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Showing papers by "University of Saskatchewan published in 1979"



Journal ArticleDOI
TL;DR: In this paper, a new algorithm suitable for calculating impedances from digitized voltages and currents sampled at a relay location is presented, where each input is assumed to be composed of a decaying d.c. component and components of the fundamental and harmonic frequencies.
Abstract: This paper presents a new algorithm suitable for calculating impedances from digitized voltages and currents sampled at a relay location. Each input is assumed to be composed of a decaying d.c. component and components of the fundamental and harmonic frequencies. Parameters of a digital filter determined by using the least error squares approach are then used to compute the real and imaginary components of the voltage and current phasors. Impedances as seen from a relay location are then calculated. The proposed algorithm was tested using the fault data recorded at the Regina South switching station of the Saskatchewan Power Corporation; some of the test results are included.

274 citations


Journal ArticleDOI
TL;DR: Oxygen isotope analyses have been obtained on rocks and coexisting minerals, principally plagioclase and clinopyroxene, from about 400 samples of the Skaergaard layered gabbro intrusion and its country rocks as mentioned in this paper.
Abstract: Oxygen isotope analyses have been obtained on rocks and coexisting minerals, principally plagioclase and clinopyroxene, from about 400 samples of the Skaergaard layered gabbro intrusion and its country rocks. The δ^(18)O values of plagioclase decrease upward in the intrusion, from ‘normal’ values of about +6.0 to +6.4 in the Lower Zone and parts of the Middle Zone, to values as low as −2.4 in the Upper Border Group. The ^(18)O depletions of the plagioclase all took place under subsolidus conditions, and were produced by the Eocene meteoric-hydrothermal system established by this pluton. Clinopyroxene, which is more resistant to ^(18)O exchange than is plagioclase, also underwent depletion in ^(18)O, but to a lesser degree (δ^(18)O = +5.2 to +3.5). The ^(18)O-depleted rocks typically show reversed Δ^(18)Oplag−px fractionations, except at the top of the Upper Zone, where the pyroxenes are very fine-grained aggregates pseudomorphous after ferrowollastonite; these inverted pyroxenes were much more susceptible to subsolidus ^(18)O exchange (δ^(18)O = +3–9 to +0.7). D/H analyses of the chloritized basalt country rocks and of the minor quantities of alteration minerals in the pluton (δD = −116 to −149) confirm these interpretations, indicating that the rocks interacted with meteoric groundwaters having an original δD ≈ −100. and δ^(18)O ≈ −14. Low δD values (≈ −125) were also found throughout the biotites of the Precambrian basement gneiss, requiring that small amounts of water penetrated downward to depths of at least 6 to 10 km. These values, together with the lack of ^(18)O depletion of the gneiss, imply that the overall water/rock ratios were very small in that unit (<0.01), and thus that convective circulation of these waters was much more vigorous in the overlying highly jointed plateau basalts (δ^(18)O ≈ −4.0 to +4–0) than in the relatively impermeable gneiss (δ^(18)O ≈ +7–3 to +7–7). This contrast in permeabilities of the country rocks is also reflected in the distribution of δ^(18)O values in the pluton; the plagioclases with ‘normal’ δ^(18)O values all lie stratigraphically beneath the projection of the basalt-gneiss unconformity through the pluton. Elsewhere, the ^(18)O depletions are correlated with abundance of fractures and faults, particularly in the NE portion of the intrusion, where the Layered Series is very shallow-dipping and permeable basalts underlie the gabbro. The transgressive granophyres in the lower part of the intrusive have δ^(18)O values identical to those of the basement gneiss, indicating they were probably formed by partial melting of stoped blocks of gneiss. In the upper part of the intrusion these granophyre dikes have δ^(18)O values similar to the adjacent host gabbro; this suggests that much of the hydrothermal alteration occurred after their emplacement. However, because of the rarity of low-temperature hydrous alteration minerals, it is also clear that most of the influx of H_2O into the layered gabbro occurred at very high temperatures (>400–500 °C). Prior to flowing into the gabbro, these fluids had exchanged with similar mineral assemblages in the basaltic country rocks, explaining the lack of chemical alteration of the gabbro. Xenoliths of roof rock basalt and of Upper Border Group leucogabbro were strongly depleted in ^(18)O by the hydrothermal system prior to their falling to the bottom of the magma chamber and being incorporated in the layered series. This proves that the hydrothermal system was established very early, at the time of emplacement of the Skaergaard intrusion. However, no measurable ^(18)O depletion of the gabbro magma could be detected, indicating that very little H_2O penetrated directly into the liquid magma, in spite of the fact that a hydrothermal circulation system totally enveloped the magma chamber for at least 100,000 years during its entire period of crystallization. Only as crystallization proceeded was the hydrothermal system able to collapse inward and interact with the solidified and fractured portions of the gabbro. Nevertheless some H_2O was clearly added directly to the magma by dehydration of the stoped blocks of altered roof rock. It is also plausible that small amounts of meteoric water diffused directly into the magma, most logically in the vicinity of major fracture zones that penetrated close to, or were underneath, the late-stage sheet of differentiated ferrodiorite magma. It is suggested that such influx of meteoric waters was responsible for many of the gabbro pegmatite bodies that are common in the Marginal Border Group; also, such H_2O might have produced local increases in Fe^(+3)/Fe^(+2) in the magma that in turn could explain some of the asymmetric crystallization effects in the magma chamber. Local lowering of the liquidus temperature would also occur, perhaps leading to topographic irregularities on the floor of the magma chamber (e.g. the trough bands?).

259 citations


Journal ArticleDOI
TL;DR: Existing data on the specific gravity and the water and nutrient content of microorganisms grown in shake cultures cannot be applied when quantifying the soil microbial biomass, indicating further work is necessary to obtain accurate conversion factors between biovolume and biomass.
Abstract: Direct microscopic measurements of biomass in soil require conversion factors for calculation of the mass of microorganisms from the measured volumes These factors were determined for two bacteria, five fungi, and a yeast isolated from soil Moisture stress conditions occurring in nature were simulated by growth in two media using shake cultures, on agar plates, and on membranes held at 34, 330, and 1,390 kPa of suction The observed conversion factors, ie, the ratio between dry weight and wet volume, generally increased with increasing moisture stress The ratios for fungi ranged from 011 to 041 g/cm3 with an average of 033 g/cm3 Correction of earlier data assuming 80% water and a wet-weight specific gravity of 11 would require a conversion factor of 144 The dry-weight specific gravity of bacteria and yeasts ranged from 038 to 14 g/cm3 with an average of 08 g/cm3 These high values can only occur at 10% ash if no more than 50% of the cell is water, and a specific conversion factor to correct past data for bacterial biomass has not yet been suggested The high conversion factors for bacteria and yeast could not be explained by shrinkage of cells due to heat fixing, but shrinkage during preparation could not be completely discounted Moisture stress affected the C, N, and P content of the various organisms, with the ash contents increasing with increasing moisture stress Although further work is necessary to obtain accurate conversion factors between biovolume and biomass, especially for bacteria, this study clearly indicates that existing data on the specific gravity and the water and nutrient content of microorganisms grown in shake cultures cannot be applied when quantifying the soil microbial biomass

246 citations


Journal ArticleDOI
02 Nov 1979-Science
TL;DR: Hemparin is a biochemical representative of a distinct class of compounds known as linear anionic polyelectrolytes, mixtures of individual highly negatively charged chains that show a wide spectrum of specific reactions with biologically active proteins.
Abstract: Recent studies have shown that heparin is a biochemical representative of a distinct class of compounds known as linear anionic polyelectrolytes. Members of this class are mixtures of individual highly negatively charged chains that show a wide spectrum of specific reactions with biologically active proteins. Upon administration, heparin chains enter a cellular pool and effectively prevent thrombosis by increasing the electronegative potential of the vessel wall. Anticoagulant activity is an unusual feature of a few heparin chains and appears to play a minor role in many clinical uses and in physiological and pathological responses.

184 citations


Journal ArticleDOI
TL;DR: In many new oilseed protein sources, phenolic compounds are as important as unsaturated lipids, carbonyl compounds, and nonenzymatic browning in the development of adverse flavors and colors in food products as discussed by the authors.
Abstract: In many new oilseed protein sources, phenolic compounds are as important as unsaturated lipids, carbonyl compounds, and nonenzymatic browning in the development of adverse flavors and colors in food products. The free phenolic acids are of particular concern because of enzymatic oxidation too-quinones and subsequent binding to lysine and methionine in the proteins. Numerous free phenolic acids have been identified in all oilseed flours with syringic, ferulic and vanillic being the major components in cottonseed, peanut and soybean flours. Gossypol in cottonseed, chlorogenic acid in sunflower, and sinapine in rapeseed are microconstituent phenolics which cause unique problems in the utilization of these defatted flours and their protein isolates in food applications. The roles of bound phenolics and tannins in the binding of essential nutrients or altering chemical and functional properties require further investigation.

153 citations


Journal ArticleDOI
09 Aug 1979-Nature
TL;DR: Experimental results raise the theoretical possibility of controlling some species of cattle ticks by appropriate immunisation of their hosts by apparently novel immunological method of tick control in guinea pigs and cattle.
Abstract: IXODID TICKS attach to the skin of their host and remain there for several days, engorging on blood and intermittently passing salivary secretions into the host1. Several species of Ixodid ticks transmit pathogenic microorganisms along with their saliva into the host, and tick-borne diseases are of great economic importance, particularly in cattle in subtropical and tropical areas2. The control of cattle ticks by chemical acaricides has become increasingly difficult due to the emergence of acaricide-resistant strains of ticks3. An apparently novel immunological method of tick control in guinea pigs and cattle is reported here. Hosts were immunised with antigens extracted from the gut and other internal organs of partially fed ticks. Ticks which subsequently parasitised these hosts showed significantly reduced feeding and reproductive performance. These experimental results raise the theoretical possibility of controlling some species of cattle ticks by appropriate immunisation of their hosts.

150 citations


Journal ArticleDOI
TL;DR: In this paper, two algorithms are described to solve the line overload problem in the Newton-Raphson and decoupled load flow programs, which can be used to determine the generation rescheduling and load curtailment pattern to alleviate line overloads.
Abstract: This paper deals with the problem of alleviating line overloads in a power system by generation rescheduling and load shedding. Mathematical models based on linearized relationships between line currents and state variables, and bus injected powers and state variables are systematically developed to considerthe line overload problem. Two algorithms are described to solve the models in the Newton-Raphson and decoupled load flow programs. The techniques developed can beused to determine the generation rescheduling and load curtailment pattern to alleviate line overloads. The approaches presented in this paper shouldprove useful in system security studies and reliability studies for examining line overload alleviation with minimum computational expense. The analytical results can also serve as an operating guide to the system dispatcher. In a companion paper, the effectiveness of these techniques in alleviating line overloads in several test systems is investigated.

142 citations


Journal ArticleDOI
TL;DR: The observations are compatible with the hypothesis of an in vivo flow of glutamate (and GABA) from neurons to astrocytes where it is taken up and metabolized, and a compensatory flow of glutamine towards neurons and away from astroCytes although the latter cell type may be more deeply involved in glutamine metabolism than envisaged in the hypothesis.
Abstract: — Uptake and release of glutamine were measured in primary cultures of astrocytes together with the activity of the phosphate activated glutaminase (EC 3.5.1.2). In contrast to previous findings of an effective, high affinity uptake of other amino acids (e.g. glutamate, GABA) no such uptake of glutamine was observed, though a saturable, concentrative uptake mechanism did exist (Km= 3.3 ± 0.5 mm; Vmax= 50.2 ± 12.6 nmol ± min−1± mg−1). The phosphate activated glutaminase activity in the astrocytes (6.9 ± 0.9 nmol ± min−1± mg−1) was similar to the activity found in whole brain (5.4 ± 0.7 nmol ± min −l± mg−1), which may contrast with previous findings of a higher activity of the glutamine synthetase (EC 6.3.1.2) in astrocytes than in whole brain. The observations are compatible with the hypothesis of an in vivo flow of glutamate (and GABA) from neurons to astrocytes where it is taken up and metabolized, and a compensatory flow of glutamine towards neurons and away from astrocytes although the latter cell type may be more deeply involved in glutamine metabolism than envisaged in the hypothesis.

134 citations


Journal ArticleDOI
TL;DR: Eight legumes were pin-milled and air-classified into protein and starch fractions and their functional properties compared with those of soybean and lupine flours and high values for oil absorption, oil emulsification, whippability and foam stability were characteristics of the protein fractions, while starch fractions gave high water absorptions, peak and cold viscosities.
Abstract: Eight legumes were pin-milled and air-classified into protein (fine) and starch (coarse) fractions and their functional properties compared with those of soybean and lupine flours. The fine material which represented 22.5 to 29% of the original flours contained from 29 to 66% protein as well as a high proportion of the flour lipids and ash. The coarse material contained 51 to 68% starch and much of the crude fiber which was dense and concentrated in the starch fraction. Generally legumes which showed highly efficient starch fractionation gave lower recoveries of protein in the fine material. High values for oil absorption, oil emulsification, whippability and foam stability were characteristics of the protein fractions, while starch fractions gave high water absorptions, peak and cold viscosities. Gelation occurred in both air-classified fractions. Pea and northern bean, chickpea and lima bean flours, and airclassified fractions gave generally higher values in the functional property tests, while fababean, field pea, mung bean and lentil gave high protein fractionation in the air classification process.

131 citations


Journal ArticleDOI
TL;DR: Under the present experimental conditions the following compounds inhibited preferentially the glial transport system: (3RS, 4SR)‐4‐hydroxynipecotic acid, guvacine, (RS)‐N‐methylnipecotics acid, (R)‐β‐proline and β‐alanine preferently inhibited neuronal transport as studied in mini‐slices of brain cortex.
Abstract: —The effects of a variety of acyclic or heterocyclic GABA analogues on GABA receptor binding and on high affinity transport of GABA in cultured astrocytes and mini-slices of brain cortex were studied. The receptor and transport sites were found to be stereospecific and they exhibited opposite stereoselectivity for (R)- and (S)-trans-4-amino-4-methylcrotonic acid and (R)- and (S)-β-proline. The most potent inhibitors of GABA binding were (RS)-4, 5-dihydromuscimol, muscimol, GABA, isoguvacine and isonipecotic acid with IC50values of, respectively, 0.009, 0.006, 0.033, 0.037 and 0.33 μM. Under the present experimental conditions the following compounds inhibited preferentially the glial transport system: (3RS, 4SR)-4-hydroxynipecotic acid, guvacine, (RS)-N-methylnipecotic acid, (RS)-β-proline and β-alanine (IC50 values 10, 25, 70, 320 and 1000 μM, respectively vs. 200, 100, 300, 1200 and >5000 for neuronal transport). On the other hand, (R)-trans-4-amino-4-methylcrotonic acid, (3RS, 4SR, 5SR)-4-hydroxy-5-methymipecotic acid and (RS)-3-hydroxy-5-aminovaleric acid preferentially inhibited neuronal transport as studied in mini-slices of brain cortex (IC50 values 160, 300 and 430 μM, respectively vs. 500, > 5000 and 1400 μM for glial transport).

Journal ArticleDOI
TL;DR: In this article, simultaneous measurements of the nightglow profiles of the O2(b1g+−X3Σg−) A-band, the atomic oxygen green line and the OH (8−3) Meinel band are presented.

Journal ArticleDOI
TL;DR: In this paper, a study of the A horizons of cultivated soils from Saskatchewan, Canada showed that the organic carbon contents were in the sequence semi-arid Dark Brown soils (1.7 per cent), < Black soils (2.8 per percent), < sub-humid Dark Gray soils (4.5 per cent).
Abstract: Summary A study of the A horizons of cultivated soils from Saskatchewan, Canada showed that the organic carbon contents were in the sequence semi-arid Dark Brown soils (1.7 per cent), < Black soils (2.55–2.8 per cent), < sub-humid Dark Gray soils (4.5 per cent). The relative proportions of humic acids and the ratios of humic acid: fulvic acid increased in a similar sequence. There were accompanying increases in extinction values at 280 nm, and in levels of nonhydrolyzable nitrogen suggesting more extensive polycondensation of humic materials. These observations are discussed in terms of a working hypothesis for humus formation and transformations, that gives particular emphasis to the soil environment and to interactions between organic and inorganic components.

Journal ArticleDOI
TL;DR: Detailed clinical records were kept on a series of 55 agoraphobic patients who presented to a general hospital psychiatric practice over a 3 year period and a review of the records revealed that 91% of these patients were diagnosed as suffering from a unipolar or bipolar primary affective disorder.
Abstract: Detailed clinical records were kept on a series of 55 agoraphobic patients who presented to a general hospital psychiatric practice over a 3 year period. A review of the records revealed that 91% of these patients were diagnosed as suffering from a unipolar or bipolar primary affective disorder. The anxiety and phobic symptoms tended to mask the presence of the affective disorder. This observation is consistent with most of the published data on the agoraphobic syndrome. It could also explain the inconsistent effects of treatment of agoraphobia compared with simple phobias. The possible biological and psychological connections between primary affective disorders and the agoraphobic syndrome are discussed.

Journal ArticleDOI
TL;DR: Results were interpreted as providing no support for the widely belief that the aged are more depressed than any other age group, and it was argued that somatic complaints can be valid indicators of depression in the elderly.
Abstract: Beck Depression Inventory scores were obtained from 48 elderly who had been residing in homes for the aged for more than one year, 31 elderly residing in the community and waiting to enter an old-age home, and 424 young adults enrolled in a fist-year psychology course. The residents of old-age homes reported no more symptoms of depression than the waiting-list controls, a finding that provides no support for the hypothesis that the institional nature of old-age homes increases depression in the elderly. Both the institutionalized and noninstitutionalized aged reported more somatic symptoms of depression than the young adults, but no greater cognitive or affective symptoms of depression. These results were interpreted as providing no support for the widely belief that the aged are more depressed than any other age group. Finally, it was argued that somatic complaints can be valid indicators of depression in the elderly if normative differences between young and old are taken into account.

Journal ArticleDOI
TL;DR: In vivo experimentation indicated that the convulsant agents hydrazine, isonicotinic acid hydrazide and aminooxyacetic acid brought about similar decreases in the GABA content of the synaptosomal‐enriched fractions prepared from tissue at the onset of seizures despite the fact that no correlation was observed between seizure activity and whole brain GABA levels.
Abstract: —The stability of the GABA content of synaptosomal-enriched fractions was evaluated by two approaches. Firstly, the addition of 10−3m-aminooxyacetic acid to the homogenizing medium totally inhibited the GABA-degrading enzyme in the fractions but did not affect the GABA levels. This indicated that GABA was not being metabolized during the normal preparation of the synaptosomal-enriched fraction. Secondly, when synaptosomal-enriched fractions were re-fractionated by discontinuous density gradient centrifugation, the GABA contents of the fractions before and after the second fractionation were very similar provided they were expressed on a per mg protein basis. It was therefore concluded that the GABA content of the organelles was not subject to change during the fractionation procedures. On the basis of these findings and others it was suggested that the synaptosomal-enriched fraction could be used as a model to evaluate drug-induced changes in GABA levels in nerve endings. In vivo experimentation indicated that the convulsant agents hydrazine, isonicotinic acid hydrazide and aminooxyacetic acid brought about similar decreases in the GABA content of the synaptosomal-enriched fractions prepared from tissue at the onset of seizures despite the fact that no correlation was observed between seizure activity and whole brain GABA levels.

Journal ArticleDOI
TL;DR: In a series of three expeditions to a part of the Peace River valley of eastern British Columbia shortly to be submerged by a reservoir, a rich assemblage of dinosaur footprint tracks has been recovered as mentioned in this paper.

Journal ArticleDOI
TL;DR: Results indicate that substance P facilitates nociceptive pathways by potentiating the subliminal fringe and, in greater amounts, by depolarizing the cells.

Journal ArticleDOI
TL;DR: In this paper, the residual strength is defined as the surface roughness developed along the rock discontinuity during the failure process, and the term ultimate frictional resistance is used to describe the strength of the resulting roughness.

Journal ArticleDOI
TL;DR: A survey of the known results about root systems can be found in this article, where the authors define hyperbolic root systems as the points of intersection of a lattice and a cone.


Journal ArticleDOI
TL;DR: Heparin at a dose of 50–100 units/kg intravenously will suppress increased vascular permeability induced by logarithmic doses of histamine, bradykinin, and prostaglandin E1, and these findings support the hypothesis that heparin affects the micro-circulation.

Journal ArticleDOI
TL;DR: In this paper, the authors collected price information for major Ottawa supermarkets over a twenty-eight-week period and published in daily newspapers during a five-week test period in response to the information, the dispersion of prices across stores and chains narrowed, the average level of prices of the market dropped and consumer satisfaction increased relative to the control market.
Abstract: Comparative price information for major Ottawa supermarkets was collected over a twenty-eight-week period and published in daily newspapers during a five-week test period In response to the information, the dispersion of prices across stores and chains narrowed, the average level of prices of the market dropped, and consumer satisfaction increased relative to the control market Consumers transferred patronage to the lower priced stores Consumers indicated a willingness to pay 34¢ per week on average for the price comparison information Estimated consumer benefits far exceeded the cost of the program

Journal ArticleDOI
TL;DR: In this article, two classes of boundary approximations are studied for viscous flow in a square cavity and compared with the results obtained by different methods of approximating the boundary values of the vorticity.

Journal ArticleDOI
TL;DR: Although the pantothenate-requiring cell line appears to be largely tetraploid ( 4n = 48 ), date are presented to show that it could have arisen from single, haploid cells.

Journal ArticleDOI
TL;DR: The results of these studies indicate that morphine- and met-enkephalin-induced analgesia is, at least, partly due to the ability of the agents to potentiate “presynaptic inhibition” of nociceptive pathways in the spinal cord.

Journal ArticleDOI
TL;DR: A new method is presented to calculate the synchronizing and damping components of electrical torque developed in a synchronous machine with arbitrary complexity of machine and control configuration using a least squares error criterion.
Abstract: A new method is presented to calculate the synchronizing and damping components of electrical torque developed in a synchronous machine with arbitrary complexity of machine and control configuration. The individual contributions of field, damper, and reluctance components are determined explicitly. The method is based on numerical analysis of system time responses using a least squares error criterion. The method is equally applicable to responses obtained from on-line measurements or system simulation.

Journal ArticleDOI
TL;DR: It has been suggested that some of the trace amines, p-tyramine (p-TA), poctopamine ( p-OA), fl-phenylethylamine (PE) and phenylethanolamine (PEO) may act as coor false neurotransmitters, neuromodulators or transmitters in their own right in the mammalian central nervous system.

Journal ArticleDOI
TL;DR: Autoradiographic analysis and electron micrographs clearly illustrated a tight association of virulent A. tumefaciens strain B6 cells to the Datura cell wall, and that often binding of bacteria was localized.
Abstract: In vitro binding experiments were carried out using 32P-labeled cells of the virulent Agrobacterium tumefaciens strain B6 and Datura innoxia cells from suspension culture. Binding kinetics showed that adherence of bacteria to Datura cells increased gradually during the first 60 minutes and attained a maximum level within 120 minutes of incubation. Maximum binding occurred at pH 6.0. The presence of Ca2+ and Mg2+ reduced binding slightly and EDTA had little effect at concentrations of 0.1 to 10 millimolar. The binding of bacteria to Datura cells was temperature-dependent. Escherichia coli, Salmonella typhimurium, Rhizobium japonicum, and Micrococcus lysodeikticus did not compete with virulent A. tumefaciens strain B6 for binding to Datura cells. The admixture of avirulent A. tumefaciens strain IIBNV6 enhanced adherence of virulent A. tumefaciens strain B6 to Datura cells. Octopine had no effect on the binding of virulent A. tumefaciens strain B6 to Datura cells, but 10 millimolar canavanine was inhibitory. Arginine enhanced the adherence of the bacteria at concentrations higher than 0.1 millimolar. Incubation with DNase, RNase, and lipase did not affect the binding, but protease stimulated the adherence of bacteria to Datura cells. Concanavaline A and soybean lectin had little effect whereas lecithin and lysolecithin enhanced binding slightly. Poly-l-lysine markedly stimulated the bacteria-plant cell adherence. Cells from suspension cultures of pea, vetch, and soybean had a 2- to 3-fold higher binding capacity than Datura cells, whereas cells from wheat, corn, rice, and sorghum had a considerably lower affinity for binding with virulent A. tumefaciens strain B6. Bacterial adherence to plant cells was confirmed by autoradiography and electron microscopy. Autoradiographic analysis showed that bacteria were associated with the cell wall, and that often binding of bacteria was localized. Electron micrographs clearly illustrated a tight association of virulent A. tumefaciens strain B6 cells to the Datura cell wall.

Journal ArticleDOI
TL;DR: Oxygen uptake was measured in primary cultures of astrocytes from the brain hemispheres of newborn DBA mice by the aid of an oxygen electrode inserted directly into the culture flastk, i.e. using the flasks, completely filled with MEM medium, as the respirometer chamber.
Abstract: Oxygen uptake was measured in primary cultures of astrocytes from the brain hemispheres of newborn DBA mice by the aid of an oxygen electrode inserted directly into the culture flastk, i.e. using the flasks, completely filled with MEM medium, as the respirometer chamber. The respiration was inibitally intense (300 μmol per hr per 100 mg protein) but delined somewhat during the 6 hr of measurement, probably due to a depletion of intermediary metabolites released to the large surplus of medium. The respiratory rates were approximately identical in the presence of a CO2/ bicarbonate and a HEPES buffer. Exposure to a high concentration of potassium led to a transient stimulation of the oxygen uptake of almost 100%, a response that was very easily observed using the present method. Since no mechanical damage was inflicted upon the cells, culturing could be continued, if so desired, after the measurement.