Showing papers by "University of Melbourne published in 1987"
TL;DR: The blood supply to the skin and underlying tissues was investigated by ink injection studies, dissection, perforator mapping and radiographic analysis of fresh cadavers and isolated limbs, giving rise to the angiosome concept.
1,467 citations
TL;DR: In this paper, a series of models relating some function g ( r ) and another function f {ln( t ), T −1 }, which contain most previously published relationships, as well as a number of novel forms, are considered.
Abstract: An extensive set of laboratory annealing data, relating the reduction in mean confined track length of induced fission tracks in Durango apatite (Mexico) to annealing temperature and time, has been used to construct an empirical mathematical description of the annealing process. Firstly, Laplacian smoothing splines are used to reveal the gross nature of the dependence of the length reduction, r , on logarithm of time (ln( t )) and inverse absolute temperature ( T −1 ). This suggests that contours of equal length reduction in an Arrhenius plot can be described by parallel or only slightly fanning straight lines. In seeking a more rigorous description, we construct a series of models relating some function g ( r ) and another function f {ln( t ), T −1 }, which contain most previously published relationships, as well as a number of novel forms. Within this composite model, both parallel and fanning Arrhenius plots are considered. The models are fitted and compared using formal statistical methods. None of the previously suggested relationships satisfactorily describe the data, and a novel form is proposed with g ( r )=ln(1− r ) for the parallel Arrhenius plot. The best fitting model accounts for 96.7% of the variation of g ( r ), but residual plots show some structure; suggesting that some improvement in the model is possible. The best fanning model accounts for 98.0% of the variation in g ( r ), and gives a significantly better fit than the parallel model, with residual plots showing no obvious structure. The degree of fanning is much less than in most previously published Arrhenius plots for apatite, which may be due to the presence of apatites of various compositions in those previous studies, whereas the present study relates to only a single composition. The slight amount of fanning observed in this study may be an artefact introduced by several intermediate steps between the physical processes taking place during annealing and their manifestation as the reduction in mean track length.
840 citations
TL;DR: The purified PTH-related protein had a specific biological activity approximately equal to 6 times greater than that of bovine PTH(1-34) and may have a role in the syndrome of humoral hypercalcemia of malignancy.
Abstract: A protein with biological activities similar to parathyroid hormone (PTH) has been purified from serum-free culture medium obtained from a human lung cancer cell line (BEN). A major protein band of 18 kDa was obtained on NaDodSO4/polyacrylamide gels, with faint bands at 35 kDa and 67 kDa. Biological activity was associated only with the 18-kDa band. Amino acid sequence analysis of the material purified by HPLC revealed that 8 of the 16 residues were identical with those of human PTH. Antibody raised to a corresponding synthetic peptide recognized the PTH-related material but showed less than 1% cross-reactivity with human PTH amino-terminal peptides. BEN cells contained PTH DNA, but not PTH messenger RNA, indicating involvement of another gene. The purified PTH-related protein had a specific biological activity approximately equal to 6 times greater than that of bovine PTH(1-34). The PTH-related protein may have a role in the syndrome of humoral hypercalcemia of malignancy.
719 citations
TL;DR: Afferents to the nucleus accumbens septi utilizing glutamate or aspartate have been investigated in the rat by autoradiography following injection and retrograde transport of D[3H]aspartate and [3H]:GABA failed to label perikarya in thalamus and amygdala, and a topographic distribution of label was absent in neocortex.
338 citations
TL;DR: Fission track analysis of apatites from basement rocks of the Wright Valley in southern Victoria Land provides information about the timing, the amount and hence the rate of uplift of the Transantarctic Mountains in this area as discussed by the authors.
315 citations
TL;DR: Both non-tolerance and the autoimmune response appear to result from delayed onset of T antigen expression during β cell development.
Abstract: Transgenic mice expressing simian virus 40 T antigen under control of the insulin gene regulatory region vary in their response to this protein. Each lineage is characteristically either tolerant to T antigen, or not, in which case autoantibodies arise with high frequency, and lymphocytes infiltrate and disrupt the pancreatic islets. Both non-tolerance and the autoimmune response appear to result from delayed onset of T antigen expression during beta cell development.
276 citations
TL;DR: The possibility that atrial natriuretic polypeptides may induce natriuresis by suppression of proximal tubular sodium and water reabsorption is investigated and it is reported that 20 nanomolar α-rANP1–23 (the main component of ANP in rat plasma) added to the peritubular fluid had no direct effect on proximal fluid uptake.
Abstract: The discovery that atrial extracts have potent diuretic and natriuretic properties revealed a possible endocrine function of the heart in the regulation of extracellular fluid volume. Since that first report intense research activity has been directed towards determining the mechanism of action of the active atrial natriuretic polypeptides (ANP) found in these extracts. Despite these efforts it remains controversial whether the renal actions of ANP are exerted solely on the process of glomerular filtration or involve additional direct actions on tubular transport. We have investigated the possibility that atrial natriuretic polypeptides may induce natriuresis by suppression of proximal tubular sodium and water reabsorption. Using shrinking split-drop micropuncture combined with simultaneous capillary perfusion in anaesthetized rats we report that 20 nanomolar alpha-rANP (the main component of ANP in rat plasma) added to the peritubular fluid had no direct effect on proximal fluid uptake whereas picomolar angiotensin II had a marked stimulatory action as reported. The stimulatory effect of angiotensin II on fluid reabsorption was inhibited by peritubular ANP at physiological concentrations and abolished by higher concentrations of ANP. Thus at physiological concentrations ANP acts within the kidney to decrease proximal reabsorption by inhibition of angiotensin-stimulated sodium and water transport.
262 citations
TL;DR: A 22-residue peptide is synthesized corresponding to residues 480-501 (determined from the cDNA) of the smooth muscle myosin light chain kinase and raises the possibility that the calmodulin binding region of the myos in light chain Kinase may act as a pseudosubstrate inhibitor of the enzyme.
226 citations
TL;DR: Recent laboratory and clinical investigations have shown that EPEC strains constitute a distinctive group of pathogenic microorganisms displaying characteristic adherence to cultured epithelial cells and producing pathognomonic histopathologic changes in experimentally infected animals and naturally infected children.
Abstract: First described in 1885, Escherichia coli gradually emerged as a cause of infantile diarrhea. Currently, four pathogenic categories of diarrheagenic E. coli are recognized: enteropathogenic (EPEC), enterotoxigenic (ETEC), enteroinvasive (EIEC), and enterohemorrhagic (EHEC). Of these, ETEC and EPEC are important causes of pediatric diarrhea, especially in developing countries. ETEC strains are characterized by their production of well-defined heat-labile or heat-stable enterotoxins. In the absence of other identifying characteristics, EPEC strains have been identified by serotyping only; recent laboratory and clinical investigations have shown that these strains constitute a distinctive group of pathogenic microorganisms displaying characteristic adherence to cultured epithelial cells and producing pathognomonic histopathologic changes in experimentally infected animals and naturally infected children. The pathogenicity of most strains of EPEC is associated with the carriage of a 55- to 70-megadalton plasmid that specifies the production of an adherence factor. EPEC strains may also owe their pathogenicity to the production of at least one enterotoxin, possibly a Shiga-like cytotoxin.
218 citations
TL;DR: In this paper, the authors investigated the rheology of strongly-flocculated dispersions of colloidal particles in a continuous network and showed that these networks possess a true yield stress in both shear and uniaxial compression (as realised in a centrifuge).
Abstract: The rheology of strongly-flocculated dispersions of colloidal particles has been investigated at particle concentrations where a continuous network is formed rather than a collection of discrete flocs. Such networks are shown to possess a true yield stress in both shear and in uniaxial compression (as realised in a centrifuge). Properties measured as a function of particle concentration and particle size include the yield stresses in shear (σ y ) and compression ( P y ); the limiting and strain-dependent, instantaneous shear moduli G O and G (γ); the elastic recovery at finite strains, and the rate of centrifugally-driven compaction. The yield stresses and moduli appear to show a power-law dependence on particle concentration with G O and P y , having the same power-law index and σ y a somewhat lower one. The data are in part consistent with predictions based on the idea that the networks have a heterogeneous structure comprising a collection of interconnected fractal aggregates. The behaviour as a function of particle size and concentration is however not completely scaleable as might be expected on this basis. Thus, whereas the shear yield stress could be scaled to remove its dependence on particle radius a and volume fraction φ (over the measured range 0.25 μm ⩽ a ⩽ 3.4 μm; 0.05 ⩽ φ ⩽ 0.25) as could the strain dependent modulus (0.25 ⩽ a ⩽ 1.3 μm; 0.08 ⩽ 0.25), the particle-size and concentration dependence of P y and G O could only be scaled for particles with radii between 0.16 and 0.5 μm, smaller and larger particles having different and much higher power-law index in respect of their concentration dependencies. In the case of the smaller particles the failure of the scaling is thought to be due to an anomaly since these particles distort significantly under the influence of the strong van der Waals forces and this causes the aggregates to be more compact then they otherwise would be. The reasons for the failure at larger sizes is not clear.
213 citations
TL;DR: In this article, the authors argue for a particular view of teaching and learning in higher education, and propose a relational perspective to link the improvement of the professional practice of teaching with research into student learning.
Abstract: The article argues for a particular view of teaching and learning in higher education. A relational perspective links the improvement of the professional practice of teaching with research into student learning. It offers an alternative to paradigms which reduce the complex relations between students, subject content, and teaching to characteristics of instruction and of students, and whose findings and prescriptions often appear distant from everyday teaching problems. Learning in institutional settings is bound up with content and context; isolating general mechanisms that ‘good learners˚s use to learn any subject matter may be less than helpful. A relational perspective conceptualises the teaching and learning process holistically. It involves inquiry into and reflection on how students learn specific subject matter in particular contexts. The results are used to amend teaching and assessment. The perspective has far-reaching implications for staff development and the quality of teaching in hi...
TL;DR: The ability of casein and tryptic peptides to prevent enamel demineralization was related to their incorporation into plaque, thereby increasing plaque calcium phosphate and acid-buffering capacity by the phosphoseryl, histidyl, glutamyl, and aspartyl residues and indirectly through catabolism by plaque bacteria.
Abstract: The ability of bovine milk phosphoprotein (casein) to be incorporated into plaque, prevent enamel sub-surface demineralization, and affect bacterial composition was determined using a modified intra-oral caries model. The intra-oral model consisted of a removable appliance containing a left and right pair of bovine enamel slabs placed to simulate an approximal area. Supragingival plaque was collected and impacted into the left and right inter-enamel spaces. The left side of the appliance was exposed to various sugar and salt solutions, while the right side was exposed to sugar and casein solutions. Sodium caseinate, the major fraction alpha s1-casein, and a tryptic digest of alpha s1-casein (TD-casein) were studied. Sodium caseinate at a level of 2% w/v in a 3% sucrose-3% glucose-salt solution (pH 7.0) prevented sub-surface enamel demineralization over a ten-day period as shown by microradiography and microhardness. Two exposures of a 2% w/v sodium caseinate, alpha s1-casein, or TD-casein solution (pH 7.0) per day prevented sub-surface enamel demineralization caused by six exposures of a 3% sucrose-3% glucose-salt solution per day over a ten-day period. Intact alpha s1-casein and tryptic peptides were shown immunochemically to be incorporated into the inter-enamel plaque. The incorporation of casein and its breakdown in plaque did not produce a significant change in the amount or composition of plaque bacteria. The ability of casein and tryptic peptides to prevent enamel demineralization was related to their incorporation into plaque, thereby increasing plaque calcium phosphate and acid-buffering capacity by the phosphoseryl, histidyl, glutamyl, and aspartyl residues and indirectly through catabolism by plaque bacteria.
TL;DR: It is shown that insecticide-resistant phenotypes of the Australian sheep blowfly, Lucilia cuprina, show greater fluctuating asymmetry than susceptible phenotypes when resistance first evolves, and that continued use of an insecticide after resistance develops leads to a return in the asymmetry of resistant phenotypes to the level of susceptibles.
Abstract: Maynard Smith et al.1 have recently suggested that newly evolved phenotypes will be more variable than long-established ones when developmental constraints have evolved through canalizing selection in which similar phenotypic expression is stabilized across a range of genotypes2. There is as yet little evidence for this1,3. Fluctuating asymmetry1 (random differences between left and right sides of a normally bilaterally symmetric organism) has been used to indicate developmental stability and to define environmental or genetic stresses on development4–14. Here we show that insecticide-resistant phenotypes of the Australian sheep blowfly, Lucilia cuprina, show greater fluctuating asymmetry than susceptible phenotypes when resistance first evolves, and that continued use of an insecticide after resistance develops leads to a return in the asymmetry of resistant phenotypes to the level of susceptibles. The asymmetry of resistant phenotypes increases during repeated back-crossing to a susceptible strain, suggesting that developmental stability may be modified by selection.
TL;DR: A model is proposed for Thyroxine transport from the bloodstream into cerebrospinal fluid based on partitioning of thyroxine between choroid plexus and surrounding fluids and binding of thyoxine to transthyretin newly synthesized and secreted by choroids plexi.
TL;DR: It is concluded that the enzyme may act to convert circulating angiotensin I to angiotENSin II in circumventricular organs; generate intraneuronal angiotensor II in pathways such as the hypothalamic-hypophyseal tract; and process neuropeptides other than angioten II in regions such as basal ganglia.
TL;DR: It is found that a maximum of 14 mouse kallikrein genes have the potential to encode functional proteins, and those which are pseudogenes or encode proteins of unknown function are assigned.
TL;DR: In RA patients, there was a depletion of SI cells in blood andsynovial fluid, and the ratio of HI cells to SI cells was elevated, particularly in the synovial lymphocytes, which provide new evidence for T cell dysregulation in the perpetuation of RA.
Abstract: New monoclonal antibodies allow CD4 lymphocytes to be categorized into helper/inducer (HI) CD4+ 4B4+, and suppressor inducer (SI) CD4+ 2H4+ subpopulations. Blood and synovial lymphocytes from 30 patients with rheumatoid arthritis (RA), 13 patients with other articular diseases, and 24 control subjects were exposed to these monoclonal antibodies and analyzed by flow cytometry. CD4:CD8 ratios were similar for the 3 groups. In RA patients, there was a depletion of SI cells in blood and synovial fluid, and the ratio of HI cells to SI cells was elevated, particularly in the synovial lymphocytes. These data provide new evidence for T cell dysregulation in the perpetuation of RA.
TL;DR: In this paper, postmodernism or post-colonality in textual practice is discussed, with a focus on post-colonialism and post-structured textual practices.
Abstract: (1987). Postmodernism or post‐colonialism today. Textual Practice: Vol. 1, No. 1, pp. 32-47.
TL;DR: In this paper, the phase-averaged velocity vector fields are discussed in terms of critical point theory and an investigation of turbulent wakes is conducted, as well as phaseaveraged and global Reynolds normal and shear stresses.
Abstract: An investigation of turbulent wakes was conducted and phase-averaged velocity vector fields are presented, as well as phase-averaged and global Reynolds normal and shear stresses. The topology of the phase-averaged velocity fields is discussed in terms of critical point theory. Here in Part 1, the vortex formation process in the cavity region of several nominally two-dimensional bluff bodies is investigated and described using phase-averaged streamlines where the measurements were made in a nominal plane of symmetry. It was found that the flows encountered were always three-dimensional and that the mean-flow patterns in the cavity region were quite different from those expected using classical two-dimensional assumptions.
TL;DR: The low mortality and high longevity of A. tranteri are consistent with the observed low abundances of planktonic predators and with the low consumption rates of Acartia by planktivorous fish in the bay.
Abstract: We measured the growth rate of Acartia tranteri and related variables in Westernport Bay, Australia, on 19 occasions in 1982-1984. Acartia tranteri is numerically dominant in the bay zooplankton, with a mean abundance of all life stages of 12,000 m-3. Growth rates, measured by an incubation method, varied between 0.025 and 0.26 d-l with a time-weighted mean of 0.11 d-l. Temperature and chlorophyll concentrations together explained 50% of the variance in growth rate, which was usually food limited. Annual secondary production of A. tranteri was 130 mg C m- 3, 2O”C. The low mortality and high longevity are consistent with the observed low abundances of planktonic predators and with the low consumption rates of Acartia by planktivorous fish in the bay.
TL;DR: In this article, the extent of intra-industry information transfers associated with the half-yearly earnings announcements of a sample of Australian firms was investigated using a recursive systems specification of the return generating process to model extra-market return covariation in cross-section.
TL;DR: This hypothesis is consistent with what is known of the α‐crystallin molecule and aggregate, and can be tested experimentally, and if shown to be true, then α‐ Crystallin will be the first example of a naturally occurring protein micelle.
TL;DR: It is concluded that S2-gene expression correlates well with the expression of incompatibility, and is reported here that expression of the gene occurs in the stigma and throughout the secretory tissue, but not in other parts, of mature pistils.
Abstract: In many flowering plant species, a system of self-incompatibility, typically controlled by a single gene with multiple alleles (S-gene)1, enables individual plants to recognize and reject their own pollen. In gametophytically determined systems, the growth of self-pollen tubes is arrested in the style or occasionally the ovary. The expression of this self-incompatibility is developmentally regulated, being strongest in mature flowers and weak in immature styles1,2. We have used a complementary DNA clone, believed to encode the S2-allele of Nicotiana alata2,3, to detect S2 messenger RNA by in situ hybridization to sections. We report here that expression of the gene occurs in the stigma and throughout the secretory tissue, but not in other parts, of mature pistils. In immature flowers, S2 mRNA is confined to the proliferated epidermis of the stigma. We conclude that S2-gene expression correlates well with the expression of incompatibility.
Journal Article•
TL;DR: Serum levels of relaxin in normal and special-interest pregnancies using an homologous radioimmunoassay for human relaxin were higher than those reported in studies using heterologous assays, but the trend in serum levels was similar.
TL;DR: The differential approach to query evaluation in function free, recursively defined, Horn clauses was recently proposed as an improvement to the naive bottom-up evaluation strategy and is extended to efficiently accomodate n recursically defined predicates in the body of a Horn clause.
Abstract: The differential (or seminaive) approach to query evaluation in function free, recursively defined, Horn clauses was recently proposed as an improvement to the naive bottom-up evaluation strategy. In this paper, we extend the approach to efficiently accomodate n recursively defined predicates in the body of a Horn clause.
TL;DR: For large data files, it is shown that the two-level implementation is generally more efficient for queries with a small number of matching records and when blocks of records match the query but individual records within these blocks do not.
Abstract: Both single-level and two-level indexed descriptor schemes for multikey retrieval are presented and compared. The descriptors are formed using superimposed coding techniques and stored using a bit-inversion technique. A fast-batch insertion algorithm for which the cost of forming the bit-inverted file is less than one disk access per record is presented. For large data files, it is shown that the two-level implementation is generally more efficient for queries with a small number of matching records. For queries that specify two or more values, there is a potential problem with the two-level implementation in that costs may accrue when blocks of records match the query but individual records within these blocks do not. One approach to overcoming this problem is to set bits in the descriptors based on pairs of indexed terms. This approach is presented and analyzed.
Book•
04 Sep 1987TL;DR: It is indicated that some prelingually deaf patients may get worthwhile help from a multiple-electrode cochlear implant which extracts formants, and that deaf children are severely disadvantaged however good their teacher of the deaf is.
Abstract: To summarize, our preliminary results indicate that some prelingually deaf patients may get worthwhile help from a multiple-electrode cochlear implant which extracts formants. They can understand words and running speech better when using the cochlear implant with lip-reading compared to lip-reading alone. It has been encouraging that these improvements can occur in young adults and teenagers. It has also been encouraging that some can recognize place pitch as well as rate pitch. There are, however, considerable variations in performance and this may be due to the following factors: whether they have had some hearing after birth, the method of education used, the motivation of the patient and age at implantation. In conclusion it is important to emphasize that deaf children are severely disadvantaged however good their teacher of the deaf. Research on cochlear implants offers hope for profoundly-totally deaf children. These developments will not replace the caring, competent educators but complement their skills. There is also a greater need than ever for an interdisciplinary approach to these children.
TL;DR: The scale of spatial and temporal fluctuations is described for populations of the arborescent bryozoan Bugula neritina, and observational and experimental data were used to explain these fluctuations.
Abstract: The scale of spatial and temporal fluctuations is described for populations ofthe arborescent bryozoan Bugula neritina, and observational and experimental data were used to explain these fluctuations Colonies were found to be abundant on seagrasses in the northern Gulf of Mexico from mid to late fall through winter Populations increase in mid to late fall, roughly with the onset of cooler weather They decline between midwinter and early summer, apparently when cold fronts pass We found no colonies on seagrass in summer, but some large colonies attached to polychaete tubes lie dormant through summer, regenerating in fall Spatial variation occurs on very small scales Bugula were absent from some seagrass patches, even when substantial populations were 80?/o at Lanark Growth rates were also higher at the site without natural Bugula colonies, and colonies there began to reproduce 1 wk sooner than those at the marine lab site Juveniles transplanted to Lanark reproduced, and their offspring grew and reproduced successfully, producing a second generation of Bugula The newly established population persisted through summer and was still present in 1986 Local extinctions of Bugula populations are probably caused by storms; one such ex? tinction was observed The spatial pattern is maintained by restricted dispersal and pop? ulation bottlenecks Unoccupied seagrass patches are unlikely to be colonized by larvae, but rafting of mature colonies on seagrass occurs frequently, with the potential of seeding new habaitats
TL;DR: An error diagnoser which finds errors in logic programs which use the extended syntax and advanced control facilities is presented, arguing that declarative error diagnosers will be indispensable components of advanced logic programming systems, which are currently under development.
Abstract: This paper presents an error diagnoser which finds errors in logic programs which use the extended syntax and advanced control facilities. The diagnoser isdeclarative, in the sense that the programmer need only know the intended interpretation of an incorrect program to use the diagnoser. In particular, the programmer needs no understanding whatever of the underlying computational behaviour of the PROLOG system which runs the program. It is argued that declarative error diagnosers will be indispensable components of advanced logic programming systems, which are currently under development.
TL;DR: It appears unlikely that CGRP releases an endothelium‐derived relaxing factor similar to that released by acetylcholine, because of the high concentration of cyclic GMP in the smooth muscle of rats without any exogenous vasodilator agent.
Abstract: 1 Acetylcholine and rat calcitonin gene-related peptide (CGRP) produced a relaxation in rat isolated aortic rings which was entirely dependent on the presence of the endothelium. 2 In the absence of any exogenous vasodilator agent, the cyclic guanosine monophosphate (cyclic GMP) content was higher in rings with endothelium than in those without. 3 The vasorelaxation produced by acetylcholine and sodium nitroprusside was accompanied by increases in cyclic GMP in the smooth muscle, whereas that produced by CGRP was not accompanied by cyclic GMP accumulation. 4 Therefore, it appears unlikely that CGRP releases an endothelium-derived relaxing factor similar to that released by acetylcholine.