Showing papers by "University of Glasgow published in 1973"
TL;DR: It is shown that typical road surfaces may be considered as realizations of homogeneous and isotropic two-dimensional Gaussian random processes, and a single direct spectral density function provides a road surface description which is sufficient for multi-track vehicle response analysis.
586 citations
TL;DR: No technique has been able to relate the parenchymal extracellular pH change quantitatively to the cerebral vasodilatation associated with hypercapnia and the possibility of another mechanism remains.
Abstract: CEREBRAL blood flow in the dog and primate is linearly related to the arterial carbon dioxide tension (paCO2) in the range 30 to 60 mm Hg1. It is not certain that the effect of paCO2 is completely explained by the change in cerebrovascular, extracellular pH evoked by the rapid diffusion of carbon dioxide across the blood-brain barrier3–4. Micropipette technique5 has clearly shown that the pial vessels will respond to extracellular pH changes but no technique has been able to relate the parenchymal extracellular pH change quantitatively to the cerebral vasodilatation associated with hypercapnia and the possibility of another mechanism remains.
193 citations
TL;DR: In this article, an analysis of the heating of the deep chromosphere by a vertically descending beam of non-thermal electrons with power-law energy spectrum, in flares, is presented.
Abstract: Heating of the deep chromosphere by a vertically descending beam of non-thermal electrons with power-law energy spectrum, in flares, is analysed. In lower regions of the flare, radiative losses can balance the energy input and the flare structure is described in terms of instantaneous quasi-steady temperature/depth profiles. Motion of the optical flare material is at constant pressure and is constrained to be purely vertical by a vertical magnetic field. The ionisation of hydrogen is determined by the same non-LTE processes as in the quiet chromosphere. Temperature profiles are obtained for a wide range of electron beam intensities and spectral indices and are discussed in terms of optical flare observations. Due to the steepness of the electron spectra, typical densities in the optical flare vary only over a narrow range, despite the diversity of beam intensities, in agreement with observation. Above a certain region, the flare material cannot attain a radiatively steady state against the electron input but evaluation of the level at which this occurs leads to an estimate of the mass of material involved in the high temperature flare plasma in this model. Results, which are again insensitive to the electron beam parameters, are found to be in satisfactory agreement with observations of the mass of flare ejecta and of soft X-ray flare emission measures.
190 citations
TL;DR: From the results obtained when the crabs were starved and when starved crabs were fed, it is suggested that, during starvation, the metabolic rate of C. maenas first drops from the elevated “feeding level” to alevel at which carbohydrate reserves are utilised, and subsequently to a minimum level at which lipid reserves and proteins are used.
Abstract: The relationship between food intake and metabolic rate (as measured by oxygen consumption) of Carcinus maenas (L.) was studied. The metabolic rate of feeding crabs which had been starved for a short period increased, and several days were required for it to return to its original level. During prolonged starvation, the metabolic rate of C. maenas fell in two stages. The first reduction was to about 60% of the “feeding level”; this occurred during the first week of starvation. There was then a further reduction to about 40% of the “feeding level” and, at this level of metabolism, the crabs were able to survive for 3 months, with only 50% mortality; most of this occurred in the last 2 weeks. Metabolic rate was found to affect food intake; crabs acclimated to 24°C took 2.4 times as much food as crabs acclimated to 10°C, although the metabolic levels of the two groups differed by a factor of only 1.4. From the results obtained when the crabs were starved and when starved crabs were fed, it is suggested that, during starvation, the metabolic rate of C. maenas first drops from the elevated “feeding level” to a level at which carbohydrate reserves are utilised, and subsequently to a minimum level at which lipid reserves and proteins are used.
171 citations
TL;DR: Compared mice with inherited pituitary dwarfism (homozygotes for Snell's dwarf mutation, dw) with normal mice from the same stock, the uptake of 3H-thymidine by several tissues, including the thymus, of a 5-month-old dwarf was less than by the corresponding tissues of a 17-month old normal mouse.
Abstract: IT has often been suggested that the immune system may be involved in ageing1–4 Fabris et al.5 claim that such immune deficiencies are caused by inadequate stimulation of the lymphoid system by growth hormone (GH). They compared mice with inherited pituitary dwarfism (homozygotes for Snell's dwarf mutation, dw) with normal mice from the same stock. The life span of the dwarfs was only 3 to 5.5 months (mean 4.5 months) although the mean life span of their normal sibs was 20 months. The early death of the mutants was taken as a sign of premature ageing. The loss and greying of the hair, cutaneous atrophy, and bilateral cataracts which occurred in the dwarf mice from the age of 2 to 3 months were also taken as signs of ageing, as such changes only occurred in normal littermates during their last few months of life. The uptake of 3H-thymidine by several tissues, including the thymus, of a 5-month-old dwarf was less than by the corresponding tissues of a 17-month-old normal mouse. The uptakes were greater in both dwarf and normal mice aged 1 month.
158 citations
Book•
01 Jan 1973TL;DR: In a new postscript the author examines the political and constitutional developments posed by the current imbalance of forces as between Westminster and Scotland as mentioned in this paper, which has long been recognised as the standard textbook in the field.
Abstract: First published in 1973, Professor Kellas's account of Scottish government and politics has long been recognised as the standard textbook in the field. In a new postscript the author examines the political and constitutional developments posed by the current imbalance of forces as between Westminster and Scotland.
146 citations
TL;DR: It was suggested that the specialization of the metathoracic legs in the locust gave rise to most of the variability in leg movements and that the relative independence of the prothoracIC legs reflects an exploratory role in walking.
Abstract: 1. The patterns of leg movements during normal straight-line walking of the locust Schistocerca gregaria and the grasshopper Romalea microptera were recorded and analysed. 2. The ratio of protraction to retraction increased with walking speed except in the prothoracic legs. At any one speed both protraction and retraction durations were variable but the variation was greatest for protraction. 3. The locust employed an alternating tripod gait at all walking speeds recorded (2-8 steps/sec.) It displayed a high level of variability in its leg movements which appeared to be held in check by stabilising mechanisms operating on the first and last leg pairs. 4. The movements of individual legs of the grasshopper were very similar to those of the locust but the gait used was not alternating tripod. 5. Comparisons were made with other insects and it was suggested that the specialization of the metathoracic legs in the locust gave rise to most of the variability in leg movements and that the relative independence of the prothoracic legs reflects an exploratory role in walking.
138 citations
TL;DR: The combined effects of glutamate and ibotenic acid suggest the existence of non-synaptic glutamate receptors with different pharmacological properties and ion specificities from those found on the excitatory postsynaptic membrane.
124 citations
TL;DR: Transformation of Trypanosoma brucei 792G in a monophasic blood lysate medium started from populations of bloodstream trypanosomes containing over 90 per cent intermediate and stumpy forms resulted in optimal growth and morphological transformation.
119 citations
TL;DR: Sodium and potassium ions are involved in the conductance increase seen during activation of both junctional and extrajunctional ACh receptors on frog muscle fibres, but the relative contribution of potassium is greater in the case of the extrajunctionsal receptors4.
Abstract: The presence of extrajunctional acetylcholine (ACh) receptors on vertebrate skeletal muscle fibres is well established1, 2. Fast muscle fibres in the rat possess extrajunctional receptors only in the vicinity of neuromuscular junctions while slow fibres exhibit a measurable ACh sensitivity over the entire non-synaptic membrane with peaks of sensitivity at the nerve-muscle and muscle-tendon junctions3. Sodium and potassium ions are involved in the conductance increase seen during activation of both junctional and extrajunctional ACh receptors on frog muscle fibres, but the relative contribution of potassium is greater in the case of the extrajunctional receptors4.
111 citations
TL;DR: Electron microscopic and histochemical analysis of the cell death process in wingless wing-buds revealed the presence of both isolated dead cells and macrophages, which contained intense acid phosphatase activity, interpreted as showing that isolated dead Cells are ingested by neighbouring mesenchymal cells which thus become transformed into macrophage, first ingesting and then digesting further dead cells.
Abstract: The wingless condition resulting from the action of the sex-linked wingless ( ws ) gene arises from the precocious appearance of cell death in the anterior necrotic zone (ANZ) of the forelimb-bud at stage 19 (3 days) and its progressive extension beyond its normal area during stages 20–23. A similar though less pronounced effect occurs in the hindlimb-bud. Although some wingless hindlimb-buds are normal, others are affected by the precocious appearance of cell death in the ANZ.
The ws wingless mutant resembles the different wingless mutant investigated by Zwilling (1956) in that the apical ectodermal ridge (AER) is absent in most ws wing-buds. AER absence could be due to ws mesenchymal cell death interfering with the production of apical ectodermal maintenance factor (AEMF), which Zwilling claims is necessary to maintain the AER which plays an essential role in inducing limb outgrowth.
Wingless mutant phenotypes range from birds with rudimentary wings and normal legs through a modal type with forelimbs absent and hindlimbs normal to wingless and legless forms showing a high degree of expressivity. Individual wingless embryos vary in the degree to which the precocious ANZ appearing at 3 days is extended into the limb-bud and the wide range of wingless phenotypic expression is attributed to this variation.
Electron microscopic and histochemical analysis of the cell death process in wingless wing-buds revealed the presence of both isolated dead cells and macrophages, which contained intense acid phosphatase activity. These findings are interpreted as showing that isolated dead cells are ingested by neighbouring mesenchymal cells which thus become transformed into macrophages, first ingesting and then digesting further dead cells.
A study was made of the origin of the anomalous hindlimb condition, including absence or reduction of the tibia and digits, characteristic of severely affected wingless embryos. Autoradiographic analysis of the pattern of 35SO4 uptake revealed that at stage 24/5 (4½ days) wingless hindlimb-buds which were smaller than normal had a normal prospective fibula region, but that the prospective tibia region was small or absent. Thus the effect of a precocious hindlimb ANZ at stages 19–22 is to reduce or delete the pre-axial prospective tibia at stage 24/5.
TL;DR: The ability of the flagellum of trypanosomatids to form Junctional complexes may be a factor contributing to their success as parasites, this adaptation enabling them to multiply while attached to host surfaces.
Abstract: SYNOPSIS. The ultrastructure of attached Trypanosoma vivax epimastigote clusters in the proboscis of the tsetse fly Glossina fuscipes is described from electron micrographs of thin sections. Some flagellates are attached directly to the lining of the insect's labrum by their flagella, most of which are aligned along the long axis of the proboscis. Other trypanosomes are attached indirectly, their flagella adhering to those of flagellates which are directly attached. Junctional complexes similar to those described from metazoan epithelia are found on the flagellar membrane. A long zonular hemidesmosome attaches the flagellum to the proboscis wall and a series of closely set macular desmosomes link the flagellar membranes of adjacent flagellates. Unlike the trypomastigote stages of T. vivax, more than one row of macular desmosomes may be present along the flagellum-body junction of the trypanosome. It is suggested that all these Junctional complexes serve to buttress the flagellate's attachment to its insect host and so maintain anchorage of the parasite during the fly's blood meals. The ability of the flagellum of trypanosomatids to form Junctional complexes may be a factor contributing to their success as parasites, this adaptation enabling them to multiply while attached to host surfaces.
TL;DR: Evidence of a long-standing host-parasite relationship which has evolved to an advanced state of adaptation on the part of the parasite and tolerance on thePart of the host is shown.
Abstract: Eighty-nine O-group plaice from a natural population were exposed at 15°C to heavy infection by Cryptocotyle lingua cercariae. Subsequently 45 fish were retained at 15°C, whilst 44 were held at 5°C. Both groups were sampled by killing individual fish at intervals of 6,18,42 h and daily thereafter up to 710 h. Entire fish were fixed immediately in formol saline, transversely sectioned and stained by H & E, PAS, PAS-diastase, JSDB 109, Picro-Mallory, Masson's trichrome, Gram-Weigert and Alcian blue. Histopathological observations showed: (a) epidermal lesions associated with encysted metacercariae in adjacent tissues; (b) myofibrillar necrosis associated with bacteria possibly introduced by the parasite; and (c) a reactive swelling of the intermuscular septa. The progressive development of the parasite cyst and host capsule is described. Development of both was markedly inhibited at the lower temperature, but the inflammatory response at either temperature was slight. This may be evidence of a long-standing host-parasite relationship which has evolved to an advanced state of adaptation on the part of the parasite and tolerance on the part of the host.
TL;DR: New data support the hypothesis that the distribution of antigen between the liver and spleen determines the magnitude of the immune response, and the increased production of antibody to both gut-derived and non-gut-derived antigen is shown to be due to a reduction in the capacity of the liver to trap antigen.
TL;DR: It appears that Fe(2+) is the form in which iron is taken up by ferritin in a reaction where the protein acts as an enzyme which traps the product in the interior of the protein shell.
Abstract: 1. Horse spleen apoferritin catalyses the oxidation of Fe2+ to Fe3+ with molecular O2 as electron acceptor under conditions where a number of other proteins have no such effect. The product is similar to ferritin by a number of criteria. 2. The progress curve is hyperbolic and the increase in initial velocity is linear with increasing apoferritin concentration. With respect to Fe2+ the reaction follows Michaelis–Menten kinetics. The pH-dependence of the reaction was determined between pH4.3 and 6.0. 3. Modification of both tryptophan residues/apoferritin subunit with 2-nitrophenylsulphenyl chloride does not affect either kcat. or Km for the oxidation. Neither does the guanidination of seven out of nine lysine residues/subunit, the modification of nine out of ten arginine residues/subunit with cyclohexanedione, or the nitration of one out of five tyrosine residues/subunit with tetranitromethane. 4. The carboxymethylation of two out of three cysteine residues/subunit and of one out of six histidine residues/subunit can be achieved with iodoacetic acid. This carboxymethylated apoferritin is completely inactive in Fe2+ oxidation. 5. Apoferritin does not take up Fe3+. It appears from these results that Fe2+ is the form in which iron is taken up by ferritin in a reaction where the protein acts as an enzyme which traps the product in the interior of the protein shell.
TL;DR: In this article, a unified treatment of equivalence theorems for D-optimal and Ds-optimality is provided in the form of duality theorem established by means of Strong Lagrangian Theory.
Abstract: SUMMARY A geometric interpretation of optimal design problems is given. This provides a unified treatment of the equivalence theorems for D-optimal and Ds-optimal designs in the form of duality theorems established by means of Strong Lagrangian Theory. The appropriate theorem for Ds-optimality is proved. A monotonic procedure for construoting D-optimal designs is suggested by the duality. This is described and its convergenee established.
TL;DR: In this article, a Mellin transform is used to find an integral equation related to the stress intensity factor and the formation energy of a crack at the edge of a circular hole in an infinite elastic solid.
TL;DR: A study has been made of the haemoglobin levels of 475 people over the age of 65 living at home, and anaemia (Hb less than 12 g/100 ml) was commoner in women than men and increased in frequency with age.
Abstract: A study has been made of the haemoglobin levels of 475 people over the age of 65 living at home. Anaemia (Hb less than 12 g/100 ml) was commoner in women than men and increased in frequency with age. Haemoglobin concentrations below 10 g/100 ml were found in only 2·4 per cent.
Iron deficiency was the cause of anaemia in 45 per cent, and 10 per cent of non-anaemic subjects also had evidence of iron deficiency. Gastrointestinal lesions and regular salicylate ingestion were common causes of iron deficiency, but evidence of dietary iron deficiency was indefinite.
Vitamin B12 deficiency was found in 9 per cent of anaemic and 5 per cent of non-anaemic subjects. Folate deficiency was rare (1 per cent of subjects), and there was no evidence that dietary folate deficiency contributed to anaemia.
No cause for anaemia was found in 30 per cent of anaemic subjects. In the majority of these the haemoglobin concentration was just below 12 g/100 ml, and was probably normal for them.
These findings are discussed with regard to population screening procedures in old age.
TL;DR: Cholesterol linoleate hydroperoxides, isolated from the lipids of advanced atherosclerotic plaques of human aortas obtained during post mortem examination, have been shown to comprise a mixture of 9- and 13-hydroperoxide similar to those produced by autoxidation.
TL;DR: It is shown that in several promising cases, the coincidence of a deletion and the familial segregation of an undetectable or “silent” allele has raised false hopes1.
Abstract: DEVELOPMENT malformations associated with gross chromosomal deletions are well known in man. Those cases in which the extent of the deletion can be defined accurately by chromosome banding techniques should provide an opportunity for identifying some of the gene loci located within the deleted segment. But the positive assignment of a gene locus to a particular region in the human karyotype does not seem to have been achieved by this method. In several promising cases, the coincidence of a deletion and the familial segregation of an undetectable or “silent” allele has raised false hopes1.
TL;DR: From the experimental animal results and results from patients, it is suggested that a more suitable index of cyanide exposure may be the alteration of plasma thiocyanate rather than the direct determination of whole blood cyanide.
Abstract: A microdiffusion technique has been used to separate and concentrate the nanomole amounts of cyanide in whole blood, and to permit its simplified colorimetric estimation ( 1 ). With this technique cyanide was measured in whole blood from normal smokers, normal nonsmokers, and patients suffering from tobacco amblyopia. Cyanide was also measured in whole blood from vitamin B12-deficient and normally fed Wistar rats. From the experimental animal results and results from patients, it is suggested that a more suitable index of cyanide exposure may be the alteration of plasma thiocyanate rather than the direct determination of whole blood cyanide.
TL;DR: An ethanol-induced increase in the activities of the enzymes glutathione (GSH) peroxidase and (GSSG) reductase and the role of these enzymes in a protective mechanism against lipid peroxidation is discussed.
TL;DR: In rats in which N. brasiliensis infection was superimposed on a previously existing T. brucei infection, the normal process of immune expulsion of adult worms did not occur, the production of circulating protective antibody and of reaginic antibody was grossly impaired and there was no increase in the numbers of mast cells in the intestinal villi.
Abstract: In rats in which N. brasiliensis infection was superimposed on a previously existing T. brucei infection of 3 weeks' duration, the normal process of immune expulsion of adult worms did not occur, the production of circulating protective antibody (IgG) and of reaginic antibody (IgE) was grossly impaired and there was no increase in the numbers of mast cells in the intestinal villi. In contrast to this failure of humoral and immediate-type responses, cell-mediated immunity, as measured by oxazolone sensitization of mice with a T. brucei infection, still occurred to a significant extent although not so markedly as in uninfected mice. These results, which provide further evidence that infection with T. brucei may induce a significant degree of immunosuppression of the host, are discussed with particular regard to the aetiology of the phenomenon.
TL;DR: A ribonucleoprotein complex (TNP) containing an active RNA polymerase was isolated from purified vesicular stomatitis virus particles as mentioned in this paper, which sedimented through a sucrose gradient as a single band and appeared under the electron microscope as discrete long filaments in a spiral configuration.
Abstract: A ribonucleoprotein complex (TNP) containing an active RNA polymerase was isolated from purified vesicular stomatitis virus particles. The TNP sedimented through a sucrose gradient as a single band and appeared under the electron microscope as discrete long filaments in a spiral configuration. TNP contained one major and two minor polypeptides, but not the polypeptides associated with the outer coat of vesicular stomatitis virus. BHK-21 clone 13 cells could be infected with TNP, yielding infectious virus particles.
TL;DR: A model for ammonium regulation in Aspergillus nidulans is put forward which suggests NADP-GDH located in the cell membrane complexes with extracellular ammonium determines the level of methylammonium uptake by repression or inhibition, or both.
Abstract: l-Glutamate uptake, thiourea uptake, and methylammonium uptake and the intracellular ammonium concentration were measured in wild-type and mutant cells of Aspergillus nidulans held in various concentrations of ammonium and urea. The levels of l-glutamate uptake, thiourea uptake, nitrate reductase, and hypoxanthine dehydrogenase activity are determined by the extracellular ammonium concentration. The level of methylammonium uptake is determined by the intracellular ammonium concentration. The uptake and enzyme characteristics of the ammonium-derepressed mutants, meaA8, meaB6, DER3, amrA1, xprD1, and gdhA1, are described. The gdhA mutants lack normal nicotinamide adenine dinucleotide phosphate-glutamate dehydrogenase (NADP-GDH) activity and are derepressed with respect to both external and internal ammonium. The other mutant classes are derepressed only with respect to external ammonium. The mutants meaA8, DER3, amrA1, and xprD1 have low levels of one or more of the l-glutamate, thiourea, and methylammonium uptake systems. A model for ammonium regulation in A. nidulans is put forward which suggests: (i) NADP-GDH located in the cell membrane complexes with extracellular ammonium. This first regulatory complex determines the level of l-glutamate uptake, thiourea uptake, nitrate reductase, and xanthine dehydrogenase by repression or inhibition, or both. (ii) NADP-GDH also complexes with intracellular ammonium. This second and different form of regulatory complex determines the level of methylammonium uptake by repression or inhibition, or both.
TL;DR: It is reported that using this technique the DNA of herpes simplex virus type I (HSV-I) can be shown to be infectious and plaques can be obtained on BSC-1 cells (African green monkey kidney cells).
Abstract: RABBIT kidney and fibroblast cells, after exposure to the isolated DNA of herpes simplex virus in the presence of DEAE-dextran, have been shown to develop a cytopathic effect1. Enhancement of plaque formation with DNA using DEAE-dextran has been described2,3 but a new technique has been recently reported which gives a 100-fold increase in efficiency over the DEAE-dextran method for human adenovirus DNA4. Here we report that using this technique the DNA of herpes simplex virus type I (HSV-I) can be shown to be infectious and plaques can be obtained on BSC-1 cells (African green monkey kidney cells).
TL;DR: Analysis of the dissociation and reassociation of apoferritin at low pH values suggests that this is a co-operative process involving protonation and deprotonation of at least two carboxyl functions of rather low intrinsic pK.
Abstract: 1. The dissociation of horse spleen apoferritin as a function of pH was analysed by sedimentation-velocity techniques. The oligomer is stable in the range pH2.8–10.6. Between pH2.8 and 1.6 and 10.6 and 13.0 both oligomer and subunits can be detected. At pH values between 1.6 and 1.0 the subunit is the only species observed, although below pH1.0 aggregation of the subunits to a particle sedimenting much faster than the oligomer occurs. 2. When apoferritin is first dissociated into subunits at low pH values and then dialysed into buffers of pH1.5–5.0, the subunit reassociates to oligomer in the pH range 3.1–4.3. 3. U.v.-difference spectroscopy was used to study conformational changes occurring during the dissociation process. The difference spectrum in acid can be accounted for by the transfer of four to five tyrosine residues/subunit from the interior of the protein into the solvent. This process is reversed on reassociation, but shows the same hysteresis as found by sedimentation techniques. The difference spectrum in alkali is more complex, but is consistent with the deprotonation of tyrosine residues, which appear to have rather high pK values. 4. In addition to the involvement of tyrosine residues in the conformational change at low pH values, spectral evidence is presented that one tryptophan residue/subunit also changes its environment before dissociation and subsequent to reassociation. 5. Analysis of the dissociation and reassociation of apoferritin at low pH values suggests that this is a co-operative process involving protonation and deprotonation of at least two carboxyl functions of rather low intrinsic pK. The dissociation at alkaline pH values does not appear to be co-operative. 6. Of the five tyrosine residues/subunit only one can be nitrated with tetranitromethane. Guanidination of lysine residues results in the modification of seven out of a total of nine residues/subunit. Nine out of the ten arginine residues/subunit react with cyclohexanedione.
TL;DR: Haemocytes of the common shore crab have been examined under the light and electron microscopes and preliminary analysis suggests that haemocytes may contain glucose-6-phosphatase, and since it is known that the blood polysaccharide fraction incorporates radioactive glucose, a central role for haemocyte in the metabolism of carbohydrates is strongly suggested.
TL;DR: To determine if adenovirus type 5 can transform permissive cells, hamster embryo fibro-blasts (HEF) were infected with temperature sensitive mutants5 at the restrictive temperature which prevents cell killing caused by virus replication.
Abstract: JUDGED on the basis of virus inoculation tests in newborn hamsters1, human adenovirus type 5 is considered to be non-oncogenic. The virus does transform rat embryo cells with low efficiency in vitro2,3, although these cells do not form tumours in rats (my unpublished results). Infection of hamster cells in vitro with type 5 adenovirus gives rise to a productive infection (ref. 4 and my unpublished results) and most of the cells are killed. Because of this extensive cell killing transformation of hamster cells by adenovirus type 5—if it does occur—is unlikely to have been detected. To determine if adenovirus type 5 can transform permissive cells, hamster embryo fibro-blasts (HEF) were infected with temperature sensitive (ts) mutants5 at the restrictive temperature which prevents cell killing caused by virus replication. The mutants used transform non-permissive rat embryo cells at the restrictive temperature (my unpublished results) with frequencies similar to wild type virus, thus the viral function(s) involved in transformation of those cells are not affected by these particular ts mutations.