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Showing papers by "University of Melbourne published in 1973"


Journal ArticleDOI
TL;DR: Electron microscopy of duodenal mucosa from nine children with acute non-bacterial gastroenteritis revealed virus particles in epithelial cells from six patients, believed to have been an important cause of sporadic gastroEnteritis in children in Melbourne during the 3 months of the survey.

870 citations


Journal ArticleDOI
TL;DR: Study of tooth movement within the bony socket and tooth translation through bone reveals three different biologic systems involving (1) bioelastic, (2) connective tissue, and (3) cellular processes which result in biologic adaptation to normal and abnormal environmental forces.

267 citations


Journal ArticleDOI
Davey Cp1
TL;DR: For instance, this article found that a sub-maximal amount of physical exertion improved mental performance on the Brown and Poulton test of attention which relies heavily on short term memory.
Abstract: The problem of why people in a state of fatigue make wrong decisions prompted a series of laboratory experiments of which two are described. Subjects pedalled a bicycle ergometer for varying periods of time and were tested for mental performance after different amounts of physical exertion. The results showed that a sub-maximal amount of physical exertion improved mental performance on the Brown and Poulton test of attention which relies heavily on short term memory. When the exertion was increased over longer periods of time the graph showing the relationship of mental performance to physical exertion followed the form of an inverted U. The evidence suggests that physical exertion affects mental performance by raising the level of arousal. Areas for further research are suggested.

169 citations


Journal ArticleDOI
TL;DR: Stereochemical studies predict that α‐amino isobutyric acid, one of the amino acids found in antibiotics, can fold only into left‐ or righthanded α‐helical conformations, which should be useful in synthetic analogs of protein sequences to increase helix stability.
Abstract: Stereochemical studies predict that α-amino isobutyric acid, one of the amino acids found in antibiotics, can fold only into left- or righthanded α-helical conformations Such residues will direct chain folding and should be useful in synthetic analogs of protein sequences to increase helix stability

166 citations



Journal ArticleDOI
TL;DR: The pharmacology of transmission from a group of such nerves to the smooth muscle of the guinea-pig proximal colon is described and evidence is presented to suggest that 5-hydroxytryptamine (5-HT) may be the transmitter substance.
Abstract: Mammalian gastrointestinal muscle is supplied by non-adrenergic, intrinsic inhibitory neurons. The substantial evidence which exists to suggest that adenosine triphosphate is the transmitter released from these nerves is discussed briefly. It is shown that the intrinsic inhibitory neurons compose the efferent link in a cascade of descending reflexes extending from the oesophagus to the anal sphincter. Gastrointestinal muscle is also supplied by non-cholinergic excitatory nerves. The pharmacology of transmission from a group of such nerves to the smooth muscle of the guinea-pig proximal colon is described and evidence is presented to suggest that 5-hydroxytryptamine (5-HT) may be the transmitter substance. The contraction is blocked by phentolamine and methysergide which both antagonize the contractile action of 5-HT. When the muscle is desensitized by continued exposure to 5-HT, the non-cholinergic contraction can no longer be elicited.

132 citations


Journal ArticleDOI
TL;DR: It is suggested that the direction and extent of nerve fiber growth may be related to the density of the normal potential sympathetic innervation of the tissues, and that a chemical substance diffusing from the explants is involved in this process.

118 citations


Journal ArticleDOI
01 Jul 1973-Fuel
TL;DR: In this article, the porosity of Yallourn coal cylinders was measured and porosities were calculated from mass and volume losses, showing that porosity drops to zero and may eventually become negative with the development of further porosity.

109 citations


Journal ArticleDOI
TL;DR: This animal is presented as a valuable experimental model of hypertrophic interstitial neuropathy in man with hypomyelination, segmental demyelination and well-developed inion bulbs, and an increase in endoneurial and perineurial connective tissue.
Abstract: The trembler mouse is a spontaneous mutant showing dominant inheritance. Clinical symptoms become manifest from 10 to 14 days of age as an action tremor affecting the head, neck and limbs, convulsions which decrease with increasing age, and weakness and rigidity of the limbs. Histological examination revealed a normal central nervous system, and a peripheral onion bulb neuropathy similar to hypertrophic interstitial neuropathy in man. Peripheral nerves of 14 day old and adult affected and control animals were examined with the electron microscope. The young mice showed retardation of myelin development, generalized myelin degeneration and early onion bulb development. Adult animals presented a picture almost identical to hypertrophic interstitial neuropathy in man with hypomyelination, segmental demyelination and well-developed inion bulbs, and an increase in endoneurial and perineurial connective tissue. This animal is presented as a valuable experimental model of hypertrophic interstitial neuropathy in man.

108 citations


Journal ArticleDOI
TL;DR: Driver steering control and performance were studied for straight-lane driving under conditions of restricted far-sight distance and cross-correlation analysis suggested that the peaks were associated with the driver's control of vehicle heading angle.
Abstract: Driver steering control and performance were studied for straight-lane driving under conditions of restricted far-sight distance. The far-sight distance necessary for the driver to adequately align the car was found to be 70 ft. and was independent of vehicle speeds of 20 and 30 m.p.h. With far-sight distances beyond 70 ft., there was no improvement in driver steering performance. Spectral analysis of steering wheel angle showed peaks in the frequency range 0.1 to 0.3 Hz. The value of the peak frequency was affected by allowed preview time, where preview time was far-sight distance divided by vehicle speed. Cross-correlation analysis suggested that the peaks were associated with the driver's control of vehicle heading angle. Higher frequency peaks were observed in the range 0.35 to 0.6 Hz. These peaks were more likely to occur under conditions of severely reduced preview.

105 citations


Journal ArticleDOI
TL;DR: Chaotropic salts should prove most useful in dissociating multienzyme complexes and in improving the solubility of membrane-bound proteins.

Journal ArticleDOI
TL;DR: Findings provide further support for the conclusions drawn from studies of plasma catecholamines that the sympathetic nervous system contributes toward the maintenance of the elevated blood pressure in essential hypertension.
Abstract: 1. Plasma dopamine β-hydroxylase (DβH) amounts were measured by radioimmunoassay in twenty-eight patients, twenty of whom had essential hypertension. There was a positive correlation between resting diastolic blood pressure and plasma DβH concentration. 2. Plasma DβH amounts also correlated significantly with those of plasma noradrenaline (NA) in individual patients. 3. These findings provide further support for the conclusions drawn from studies of plasma catecholamines that the sympathetic nervous system contributes toward the maintenance of the elevated blood pressure in essential hypertension.

Journal ArticleDOI
07 Nov 1973-Nature
TL;DR: Recording renal blood flow while electrically stimulating specific loci in the mid-brain and hypothalamus proves the existence of any vasodilator innervation of the renal vasculature.
Abstract: As the renal vascular beds of dog and man have been shown to contain inhibitory receptors which seem to be specific for dopamine (DA)1,2 and the kidneys of a number of species contain high levels of DA 3,4, it has been suggested that DA may constitute an endogenous vasodilator factor in the regulation of renal function2,5. The existence in the central nervous system of neurones which seem to use DA as a transmitter has been established by histochemical and biochemical techniques6, and it is reasonable to consider that if DA were concerned in renal vascular control then this might be mediated through dopaminergic nerves. On the other hand, studies in which renal blood flow has been measured during stimulation of the peripheral renal nerves have not succeeded in demonstrating the existence of any vasodilator innervation of the renal vasculature7–9. We have adopted a different approach to this question by recording renal blood flow while electrically stimulating specific loci in the mid-brain and hypothalamus.

Journal ArticleDOI
TL;DR: In this article, the synthesis and characterization of dicyclopentadienyltitanium(III) fluoride completes the series (Cp 2 Ti III X) 2 [where X = F, Cl, Br or I].

Journal ArticleDOI
TL;DR: Young boys who are small for age and have undescended testes, lumbar lordosis, thoracic kyphosis, and pectus carinatum have an unusual facial appearance and the clinician should look for clinical and biochemical evidence of muscle disease.

Journal ArticleDOI
TL;DR: A theoretically derived, three-dimensional typology of family systems is described in this article, based on the notion of a balance between morphostatic and morphogenic properties of the family system, as defined.
Abstract: This paper attempts to review and evaluate the theoretical models used in family therapy. Speer's (20) critique is given special attention. This critique provides a starting point for a theoretical reformulation, supported by the author's (20, 21) and other workers' (5) experimental findings. A theoretically derived, three-dimensional typology of family systems is described. This is based on the notion of a balance between morphostatic and morphogenic properties of the family system, as defined. Using a high and low value for each of the three dimensions, eight family types are isolated and each type is tied to therapeutic predictions. The proposed typology is discussed in relation to an inductively derived typology recently reported by Reiss (16) The need for further validation of the typological scheme is stressed, and its possible clinical applications are outlined.

Book ChapterDOI
TL;DR: In this paper, the mechanisms of reactions undergone by the carbon skeletons of aliphatic and alicyclic hydrocarbons in the presence of metallic catalysts are discussed and discussed.
Abstract: Publisher Summary This chapter reviews the mechanisms of reactions undergone by the carbon skeletons of aliphatic and alicyclic hydrocarbons in the presence of metallic catalysts. Film deposition on a single crystal substrate can lead to the formation of an epitaxed single crystal film. Only two crystalline substrates have had appreciable use for the preparation of the metal film catalysts. These are mica and rocksalt. Mica is a convenient substrate for film growth. In actual catalytic experiments, ultrathin metal films have been used on mica, glass, and silica substrates. It would also be possible to use substrates such as cleaved or evaporated rocksalt or other crystallite substrate. A mica substrate has the considerable advantage that it can be made to present a large and uniform surface and that mica slivers carrying film crystallites can readily be cleaved from the mica sheet. Because these slivers can be made thin enough to pass a 100-keV electron beam, the metal crystallites can be observed directly in the electron microscope.

Journal ArticleDOI
TL;DR: Myelin basic protein was shown to be a substrate for protein kinase from rabbit muscle and one of the major sites of phosphorylation was the serine residue in the sequence Gly-Arg-Gly-Leu-Ser- Leu.
Abstract: Myelin basic protein was shown to be a substrate for protein kinase from rabbit muscle. One of the major sites of phosphorylation was the serine residue in the sequence Gly-Arg-Gly-Leu-Ser-Leu. The arginine residue in this sequence is known to be a substrate for a protein methylase.

Journal ArticleDOI
TL;DR: Several isolated outcrops of melanocratic leucitite lava in central New South Wales are interpreted as remnants of flows erupted in late Cainozoic time by small lava-volcanoes.
Abstract: Several isolated outcrops of melanocratic leucitite lava in central New South Wales are interpreted as remnants of flows erupted in late Cainozoic time by small lava‐volcanoes. The general distribution of outcrops conforms to the regional structural trends of the Palaeozoic basement complex, characterized by a prolonged post‐orogenic stabilization history dominated by block‐faulting and multiple uplift. The lavas are generally microphyric to aphyric and essentially composed of olivine (Fa7–21), diopsidic pyroxene, leucite, and iron‐titanium oxide minerals, with subordinate titaniferous phlogopite and amphibole (richterite), nepheline, and alkali feldspar. The Colour Index is generally close to 70. Bulk‐rock analyses and electron microprobe data on the constituent phases show the unusual chemistry of the suite and its close affinities to the alkali ultrabasic lavas of the ‘stable’ continental regions. Compositional variations are similar, in, their predominant trends, to their analogues in the alk...

Journal ArticleDOI
TL;DR: The organs of the lower abdominal and pelvic regions of the guinea-pig receive nerves from the inferior mesenteric ganglia and pelvic plexuses, which contain adrenergic fibres.
Abstract: The organs of the lower abdominal and pelvic regions of the guinea-pig receive nerves from the inferior mesenteric ganglia and pelvic plexuses. The inferior mesenteric ganglia connect with the sympathetic chains, the superior mesenteric ganglia, the pelvic plexuses via the hypogastric nerves, and with the gut. Each pelvic plexus consists of anterior and posterior parts which send filaments to the internal generative organs and to the rectum, internal anal sphincter and other pelvic organs. The pelvic nerves enter the posterior plexuses, which also receive rami from the sacral sympathetic chains. The adrenergic neurons of the pelvic plexuses are monopolar, do not have dendrites and are supplied by few varicose adrenergic axons. Nearly all the nerves contain adrenergic fibres. After exposure to formaldehyde vapour the chromaffin cells appear brightly fluorescent with one or two long, often varicose, processes. Most of the chromaffin cells are in Zuckerkandl's organ or in chromaffin bodies associated with the inferior mesenteric ganglia. Groups of chromaffin cells are found along the hypogastric nerves and in the pelvic plexuses; they become smaller and fewer as regions more posterior to Zuckerkandl's organ are approached.

Journal ArticleDOI
TL;DR: The constancy of the interval between LH release and ovulation in these experiments confirms the importance of the role of LH in the ovulatory physiology.
Abstract: To investigate the time relationships between the preovulatory luteinizing hormone (LH) peak and ovulation in the ewe a "short" radioimmunoassay for measuring plasma LH concentration was developed. The technique is described. This short assay permitted the determination of LH concentration within 6 hours of sampling. The interval from LH peak to ovulation was then defined by a single laparotomy on each ewe at a known interval after the start of the LH surge. Blood samples were taken immediately after onset of estrus and then at hourly intervals until the LH peak had been identified by 2 consecutive samples. An indwelling silicate cannula had been placed in the jugular vein. Vasectomized rams were used in determining estrus. Using this method the time interval was investigated in 47 ewes experiencing normal estrous cycles in 11 young and 16 old ewes experiencing their second estrus after withdrawal of Cronolone-impregnated sponges and in 19 ewes experiencing their first estrus after withdrawl of such sponges. The results indicated that normally cycling ewes ovulated between 21-26 hours after the LH peak while the young and the old ewes and the Cronolone-treated ewes ovulated 22-26 hours after. At 23 hours 16.6% of ewes from all four groups had ovulated whereas by 24 hours 66.6% of ewes had ovulated indicating that a high proportion of ewes ovulated between 23-24 hours after the start of the LH peak. No correlation was noted between the onset of LH release or the first signs of estrus and the time of day. It is concluded that the constancy of the interval between LH release and ovulation in these experiments confirms the importance of the role of LH in the ovulatory physiology. The present procedure is too cumbersome and too costly for commercial use.

Journal ArticleDOI
TL;DR: A simple method for the simulatenous isolation of a number of samples of rat liver plasma membranes, with high yield, purity and reproducibility is described, using criteria used in other published procedures.

Journal ArticleDOI
TL;DR: The results indicate that the activation of both muscarinic and nicotinic cholinergic mechanisms leads to cardiovascular and behavioural effects in the conscious dog although the site of action and peripheral mechanisms have not been determined.
Abstract: 1. The cardiovascular and behavioural effects of cholinomimetic drugs injected through a cannula chronically implanted into a lateral cerebral ventricle were examined in unanaesthetized dogs.2. Acetylcholine (ACh) (10-20 mug) produced an increase in arterial pressure and heart rate, the dogs became more alert, moved their heads, licked and swallowed and then became drowsy.3. The responses to ACh were potentiated by intraventricular physostigmine (5 mug), were abolished by intraventricular atropine (100 mug) but were unaffected by intraventricular mecamylamine (250 mug). The responses to ACh were reproducible on any one day if injections were given again after a 30 min interval but tolerance developed when ACh was injected repeatedly over periods of several days.4. Methacholine (40 mug) produced similar behavioural and cardiovascular effects to ACh but of a longer duration. The responses to methacholine were abolished by intraventricular atropine (100 mug).5. Nicotine (20-60 mug) produced a biphasic cardiovascular response of an initial brief pressor response and tachycardia followed by a secondary increase in arterial pressure and heart rate which was greater in magnitude and duration. The secondary cardiovascular effects were associated with restlessness and vomiting.6. The responses to nicotine were abolished by prior injection of mecamylamine (250 mug) but were unaffected by atropine (100 mug). The responses to nicotine were not reproducible if injections were repeated on the same day but could be again produced if a few days were allowed to elapse between injections.7. An increased heart rate occurred during the pressor response to the cholinomimetic drugs but when a comparable pressor response was produced by intravenous infusion of noradrenaline in the same unanaesthetized dogs pronounced reflex bradycardia resulted.8. The results indicate that the activation of both muscarinic and nicotinic cholinergic mechanisms leads to cardiovascular and behavioural effects in the conscious dog although the site of action and peripheral mechanisms have not been determined.

Journal ArticleDOI
TL;DR: Serial measurements of maternal plasma progesterone, corticosteroids, estrone, estradiol-17�, LH, and prolactin have been made in six sheep, during late pregnancy and at parturition, and possible explanations for the absence of an increase in LH secretion are discussed.
Abstract: Serial measurements (up to four times per day) of maternal plasma progesterone, corticosteroids, estrone, estradiol-17�, LH, and prolactin have been made in six sheep, during late pregnancy and at parturition (Day 0). The mean progesterone concentration on Day -10 was 15.5 ng/ml. From Day -4 the level began to decrease and by Day 0, the mean progesterone level was 1.0 ng/ml. The mean concentrations of estrone and estradiol-17p on Day -3 (62.4 and 24.0 pg/ml, respectively) began to rise during the 48 hr preceding parturition, reaching peak values of 228.0 and 141.8 pglml, respectively. The mean corticosteroid level (17.3 ng/ml) rose during the 18 hr preceding parturition, reaching a peak of 38.6 ng/ml. Estrone, estradiol-17�, and corticosteroids returned to low levels within 12 hr after parturition. LH levels remained relatively coastant (2.0-6.0 ng/ml) from -36 h to +30 h but prolactin levels rose sharply from about Day -2. Possible explanations for the absence of an increase in LH secretion, in response to the preparturient rise in estrogens, are discussed.

Journal ArticleDOI
TL;DR: Plasma membranes were purified from bovine kidney cortex, with a fourfold increase in specific activity of parathyroid hormone-sensitive adenylate cyclase over that in the crude homogenate, and the labelled hormone shown to bind to the plasma membranes and to be specifically displaced by unlabelled hormone.
Abstract: 1. Plasma membranes were purified from bovine kidney cortex, with a fourfold increase in specific activity of parathyroid hormone-sensitive adenylate cyclase over that in the crude homogenate. The membranes were characterized by enzyme studies. 2. Parathyroid hormone was labelled with 125I by an enzymic method and the labelled hormone shown to bind to the plasma membranes and to be specifically displaced by unlabelled hormone. Parathyroid hormone labelled by the chloramine-t procedure showed no specific binding. 75Se-labelled human parathyroid hormone, prepared in cell culture, also bound to the membranes. 3. Parathyroid hormone was shown to retain biological activity after iodination by the enzymic method, but no detectable activity remained after chloramine-t treatment. 4. High concentration of pig insulin inhibited binding of labelled parathyroid hormone to plasma membranes and partially inhibited the hormone-sensitive adenylate cyclase activity in a crude kidney-cortex preparation. 5. EDTA enhanced and Ca2+ inhibited binding of labelled parathyroid hormone to plasma membranes. 6. Whereas rat kidney homogenates were capable of degrading labelled parathyroid hormone to trichloroacetic acid-soluble fragments, neither crude homogenates nor purified membranes from bovine kidney showed this property. 7. Binding of parathyroid hormone is discussed in relation to metabolism and initial events in hormone action.

Journal ArticleDOI
TL;DR: The interactions between sympathetic nerve fibers and smooth muscle cells and fibroblasts from the newborn guinea pig vas deferens were studied in tissue culture with phase contrast microscopy, time-lapse microcinematography, catecholamine fluorescence histochemistry and scanning and transmission electron microscopy.

Journal ArticleDOI
TL;DR: In this paper, a functional abomasal lesion was apparent within 4 days of infection judged by the changes in plasma pepsinogen levels and the sodium concentrations of the pouches contents.
Abstract: Sheep in which abomasal fundic pouches had been made were infected with Ostertagia circumcincta (150000 larvae in one sheep, 100000 in three sheep). Subsequently studies were made on pouch secretion, food intake, plasma pepsinogens and abomasal pouch secretory responses when the sheep first ate. A functional abomasal lesion was apparent within 4 days of infection judged by the changes in plasma pepsinogen levels and the sodium concentrations of abomasal contents. Whereas the secretory activity of the abomasal fundic pouches (never exposed to parasites) was maintained or increased, the pH and sodium concentration of contents taken from the infected part of the abomasum were indicative of either a failure to secrete or of a permeability reabsorptive lesion. Ultrastructural studies demonstrated that parietal cells of the pouches had the appearance of cells subjected to strong secretory stimuli, but those of infected abomasa were similar to cells of gastric mucosa subjected to agents suppressing secretion. Factors which might operate, on the one hand, to stimulate secretion from separated fundic abomasal pouches, and on the other to inhibit or modify the secretory activity of the fundic mucosa of the infected abomasa, are discussed.

Journal ArticleDOI
TL;DR: It is concluded that acylation reactions are important for the incorporation of stearic and arachidonic acids while direct exchange with free choline is a relatively minor pathway.

Journal ArticleDOI
TL;DR: The thermodynamic information on the adsorption density of the salts at the air-water and air-monolayer-water interfaces has been examined in terms of various classifications of “structure making” and "structure breaking" ions as discussed by the authors.