Showing papers by "University of Queensland published in 1978"

Identification of ataxia telangiectasia heterozygotes, a cancer prone population

Abstract: IN ataxia telangiectasia (AT), an autosomal recessive disease of man with neurological, cutaneous and immunological abnormalities1, cells from homozygotes are sensitive to ionising radiation2 and have a low capacity to repair the resulting DNA damage3. Heterozygotes lack the main clinical features of the syndrome but share with homozygotes a high predisposition to cancer4. One study has demonstrated an increased level of chromosomal abnormalities in some heterozygotes5. Because these heterozygotes represent ⩾1% of the population4 and cannot be diagnosed clinically, their characterisation represents a major challenge in cancer epidemiology. We report here the laboratory identification of a series of obligate heterozygotes for AT, based on the sensitivity of lymphoblastoid cell lines to ionising radiation.

Microbial associations in sponges. I. Ecology, physiology and microbial populations of coral reef sponges

Abstract: Illumination, current strength and physical turbulence influence the distribution of 4 tropical sponges. Three sponges with cyanobacteria in exposed tissues grow only in poen shallow habitats: Pericharax heteroraphis in moderate-current, lowturbulence regions on the reef slope; Jaspis stellifera in low-current, moderate-turbulence regions of the outer reef flat; and Neofibularia irata in moderate-current, high-turbulence areas below the reef crest. Ircinia wistarii contains no cyanobacteria and occurs in deeper, strong-current, high-turbulence regions. N. irata agressively overgrows neighbouring corals and its growth form is influenced by the current strength. The sponges efficiently filter bacteria from the water. The efficiency is related to the aquiferous structure, particularly the size of choanocyte chambers, and is unrelated to the existing bacterial populations in sponge tissue. The numbers of bacteria associated with the sponges are proportional to the sponge mesohyl density, with the dense sponges J. stellifera and I. wistarii containing many bacteria whereas P. heteroraphis is not dense and has few bacteria.

Microbial associations in sponges. II. Numerical analysis of sponge and water bacterial populations

Abstract: Three taxonomically distant sponges Pericharax heteroraphis, Jaspis stellifera and Neofibularia irata contain phenotypically similar bacterial symbionts which differ from bacteria in the ambient water. These symbionts are predominant in the sponges and were detected after computer analysis of 526 heterotrophic bacterial strains tested for 76 characters. These facultative anaerobic symbionts metabolize a wide range of compounds and may be important in removing waste products while the sponges are not circulating water. The bacteria produce sticky-mucoid colonies and thus would contribute to sponge structural rigidity. The fourth sponge Ircinia wistarii contains a mixed aerobic population similar to that in the ambient water. The majority of the bacteria are located around the inhalant canals, facilitating the uptake of dissolved organic matter and oxygen from the incoming water.

Effects of helpers on feeding of nestlings in the Grey-crowned Babbler ( Pomatostomus temporalis )

Abstract: 1. The benefits of helping behavior to recipients were studied by analyzing the factors that influence rates of feeding of nestlings by parents and helpers in Pomatostomus temporalis. 2. Considering the nestlings as recipients, no benefits were detected from helpers that would not have been received from the parents alone: total feeding rate was independent of the number of helpers. Total feeding rate was dependent on the energy needs of the nestlings and on environmental factors, such as temperature and rainfall. 3. Considering parents as recipients, benefits were detected in the form of energy savings. As the number of helpers increased, the feeding rates of parents declined in terms of both percentage (Fig. 1) and absolute feeding rates. The percentage of decline with each additional helper diminshed as the number of helpers increased up to four. With eight helpers there was little or no more savings to the parents than with four. 4. Helpers benefited from the presence of other helpers in the same way as adults, namely, by an energy savings (Fig. 1). 5. Feeding rates of nestlings by fathers and helpers were lower in the presence of dependent juveniles from a previous brood than in their absence.

The effect of ascorbic acid on infection of chick-embryo ciliated tracheal organ cultures by coronavirus.

Abstract: Chick embryo tracheal organ cultures showed increased resistance to infection by a coronavirus after exposure to ascorbate, while chick respiratory epithelium and allantois-on-shell preparations showed no increase in resistance to infection by an influenza virus or a paramyxovirus.

The pathology and pathogenesis of chronic lead nephropathy occurring in Queensland

Abstract: Many children who suffered acute lead poisoning in Queensland eventually died with contracted kidneys. In most cases the kidneys were granular and showed microscopically fibrosis, hypertensive vascular changes and "alterative glomerulitis". Clinically in these patients, hypertension and chronic renal insufficiency had always preceded death which was usually due to uraemia. In a minority of cases the kidneys showed the changes of benign hypertension but were unusually small; fibrosis and "alterative glomerulitis" were not present. Clinically these patients had had hypertension but minimal renal insufficiency and death was usually due to cerebral haemorrhage. The evidence indicates that lead caused severe damage to the kidney at the time of the lead intoxication by some mechanism other than hypertension. The sequence of events postulated comprises severe renal damage with destruction of glomeruli during childhood lead poisoning, disappearance of the destroyed tissue during childhood and adolescence, onset of hypertension in adolescence or early adult life, gradual onset and progress of chronic uraemia during which fibrosis and granularity developed. In milder cases the sequence is not complete because renal function has remained adequate.

Two-component monolayers IV. The excess enthalpies and entropies of mixing in the octadecanol-docosyl sulfate system

Abstract: Surface pressure-area isotherms have been determined for the octadecanol-docosyl sulfate monolayer system on 0.1 M potassium chloride solution. Four different temperatures in the range 288 to 318°K and 11 different monolayer compositions were investigated. The Goodrich method was used to calculate the free energies, enthalpies, and entropies of mixing as excesses over the values of the corresponding properties at the lowest observable surface pressure. The small negative values of the excess free energy of mixing thus obtained were found to result from the near cancellation of relatively large contributions from the positive values of the excess enthalpy and the excess entropy. These results are attributed to changes in the hydration of the monolayers during mixing.

The ACTH ‘family tree’ of the rhesus monkey changes with development

Abstract: THE pituitary hormone adrenocorticotrophin (ACTH) belongs to a ‘family’ of peptides derived from a common ‘stem hormone’ (Fig. 1). Depending on the way in which the stem hormone is cleaved, the various peptides are expressed and it is possible that qualitative changes in the expression of the peptide ‘family tree’ may be responsible for the alteration in fetal adrenal function which precedes birth1. We now report evidence for such changes in the rhesus monkey, which has a fetal adrenal comparable with that of man.

The density of adrenergic nerves at various levels in the guinea‐pig lung

Abstract: 1. Guinea‐pig tracheal and lung segments were systematically examined for adrenergic nerves using the fluorescence histochemical technique. Fluorescence in nerves was enhanced with α‐methylnoradrenaline or by pretreating the animals with nialamide. 2. There was a progressive decrease in density of fluorescent fibres in airway smooth muscle from the laryngeal end of the trachea, which was densely innervated, to the bronchioles, which contained only occasional fibres. This was despite obvious fluorescence in blood vessels in the lung. 3. It is suggested that, if adrenergic nerves are involved in reflex bronchodilatation in this species, they directly control larger airways and other factors, e.g. non‐adrenergic inhibitory nerves, may be important in the control of smaller airways. Copyright

Breeding Biology and Development of the Young of Manorina Melanocephala, a Communally Breeding Honeyeater

Abstract: The Noisy Miner is a communal breeder: many individuals participate in activities at each nest. However, much of the species’s behaviour and social organization is unique, even among communal breeders. Marked populations were observed in south-eastern Queensland between 1969 and 1974 but most data are from one intensely studied area in 1972, with additional data from 1971 and 1973.In this study area of seven hectares, 137 birds were colour-banded. The resident population declined in the three years from 9.0 to 7.7 birds per hectare. The sex ratio favoured males by as much as 3.3:1. Most breeding occurred between July and November. The onset of nesting varied from year to year and could not be easily related to environmental variables. Most nests were built in sites that did not afford much concealment. The height of nests varied but preference was mot shown by particular females. Successive nests tended to be higher, effected by females selecting higher trees. Spiders’ web and silk from cocoons was used in the construction of nests. The female built the nest and advertised its position with a flight display. Previous nests were dismantled and used in the construction of the nests. Building visits averaged 8.7 per hour and as many as seven males visited a nest at this stage. Females did not visit other nests. Males visiting the nest of an incubating female were all found to be producing spermatoza and at any time of year probably some males in a population are producing sperm. In some years some adult females made no nesting attempts.Clutches varied from one to four and averaged 2.64 eggs. The first egg was laid in fewer than three days or more than nine after completion of the nest. Eggs were laid one each day usually, in the early morning, and females began to sit after the second egg was laid. Only one female incubated and incubation took sixteen days. Attendance at the nest by females at different stages in incubation averaged from 35.2 to 41.2 minutes per hour.The mean brood size was 2.52; 15.9 per cent of eggs, excluding those lost, failed to hatch. The nestling period was about sixteen days. Only the female brooded.Fledging proceeded over several days, the young gradually moving out on supporting branches in the day and returning to the nest at night. Once away from the nest, the young made their way to the top of a tree. They were highly vocal in soliciting food. When fed, the wings were not quivered, perhaps a behaviour counteracting the high activity of feeding adults. Feeding rates at this stage were as high as 87.8 times per hour. Juveniles between twenty-six and thirty days from the nest were first threatened by adults. Between thirty-one and thirty-five days, they began to utter a quiet warbling subsong. Attacks by adults became more frequent and reached their greatest intensity between fifty and seventy days. Both males and females attacked juveniles.Nest success was very low, less than ten per cent in each of the three years. Even if some nests were never laid in, success calculated to exclude this possibility was still no greater than 16.7 per cent in any year. Some loss could be attributed to wind and storms; presumably the remainder was through predation or activities of the Miners themselves. A new nest was usually started when a female lost eggs or nestlings, in one case in fewer than sixty hours.

A Clinical Study of Gingival Inflammation in Renal Transplant Recipients Taking Immunosuppressive Drugs

Abstract: The relationship between the gingival inflammation and plaque scores of patients who had received kidney transplants and were taking immunosuppressive drugs to combat rejection pheomena was compared with data from a control group. Equivalent plaque scores were associated with less gingival inflammation in the patients taking the immunosuppressive drugs. While there was no signficant difference between the plaque scores of the two groups the control group displayed signficantly more gingival inflammation. The implications of these results with respect to possible etiological mechanisms operating in periodontal disease are discussed.

Sedimentation Trends in the Lee of Outer (Ribbon) Reefs, Northern Region of the Great Barrier Reef Province

Abstract: A programme of surface sediment sampling, continuous high resolution seismic reflexion profiling, and side-scan sonar surveys, carried out in the Northern Region of the Great Barrier Reef Province between latitudes 14° 319 S and 14° 459 S, extending between the continental shelf edge and a line of mid-shelf continental islands, has demonstrated the diversity of sedimentation factors controlling sediment distribution patterns, and revealed complex petrological variations and unsuspected stratigraphic relations. The granulometric characteristics of many inter-reef sediments are imparted chiefly by mixing, whereas sorting under high energy conditions, and the effectiveness of the * Sorby Principle ’ are primarily responsible for the granulometric characteristics of the reef-top sediments. Terrigenous end-members of mainland and/or continental island provenance are im portant on the southwestern margin of the area, but Halimeda debris dominates sediments coinciding with luxuriant Halimeda growth on back-reef ‘banks’ and ridges. A major disconformity indicating marine regression and shelf emergence is the most prominent seismic reflector, which outcrops near Cook’s Passage to coincide with the rocky, current swept, seabed at — 45 m, and which is incised near the shelf edge to — 69 m. The succeeding transgression resulted in the filling of the incised channels with sediment, followed by rapid sedimentation in the back-reef area and the establishment of platform reefs on this surface. Periods of still-stand or minor regressions are indicated by marine terraces at —22.5 m and —30 m, and by erosion surfaces within back-reef sedimentary deposits and reef masses. The seismic profiles suggest that the Holocene sedimentation pattern is a repetition of an ancient trend.

Defining Democracy: A Bid for Coherence and Consensus:

Abstract: For a short, definite, non-sectarian definition of democracy, I nominate Responsive Rule qua necessary correspondence between acts of governance and the desires with respect to those acts of the pe

Two Criteria for Preventive Maintenance

Abstract: The purposes of this paper are to model the effects of imperfect maintenance, and from the model to derive conditions under which preventive maintenance is beneficial. The criteria are derived via: 1) maximization of the steady state availability and 2) minimization of the s-expected cost per unit time over an infinite time span when the maintenance times are non-zero.

Salivation: the significance of imagery in its voluntary control.

Abstract: In a series of experiments, with over 100 subjects ranging in age from 14 to 43, issues in the control of salivation were examined. Using the sublingual cotton swab technique it was shown that salivation can be controlled by practitioners and non‐practitioners of transcendental meditation. Sex differences were unimportant; the use of specific imagery relating to food and anxiety aided control, and there was a highly significant relationship between the degree of self‐reported imagery vividness and the ability to increase and decrease salivation. Results were discussed in terms of the Pavlovian notion of signalling systems, and the suggestion was made that self‐generated imagery could be important for the control, and in the conditioning, of other autonomic effectors. Copyright

Photoelectrochemical cell with cadmium telluride film

Abstract: ELLIS et al.1 reported studies of single crystal CdX based photoelectrochemical cells when X = S, Se or Te and found that the best efficiencies were obtained when CdTe was used as the photoelectrode. Photoelectrochemical cells using thin films of CdS and CdSe have been reported by Miller and Heller2 and by Hodes et al.3 In this paper, we report on a photoelectrochemical cell using a thin polycrystalline film of CdTe.