Showing papers by "University of Saskatchewan published in 1978"
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TL;DR: By measuring dopamine receptors in the putamen and caudate of postmortem brains from Parkinson patients, evidence is reported in support of the theory of dopaminergic supersensitivity in Parkinson's disease.
Abstract: IN patients with Parkinson's disease, the concentration of dopamine in the basal ganglia of the brain is markedly reduced in accordance with the degeneration of the nigrostriatal dopamine-containing neurones1,2. This fact provided the basis for the successful clinical introduction of L-dopa (L-3,4-dihydroxyphenylalaline) for Parkinson's disease3,6. It has been suggested that one of the critical factors compensating for the loss of dopamine neurones may be the development of “denervation supersensitivity” in the striatum, as severe cases react more sensitively to L-dopa than milder cases or controls7–9. By measuring dopamine receptors in the putamen and caudate of postmortem brains from Parkinson patients, we report here evidence in support of the theory of dopaminergic supersensitivity in Parkinson's disease.
466 citations
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TL;DR: The results show that no one measurement of microbial biomass or activity is sufficient to interpret microbial growth in the soil system and ATP was therefore not a specific indicator of biomass in the detailed studies where P concentrations and sequential growth of bacteria and fungi were major factors.
Abstract: Changes in CO2 evolution, phosphatase and urease activity and ATP contents were related to bacterial and fungal biomass determined microscopically during glucose mineralization at different concentrations of mineral nutrients. Similar results were obtained in a sandy loam and a clay soil except that in the clay the increase in microbial and enzyme activities were delayed. Higher initial rates of CO2 evolution were noted after the addition of P to a glucose and N amended soil at C:P ratios greater than 30:1. Increases in phosphatase activity coincided with increases in bacterial and fungal populations only in treatments without inorganic P. Peak rates of CO2 evolution preceded biomass production by 18–24 h, therefore, CO2 evolution rates did not show a correlation on normal regression analysis with biomass. Soil ATP content was influenced by P concentrations and soil type. ATP was therefore not a specific indicator of biomass in the detailed studies where P concentrations and sequential growth of bacteria and fungi were major factors. Soil urease increased with bacterial and fungal populations. It did not respond to P other than through microbial biomass and was highly correlated with microbial biomass. The results show that no one measurement of microbial biomass or activity is sufficient to interpret microbial growth in the soil system. Each of the criteria measured were sensitive to specific conditions affecting biomass and activity.
248 citations
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TL;DR: Evidence of an association between an increased intake of nutrients, especially total fat, in both pre- menopausal and post-menopausal women with breast cancer and its consistency with other evidence, both experimental and international, suggests that it is causal.
Abstract: A case-control study has been conducted in four areas in Canada in which 400 cases of breast cancer matched by age and marital status with neighborhood controls were administered a medical and dietary history questionnaire, a 24-hour recall for dietary information and a four-day diet record. The Study has produced evidence of an association between an increased intake of nutrients, especially total fat, in both pre-menopausal and post-menopausal women with breast cancer. Reasons why a weak association might have been anticipated are discussed, and it is concluded that in reality the association is stronger. Furthermore, its consistency with other evidence, both experimental and international, suggests that it is causal.
233 citations
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TL;DR: The release of glutamate was much smaller than the uptake, and only little affected by an increase of the external glutamate concentration, suggesting a net accumulation of glutamate rather than a homoexchange, and may play a major role in brain metabolism and may keep the extracellular glutamate cohcentration below excitatory levels.
Abstract: Kinetics for uptake and release of glutamate were measured in normal, i.e., nontransformed, astrocytes in cultures obtained from the dissociated, cortexenriched superficial parts of the brain hemispheres of newborn DBA mice. The uptake kinetics indicated a minor, unsaturable component together with an intense uptake following Michaelis-Menten kinetics. TheK
m
(50 μM) was reasonably comparable to the corresponding values in brain slices and in other glial preparations. TheV
max (58.8 nmol min−1 mg−1 protein) was, however, much higher than that observed in glial cell lines or peripheral satellite cells, and also considerably higher than that generally reported for brain slices. The release of glutamate was much smaller than the uptake, and only little affected by an increase of the external glutamate concentration, suggesting a net accumulation of glutamate rather than a homoexchange. Such an intense accumulation of glutamate into normal astrocytes may play a major role in brain metabolism and may help keep the extracellular glutamate cohcentration below excitatory levels.
204 citations
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TL;DR: A case-control study in four areas of Canada is suggestive of an increased risk of breast cancer in post-menopausal women with younger age at menarche and an increase risk with delay of age at natural menopause, and a weak association with increased height and weight as risk factors for breast cancer.
Abstract: A case-control study has been conducted in four areas of Canada in which 400 cases of breast cancer matched by age and marital status with neighborhood controls were administered medical and dietary questionnaires. The study is suggestive of an increased risk of breast cancer in post-menopausal women with younger age at menarche and an increased risk with delay of age at natural menopause. No protective effect of early age at first pregnancy was demonstrated in either pre- or post-menopausal women. An increased frequency of pregnancies of four months duration or less was found in cases compared to controls and a greater frequency in pre-menopausal cases compared to controls of a history of irregular menstrual periods. In pre-menopausal women no association has been found between increased height and weight as risk factors for breast cancer. For post-menopausal women, however, a weak association with increased height has been found, while a strong association with increased weight both at the time of menopause and the 12 months preceding diagnosis has ben confirmed.
201 citations
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TL;DR: Three methods of estimating group and individual dietary consumption have been developed and assessed in a case-control study of diet and breast cancer and it is concluded that the diet history is preferred when current food intake may be influenced by a disease.
Abstract: Three methods of estimating group and individual dietary consumption have been developed and assessed in a case-control study of diet and breast cancer. The methods comprised a 24-hour recall, a detailed quantitative diet history directed to the most recent two-month period and the two-month period six months before, and a four-day diet diary. There is a high degree of correlation between the estimates of food consumption for the controls using each of the methods. The highest estimate was obtained from the diet history, with a slightly higher estimate in the period six months before than the current period, while the lowest is found in the 24-hour recall. The latter corresponds with the same method in a Nutrition Canada Survey. It is concluded that all methods ara applicable to case-control studies, but the diet history is preferred when current food intake may be influenced by a disease.
181 citations
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TL;DR: This article explored the effects of employee ownership, concentrating on possible relationships between ownership and such variables as organizational identification, employee job attitudes, and organizational performance, and identifying variables which may moderate these relationships.
Abstract: Noting a paucity of research on the subject, this article attempts to explore the effects of employee ownership, concentrating on possible relationships between ownership and such variables as organizational identification, employee job attitudes, and organizational performance, and on identifying variables which may moderate these relationships. After development of a conceptual framework, empirical data obtained from study of a trucking company recently purchased by most of its employees are presented and discussed. These data support the plausibility of many of the hypothesized relationships, but do not permit strong causal inferences. Although the author tentatively concludes that employee ownership appears to have improved employee attitudes and organizational performance in this case, he stresses that much further research, in a variety of settings, specifically designed to permit causal testing of the propositions suggested here, is badly needed before firm conclusions can be drawn.
181 citations
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TL;DR: Heparin was administered intravenously and by intratracheal instillation to rats, and the drug was identified by light and electron microscopy in the endothelial tissue of rat aorta and of mouse pulmonary vessels, suggesting a heparin metabolizing activity in the artery wall and/or vessel wall.
134 citations
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TL;DR: The purpose of the present study has been directly to measure uptake linflux) of potassium, at different external concentrations, into a population of isolated glial cells which functionally and metabolically are as normal as possible.
122 citations
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Abstract: Studies on the effects of employee share ownership or employee participation in decisions (or control) have tended to focus on one or the other of the two variables or have assumed that they covary. Using data from an employee-owned company, this study attempts to empirically separate and assess the relative effects of each of these on a set of dependent variables (job attitudes) which they are both thought to affect. Results indicated that employee share ownership and participation each had significant and independent effects on some job attitudes. However, little evidence of interaction effects between the two variables, which had been predicted, was found. Implications and limitations of the findings are discussed, and possible directions for future research are suggested.
117 citations
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TL;DR: The salinity of Saskatchewan saline lakes varies up to 342% 0.0 as discussed by the authors, and the lakes are dominated by sodium, magnesium and sulphate, while calcium and potassium are proportionally much smaller.
Abstract: The salinity of Saskatchewan saline lakes varies up to 342%0. Highly saline lakes are widely distributed. Some reach saturation at high summer temperatures but salt precipitation occurs on cooling. Saline lakes tend to increase in salinity with time but the greatest changes occur in the shallow more saline lakes.
The lakes are dominated by sodium, magnesium and sulphate. The cation sequences are dominated by sodium or magnesium while calcium and potassium are proportionally much smaller. Chloride or bicarbonate-carbonate are secondary to sulphate among the anions. Ion sequences tend to be characteristic of certain physiographic regions. Lake types were magnesium (sodium) sulphate, sodium sulphate and sodium (magnesium) sulphate in order of abundance of lakes.
Phosphorus and ammonia were high in concentration but nitrate and silica were scarce. The lakes were all alkaline between pH 7.8 and 9.8.
The evolution of closed saline lakes is briefly discussed.
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TL;DR: In another study as mentioned in this paper, mothers of school-aged male stutterers were found to perceive their children as being more insecure, sensitive, anxious, withdrawn, fearful, and introverted than did mothers of nonstutterers.
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TL;DR: Moreels et al. as mentioned in this paper derived the intensity distribution of the OH Meinel bands in the airglow from the minor constituent profiles of Moreels et. al. (1977).
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TL;DR: The results, in conjunction with others describing the potent pharmacological action of the nucleotide, seem to suggest that ATP could be a mediator in a “purinergic" system in the CNS.
Abstract: The steady-state level of brain ATP was measured after the tissue had been treated with a focused microwave irradiation system. The brain ATP content (1.50 nmol/mg tissue) obtained by microwave fixation is similar to that observed by others using fast-freezing and microwave fixation techniques. The concentrations of ATP in different brain regions show a rather uniform distribution, ranging from 1.918±0.059 (brainstem) to 2.393±0.19 (caudate) nmol/mg tissue; however, insufficient microwave fixation time seems to produce a greater regional variation of ATP. Release of ATP was investigated by placing a cup on the sensory-motor cortex. The rate for basal release of ATP is 1.43±0.14 femtomole/min/mm2. A 30-fold increase in ATP release was obtained by direct stimulation of the cortex with 5 mA pulses of 0.2 msec duration at a rate of 20/sec over a period of 10 min. These results, in conjunction with others describing the potent pharmacological action of the nucleotide, seem to suggest that ATP could be a mediator in a “purinergic” system in the CNS.
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TL;DR: In this article, an extension of a well known technique for generating capacity evaluation which includes limited energy systems is illustrated by a simple numerical system example, where the authors show that the era of abundant energy is disappearing and that limitations must be included in conventional studies.
Abstract: Most generating capacity reliability studies assume that there are no inherent energy imitations and therefore concentrate on considering the effect of unit forced outages and uncertain load requirements. It appears, however, that the era of abundant energy is disappearing and that limitations must be included in conventional studies. This paper illustrates an extension of a well known technique for generating capacity evaluation which includes limited energy systems. The approach is illustrated by a simple numerical system example.
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TL;DR: The high tissue/medium ratio and the lack of a GABA-induced enhancement of the release of radioactivity indicate that the previously observed high-affinity uptake of GABA in cultured astrocytes represents a net uptake and not a homoexchange with endogenous GABA.
Abstract: Content of GABA was measured in cultured, normal astrocytes (from the brain cortex of newborn mice) together with the effect of nonradioactive GABA on the efflux of labeled GABA from cells previously loaded with [14C]GABA. An increase of external GABA concentration from 0 to 25 μM evoked a rise of the GABA content in the cells to a level which was approximately 50 times that of the incubation medium. Neither 200 nor 2000 μM nonradioactive GABA had any effect on the rate of release of radioactivity from cells loaded with [14C]GABA. Both the high tissue/medium ratio and the lack of a GABA-induced enhancement of the release of radioactivity indicate that the previously observed high-affinity uptake of GABA in cultured astrocytes represents a net uptake and not a homoexchange with endogenous GABA. This uptake is sodium dependent but was found to be unaffected in potassium-free media; the quantitative correlation between GABA transport and sodium transport differed from that reported for synaptosomes.
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TL;DR: It is concluded that the stimulation of cerebral (Na + K + ) ATPase by biogenic amines could be a receptor-mediated process and it is possible that both α- and β-receptors activate a common mechanism.
Abstract: 1. 1. Adrenergic agonists (adrenaline, noradrenaline, isoproterenol and phenylephrine) stimulate the activity of (Na + K + ) ATPase (EC 3.6.1.3) in rat cerebral cortical synaptosomal fractions. 2. 2. The potencies of the agonists on the stimulation of the enzyme arranged in descending order are adrenaline ⩾ noradrenaline > isoproterenol > phenylephrine. 3. 3. The response to noradrenaline can be antagonized by both α- and β-adrenergic blockers. 4. 4. We conclude that the stimulation of cerebral (Na + K + ) ATPase by biogenic amines could be a receptor-mediated process. 5. 5. The results also indicate that it is possible that both α- and β-receptors activate a common mechanism.
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TL;DR: In this paper, the authors evaluated the distribution of the return between consumers and producers and found that consumers captured 53 percent and producers 47 percent of the total net benefits, while the public and private investment in research and development are an important source of economic growth.
Abstract: Public and private investment in Research and Development are an important source of economic growth. This article documents the high rate of return to society from investment in agricultural research. The analysis took the form of estimating the gains in producer and consumer surplus from research that improved rapeseed yield in western Canada and related these gains to research expenditures by calculating an internal rate of return. The distribution of the return between consumers and producers were estimated. The internal rate of return was found to be 101 percent and indicates an underinvestment in this type of research. Of the total net benefits, consumers captured 53 percent and producers 47 percent.
L'argent public et prive investi dans la recherche et le developpement est une source importante de croissance economique. Le present article fournit une documentation sur le taux elve des profits que rapportent a la societe les investissements dans la recherche en agriculture. Notre analyse a pris la forme d'une estimation des gains en surplus realises par le producteur et le consommateur, a la suite de recherches ameliorant le rendement de la semence du colza dans l'ouest canadien, puis nous avons etabli un rapport entre ces gains et les depenses pour la recherche en calculant un taux de profits internes. Nous avons evalue la repartition des profits entre consommateurs et producteurs. Le taux des profits internes s'est avereetre de 101 pour cent, et cela signifie un sous-investissement dans ce type de recherche. Les consommateurs ont realise 53 pour cent du total des beneficies nets, alors que les producteurs en ont recupere 47 pour cent. 1928 ems
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TL;DR: Kinetics for uptake of adenosine, a putative inhibitory transmitter, were measured in normal, i.e. non‐transformed, astrocytes in cultures obtained from the dissociated, cortex‐enriched superficial parts of the brain hemispheres of newborn DBA mice suggesting that a considerable part of theAdenosine uptake in brain slices occurs into glial cells.
Abstract: — Kinetics for uptake of adenosine, a putative inhibitory transmitter, were measured in normal, i.e. non-transformed, astrocytes in cultures obtained from the dissociated, cortex-enriched superficial parts of the brain hemispheres of newborn DBA mice. The uptake kinetics indicated a minor, unsaturable component together with a rather intense (Vmax 0.36nmol/min per mg protein) high affinity (Km 3.4 μm) uptake following Michaelis-Menten kinetics and inhibited by 100 μm-papaverine. The Vmax was about two times higher than that reported in the literature for brain slices suggesting that a considerable part of the adenosine uptake in brain slices occurs into glial cells. Such an accumulation of adenosine into normal astrocytes may play a major role in nucleoside and nucleotide metabolism in the brain and help in regulating the extracellular adenosine concentration.
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TL;DR: The geology and physiography, climate, soils and vegetation of the saline lakes region of southern Saskatchewan are briefly reviewed in this article, where the location and morphometry of 60 saline lakes are determined.
Abstract: The geology and physiography, climate, soils and vegetation of the saline lakes region of southern Saskatchewan are briefly reviewed. The location and morphometry of 60 saline lakes was determined. Some of them are large (307 km2) but mean depths do not exceed 10 m and many are very shallow. Light penetration varied considerably from very turbid shallow lakes to Redberry Lake where the 1% light level was below 16.5 m. Light extinction coefficients for the entire water column of deeper lakes (7) varied from 0.256 to 2.558.
Shallow lakes failed to stratify thermally but a dozen deeper lakes stratified for at least several months. Higher salinity tends to prolong stratification. Thermal stratification augmented chemical stratification in two meromictic lakes. Maximum temperature up to 30 °C in very saline shallow waters was recorded while temperatures as low as-3 °C occurred under the ice. Freezing was delayed and thawing accelerated in more saline lakes. Annual heat budgets varied from 3350 to 13,900 g cal cm-2 in seven lakes.
Oxygen concentration was reduced below thermoclines and was virtually absent below the ice in very shallow lakes and, at times, in a very productive lake.
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TL;DR: The microsomal fraction, amongst the subcellular fractions, showed the highest enrichment or receptors in the myocardium of commonly used laboratory animals.
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TL;DR: In this paper, primary production by phytoplankton, efficiency of photosynthesis, and chlorophyll-a concentrations were determined for seven saline lakes that varied widely in ionic concentration and composition.
Abstract: Primary production by phytoplankton, efficiency of photosynthesis, and chlorophyll-a concentrations were determined for seven saline lakes that varied widely in ionic concentration and composition. The investigations were done during the summer months of 1972 and 1973. Productivity ranged from 0.001 to 11.135 g C m−3 day−1 and 0.053 to 7.968 g C m−2 day−1. Highest productivities were measured in two lakes that supported blooms of Aphanizomenon flos-aquae and Nodularia spumigena, respectively. Species of Cyanophyceae, Bacillariophyceae and Chlorophyceae dominated the phytoplankton of the study lakes. Active chlorophyll-a ranged from 0.01 to 116 mg m−3. Integral photosynthetic efficiency estimates were <1% except during phytoplankton blooms when they were considerably higher. The overall range of 0.03 to 3.8% is concordant with estimates for other lacustrine ecosystems. The extinction of light caused by photo-synthetic processes, or in situ efficiency, was <1% in the trophogenic zone for most lakes but, it was considerably higher during blooms. In situ efficiencies invariably increased with depth in ail lakes.
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TL;DR: Investigations were undertaken to examine whether acetylcholine and substance P are involved in mediating the effects of HIP on IPN neurones and to stimulate in the habenula 0.1.
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TL;DR: In this article, the excitation mechanism for O 2 (1 Δ) in the night-time is through the reaction between OH∗ and atomic oxygen and the recombination of atomic oxygen.
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TL;DR: The results indicate that disrupting the balance between the monoamine neuro-transmitter systems with the neurotoxins alters the free choiceanol consumption of rats but that prior chronic exposure to ethanol also changes free choice ethanol consumption in the absence of any permanent change in monoamine levels.
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01 Jul 1978TL;DR: In this paper, the authors test empirically the hypothesis that managers of small firms are less export-oriented than those of larger firms by using data gathered by the Australian National Audit Office.
Abstract: The purpose of this article is to test empirically the hypothesis that managers of small firms are less export-oriented than those of larger firms. Testing was done by using data gathered by the au...
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TL;DR: Results indicate that morphine and met-enkephalin hyperpolarize Adelta sural afferent terminals and facilitate the terminal depolarization during presynaptic inhibition, which may be, at least partly, responsible for the analgesic action of these agents.
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TL;DR: The presence of haploid sets of diplochromosomes in the early divisions of protoplasts suggests that endomitosis may be one cause for the observed ploidy increase.
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TL;DR: The first intimation of the existence of terrestrial vertebrates in the Carboniferous was the discovery by W. E. Logan in 1841 of fossil footprints at Horton Bluff, Nova Scotia as mentioned in this paper.