Showing papers by "University of Newcastle published in 1993"

Cloning of the zebrafish krox-20 gene (krx-20) and its expression during hindbrain development

Abstract: To begin to examine the function of genes that control early development in the hindbrain, we have screened an embryonic zebrafish cDNA library with a murine krox-20 gene probe that contained the conserved zinc finger regions. We have isolated two overlapping cDNAs, zf187 and zf201 which are homologues of the murine krox-20 gene. The N-terminal of the longest cDNA (zf201) contains two acidic regions identical to those of the murine krox-20. This indicates that the functional organisation of these proteins is probably conserved. Northern Blot analysis identified a single transcript of 2.0 kb. Wholemount in situ hybridisation established that expression of the zebrafish gene (krx-20) first appears at 100% epiboly as a single anterior domain of the prospective neuroepithelium, followed very soon after by a second more posterior domain. The alternating pattern of expression of this gene in rhombomeres(r) r3 and r5 is apparent by 12 hr post-fertilisation, that is prior to the morphological appearance of the rhombomeres. Around 14 hr neural crest migration begins from the dorsal surface of r5, moving caudally into r6 and then ventrally towards the pharyngeal arches. Crest migration is not apparent at or after 16 hr. No neural crest migration was observed from r3. Expression of krx-20 is down regulated firstly in r3 around 26 hr and later in r5 around 30 hr.

Comparative local anaesthetic blocks in the diagnosis of cervical zygapophysial joint pain.

Abstract: The utility of randomised, double-blind, controlled, comparative local anaesthetic blocks for the diagnosis of cervical, zygapophysial joint pain was studied in 47 patients with chronic neck pain following whiplash injury. Each patient was investigated with radiologically controlled blocks of the medial branches of the cervical, dorsal rami to anaesthetise the target cervical, zygapophysial joint. The blocks were performed using either lignocaine or bupivacaine, randomly allocated, and the patients' responses were assessed in a double-blind fashion. Any positive response was subsequently assessed by repeating the block with the complementary anaesthetic. Only those patients experiencing a longer period of pain relief from the bupivacaine were considered to have true-positive responses. Forty-four patients had pain relief from two blocks at a single level, of whom 34 had longer pain relief from bupivacaine. This result is unlikely to have occurred by chance (P = 0.0002). The durations of pain relief obtained from the anaesthetics were consistent with the known characteristics of these drugs with bupivacaine lasting significantly longer than lignocaine (P = 0.0003). A subgroup of 13 patients were identified with unexpected, prolonged responses to one or both of the anaesthetics. Comparative, diagnostic blocks are a valid technique in the identification of painful zygapophysial joints, and constitute an implementable alternative to normal saline controls.

False-positive rates of cervical zygapophysial joint blocks.

Abstract: Objective:To determine the false-positive rate of anesthetic blocks of the medial branches of the cervical dorsal rami in the diagnosis of cervical zygapophysial joint painDesign:Comparison between single diagnostic blocks, and a criterion standard of double-blind, controlled, differential

Religion: A Confounding Cultural Element in the International Harmonization of Accounting?

Abstract: Discussion of the influence of culture on the international development and harmonization of accounting has focused primarily upon indigenous characteristics which are confined within national boundaries. But cultural inputs, such as religion, which transcend national boundaries, should not be overlooked. Islam is a particular case in point. Its principles commit Muslims to a definitive code of ethical commercial and personal behaviour affecting both the structuring and financing of business affairs between the faithful, and between Muslims and non-Muslims. Islam has the potential for influencing the structure, underlying concepts and the mechanisms of accounting in the Islamic world. Its potential for influencing accounting policy is illustrative of religion as a confounding element in the analysis of national idiosyncrasies in accounting practice and in deconstructing the impediments to international harmonization.

Nonlinear System Analysis and Identification from Random Data

Abstract: Linear Systems, Random Data, Spectra Zero-Memory Nonlinear Systems Bilinear and Trilinear Systems Nonlinear System Input/Output Relationships Square-Law and Cubic Nonlinear Systems Statistical Errors in Nonlinear Estimates Parallel Linear and Nonlinear Systems.

On the nature of neck pain, discography and cervical zygapophysial joint blocks

Abstract: To determine the prevalence of disc pain and zygapophysial joint pain occurring simultaneously in the same segment of the neck, 56 patients with post-traumatic neck pain underwent both provocation discography and cervical zygapophysial joint blocks. Both a symptomatic disc and a symptomatic zygapophysial joint were identified in the same segment in 41% of the patients. Discs alone were symptomatic in only 20% of the sample. Zygapophysial joints were symptomatic but discs asymptomatic in 23%. Only 17% of the patients had neither a symptomatic disc nor a symptomatic zygapophysial joint at the segments studied. These observations indicate that the investigation of neck pain by discography alone or by zygapophysial blocks alone constitutes an inadequate approach to neck pain which fails to identify the majority of patients whose symptoms stem from multiple elements in the 3-joint complexes of the neck.

Qaly league tables: Handle with care

Abstract: This paper examines some of the difficulties in using QALY league tables in priority setting. Such tables sometimes are seen as being 'the' way to prioritise in health care and in particular, at present, with respect to priority setting among purchasers in the UK NHS. However the paper highlights the fact that the base on which such tables is built is small--relatively few studies in the English language using CUA have been conducted anywhere. Further, four issues which require handling with care are set out: (i) the relevant measure of cost in QALY league tables has to be restricted to health service resource use; (ii) the relevant measure of benefit in QALY league tables is clearly restricted to QALYs, thereby the utility of health gains and indeed the maximisation of the utility of health gains; (iii) in incorporating the results of CUA studies into QALY league tables there is a need for greater clarification on what the margin constitutes; and (iv) those who might use CUA results in QALY league tables need to ascertain whether the original context of the study will allow the results to be transferred to the local context of the decision maker. The paper suggests that there is a need to be quite clear what goal QALY league tables serve. The authors argue that the only legitimate (and clearly important) goal of QALY league tables is the maximization of the utility of health gains within a health service budget.(ABSTRACT TRUNCATED AT 250 WORDS)

Medial branch blocks are specific for the diagnosis of cervical zygapophyseal joint pain.

Abstract: Background and Objectives. To determine the specificity of cervical medial branch blocks for the diagnosis of cervical zygapophyseal joint pain by ascertaining the disposition of the local anesthetic after injection of the medial branches of the cervical dorsal rami. Methods. Sixteen consecutive patients with chronic neck pain from motor vehicle accidents underwent cervical medial branch blocks. A 22-gauge, 90-mm spinal needle was placed onto the target nerve under image-intensifier guidance. Immediately after each target nerve had been infiltrated with 0.5 ml of local anesthetic, 0.5 ml of contrast medium was injected to map the spread of injectate. Radiographs were recorded to document the pattern of spread. Results. Twenty-five injections of local anesthetic and contrast medium were performed. Contrast medium dispersed in characteristic patterns at all vertebral levels and always incorporated at least 5 mm of the perceived course of the target nerve. There was never any spread to the ventral ramus, beyond the medial fibers of semispinalis capitis or to the adjacent medial branches. No other single structure was consistently within the field of the contrast. Eleven patients obtained complete or definite relief of their pain, which could only be attributed to anesthetization of the zygapophyseal joint innervated by the nerves blocked. Conclusions. Local anesthetic blocks of the cervical medial branches are a specific test for the diagnosis of cervical zygapophyseal joint pain. The local anesthetic always reaches the target nerve and does not affect any other diagnostically important structures.

Confirmation that the velo‐cardio‐facial syndrome is associated with haplo‐insufficiency of genes at chromosome 22q11

Abstract: The velo-cardio-facial syndrome (VCFS) and DiGeorge sequence (DGS) have many similar phenotypic characteristics, suggesting that in some cases they share a common cause. DGS is known to be associated with monosomy for a region of chromosome 22q11, and DNA probes have been shown to detect these deletions even in patients with apparently normal chromosomes. Twelve patients with VCFS were examined and monosomy for a region of 22q11 was found in all patients. The DNA probes used in this study could not distinguish the VCFS locus and the DGS locus, indicating that the genes involved in these haploinsufficiencies are closely linked, and may be identical. The phenotypic variation of expression in VCFS and DGS may indicate that patients without the full spectrum of VCFS abnormalities but with some manifestations of the disorder may also have 22q11 deletions.

Influence of sulphur and nitrogen on seed yield and quality of low glucosinolate oilseed rape (Brassica napus L.)

Abstract: Influence of S and N application on seed yield and quality of a double low (low erucic acid and glucosinolate content) variety of winter oilseed rape (Brassica napus L) was examined in field experiments at both S-sufficient and S-deficient sites. At the S-sufficient site, application of S had no significant influences on seed yield, yield components, seed protein and oil contents, and resulted in only a marginal increase in seed glucosinolate content. Application of N increased seed yield and protein content, but decreased oil content concurrently. A significant increase in seed glucosinolate content in response to the increasing N rate was obtained at this site, which was more noticeable in those treatments with applied S than without. In contrast, at the S-deficient site, there were significant interactions between S and N on seed yield, protein and glucosinolate contents. Increasing the N rate beyond 150 kg ha−1 did not increase seed yield in the absence of applied S. However, with an application of 300 kg N ha−1, seed yield increased by 10·7% with an application of 50 kg S ha−1. The effect of N on seed yield was achieved mainly through enhanced pod formation, and that of S through reduced pod abortion. Sulphur application also increased seed protein content at the high N rate, and increased methionine content at the expense of aspartic acid. On average, a two-fold increase in seed glucosinolate content in response to an application of 100 kg S ha−1 was obtained at the S-deficient site. Also, increasing the N rate decreased seed glucosinolate content in the absence of applied S, but increased it when S was applied. The interaction between S and N on seed glucosinolate content was explained in terms of the allocation of S towards primary and secondary metabolites within plants.

Using nanoindentation techniques for the characterization of coated systems: a critique

Abstract: Ultralow load indentation testing, or nanoindentation, has considerable potential for studying the near-surface mechanical properties of solids and seems especially suited to the mechanical characterization of thin-film-coated systems where both low contact loads and high spatial precision can be advantageous. This paper assesses the current possibilities for, and limitations of, nanoindentation for assessing the properties of coated systems. In particular, the pursuit of hardness values alone is questioned, especially when the continuous load and depth data from the indentation cycle provide a far more complete mechanical “fingerprint” from which a number of important parameters describing the system behaviour can be calculated. The further difficulty of assessing the properties as a function of the depth into the coated system is also demonstrated. The additional information accessible through post facto microstructural characterization of the indentations themselves, the possible use of various indenter geometries and the need for parallel computer modelling to predict response are also discussed.

An inexpensive and simple method for DNA purifications on silica particles

Abstract: We have developed a simple, rapid and cheap method for the isolation of DNA from various sources by a further development of the silica binding method of Boom et al. (1). In combination with the alkaline lysis method for preparation of bacterial lysates, this constitutes a rapid and effective method for the isolation of plasmid DNA for sequencing and other purooses. In this method the DNA-binding matrix is provided by diatomaceous earth as a cheap and convenient source of silica particles. Pretreatment with nitric acid is not required, but the diatoms should be size fractionated. Very small particles are difficult to remove without filtration and may inhibit some enzymic reactions. This is performed by resuspending 50 g of diatoms (Sigma D 5-384) in 500 ml of water, and allowing them to settle in a 500 ml measuring cylinder for 3 hours. The settled particles are recovered in 10—20 ml and resuspended at 10 mg/ml in 4 M guanidine thiocyanate (Sigma G-6639), 50 mM Tris-HCl pH 7.0, 20 mM EDTA (assuming no significant loss of material during the size fractionation step). This solution (termed DNAbind) should be stored in the dark and is stable for at least three months. DNA may be recovered from solution (eg enzyme reaction mixtures or gel eluates) by the following method which is designed for a volume of DNA solution of 0.5 ml. If the sample volume is smaller than this it should be adjusted to 0.5 ml with water and transferred to a 1.5 ml microfuge tube. The DNAbind solution is shaken and 1 ml added to the sample. The tube is mixed for 2 min at room temperature to allow binding of the DNA before the diatoms are sedimented for 5 —10s in a microfuge. The supernatant is removed with a drawn-out Pasteur pipette and the pellet resuspended in 50% ethanol containing 200 mM NaCl, 10 mM EDTA, 50 mM Tris-HCl pH 7.4. Diatoms are pelleted again, and the washing step repeated. The final pellet is washed in 1.0 ml of acetone as above and briefly dried at 65°C. DNA is eluted by resuspending the pellet in 50-200 /d of water and incubating at 65 °C for 2 minutes. Diatoms are then removed by sedimentation and the aqueous solution of DNA transferred to a fresh tube. We have successfully recovered ds DNA fragments as small as 120 bp. This procedure is compatible with a modification of the alkaline lysis method for plasmid minipreparation and considerably speeds this process (2). We routinely resuspend 1.5 ml of an overnight bacterial culture in 200 /il of 25 mM Tris-HCl pH 7.4, 10 mM EDTA. If required RNAse A can be included in this solution at 50 /tg/ml. Cells are lysed by the addition of 200 /tl of 0.2 M NaOH, 1 % SDS and gentle inversion. When the suspension has cleared 0.2 ml of 2.55 M potassium acetate pH 4.8 is added and mixed. The flocculent precipitate is removed by centrifugation and the supernatant transferred to a clean tube. 1 ml of DNAbind solution is added and processed as above. This method yields in excess of 5 fig of DNA from a typical minipreparation of plasmid pTZ18R and requires 10-15 minutes to perform. Total costs involved (plasticware and chemicals) are low (approximately 12p per minipreparation). Single-stranded DNA is also recoverable from PEG-precipitates of bacteriophage after resuspension of the pellet in 0.5 ml of water. We have found DNA prepared this way to be immediately suitable for most laboratory procedures: both single and doublestranded sequencing reactions, restriction enzyme digestion, ligation, and for transfection of eukaryotic cells using lipofectin (data submitted but not shown). The method is suitable for the recovery of DNA between enzyme reactions and we estimate the efficiency as 60—80%. However losses become appreciable after 4 successive re-isolations. DNA made this way is lost during phenol extraction unless acidified beforehand by addition of sodium acetate pH 5.0 to 0.1 M. No further salt addition is then required for ethanol precipitation.

Families of mtDNA re-arrangements can be detected in patients with mtDNA deletions: duplications may be a transient intermediate form

Abstract: In three patients with mitochondrial DNA duplications, there are two additional re-arranged molecules derived from mitochondrial DNA. Two forms of closed circular deletions of mitochondrial DNA have been characterised in all three patients, one being a monomer, and the other a dimer. The junction fragments appear to be the same in the deletion and the duplication, suggesting that both re-arrangements arose from the same initial recombination event, followed by homologous recombination. Sequential muscle biopsy and cell culture studies suggest that the duplication is present only transiently in muscle and cloned fibroblast lines. The duplicated molecule could thus be an intermediate in the formation of the deletion. Evidence is presented for the presence of duplicated mtDNA in 6/11 patients known to have deletions of mitochondrial DNA in muscle, suggesting that this could be a general mechanism for major re-arrangements of mitochondrial DNA. There may be parallels between the families of re-arrangements found in plant mitochondrial DNA, and the three distinct re-arranged molecules described here.

Pacemaker potentials in lymphatic smooth muscle of the guinea-pig mesentery.

Abstract: 1. Intracellular microelectrode recordings have been made from lymphatic smooth muscle (SM) to investigate pacemaker mechanisms underlying lymphatic pumping. 2. The SM of small lymphangions or that of short segments, cut from lymphangions of any length, behaved similarly. Both preparations exhibited spontaneous transient depolarizations (STDs) and exhibited simplified electrical characteristics approximating those of a spherical cell. 3. STDs were found to underlie activation of action potentials and hence constrictions. 4. The level of STD activity correlated to the pumping activity of lymphangions, the SM from more active chambers exhibiting increased STD activity. 5. Lymphatic SM exhibited STDs with properties similar to the STDs of mesenteric veins. STDs appeared to be of myogenic origin as they were present despite denervation or substantial destruction of the endothelium. 6. Noradrenaline enhanced the size and frequency of STDs. 7. STD activity was abolished by chelation of cytosolic Ca2+. 8. It is proposed that STDs provide a mechanism for pacemaking in the lymphatic SM studied here. Furthermore, it is postulated that STDs are the consequence of Ca(2+)-dependent pulsatile release of an intracellular messenger, probably Ca2+ itself. This mechanism provides a novel means for pacemaking.

Isolation of a putative transcriptional regulator from the region of 22q11 deleted in DiGeorge syndrome, Shprintzen syndrome and familial congenital heart disease

Abstract: A wide spectrum of birth defects are caused by deletions of the DiGeorge syndrome critical region (DGCR) at human chromosome 22q11. Over one hundred such deletions have now been examined and a minimally deleted region of 300kb defined. Within these sequences we have identified a gene expressed during human and murine embryogenesis. The gene, named TUPLE1, and its murine homologue, encodes a protein containing repeated motifs similar to the WD40 domains found in the beta-transducin/enhancer of split (TLE) family. The TUPLE1 product has several features typical of transcriptional control proteins and in particular has homology with the yeast Tup1 transcriptional regulator. We propose that haploinsufficiency for TUPLE1 is at least partly responsible for DiGeorge syndrome and related abnormalities.

Evaluation of Interventions to Improve Solar Protection in Primary Schools

Abstract: Childhood and adolescence are critical periods in the etiology of subsequent melanoma and nonmelanocytic skin cancers. The aims of the study were (a) to develop a valid measure of solar protection in 9 to 11-year-old school students, (b) to evaluate the differential effectiveness of two interventions aimed at changing solar protection in this age group, and (c) to identify the predictors of use of a high level of solar protection. A Solar Protection Behavior Diary was developed and validated during a pilot, after which 11 schools were randomly allocated to one of three groups: intensive intervention (247 students), standard intervention (180 students), or control (185 students), with students in years 5 and 6 participating in the study. Students completed the validated diary (for 5 days) and a knowledge and attitudes questionnaire at pretest and at two posttest periods (4 weeks and 8 months after pretest). Results indicated that students in the intensive intervention group were significantly more likely to have used a high level of protection at both posttest periods compared to the control and standard intervention groups. There was no difference in the protection level of the control and standard intervention groups at either posttest, indicating that this minimal intervention was not effective in changing the solar protection behavior of the students. Students with a high level of solar protection at pretest were also significantly more likely to have a high level of protection at both posttest periods, and those with a greater number of opportunities to protect were less likely to protect at the second posttest.

Secondary prevention after acute myocardial infarction.

Abstract: The hypothesis that 6 months after acute myocardial infarction, adoption of secondary prevention activities would be higher, quality of life better, and blood cholesterol lower in patients randomly allocated to a mail-out intervention program than in those receiving usual care was tested. Patients were aged < 70 years, admitted to hospitals in and around Newcastle, Australia with a suspected heart attack and discharged alive from the hospital. Cluster randomization, based on the patient's family practitioner, was used to allocate consenting patients to an intervention or usual care group. A low-cost mail-out program was designed to help patients reduce dietary fat, obtain regular exercise by walking and (for smokers only) to quit smoking. Supplementary telephone contact was also used. In addition, a letter was sent to the family doctor regarding the benefit of aspirin and beta blockers for secondary prevention. Of eligible patients, 71% participated, and 79% of the 213 intervention subjects and 87% of the 237 usual care ones returned a 6-month follow-up questionnaire. Self-reported fat intake was significantly lower, an "emotional" score obtained from a quality-of-life questionnaire was significantly higher in the intervention than in the usual care group, and "physical" and "social" scores for quality of life were slightly higher. Blood cholesterol level and other variables were not different between the groups at 6 months. Simple low-cost programs providing support and advice on lifestyle change may be beneficial, particularly in improving patients' perceived quality of life.

Momentum and heat transport in the turbulent intermediate wake of a circular cylinder

Abstract: Hot-wire anemometry has been used in the intermediate wake (x/d= 10 to 40) of a slightly heated circular cylinder in order to quantify the contribution from the coherent motion to various conventionally averaged quantities, in particular the average momentum and heat fluxes. The overall contribution to the lateral heat flux is always greater than that to the Reynolds shear stress, indicating that the turbulent Karman vortex street transports heat more effectively than momentum. The difference in these contributions is reflected in the topologies of the velocity and temperature fields. There is significant streamwise evolution of these topologies throughout the intermediate wake. At x/d = 10, the net heat transport associated with the vortical motion occurs in the downstream region of each vortex. At other downstream stations, the net heat transport is equally distributed between the upstream and downstream regions of individual vortices.

Attitudes, knowledge, and stages of change: a survey of exercise patterns in older Australian women.

Abstract: This article describes a telephone survey of attitudes and behavior relevant to exercise adoption among 286 Australian women aged 50 to 64. Stages of change identified by the transtheoretical model of behavior change were related to attitudes, knowledge, and demographic variables. In comparison with exercisers, precontemplators were older, had lower exercise knowledge, perceived lower levels of family support for exercise, expected fewer psychological benefits from exercise, and rated exercise as less important than avoiding smoking. The main significant difference between contemplators and those in the action or maintenance stage involved the perception of practical barriers. Despite the limitations of this cross-sectional self-report study, it identifies attitudes and knowledge as potential targets for intervention with middle-aged women.

Autoantibodies to Igf-1 Binding Sites in Thyroid Associated Ophthalmopathy

Abstract: Graves' disease is an autoimmune disorder but the nature of the association between hyperthyroidism and ophthalmopathy is not yet understood. Serum autoantibodies to orbital tissues have previously been identified and the cross-reactivity with orbital and thyroid antigens has been implicated in the development of thyroid-associated ophthalmopathy (TAO). The ophthalmopathy of Graves' disease is remarkable for the hypertrophy of extraocular muscles and proliferation of fibroblasts within the orbit; features which suggest a possible involvement of growth factors. The present study was therefore undertaken to investigate the interaction of IgGs extracted from the sera of patients with Graves' disease, with or without overt ophthalmopathy, with respect to IGF-1 receptor binding sites on fibroblasts from human orbital tissue. IGF-1 binding sites were demonstrated on human orbital fibroblast monolayers grown from eye muscle explants. These cells exhibited a population of high affinity IGF-1 binding sites (Kd, 0.5nM SEM +/- 0.05). IgG prepared from sera taken from patients with Graves' disease (n = 23) significantly inhibited [125I]IGF-1 binding to orbital fibroblasts when compared to IgGs prepared from normal volunteers (n = 13, p < 0.002). It was found that 12 of 23 (52%) patients' IgG samples gave rise to significant levels of inhibition of [125I]IGF-1 binding to orbital fibroblasts. The IgG preparations did not bind directly to IGF-1. This study demonstrates that IgG prepared from patients with Graves' disease with or without overt ophthalmopathy interact with IGF-1 binding sites on orbital fibroblasts whereas IgG from normal subjects had no significant effect.(ABSTRACT TRUNCATED AT 250 WORDS)

Dynamic balanced randomization for clinical trials

Abstract: Common methods of treatment allocation for multi-centre and/or stratified randomized clinical trials can result in substantial differences between the number of patients allocated to each treatment arm. This can occur in the overall trial for a permuted block design or within individual institutions/strata when using a minimization scheme. This may lead to a bias in the result. Also, these procedures can be predictable, with the possibility of an investigator-introduced selection bias. An easily implemented method of randomization is proposed which attempts to overcome these problems by balancing treatment allocations both within strata and across the trial as a whole. The method keeps a running tally on total treatment allocation numbers at all stratification levels. When a patient accrues a hierarchical decision rule is applied, and the allocation is deterministic if certain pre-defined limits are exceeded, and random otherwise. The method is an extension of the big stick design of Soares and Wu, and is related to both Zelen's key number randomization methods and the schemes of Nordle and Brantmark. Simulation studies are used to demonstrate that major imbalances possible with other schemes do not occur using this method, and that the potential for selection bias is much reduced.