Showing papers by "University of Manitoba published in 1976"
TL;DR: It is suggested that the mechanism of muscle-cell necrosis in various muscle diseases is explained by an increased net influx of calcium into cells which triggers a "vicious cycle" of mitochondrial calcium overloading and energy depletion.
474 citations
TL;DR: Testosterone, estradiol, 170H-progesterone, and androstenedione concentrations were determined in cord sera and in peripheral sera from infants and it is suggested that there is also ovarian secretion of sex steroids in some female infants in response to the elevated FSH and LH levels which are seen at this time.
Abstract: Testosterone, estradiol, 17OH-progesterone, and androstenedione (except in cord samples) concentrations were determined in cord sera (30 male and 14 female) and in peripheral sera from infants (121 male and 110 female), age 1 day to 2 years. Male and female cord serum levels of these steroids were not significantly different. In both sexes levels during the first week were lower than those in cord sera. In male infants serum testosterone and 17OH-progesterone levels rose sharply in die second week of life, reached a peak at 1–2 months, and then declined to the range seen in later childhood by 6 months of age; male serum androstenedione and estradiol concentrations were higher during the first 2 months of life, but no distinct pattern of rise and fall was seen. In girls serum testosterone levels fell in the first week to the range seen throughout childhood; serum concentrations of estradiol, androstenedione, and 17OH-progesterone in girls were markedly variable, with many values above the childhoo...
338 citations
TL;DR: The results of the present study when combined with five other comparable studies, thus comprising a total of 46,150 newborn infants, indicates that the frequency of major chromosome abnormalities is between 1:150 and 1:200 live-born babies.
Abstract: Data from a chromosome examination of 14,069 consecutive newborn infants is presented. Successful karyotypes were obtained on 13,939 babies using short-term blood cultures and conventional staining methods. Of those, 13,645 babies had normal chromosomes; 64 (0.46%) had a major chromosome abnormality; and 230 (1.65%) had a marker chromosome; giving a total of 294 (2.11%) babies with a major chromosome abnormality or distinctive marker chromosomes. Six male babies with sex chromosome abnormalities had a 47,XXY and four a 47,XYY karyotype, and three were mixoploids. Five female babies had a 47,XXX karytotype and two were mixoploids. There were three babies with ambiguous external genitalia, all with normal karyotypes. Fourteen babies had 21-trisomy; there were three 18-trisomics and one 13-trisomic. The mother of one 18-trisomy baby had a balanced (18;21) translocation. Twenty-four infants had a balanced chromosome rearrangement. Eleven of these were reciprocal and thirteen were Robertsonian translocations. One baby had an unbalanced derivative chromosome resulting from an 18;11 insertion. Two infants with additional unidentified fragments were detected. Two hundred and thirty babies (1:60) carying distinctive chromosome variants were detected. The commonest variant was the Yq+ among males (0.89%). Other common variants involved the short arms of the D and G groups (0.32% and 0.57%, respectively) 16q+ (0.09%), and 1q+ (0.04%). The results of the present study when combined with five other comparable studies, thus comprising a total of 46,150 newborn infants, indicates that the frequency of major chromosome abnormalities is between 1:150 and 1:200 live-born babies. This represents a small proportion of all conceptuses with chromosome abnormalities, which has been estimated as being approximately 1:20. It is thus clear that chromosome abnormalities form a major part of the genetic load carried by the human population. The development of chromosome banding techniques already has increased, and with further increase, the complexities of human cytogenetics and may reveal many additional rearrangements undetectable by conventional methods.
233 citations
TL;DR: Fetal sera (9-20 weeks fetal age, n = 80) and pituitary glands were assayed for FSH, LH (βLH assay) and CG (βCG assay).
Abstract: Fetal sera (9-20 weeks fetal age, n = 80) and pituitary glands (9.5-20 weeks, n = 36) obtained from hysterotomy specimens, and amniotic fluids (amniocentesis; 8-40 weeks, n = 123) were assayed for FSH, LH (βLH assay) and CG (βCG assay). Results are expressed as mass of pure hormone. Prior to 12 weeks fetal age, pituitary, serum and amniotic fluid concentrations of LH and FSH were low or unmeasurable. In contrast, levels of CG in serum and in amniotic fluid were clearly measurable prior to 12 weeks. There was a definite CG peak at 11-14 weeks with levels up to 550 ng/ml in serum and 7400 ng/ml in amniotic fluid. Although LH levels began to rise at 12 weeks, when CG levels started to decline, serum levels of LH from 14-20 weeks in males (2-13 ng/ml) were still lower than the majority of CG levels at this time (6-115 ng/ml). These observations suggest that CG is the primary stimulus to the fetal Leydig cell which results in testosterone secretion (peak 11-17 weeks) and masculine differentiation of the genital tract. Significantly lower concentrations of both FSH and LH were observed in pituitary, serum and amniotic fluid between 12-20 weeks fetal age in males compared to females. This may be a result of feedback inhibition by the higher concentrations of testosterone in males at this time. Amniotic fluid FSH and LH concentrations correlated with their respective serum and pituitary values (P less than 0.01) indicating that amniotic fluid may provide a convenient index of fetal serum concentrations.
221 citations
TL;DR: Gel filtration studies of serum samples revealed that PL and GHLA in the hamster, mouse and rat had different elution volumes, whereas, in the remaining species, the two activities co-eluted.
Abstract: Factors with growth hormone and lactogenic activities have been identified in serum samples and placental extracts of 9 species using a radioreceptor assay for prolactin or lactogens (RRA-PRL) and one for growth hormone-like activity (RRA-GH). The concentrations of placental kctogen (PL) and growth hormone-like activity (GHLA) in pregnancy were different in each species. The levels of PL began to rise at or before midpregnancy and either remained elevated until term (hamster, goat, sheep, monkey, and human), declined gradually after reaching peak concentrations just beyond mid-pregnancy (guinea pig), or had 2 peaks of activity (mouse, rat). The peak concentrations in different species ranged from 350 ng/ml in the cow to 45,000 ng/ml in monkey serum samples. The concentrations of GHLA were similar to PL levels in the guinea pig, goat, cow, and monkey but were lower than PL levels in the sheep and human. The maximal concentrations of PL and GHLA in placental extracts varied from 1 μg/g in guinea pigs to 200...
158 citations
TL;DR: In this paper, it was shown that during summer stratification, methane oxidizers become oxygen-sensitive and oxidation occurs rapidly throughout the water column, and this oxygen insensitivity likely occurs as a result of high in situ concentrations of dissolved inorganic nitrogen.
Abstract: During summer stratification methane-oxidizing bacteria in Lake 227 are confined to a narrow zone within the thcrmoclinc because of their sensitivity to high epilimnctic oxygen concentrations. This oxygen sensitivity is based on the dependence of the oxi- dizers on an oxygen-sensitive nitrogen fixation process. Thus epilimnetic methane oxi- dation is absent during periods of nitrogen limitation, since high epilimnetic oxygen concentrations prevent nitrogen fixation. During periods of overturn and throughout the winter, the methane oxidizers become oxygen insensitive and oxidation occurs rapidly throughout the water column. This oxygen insensitivity likely occurs as a result of high in situ concentrations of dissolved inorganic nitrogen, which replaces nitrogen fixation as a source for fixed nitrogen, Under ice-cover, rapid mcthanc oxidation throughout the water column can be a major cause of total anoxia.
136 citations
TL;DR: Bovine brain cyclic nucleotide phosphodiesterase was found to require higher concentrations of the Ca 2+ -regulated protein modulator for activation than the heart enzyme due to the presence of an inhibitory factor in brain preparations.
135 citations
TL;DR: The hypothalamic hormones, somatostatin (SRIF or GH-RIH) and thyrotropin releasing hormone (TRH) applied intraventricularly into rat brain had a considerable effect on motor function and resulted in profound alterations in the sleep-waking pattern.
Abstract: The hypothalamic hormones, somatostatin (SRIF or GH-RIH) and thyrotropin releasing hormone (TRH) applied intraventricularly into rat brain had a considerable effect on motor function and resulted in profound alterations in the sleep-waking pattern. While TRH induced primarily an increase in exploratory and motor stereotyped behavior, the effect of somatostatin was strinking and prolonged: stereotyped circular running in many instances evolved into catatonia, paraplegia-in extension and/or tonic-clonic seizures.
135 citations
TL;DR: Of several species of growth hormone tested, only primate GH displaced 125I-hGH from its binding sites in human liver, and no displacement was seen with ovine or human prolactin or with insulin.
Abstract: Specific binding of 125I-hGH to human liver was found in autopsy specimens from 12 of 15 patients. Specific binding was studied using a new technique employing 20 μ thick ‘microslices’ cut on a cryostat. About 0.5 to 1 mg of tissue per assay tube makes feasible the study of small samples. The range of specific binding was 1.4 to 11.7% of 80,000 cpm 125I-hGH added expressed per mg dry weight of tissue. Specific binding was also demonstrable in homogenates and crude membrane preparations from liver. No correlation was seen between 125I-hGH binding and age, sex, or pathology in the series of patients studied. No specific binding of 125I-hGH was observed in lung, adrenal, spleen, or kidney, although all the tissues bound 125I-insulin. Of several species of growth hormone tested, only primate GH displaced 125I-hGH from its binding sites in human liver. No displacement was seen with ovine or human prolactin or with insulin. Primate placental lactogens had only 0.5–1.0% potency of native hGH in displacing 125I-h...
128 citations
TL;DR: Findings provide direct evidence for an obligatory functional role of a membrane receptor in mediating the action of a polypeptide hormone.
Abstract: A guinea pig antiserum to prolactin receptors selectively inhibited the binding of [125I] prolactin to its membrane receptors as well as prolactin-mediated incorporation of [3H] leucine into casein and transport of [14C] aminoisobutyric acid, but was without effect on the binding of [125I] insulin and insulin-mediated events in explants of rabbit mammary glands maintained in culture These findings provide direct evidence for an obligatory functional role of a membrane receptor in mediating the action of a polypeptide hormone
118 citations
TL;DR: Ovine placental lactogen, has been purified approximately 1,000-fold from sheep cotyledons using conventional protein purification procedures, and in a receptor assay for growth hormone using human liver, oPL and hGH are equipotent in competing for receptor sites, suggesting that oPL has common structural features that are lacking in other non-primate hormones.
Abstract: Ovine placental lactogen (oPL), has been purified approximately 1,000-fold from sheepcotyledons using conventional protein purification procedures. Radioreceptor assays using rabbit liver particulate fractions for growth hormone (RRA-GH) and using rabbit mammary gland particulate fractions for prolactin (RRA-PRL) were employed to monitor the hormonal activities. The molecular weight of oPL is approximately 22,000 as determined by gel filtration on Sephadex G-100, and its isoelectric point as determined by isoelectric focusing is 8.8. In the two RRA's, the displacement curve of oPL is parallel to bovine growth hormone (bGH) and ovine prolactin (oPRL) standards and the ratio of GH-activity to PRL-activity of oPL is 1:2. In a body weight gain assay using hypophysectomized rats, oPL has a growthpromoting potency of 1.3 U/mg. In rabbit mammary explants, oPL stimulates casein synthesis. In a receptor assay for growth hormone using human liver, oPL and hGH areequipotent in competing for receptor sites, suggestin...
TL;DR: An affinity chromatography technique for purifying of α-amylase from triticale (X Triticosecale Wittmack) gives a yield in excess of 90% with a purification of up to 180-fold over crude extracts.
TL;DR: The thermal activation theory of magnetic viscosity is reviewed in this paper, where the authors derived the maximum slope of the magnetization decrement in (time) curve to absolute temperature, irreversible susceptibility, and the rate of change of activation energy with field at constant temperature.
Abstract: The thermal activation theory of magnetic viscosity is reviewed Equations are derived relating the maximum slope of the magnetization decrement in (time) curve to absolute temperature, irreversible susceptibility, and the rate of change of activation energy with field at constant temperature, (∂∊/∂H)T The activation energy ∊ is, in general, a function of the applied field H and an intrinsic function of the temperature T If, however, (∂∊/∂T)H=0 then (∂∊/∂H)T≃28·5k/(dH/dT) where H is the field at which the viscosity curve slope is a maximum Deviations from this relationship indicate an intrinsic temperature variation of the activation energy ∊ and thus enable thermal activation and intrinsic temperature effects to be separated Experimental data on magnetic viscosity are re-examined from this point of view
TL;DR: Serum concentrations of 17OH-progesterone were studied serially over 24 hours in 13 treated and untreated patients with the C21 hydroxylase form of congenital adrenal hyperplasia to confirm the value of 17 OH-proGESterone assays in both the diagnosis and management of CAH.
TL;DR: It is suggested that ventilation enhances the movement of surfactant in airways and that positive end-expiratory pressure prevents this effect of ventilation.
TL;DR: The data of both samples supported the predictions that hopelessness would be positively related to external locus of control and to depression.
Abstract: This research examined the relationship between hopelessness, defined as a system of negative expectancies about the future, and two theoretically relevant constructs: internal-external locus of control, and depression. Two samples of 67 and 44 undergraduates were administered the Beck, et al. Hopelessness Scale, the Rotter Internal-External Scale, and the Beck Depression Inventory. The data of both samples supported the predictions that hopelessness would be positively related to external locus of control and to depression.
TL;DR: It is suggested that distension of the lung enhances the release of surfactant and that this release is a metabolically active process and also that 100% O2 has an inhibitory effect on this process.
TL;DR: This paper found that white receivers were able to identify the emotional content of tone of voice more accurately than Indian receivers when judging the samples from Indian speakers, while Indian receivers were more accurate than whites when judging samples from white speakers.
Abstract: White and Indian adult males, speaking whatever words came to mind in their native languages (English and Cree, respectively), attempted to express vocally the emotions of happiness, sadness, love, and anger. After these simulations of emotional state were recorded, the speech samples were rendered unintelligible by means of an electronic filter (which removed verbal meaning while leaving intact the tonal aspects of speech). The filtered vocal expressions from the white and Indian speakers were then played to other groups of white and Indian adult males (receivers). When both heard the samples from the white speakers, the white receivers were able to identify the emotional content of tone of voice more accurately than the Indian receivers. On the other hand, Indian receivers performed more accurately than whites when judging the samples from Indian speakers. The significant interaction suggested that language and culture are crucial factors in the transmission of emotion-even on the nonverbal vocal level.
TL;DR: The competitive inhibition of ammonia oxidation by methane, carbon monoxide or methanol and the presence of an ammonia-dependent NADH oxidation activity in Nitrosomonas extracts is reported and requirement for NADH or hydroxylamine as electron donor in ammonia oxidation is demonstrated.
TL;DR: The results indicate that the hippocampus is involved in mediating the central, nonendocrine action of SRIF and are consistent with the hypothesis proposing the existence of a limbic pacemaker controlling stereotyped behaviour.
TL;DR: Intraperitoneal administration of SRIF induced several other effects in addition to those seen after cortical application, however, the latter were however, restricted in variety, intensity and duration.
Abstract: Cortical administration of SRIF in unrestrained, freely moving rats produced an early activation, stereotyped behavior patterns and later, coordination difficulties often associated with drowsiness. A few animals showed a tendency toward paraplegia-in-extension. A considerable, prolonged alteration in the sleep-waking cycle was also observed. Similar results were obtained in both intact and hypophysectomized animals. Intraperitoneal administration of SRIF induced several other effects in addition to those seen after cortical application. The latter were however, restricted in variety, intensity and duration.
TL;DR: The soluble supernatant fraction of bovine heart homogenates may be fractionated on a DEAE cellulose column into two cyclic nucleotide phosphodiesterases, in the order of emergence from the column, which appears to have much higher affinities toward cyclic GMP than cyclic AMP.
TL;DR: It is shown that a finite lattice is planar if and only if the graph obtained from its (Hasse) diagram by adding an edge between its least and greatest elements is a planar graph.
TL;DR: For the special class of local fields treated by Schlieder and Seiler as discussed by the authors, the necessary conditions for the existence of the Wilson-Zimmermann expansion of the product of real scalar fields under the assumption that the singularities occurring asx j →xj+1;j=1, 2,...,n−1, do not influence each other as long as these limits are simultaneously taken.
Abstract: This paper contains a few simple remarks on a paper by S. Schlieder and E. Seiler. For the special class of local fields treated by these authors we arrive at the same necessary condition for the existence of the Wilson-Zimmermann expansion (considered both as an operator expansion and as an expansion in bilinear forms) of the product ofn real scalar fields under the assumption that the singularities occurring asx j →xj+1;j=1, 2, ...,n−1, do not influence each other as long as these limits are simultaneously taken.
TL;DR: In this paper, the local mode model for polyatomic vibrational overtone absorption is extended to include the effects of nonequivalent XH groups in a molecule, and to describe the major features in the more complex combination regions of the spectrum.
TL;DR: A new postulate that states that the effectiveness of a contextual magnitude decreases as the distance between the contextual magnitude and the standard magnitude increases was translated into a mathematical form in a manner analogous to the way the “attentive field” postulate was quantified.
Abstract: It is argued that the parallel lines illusion is the basic model for many visual distortions that are produced by geometric patterns. An experiment assessed the effect of moving the contextual contour away from the standard contour in two directions—away from the center of the attentive field and toward the center of the attentive field. The degree of illusion declined as the contextual magnitude moved away from the standard magnitude, but the rate of decline was more rapid when the contextual stimulus was moved away from the center of the attentive field. The results necessitated the addition of a new postulate for the assimilation theory of geometric illusions. This postulate states that the effectiveness of a contextual magnitude decreases as the distance between the contextual magnitude and the standard magnitude increases. The postulate was translated into a mathematical form in a manner analogous to the way in which the “attentive field” postulate was quantified. The new formula was successful in predicting both the pattern of means and the pattern of variances found in this study. The formula was cross-validated with data from the Ponzo and reversed Mueller-Lyer illusions.
TL;DR: In this paper, magnetic viscosity measurements have been made on Co5Ce particles with diameters from 1−5 to 8 μm and over a temperature range from 95 to 290 K.
Abstract: Magnetic viscosity measurements have been made on Co5Ce particles with diameters from 1–5 to 8 μm and over a temperature range from 95 to 290 K. The temperature variation of the properties could not be explained in terms of thermal activation effects alone. A wall barrier model has been used to analyse the data and to separate intrinsic temperature and thermal activation effects. The temperature variation of barrier interaction strength is shown to be the same for all particle sizes and to be the major factor in the rise in coercive force as the samples are cooled.
TL;DR: Examination of the effects of intraventricular infusion of an endogenous opioid peptide, methionine-enkephalin3 (Met5-en kephalin), on responses to a sustained mildly noxious stimulus in rats finds it to have increased responsiveness, and moreover to have induced behaviour typical of opiate withdrawal.
Abstract: PEPTIDES with opiate properties have been demonstrated in brain1–3 and pituitary4–7. Goldstein8 has postulated that sustained low-intensity pain might promote the central mobilisation of endogenous opioid as part of an adaptive response to noxious stimuli which cause suffering but do not threaten survival. We have examined the effects of intraventricular infusion of an endogenous opioid peptide, methionine-enkephalin3 (Met5-enkephalin), on responses to a sustained mildly noxious stimulus9 in rats. We expected Met5-enkephalin to attentuate responsiveness to the noxious stimulus, as has been reported10 for its effects on acute pain. On the contrary in our experiments, however, it seems to have increased responsiveness, and moreover to have induced behaviour typical of opiate withdrawal.
TL;DR: In adult males, the excretion of testosterone in saliva appeared to follow a circadian rhythm and levels averaged 295±36 and 195±25 pg/ml in adult males and females, respectively.
Abstract: Testosterone has been detected in whole human saliva. Levels averaged (±SE) 295±36 and 195±25 pg/ml in adult males and females, respectively, and usually were undetectable in children. In adult males, the excretion of testosterone in saliva appeared to follow a circadian rhythm.