and the amplitude of the systolic wave in impedance pneumorheogram (delta H%) were used to estimate the strength of HPV. It ...
Schreiber M - - 1992
Control (physiological saline treated) and ascorbic acid (AA) treated (1 mg.g-1 b.w. one hour before exposure) 18-day-old rats were exposed for 1 hour to high altitude in a hypobaric chamber and the mean lethal altitudes were calculated. AA displayed a protective effect, so that in two identical experiments the mean ...
Arlinghaus L - - 1991
In vitro hippocampal slices from adult rats were subjected to transient hypoxia in the presence of a cell-penetrating, calpain inhibitor (Cbz-Val-Phe-H; MDL-28170). The posthypoxic recovery of synaptic potentials was greatly improved in protease inhibitor-treated slices relative to control slices. These findings support a role for calcium-activated proteolysis in the process ...
Oddoy A - - 1991
Ligustrazine, the synthesized principle of a Chinese herbal remedy shown previously to be a pulmonary vasodilator, was tested in chronically hypoxic and normal rats. Pressure/flow, (P/Q), relations were measured in isolated perfused lungs during normoxia, hypoxia and after reversal of hypoxic vasoconstriction by increasing doses of ligustrazine. P/Q lines were ...
Oei H H - - 1991
The effects of 5-amino-4-imidazolecarboxamide riboside (rAICA) on coronary adenosine efflux were examined in blood-free perfused working rat heart preparations subjected to mild (70% O2) and severe hypoxia (45% O2). Under these hypoxic conditions, no significant increase of coronary adenosine effluxes was observed in the presence of 300 microM rAICA alone. ...
Gautier H - - 1991
The effects of hypoxia (inspired O2 fraction = 0.12) on thermoregulation and on the different sources of thermogenesis were studied in rats before and after periods of 1-4 wk of cold acclimation. Measurements of metabolic rate (VO2) and body temperature (Tb) were made at 5-min intervals, and shivering activity was ...
Hotchkiss R S - - 1991
Underlying cellular hypoxia, which may be difficult to detect, has been postulated to be a major cause of morbidity and mortality in sepsis. We employed the novel hypoxic marker [18F]fluoromisonidazole to determine whether cellular hypoxia was present in a peritonitis model of sepsis in the rat. A second group of ...
Mortola J P - - 1991
Burrowing mammals often demonstrate structural and functional characteristics which could be interpreted as aspects of adaptation to the low PO2 and high PCO2 of their environment. Whether these characteristics are acquired by each individual as the result of life in the burrow or are genetic traits established through evolution is ...
Aw T Y - - 1991
The effect of chronic hypoxia (10.5% O2 for 8-9 days) on acetaminophen metabolism was studied in vivo or in isolated cell or microsomal systems. Results from in vivo studies with oral administration of acetaminophen showed that in hypoxic rats, the plasma appearance of the drug was delayed and the plasma ...
Edwards R J - - 1991
The effect of hyperbaric oxygen, administered during storage, on the survival of replanted limbs was evaluated in rats. The right hindlimbs of male Sprague-Dawley rats were severed and were replanted by microvascular anastomoses after storage in either room air or hyperbaric oxygen (100% oxygen at 2.9 atm absolute) at 23 ...
Quatrini U - - 1991
We determined the "in vivo" (arterial pH and PCO2) and standard (pH = 7.4, PCO2 = 40 mm Hg) PO2 at 50% O2 saturation of hemoglobin (P50, vv and P50, st) in Wistar albino rats when living in a normobaric hypoxic environment. Two generations of hypoxic rats were observed for ...
Barraco R A - - 1991
A new technique for achieving repeated sampling of fourth ventricular cerebrospinal fluid (CSF) from the cisterna magna of unanesthetized rats is described. The sampling cannula is positioned extracranially, in contrast to previously published techniques which require insertion through the skull. CSF samples, withdrawn from unanesthetized rats before, during and after ...
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