Biomedical subjects
Publications and source records attributed to J McPherson.
Our sequence-tagged site-content map of chromosome 12 is now integrated with the whole-genome fingerprinting effort. It provides accurate and nearly complete bacterial clone coverage of chromosome 12. We propose that this integrated mapping protocol serves as a model for constructing physical maps for entire genomes.
OBJECTIVES: To determine the prevalence of dementia in an Irish sample of people with Down's syndrome (DS) and to examine associated clinical characteristics of dementia in this group. METHOD: 285 people with DS (Age 35-74 years, mean age +/- SD 46.5 +/- 8.2 years) were included in this cross-sectional study. The diagnosis of dementia was made using modified DSMIV criteria. Cognitive tests used were the Down's syndrome Mental Status Examination (DSMSE), Test for Severe Impairment (TSI) and adaptive function was measured by the Daily Living Skills Questionnaire (DLSQ). RESULTS: The overall prevalence of dementia was 13.3%. The presence of dementia was associated with epilepsy, myoclonus, and head injury. The demented DS group were significantly older (n = 38, mean age 54.7 years SD +/- 7.5) than the non-demented (n = 246, mean age 45.6, SD +/- 7.3). The TSI and DLSQ had a satisfactory spread of scores without 'floor' or 'ceiling' effects in people with moderate and severe learning disability. Median scores in demented versus the non-demented groups were significantly different for each measure of function. CONCLUSIONS: Dementia had a prevalence of 13.3% and occurred at a mean age of 54.7 years. The combination of DLSQ score, age and presence of epilepsy were found to predict presence of dementia.
To increase the density of a gene map of the zebrafish, Danio rerio, we have placed 3119 expressed sequence tags (ESTs) and cDNA sequences on the LN54 radiation hybrid (RH) panel. The ESTs and genes mapped here join 748 SSLp markers and 459 previously mapped genes and ESTs, bringing the total number of markers on the LN54 RH panel to 4226. Addition of these new markers brings the total LN54 map size to 14,372 cR, with 118 kb/cR. The distribution of ESTs according to linkage groups shows relatively little variation (minimum, 73; maximum, 201). This observation, combined with a relatively uniform size for zebrafish chromosomes, as previously indicated by karyotyping, indicates that there are no especially gene-rich or gene-poor chromosomes in this species. We developed an algorithm to provide a semiautomatic method for the selection of additional framework markers for the LN54 map. This algorithm increased the total number of framework markers to 1150 and permitted the mapping of a high percentage of sequences that could not be placed on a previous version of the LN54 map. The increased concentration of expressed sequences on the LN54 map of the zebrafish genome will facilitate the molecular characterization of mutations in this species.
The aim of this study was to compare the injuries sustained during paramilitary punishments both before and after the onset of "peace" in Northern Ireland. A retrospective chart review was performed looking at age, injuries, treatments instituted, theatre time, length of hospital stay and overall cost of care. In the 10-month period before the ceasefire, 31 patients were treated after sustaining paramilitary punishment shootings. Mean age was 25.2 years. All patients had small entrance and exit wounds with minimal soft tissue disruption. A total of 18 fractures were recorded in 15 patients and 14 arteries required repair. Mean operative time was 2.6 h, mean hospital stay 7.61 days and mean cost per patient 3102 Pounds. In the following 10-month period 28 patients were admitted after punishments, only one of whom had been shot, all others had been beaten with sticks and clubs. Mean age was 27.4 years. In 52 limbs, 64 fractures were recorded and 44% of these were open; 15 of the fractures were Gustilo and Anderson Grade III or greater and 11 of the fractures were intra-articular. There were no arterial injuries. Mean operative time was 2.6 h, mean hospital stay 12.4 h and mean cost per patient 3849 Pounds.
A spectrophotometric assay method for the analysis of polyphenol oxidase (PPO), in apple and tobacco leaves, has been optimized to increase efficiency in the screening of large numbers of transgenic plants. Crude protein extracts from leaf punches were prepared in a FastPrep homogenizer. The addition of Triton X-100 during extraction resulted in 44 and 74% increases in the PPO activity recovered, from apple and tobacco, respectively. The enzyme kinetics differed markedly between apple and tobacco. Apple leaf PPO was isolated in a latent state and was activated by the addition of SDS. In contrast, tobacco PPO activity was inhibited by SDS, particularly at acidic pH. Apple PPO showed a pronounced pH optimum around pH 6, whereas the pH profile for tobacco PPO was much flatter, with a broad optimum around pH 4. The calculated Km' value for apple PPO, using 4-methylcatechol as substrate, was 8.1, and for tobacco the Km was 4.3. The PPO reaction was strongly inhibited by tropolone, a Cu competitor, and restored by the addition of Cu2+. Several factors affecting variability in leaf PPO activity levels in plants are discussed.
There is increasing interest in continuous infusion of recombinant activated factor VII (rFVIIa) as a convenient and safe alternative to intermittent bolus therapy. In the Australian patients reported in this paper, cost savings of up to 25% in the first 12 h of treatment with continuous infusion of rFVIIa have been achieved safely, suggesting that substantial overall savings are possible. However, in the Thai patient reported, a dose reduction of 35% in the first 12 h was associated with poor haemostatic control, suggesting that a dose reduction of >25% may be inadvisable. The indications for treatment in the five Australian patients were: retroperitoneal haemorrhage (n = 3); right forearm compartment syndrome (n = 1); wrist haemarthrosis and median nerve compression (n = 2); sublingual haematoma (n = 1); and cerebral (mid-brain) haemorrhage (n = 1). Treatment was effective in four out of five patients (six bleeding episodes) and there was one treatment failure where treatment had been substantially delayed. The Thai patient was treated as part of a prospective, uncontrolled, observational study of 34 bleeding episodes in 22 patients in the Asia-Pacific region. Treatment was judged ineffective after 24 h, but full haemostatic control was subsequently achieved with intermittent rFVIIa therapy.
As people with Down syndrome (DS) age, they are at greater risk for Alzheimer disease (AD) than the general population. It has been suggested that polymorphisms at the genes for presenilin-1 (PS-1) and alpha-1-antichymotrypsin (ACT) confer an increased risk for AD in the general population, and therefore potentially to AD in people with DS. We obtained DNA from 231 individuals with DS and 233 population controls. People with DS were evaluated for dementia. Allele frequencies at PS-1 and ACT polymorphisms in people with DS were compared to those in age-matched controls. There were no frequency differences between the control sample and DS sample for PS-1 or ACT alleles or genotypes. Similarly, there were no differences in allele frequencies between the demented and age-matched non-demented DS samples. However a higher frequency of PS-1 heterozygotes in the demented DS group was noted. We conclude that unlike the general population, neither PS-1 nor ACT polymorphisms appear to have a similar detrimental effect on dementia in DS. Am. J. Med. Genet. (Neuropsychiatr. Genet.) 88:616-620, 1999.
Type II fish antifreeze protein (AFP) is active in both freezing point depression and the inhibition of ice recrystallization. This extensively disulfide-bonded 14 kDa protein was targeted for accumulation in its pro- and mature forms in the cytosol and apoplast of transgenic tobacco plants. Type II AFP gene constructs under control of a duplicate cauliflower mosaic virus 35S promoter, both with and without a native plant transit peptide sequence, were introduced into tobacco by Agrobacterium tumefaciens-mediated transformation. AFP did not accumulate in the cytosol of transgenic plants, but active AFP was present as 2% the total protein present in the apoplast. Plant-produced AFP was the same size as mature Type II AFP isolated from fish, and was comparable to wild-type AFP in thermal hysteresis activity and its effect on ice crystal morphology. Field trials conducted in late summer on R1 generation transgenic plants showed similar AFP accumulation in plants under field conditions at levels suitable for large-scale production: but no difference in frost resistance was observed between transgenic and wild-type plants during the onset of early fall frosts.
Arabidopsis thaliana has emerged as a model system for studies of plant genetics and development, and its genome has been targeted for sequencing by an international consortium (the Arabidopsis Genome Initiative; http://genome-www. stanford.edu/Arabidopsis/agi.html). To support the genome-sequencing effort, we fingerprinted more than 20,000 BACs (ref. 2) from two high-quality publicly available libraries, generating an estimated 17-fold redundant coverage of the genome, and used the fingerprints to nucleate assembly of the data by computer. Subsequent manual revision of the assemblies resulted in the incorporation of 19,661 fingerprinted BACs into 169 ordered sets of overlapping clones ('contigs'), each containing at least 3 clones. These contigs are ideal for parallel selection of BACs for large-scale sequencing and have supported the generation of more than 5.8 Mb of finished genome sequence submitted to GenBank; analysis of the sequence has confirmed the integrity of contigs constructed using this fingerprint data. Placement of contigs onto chromosomes can now be performed, and is being pursued by groups involved in both sequencing and positional cloning studies. To our knowledge, these data provide the first example of whole-genome random BAC fingerprint analysis of a eucaryote, and have provided a model essential to efforts aimed at generating similar databases of fingerprint contigs to support sequencing of other complex genomes, including that of human.
BACKGROUND: The apolipoprotein E (ApoE) e4 allele has been associated with an increased risk for Alzheimer's disease, whereas the e2 allele has been shown to be protective. Similar effects in Down's syndrome (DS) have been postulated but not yet demonstrated. METHODS: We obtained DNA from 221 DS individuals and from 162 population controls, and 77 DS children. Older DS subjects were evaluated for dementia and compared to age-matched DS controls. RESULTS: The DS sample with dementia (n = 31) had a significantly lower frequency of the ApoE e2 allele compared to age-matched nondemented DS controls (0% vs. 8.3%, p = .0136). The older DS population had a significantly lower frequency of ApoE e4 compared to population controls (11.7% vs. 20.6%, chi-square 8.9, p = .0028). CONCLUSIONS: The lower frequency of the e2 allele in demented DS subjects compared to age-matched nondemented DS controls suggests a protective effect for ApoE e2 in the development of dementia in DS. The lower frequency of ApoE e4 in our older DS sample compared to population controls points to a detrimental effect of the e4 allele on longevity.
At the University of Newcastle, the 5-year undergraduate programme in Medicine has been developed as a problem-based, self-directed, fully integrated curriculum. Curricular integration involves not only the basic and clinical sciences, but also population medicine, critical reasoning and the development of a broad range of professional skills. Medical informatics has been seen as an increasingly important professional skill and the integrated nature of the curriculum has provided an appropriate setting for the introduction and continuing development of this component of the curriculum. Over the last 3 years this component has been developed to be incorporated into the curriculum for the health sciences within the faculty, becoming health informatics. Informatics for undergraduate students in medicine and allied health professions must be developed as a relevant and useful component of the curriculum.
Explore the source record for details and available documents.
A questionnaire was sent to 28 haemophilia treatment centres known to have used recombinant activated factor VII (rFVIIa; NovoSeven, Novo Nordisk, Bagsvaerd, Denmark), to collect data on continuous infusion of this product. This mode of administration was recently introduced for rFVIIa but there are several questions which remain to be answered in order to optimize this technique. Of the 26 responding centres, 14 had used rFVIIa in continuous infusion for 40 treatment episodes over a total of 283 days. In most of the cases the treatment was targeted at a factor VII level of 10 IU/ml, monitored by the one-stage clotting assay. This seemed to be adequate for most of the haemorrhagic and surgical procedures. Pretreatment pharmacokinetic evaluation was performed in only a minority of the cases but is probably of great importance given the wide variation observed in the clearance values. A strategy was necessary to prevent local thrombophlebitis, at least for infusions in peripheral veins; parallel infusion of heparin, saline or dextrose-saline proved effective. The question of optimal monitoring needs further attention. Haemorrhagic complications were significantly less frequent when treatment was combined with the antifibrinolytic tranexamic acid.
A feasibility study was performed in 11 healthy nonpregnant premenopausal women to determine a method for collection and recovery of vaginally administered nonoxynol-9. We also determined if nonoxynol-9 could be quantitated in vaginal lavage fluid obtained 2 h after instillation of a standard precoitol dose of a foam formulation of nonoxynol-9. Samples were analyzed in batch using a validated normal phase high-performance liquid chromatography (HPLC) method. Two hours after instillation of one dose of Delfen Contraceptive Foam (100 mg), the quantity of nonoxynol-9 collected ranged from 10.8 to 67.8 mg (mean: 35.4 mg). This corresponds to a recovery of 11.70%, of the administered dose. Quantitation of vaginally administered nonoxynol-9 is both practical and feasible. These data represent a critical first step in the evaluation of the safety and effectiveness of nonoxynol-9-containing products in the prevention of sexually transmitted diseases.
It has been suggested that long term treatment with calcium antagonist drugs might inhibit platelet function and lead to an anti-atheromatous effect. However recent data have also suggested that such an effect might increase mortality due to an increased incidence of gastrointestinal bleeding. We identified 43 subjects from general practice with uncomplicated mild to moderate hypertension to compare the effects of the calcium antagonist isradipine with that of the beta-blocker atenolol on platelet function, plasma beta-thromboglobulin levels, fibrinolysis, and serum lipids in a randomised double-blind parallel group study. After careful evaluation to exclude concomitant aspirin use, only 24 subjects were eligible to enter the study. While isradipine and atenolol produced comparable and clinically significant falls in blood pressure (167 +/- 2/102 +/- 1 to 153 +/- 3/91 +/- 2 mm Hg, and 165 +/- 2/101 +/- 1 to 156 +/- 4/91 +/- 2 mm Hg, respectively), neither drug produced a detectable effect on ex vivo platelet aggregation, platelet retention, or thromboxane generation with adrenaline, collagen, adenosine-di-phosphate, or platelet activating factor. However a decrease in plasma beta-thromboglobulin levels was observed which reached statistical significance (P < 0.05) after 12 weeks treatment in the isradipine but not the atenolol group. A 39% reduction with isradipine compared with 34% following atenolol treatment. Euglobulin clot lysis time was not altered by either drug. Serum cholesterol concentrations were also unaltered by drug treatment. Therapeutic doses of the calcium antagonist isradipine may produce a minor indirect effect on platelet function after several weeks of treatment. However, this is of doubtful clinical importance and may simply reflect an effect of lowered blood pressure on platelet function.
A tod-lux transcriptional fusion bioluminescent reporter strain, Pseudomonas putida B2, was developed to permit on-line analysis of trichloroethylene (TCE) transformation by toluene dioxygenase (todC1C2BA) in Pseudomonas putida F1. Strain B2 was exposed to toluene in growing and resting cell bioluminescence assays. The growing cells showed a direct correlation between bioluminescence and toluene concentration, while resting cells showed reproducible bioluminescence with repeated toluene exposures. In addition, P. putida B2 was encapsulated in alginate beads and used in a packed bed flow-through differential volume reactor. The TCE feed into the differential volume reactor was constant at 20 mg L-1 and toluene was pulsed in square-wave perturbations at 10 mg L-1. The system showed a direct correlation between the expression of the tod operon (as monitored by light output) and the co-metabolism of TCE. Approximately 20% of the TCE and 50% of the toluene was removed at a flow rate of 0.4 ml min-1. This approach allowed the on-line monitoring of tod gene expression and its relation to TCE biotransformation.
In tobacco, both wounding and treatment with jasmonates prior to exposure of the tissue to high concentrations of ozone (250 to 500 p.p.b.) produce a dramatic decrease in ozone injury. A systemic pattern of increased ozone tolerance developed within 3-6 h after wounding and also after local application of jasmonates. Ozone treatment of transgenic (NahG) tobacco plants showed that the inability of these plants to accumulate salicylic acid is also accompanied by increased ozone tolerance. Expression of mRNA encoding the anti-oxidant enzyme ascorbate peroxidase is upregulated by ozone challenge, wounding and by methyl jasmonate exposure within 3-4 h, while levels of carbonic anhydrase mRNA are simultaneously depressed following ozone exposure and methyl jasmonate treatment. The pattern of these results shows that the response to ozone challenge in tobacco involves signalling mechanisms similar to those induced in plants by other environmental stresses that generate reactive oxygen species.
BACKGROUND: Inhibitory antibodies which neutralise factor VIII develop in 10-20% of individuals with inherited haemophilia A and rarely as autoantibodies in normal individuals to cause acquired haemophilia. The antibodies are directed against human factor VIII but cross-react to varying degrees with porcine factor VIII. Porcine factor VIII can be used for treatment in individuals with low cross-reactivity. AIMS: To determine the cross-reactivity of factor VIII inhibitors between human factor VIII and porcine factor VIII, in a population of patients with inherited and acquired haemophilia A. Also, to determine whether patients with inherited haemophilia and inhibitors have a higher incidence of factor VIII gene inversion in intron 22. METHODS: Samples and data sheets from 43 patients with inherited and ten with acquired haemophilia were submitted from hospitals in Australia and New Zealand. Inhibitor levels to human and porcine factor VIII were measured by the Bethesda method in 39 with inherited and nine with acquired haemophilia A. RESULTS: Of 39 patients with inherited haemophilia A, cross-reactivity was 0% in 17 patients, 1-19% in six, 20-39% in 11 and 40-80% in five. In six of nine patients with acquired haemophilia cross-reactivity was < or = 7%. In inherited severe haemophilia A, the frequency of the intron 22 inversion was not greater in 37 study patients than in 28 patients without an inhibitor. CONCLUSIONS: Many patients in Australia and New Zealand with inhibitors to human factor VIII presently show a low or absent level of cross-reactivity to porcine factor VIII. These may respond to treatment with this concentrate at least in the short term. There remains a group of patients with high cross-reactivity who will respond only to recombinant factor VIIa or prothrombin complex concentrates.