A generalized equation for the calculation of receptor noise limited colour distances in n-chromatic visual systems.

Researchers must assess similarities and differences in colour from an animal's eye view when investigating hypotheses in ecology, evolution and behaviour. Nervous systems generate colour perceptions by comparing the responses of different spectral classes of photoreceptor through colour opponent mechanisms, and the performance of these mechanisms is limited by photoreceptor noise. Accordingly, the receptor noise limited (RNL) colour distance model of Vorobyev and Osorio (Vorobyev & Osorio 1998 Proc. R. Soc. Lond. B265, 351-358 (doi:10.1098/rspb.1998.0302)) generates predictions about the discriminability of colours that agree with behavioural data, and consequently it has found wide application in studies of animal colour vision. Vorobyev and Osorio (1998) provide equations to calculate RNL colour distances for animals with di-, tri- and tetrachromatic vision, which is adequate for many species. However, researchers may sometimes wish to compute RNL colour distances for potentially more complex colour visual systems. Thus, we derive a simple, single formula for the computation of RNL distance between two measurements of colour, equivalent to the published di-, tri- and tetrachromatic equations of Vorobyev and Osorio (1998), and valid for colour visual systems with any number of types of noisy photoreceptors. This formula will allow the easy application of this important colour visual model across the fields of ecology, evolution and behaviour.

Estimating infectious disease in UK asylum seekers and refugees: a systematic review of prevalence studies.

BACKGROUND: The prevalence of infectious diseases such as tuberculosis (TB), HIV and hepatitis B in the UK asylum seeker and refugee population is currently uncertain. METHODS: Systematic review of published and unpublished studies. RESULTS: Five studies met the inclusion criteria. Three studies reported the prevalence of TB with rates ranging from 1.33 to 10.42 per 1000. The three studies reporting hepatitis B estimated rates from 57 to 118 per 1000. One study reported a prevalence rate for HIV of 38.19 per 1000. CONCLUSION: A small number of studies have been identified reporting prevalence rates for TB, hepatitis B and HIV that vary widely where comparisons are available. These differences may reflect true variation in risk between study populations, but are likely to be affected by sampling difficulties encountered when researching these population groups. Efforts are required to improve these difficulties which are currently limiting the validity of prevalence findings and generalizability to comparable asylum seeker and refugee populations.

Immunization with recombinant modified vaccinia Ankara (rMVA) constructs encoding the HA or NP gene protects ponies from equine influenza virus challenge.

Two novel recombinant strains of modified vaccinia Ankara (rMVA) for the vaccination of horses against equine influenza virus were developed, and preliminary evidence of their immunogenicity in ponies was demonstrated [Breathnach CC, Rudersdorf R, Lunn DP. Use of recombinant modified vaccinia Ankara vectors for equine influenza vaccination. Vet Immunol Immunopathol 2004:98;127-36]. The present study assessed the protective efficacy of these rMVA strains in ponies, examined the advantage of combining rMVA vaccination with a DNA priming dose, and investigated the protection resulting from equine influenza nucleoprotein (NP) versus haemagglutinin (HA) vaccination. Twenty yearling ponies, seronegative for equine influenza virus, were divided into four groups of five. Group 1 and Group 2 ponies were vaccinated using a DNA prime-rMVA boost vaccination regimen, with HA- or NP-expressing vectors, respectively. Group 3 ponies were vaccinated with rMVA-HA only. Group 4 ponies served as unvaccinated controls. Vaccines were administered on days 0, 42 and 70, and all ponies were challenge infected with influenza virus on day 100. Antigen-specific antibody and cellular immune responses to each vaccination regimen were monitored throughout the experiment. Both groups of HA-vaccinated ponies were significantly protected from clinical disease following challenge infection, demonstrating the efficacy of rMVA vaccination with or without a DNA prime. NP-vaccination provided more limited protection from clinical disease. The protective post-vaccinal immune responses were characterized by antigen-specific IgGa, IgGb and IgA antibodies which were induced both in serum and in nasal secretions. Virus-specific lymphoproliferative and IFN-gamma mRNA responses were also elicited by each vaccination regimen. These data demonstrate that vaccination of horses with rMVA alone, or as part of a prime-boost regimen, is an effective means of inducing protective immunity to influenza virus infection, and also indicate that NP-specific immune responses can contribute to protection of horses.

Intravenous ketamine plus midazolam is superior to intranasal midazolam for emergency paediatric procedural sedation.

OBJECTIVES: This study compared intranasal midazolam (INM) with a combination of intravenous ketamine and intravenous midazolam (IVKM) for sedation of children requiring minor procedures in the emergency department. METHOD: A single blinded randomised clinical trial was conducted in the emergency department of a major urban paediatric hospital. Subjects requiring sedation for minor procedures were randomised to receive either INM (0.4 mg/kg) or intravenous ketamine (1 mg/kg) plus intravenous midazolam (0.1 mg/kg). Physiological variables and two independent measures of sedation (Sedation Score and Visual Analogue Sedation Scale) were recorded before sedation and at regular intervals during the procedure and recovery period. Times to adequate level of sedation and to discharge were compared. RESULTS: Fifty three patients were enrolled over a 10 month period. Sedation was sufficient to complete the procedures in all children receiving IVKM and in 24 of the 26 receiving INM. Onset of sedation was an average of 5.3 minutes quicker with IVKM than with INM (95%CI 3.2, 7.4 minutes, p<0.001). Children given INM were discharged an average of 19 minutes earlier than those given IVKM (95%CI 4, 33 minutes, p=0.02). Mean Sedation Scores and Visual Analogue Sedation Scale scores for the 30 minutes after drug administration were significantly better in children given IVKM compared with INM (2.4 and 1.8 versus 3.5 and 3.8, respectively). Both doctors and parents were more satisfied with sedation by intravenous ketamine and midazolam. CONCLUSIONS: Intravenous ketamine plus midazolam used in an appropriate setting by experienced personnel provides an excellent means of achieving sedation suitable for most non-painful minor procedures for children in the emergency department. This combination is superior to INM in terms of speed of onset and consistency of effect. INM delivered via aerosol spray has a more variable effect but may still be adequate for the completion of many of these procedures.

Development of an information management system using a strategic planning process.

This article details the development of an information management system to facilitate the ability of clinicians to identify risk factors present in low-birthweight deliveries and to determine geographic clusters of risk factors. These data would serve as a basis for planning clinical interventions at the community level. The strategic planning process provided a framework for successful design and implementation of the information management system.

Aortic-origin reconstruction of the great vessels: risk factors of early and late complications.

OBJECTIVE: Great vessel reconstruction for arterial occlusive disease has been shown to be a durable procedure. The purpose of this report is the examination of the influence of cause and risk factors on outcomes for the identification of patients who may be better treated with endovascular techniques or other surgical approaches. METHODS: Data for patients who underwent aortic-origin great vessel reconstruction between 1988 and 1998 were reviewed. The data were analyzed with Fisher exact test, life-table analysis, and log-rank test. RESULTS: Ninety-two vessels underwent revascularization in 58 patients (15 men, 43 women; mean age, 54 years; age range, 20 to 82 years). Etiology was atherosclerosis obliterans (n = 40; 69%), Takayasu's arteritis (n = 13; 22%), radiation arteritis (RA; n = 4; 7%), and mediastinal fibrosis (n = 1; 2%). The symptoms were cerebrovascular (n = 25), upper extremity (n = 8), or both (n = 23), and two patients were asymptomatic. The bypass grafting was performed with single-limb synthetic grafts (n = 23) or grafts plus side arms (n = 28). Seven patients underwent innominate endarterectomy. The mean follow-up period was 45 months (range, 0 to 126 months). The perioperative stroke (n = 4; 7%) and death (n = 2; 3%) rates were not related to the cause of disease. The patients with creatinine levels of 2 or more (n = 4) had a combined perioperative stroke/death rate of 50% (vs 7% for patients with healthy creatinine levels; P <.05). The patients with hypercoagulable states (ie, thrombophilia; n = 6) had an increased perioperative stroke rate (33% vs 4% for patients without hypercoagulable states; P <.05) and an increased late thrombosis rate. The primary and secondary graft patency rates at 5 years were 80% +/- 7% and 91% +/- 5%, respectively. Patients with RA had a greater risk of stroke or death at 3 years (33% free of stroke or death vs 79% for patients with atherosclerosis obliterans and 92% for patients with Takayasu's arteritis; P =.02) and an increased major late infection rate (50% vs 2% for all others; P =.01). CONCLUSION: Patients with thrombophilia and renal insufficiency have increased perioperative stroke and stroke/death rates, respectively. Patients with RA have an increased incidence rate of late major infection, which directly contributes to an increased rate of stroke or death. Patients with thrombophilia have an increased rate of late graft thrombosis. These patient conditions should be approached cautiously, and some patients may benefit from endovascular therapy.

Bicycle riding and oral/maxillofacial trauma in young children.

OBJECTIVES: To investigate the frequency of oral/maxillofacial injuries in children who have had a bicycle incident and to relate this to the wearing of a protective helmet. DESIGN: Part of a larger prospective study in which self-administered questionnaires were completed by each child with bicycle-related injuries and their parents or caregivers. SETTING: Two tertiary-referral children's hospitals (between 1 April 1991 and 30 June 1992) and three general hospitals (between 1 August 1991 and 30 June 1992) in Brisbane. PARTICIPANTS: 813 children aged under 15 years who presented to the accident and emergency departments with bicycle-related injuries. RESULTS: There were 321 children (39.5%) who sustained oral/maxillofacial injuries. Of 1355 injuries, 340 (25.1%) were to the facial region. Of the 153 children admitted to hospital for bicycle-related injuries, 94 (61.4%) had oral/maxillofacial injury as the primary reason for admission (including those with a reduced level of consciousness). Of the 66 children with a reduced level of consciousness, 53 had concomitant facial injuries. The most common oral/maxillofacial injuries were facial abrasions, cuts and lacerations (50.3%); soft tissue injuries to the mouth (30.9%); and dentoalveolar trauma (9.7%). Over half of these children were wearing bicycle helmets. Of the 15 facial fractures (mandibular, nasal, and zygomatico-orbital), 10 were in children wearing helmets. CONCLUSIONS: Oral/maxillofacial injuries are frequent among child bicycle riders, even for those who wear Australian Standards-approved bicycle helmets. Bicycle helmets need design modifications (e.g., lightweight chin protectors) to more adequately protect the face and jaw.

Compaction assay: a rapid and simple in vitro method to assess the responsiveness of a biopolymer matrix to enzymatic modification.

A rapid and simple in vitro method is described which measures the extent of unrecoiled solids compression when a complex biopolymer is subjected to a centrifugal force. This method, termed the compaction assay, was used to assess the response of purulent cystic fibrosis (CF) sputum samples to the addition of recombinant human deoxyribonuclease I (rhDNase). Enzyme treatment resulted in a dramatic decrease in DNA size, a redistribution of total DNA content from the pellet to supernatant, a significant decrease in that pellet volume and a decrease in elastic modulus. Sample elasticity, measured by a dynamic cone and plate viscometer, could be related to compaction assay results. These results suggest that the compaction assay may be a useful in vitro method for rapidly assessing the actions of enzymatic disruption of a complex biopolymer, such as that observed for the actions of rhDNase on purulent airway secretions.

Chemical contaminants in gray whales (Eschrichtius robustus) stranded along the west coast of North America.

The concentrations of selected chlorinated hydrocarbons (e.g. PCBs, DDTs, DDEs, chlordanes) and essential (e.g. zinc, selenium, copper) and toxic (e.g. mercury, lead, arsenic) elements were measured in tissues and stomach contents from 22 gray whales (Eschrichtius robustus) stranded between 1988 and 1991 at sites from the relatively pristine areas of Kodiak Island, AK, to more urbanized areas in Puget Sound, WA, and San Francisco Bay, CA. The majority of animals were stranded at sites on the Washington outer coast and in Puget Sound. The gray whale has the unique feeding strategy among Mysticeti of filtering sediments to feed on benthic (bottom dwelling) invertebrates. Thus, the wide geographical distribution of the stranded whales allowed (1) an initial assessment of whether concentrations of chemical contaminants in these whales exhibited region specific differences and (2) whether toxic chemicals that accumulate in sediments may have contributed to the mortality and stranding of gray whales near the more polluted urban areas. Analyses for chlorinated hydrocarbons in blubber from 22 animals showed no apparent significant differences among stranding sites. The concentrations of sigma PCBs and sigma DDEs in blubber, for example, ranged from 120 to 10,000 and 9 to 2100 p.p.b. (ng/g) wet weight, respectively. Additionally, analyses of chlorinated hydrocarbons and selected elements in liver (n = 10) also showed no apparent significant differences between whales stranded in Puget Sound and whales stranded at more pristine sites (Alaska, Washington outer coast and Strait of Juan de Fuca and Strait of Georgia). For example, the concentrations of sigma PCBs and sigma DDEs in liver ranged from 79 to 1600 and 7 to 280 p.p.b., respectively, and the concentrations of the toxic elements, mercury and lead ranged from 9 to 120 and 20 to 270 p.p.b., respectively. Analyses of stomach contents revealed low concentrations of chlorinated hydrocarbons, but high concentrations (wet weight) of aluminum (1,700,000 +/- 450,000 p.p.b.), iron (320,000 +/- 250,000 p.p.b.), manganese (23,000 +/- 15,000 p.p.b.), and chromium (3400 +/- 1300 p.p.b.), but no significant differences were observed between whales stranded in Puget Sound compared to whales stranded at the more pristine sites. The relative proportions of these elements in stomach contents of stranded whales were similar to the relative proportions in sediments, which is consistent with a geological source of these elements from the ingestion of sediment during feeding. Thus, overall, the concentrations of anthropogenic chemicals in stranded gray whales showed little relation to the levels of chemical contaminants at the stranding sites.(ABSTRACT TRUNCATED AT 400 WORDS)

National asthma attack audit 1991-2. General Practitioners in Asthma Group.

OBJECTIVE: To describe the frequency and characteristics of asthma attacks in the United Kingdom and to compare actual management with recommended guidelines for the management of attacks. DESIGN: Correspondence survey. SETTING: 218 general practices in the United Kingdom. SUBJECTS: 1775 patients of all ages who had a total of 1805 asthma attacks over three months. MAIN OUTCOME MEASURES: Patient characteristics, place of management of attacks, comparison of actual management with recommended guidelines. RESULTS: Of the 1805 attacks, 300 occurred in boys aged 0-9, 144 in girls aged 0-9, and 118 in women aged 20-29. The estimated frequency of attacks in the community was 14.3 per 1000 patients per year. 1546 (86%) patients with attacks were managed within general practice, 225 (12%) were admitted to hospital, and 34 (2%) were discharged from an accident and emergency department. Two patients died. On initial presentation, 248 (14%) patients were "not breathless," 900 (50%) were "moderately breathless," 535 (30%) were "breathless and distressed," 68 (4%) were "too breathless to talk," and 2 were "moribund." Recording of clinical data was variable. Underuse of nebulised bronchodilators and systemic steroid was apparent in all grades of clinical severity. Contrary to current guidelines for asthma management, "step up" in maintenance therapy after an attack was often not practised. CONCLUSION: Reported management was at variance with recommended guidelines. This has major implications for the design and distribution of future guidelines.

Ontogeny of high- and low-affinity nerve growth factor receptors in the lumbar spinal cord of the developing chick embryo.

The binding of 125I-labeled nerve growth factor-beta (NGF) to soluble extracts of intact or dissociated embryonic chick lumbar cords was used to investigate the kinetic properties and to quantify the levels of NGF receptors (NGFRs) in the developing chick between Embryonic Day 6 (E6) and E10. Both high-affinity (type I; Kd = 7.4 x 10(-11) M) and low-affinity (type II; Kd = 2.4 x 10(-9) M) NGFRs were detected by Scatchard analysis of 125I-NGF binding to E6 spinal cord extracts. A total of 4 x 10(9) type I and 5 x 10(10) type II receptors/cord were found in extracts of E6 cords. As development progressed there was a decline of both types of NGFRs; however, the decline of type I receptors occurred more rapidly than that of type II. Between E6 and E8 greater than 90% of the type I but only 25% of the type II receptors were lost. These relative rates of loss were maintained over the next week of development, with type I receptors no longer detectable by E12, and type II receptors reduced to 0.025% of their E6 numbers by E15. Analyses of NGFR levels in subpopulations of E6 and E8 lumbar cord cells, prepared by metrizamide density gradient centrifugation, showed that during this period there is an enrichment of both types of NGFRs in the motoneuron-containing subpopulation, relative to other cell populations. The loss of NGFRs does not appear to be influenced by those peripheral-trophic interactions which control other aspects of motoneuron development: curarization of the embryos between E6 and E9 increased motoneuron number in E10 embryos by 30%, but did not significantly affect the loss of NGFRs. These results provide the first quantitative evidence that type I and type II NGFRs are differentially regulated in the spinal cord during embryonic development and raise the possibility that distinct cellular mechanisms may govern their expression.

Filtration of platelet-poor plasma specimens yields platelet-free plasma. Application for batch analysis of beta-thromboglobulin and platelet factor 4.

The authors investigated filtration of platelet-poor plasma through a 0.2-micron filter for the analysis of beta-thromboglobulin (beta-TG) and platelet factor 4 (PF4) in frozen specimens. Platelets were detected by electron micrograph in the platelet-poor plasma preparation without filtration. No platelets or platelet fragments were seen after filtration. Freezing the unfiltered specimens resulted in a significant increase in the beta-TG and PF4 concentrations, presumably because of release of these proteins from the platelet alpha-granules during freezing and thawing. There was no change in the PF4 levels and only a slight decrease in beta-TG levels after freezing of the filtered specimens. The filtered samples could be frozen for later batch analysis, resulting in considerable cost savings to the laboratory.

Conformational transitions in phosvitin with pH variation. Vibrational circular dichroism study.

The vibrational circular dichroism (VCD) spectra of metal-free phosvitin are presented as a function of pH and analyzed both qualitatively and by using a factor analysis approach referenced to a protein data set. The qualitative pattern of both the IR and VCD changes is consistent with a coil-to-sheet transition occurring as pH is progressively decreased to values lower than 3. A similar transition was seen in commercial preparation of phosvitin which still contained metal ions, but there the transition was more gradual and occurred at somewhat different pH values. Such a gradual change is also evident in the solution phase absorption band profile but is made clearer using Fourier deconvolution. Based on VCD results, the low pH transition appears to occur with two distinct manifestations of the beta-sheet form. However, at the lowest pH values the sample may precipitate. These two forms are not distinguishable with Fourier transform infrared alone and may be due to a twist of the beta-sheet form or to aggregation.

Gas-phase protein sequencing: gas flow control by positive displacement.

A modification of an automatic gas-phase protein/peptide sequencing apparatus is described; this eliminates the effect of the sample on cell gas flow rates. Consistent sequencing chemistry is achieved, yielding data from material that is intractable using standard equipment.

Hen vitellogenin genes: a study of the distribution of phosvitin phosphoprotein coding sequences using mRNA hybridization with synthetic complementary oligonucleotide probes.

Pentadecamer DNA probes were synthesized, having complementary codons for selected unique pentapeptide sequences of low codon degeneracy present in hen phosvitin minor phosphoprotein, hen phosvitin major phosphoprotein, both phosvitin phosphoproteins. These probes were 5'-32P-labelled. Vitellogenin mRNA was isolated from estrogenized chick liver, fractionated by electrophoresis using formaldehyde/agarose gels and blot transferred to nitrocellulose paper. Relative yields of the two vitellogenin mRNAs differed with the extraction method used. The minor phosphoprotein DNA probe formed a hybrid with a 1.6 megadalton component. The remaining two probes hybridized to a 2.3 megadalton component, this being the expected size of a full-length message. The smallest polyadenylated fragment to which the major phosphoprotein DNA probe hybridized was 1.0 megadalton. The remaining two probes hybridized to fragments of 0.7 megadalton and possibly smaller. Phosvitin major phosphoprotein is concluded to be coded for by part of the larger vitellogenin mRNA, while the minor phosphoprotein is coded for by part of the smaller vitellogenin mRNA. Estimates of the distances of the hybridization sites from polyadenylated tails are also given.