Learner driver experiences and crash risk as an unsupervised driver.

OBJECTIVE: The purpose of this study was to describe the driving experiences of learner licensed drivers and examine the association between these driving experiences, associated factors, and on-road car crash involvement during the unsupervised restricted license stage. METHODS: Data were drawn from a cohort investigation of newly licensed drivers. Information on demographic characteristics, personality, and risk behaviors was collected at the baseline interview. At the first follow-up interview (restricted license stage) study members were asked details about their experiences as a learner licensed driver: professional driving lessons, supervised driving, unsupervised driving, and driving courses in which they participated. During the second follow-up interview (full license stage), data were collected on crash involvement and driving exposure during the restricted license stage. Regression analysis was used to determine independent relationships between learner license driving experience variables and crash involvement. RESULTS: After adjusting for demographic, personality factors, and driving exposure at the restricted license stage, increased time spent on the learner license was associated with a reduced risk of crash involvement during the unsupervised restricted license stage. CONCLUSION: Results presented in this paper suggest that learner drivers in New Zealand should be encouraged to spend more time on their learner license to enable them to gain skills and experience to help reduce their crash risk when they are allowed to drive unsupervised. IMPACT ON INDUSTRY: Compared with novice drivers who are on their learner license for the least amount of time, those who spend the most amount of time on their learner license have reduced risk of on-road crash involvement as an unsupervised driver. Learner drivers and their supervisors need to be aware of the length of time required for practice in order to reduce the risks of crash involvement when they are able to drive unsupervised (O'Brien et al., 2012). The recently introduced increase in the minimum driver licensing age in NZ, tougher restricted license stage driving test (aimed at encouraging 120 hours of supervised driving), and the Safe Teen driver campaign (NZ Transport Agency, 2012) are all strategies targeted at improving the safety of learner drivers. These strategies need to be evaluated to ensure they are achieving their goals.

Use of alcohol intoxication codes for serious non-fatal hospitalised injury.

AIM: To determine the extent to which ICD-10 alcohol intoxication codes are used for serious hospitalised injury and the distribution of these codes according to gender, age, injury mechanism and intent, severity of injury, and whether the patient was treated in an Intensive Care Unit. DESIGN: Cross-sectional study. SETTING: New Zealand. PARTICIPANTS: All injury hospital discharges in 2010 that met specified severity criteria. MEASUREMENTS: Cases which had a measurement of BAC (Y90) coded, or only a subjective assessment of alcohol intoxication (F10.0). FINDINGS: 2.5% had a blood alcohol recorded (Y90) and a further 3% were coded as being intoxicated but there was no blood alcohol code. All factors investigated were shown to be independently associated with the assignation of codes. Notable findings were the elevated odds of an alcohol code for males, assault and the more severe injuries. CONCLUSIONS: Assessment of alcohol intoxication among seriously injured persons appears to be very uncommon. The development of a standardised instrument for clinical judgement of intoxication would be highly desirable.

Is length of stay in hospital a stable proxy for injury severity?

RESEARCH QUESTION: Is length of stay (LoS) in hospital a stable proxy for severity of injury when monitoring time trends in serious injury incidence? OBJECTIVE: To investigate whether LoS metrics (mean, median and proportion exceeding several LoS thresholds) have changed over time for injury diagnoses with known severity. DESIGN: Time series investigation. SUBJECTS AND SETTING: New Zealand population admitted to hospital for injury and discharged during the period 1989 to 1998. MAIN OUTCOME MEASURES: Interpolated median and geometric mean lengths of stay, as well as the proportion of cases that have an LoS greater than or equal to 3, 4, 7 and 14 days in hospital. METHODS: ICD-9-CM diagnoses that are approximately homogeneous in regard to severity of injury (ICD-HS diagnoses) were identified. Trends were investigated in the LoS statistics for: injury and non-injury diagnoses combined; all injury diagnoses; major body sites of injury; severity strata; and ICD-HS diagnoses. RESULTS: Almost without exception, there was a decline in the LoS statistics over time for all diagnoses, all injury diagnoses, each body site of injury investigated, severity strata, and the ICD-HS diagnoses. CONCLUSIONS: Reductions in median and geometric mean LoS over time, as well as reductions in the proportion exceeding selected LoS thresholds, were due to factors other than reductions in the incidence of serious injury; for example, changes in service delivery over time. An LoS threshold should not be used as a proxy for severity of injury if the goal is to monitor time trends in injury incidence.

14C and delta13C characteristics of organic matter and carbonate in saltmarsh sediments from south west Scotland.

The distribution of contaminant radionuclides from the Sellafield nuclear fuel reprocessing plant was used to establish chronologies for three saltmarsh sediment cores from south west Scotland. delta(13)C and (14)C analyses indicated that the cores provided a useful archive record of variations in input of organic matter and carbonate. The results imply that prior to major releases of contaminant (14)C from Sellafield, the (14)C specific activity of organic matter in Irish Sea offshore sediments was about 24 Bq kg(-1) C, while that of the carbonate component was below the limit of detection. These results provide baseline data for modelling the uptake of contaminant (14)C by the Irish Sea sediment system. The study confirmed that small(13)C analyses provide a sensitive means of apportioning the origin of saltmarsh organic matter between C(3) terrigenous plants, C(4) terrigenous plants and suspended particulate marine organic matter. For the <2 mm fraction of sediment, a clear pattern of decreasing marine organic input was observed in response to increasing elevation of the marsh surface as a result of sediment accumulation. Bulk sediment, including detrital vegetation, had a dominant input from terrigenous plants. The combined use of delta(13)C and (14)C data revealed that organic matter in the marine organic component of the <2 mm fraction of contemporary surface sediments of the saltmarshes is dominated by recycled old organic material.

Staff morale in the merger of mental health and social care organizations in England.

Following the closure of the last Victorian asylum in Somerset, the health authority and county council undertook a review of mental health services. A major outcome of this review was the creation of an integrated mental health and social care provider. The current paper explores the impact of this integration on the morale of staff members involved, using a conceptual model derived from the literature on organizational behaviour. During the year immediately following integration, the average ratings on all measures of role clarity and job satisfaction reduced. For staff members involved in the integration, by far the largest group of whom were mental health nurses, job satisfaction was related to team role clarity, team identification, emotional exhaustion and gender. These effects of the integration on staff morale are discussed in light of the wider research into the determinants of job satisfaction and the conditions for success in merging organizations. The study has significant implications for managerial and professional leadership during organizational change.

The meanings of 'culture' in health and social care: a case study of the combined Trust in Somerset.

On the 1st of April 1999 Somerset Health Authority and Somerset County Council established a Joint Commissioning Board (JCB) to commission mental health services. Simultaneously, the Somerset Partnerships Health and Social Care NHS Trust was set-up as a combined health and social care services provider; for the first time in England, the majority of social services mental health staff transferred their employment to this Trust. The JCB commissioned an evaluation of the impact of these innovations on users and carers, staff and senior officers and members in the organisations concerned. In the course of the research, one concept frequently recurred as a source of both optimism and concern: 'culture'. However, the meanings attributed to this term varied significantly between stakeholders. After summarising the methodology and the results to date of the evaluation, this paper briefly reviews the conceptions of culture in the literature on organisations, and introduces a taxonomy for discussing culture. That taxonomy is then deployed to explore the ways in which the notion of 'culture' is being applied to and within the combined Trust in Somerset, and the implications of those applications for local practice and national policy around partnership.

Women's readiness to follow milk product consumption recommendations: design and evaluation of a 'stage of change' algorithm.

OBJECTIVE: To investigate readiness to follow milk product consumption recommendations in two random samples of New Zealand women, using an algorithm designed and evaluated to assess the stage of change construct of the Transtheoretical Model. PROTOCOL: Women were classified according to stage of readiness to perform two goal behaviours: consumption of two or four servings of milk products per day. Stage classification, as determined by the algorithm, was evaluated by estimating mean calcium intake in each stage using a validated food frequency questionnaire. This was undertaken in two independent samples of women randomly selected from the electoral rolls of two cities in New Zealand's South Island. RESULTS: Over 60% of women were classified as maintaining an intake of two servings of milk products per day. Of those women not meeting the goal of two servings per day, 73% had no intention of increasing their consumption. Over 80% of women were in the precontemplation stage for consuming four servings of milk products per day. Mean calcium intakes were significantly higher in women classified in action and maintenance stages than in preaction stages of change for both goal behaviours. CONCLUSION: Of those women not currently meeting the recommendation for two servings of milk products per day, most are in precontemplation, a stage characterized by resistance to change. Use of the staging algorithm developed in this study makes possible the classification of women according to their readiness to change, and thus the provision of appropriate stage-tailored advice.

Women's confidence to consume adequate servings of milk products: validation of a summated rating scale.

OBJECTIVE: To design and validate a scale to assess women's confidence to consume adequate servings of milk products. DESIGN: Using the electoral rolls as a sampling frame, two large random population surveys of women aged 25-70 years were conducted. The structure of the self-efficacy scale was explored in the first survey of 500 women, and the component structure was refined and confirmed in an independent sample of 1200 women. RESULTS: The final single component self-efficacy scale consisted of nine items to assess confidence to consume milk products in various situations. Confidence was higher in women who were already consuming adequate servings of milk products than in women who were not yet ready to consume adequate servings of milk products, providing construct validity for the scale. CONCLUSION: The data provide preliminary support for the validity of the self-efficacy scale. The potential usefulness of the scale in interventions designed to improve women's milk product consumption is discussed.

Evaluation of community mental health services: comparison of a primary care mental health team and an extended day hospital service.

Alongside mental health policies emphasising the need to focus on people experiencing serious, long-term problems, recent general healthcare policy is leading to the development in the UK of a primary care-led National Health Service. While most primary care-led mental health initiatives have focused on supporting general practitioners (GPs) in managing milder depression and anxiety, this article describes an evaluation comparing primary care-based and secondary care-based services for people with serious long-term problems. A survey of service users was carried out at three points in time using three measures: the Camberwell Assessment of Need, the Verona Satisfaction with Services Scales and the Lancashire Quality of Life Profile. Staff views were sought at two time intervals and carers' views were obtained towards the end of the 2-year study period. The results indicate that both services reduced overall needs and the users' need for information. The primary care service also reduced the need for help with psychotic symptoms whereas the secondary care service reduced users' need for help with benefits and occupation. There were no major differences in terms of satisfaction or quality of life. Primary care-based services therefore appear to have the potential to be as effective as more traditional secondary care services. However, a more comprehensive range of services is required to address the whole spectrum of needs, a conclusion supported by the views of staff and carers.

The effect of bulk hydrogen ion concentration upon the apparent kinetic parameters of purified pig liver catechol O-methyltransferase.

In order to investigate the pH dependence of catechol O-methyltransferase (S-adenosyl-L-methionine:catechol O-methyltransferase, EC 2.1.1.6), kinetic parameters have been determined for the highly purified enzyme from pig liver over the pH range 6.75-8.20 using the substrates S-adenosylmethionine (AdoMet) and 3,4-dihydroxyphenylacetic acid (DOPAC). The Km for AdoMet was found to be invariant with pH while the Km for DOPAC decreased sharply with increasing pH. The group responsible for the latter has a pK of approx. 7.1. The logarithmic (Dixon) plot of Km against pH for both substrates and that of Vmax/Km against pH for DOPAC mirror the kinetic behaviour revealed by linear plots. However, for other parameters, linear graphs indicate peaks too narrow to be explicable by a simple kinetic mechanism, whereas logarithmic plots of these parameters produce graphs apparently not reflecting this behaviour. We conclude that these results are not the products of random error or artefactual data analysis but are too complex to be explicable by a simple model of kinetic behaviour. Possible explanations (adherence of catechol O-methyltransferase to a higher-order mechanism or a dual mode of substrate binding) are advanced.

Catechol-O-methyltransferase: substrate-specificity and stereoselectivity for beta-adrenoceptor agents.

Isoprenaline, isoetharine, rimiterol, dobutamine and nadolol were investigated as substrates for purified pig-liver catechol-O-methyltransferase using a sensitive spectrophotometric assay. Kinetic parameters, Km and Vmax, were defined and the apparent first-order rate constant (Vmax/Km) was derived. On the basis of the apparent first-order rate constant, rimiterol was found to be a 1.5-fold and dobutamine a 5-fold better substrate for catechol-O-methyltransferase than isoprenaline; isoetharine shows no improvement over isoprenaline. Nadolol is not a substrate for catechol-O-methyltransferase. O-Methylation of isoprenaline- and noradrenaline-enantiomers was found to be stereoselective: catechol-O-methyltransferase shows selectivity towards the laevo (-) isomer with respect to the (+) form or racemic mixture. The investigation indicated stereochemical and steric determinants important in the interaction of catechol-O-methyltransferase with physiologically and clinically important beta-adrenoceptor agents.

The metabolism of dopamine, NN-dialkylated dopamines and derivatives of the dopamine agonist 2-amino-dihydroxy-1,2,3,4-tetrahydronaphthalene (ADTN) by catechol-O-methyltransferase.

A variety of dopamine derivatives and analogues were investigated to assess their potential to act as catechol-O-methyltransferase (COMT) substrates using purified, homogeneous pig liver enzyme. This enabled accurate kinetic constants to be determined as opposed to previous in-vivo studies (Rollema et al 1980; Horn et al 1981; Costall et al 1982; Feenstra et al 1983). 2-Amino-6,7-dihydroxy-1,2,3,4-tetrahydronaphthalene (A-6,7-DTN) proved to be a far better substrate (Km = 0.082 mM; Vmax = 300 mu mg-1 protein) than its 5,6-dihydroxy isomer (Km = 2.60 mM; Vmax = 113.9 mu mg-1 protein). This result supports evidence suggesting that differences in brain concentration of these isomers are due to their differential susceptibility to O-methylation by COMT (Rollema et al 1980). A similar result was obtained with a series of NN-di-n-alkyl substituted ADTN derivatives: the same pattern of preferential O-methylation of A-6,7-DTN derivatives over the corresponding A-5,6-DTN isomers was observed. However, increasing the length of the alkyl chain increased the susceptibility of both isomers to metabolism by COMT as shown by a decline in Km. An homologous series of NN-di-n-alkylated dopamines showed a similar trend implying that more hydrophobic compounds are better COMT substrates.

The inhibition of catechol-O-methyltransferase by 2,3-dihydroxypyridine.

Despite its structural similarity to catechol, 2,3-dihydroxypyridine is not a substrate but a "dead-end" inhibitor of purified pig liver catechol-O-methyltransferase. It inhibits the methylation of 3,4-dihydroxyphenylacetic acid competitively with an inhibitor constant of 15 microM. Against the methyl donor, S-adenosyl-L-methionine, it is an uncompetitive inhibitor (Ki = 85 microM). Clearly, although 2,3-dihydroxypyridine interacts with the catechol-binding site of the enzyme, the presence of a nitrogen in the ring alters its susceptibility to O-methylation.

The cellular location of catechol-O-methyltransferase in rat liver.

Catechol-O-methyltransferase (COMT) activity on the extracellular face of the plasma membrane of isolated rat hepatocytes was assayed, and 4.3% of total COMT activity was located there in cells which satisfied our criteria of viability. However, since 1.2% of the cells' lactate dehydrogenase activity was also apparently extracellular, and this proportion increased to 3.4% under the conditions of the COMT assay the amounts of extracellular COMT may be even less. COMT in rat liver microsomes and plasma membranes represent 2.3% and 0.08% of total rat liver COMT respectively. This implies an insignificant role for plasma membrane COMT although reported altered kinetic behaviour could elevate microsomal COMT to a supporting role in the regulation of catecholamine concentration in the circulation. Since by far the largest fraction of COMT is located intracellularly in the soluble cell fraction, the physiological functions of COMT seem to be dependent on the passage of substrates through the cell membrane for their presentation to the enzyme.

2-hydroxyethynyloestradiol as a substrate for catechol-O-methyltransferase--implications in the metabolism of ethynyloestradiol.

Highly purified pig catechol-O-methyltransferase catalyses the methylation of 2-hydroxyethynyloestradiol (KM - 11.0 microM, Vmax = 521.2 mU/mg protein, Vmax/KM = 47.4) more efficiently than that of 2-hydroxyoestradiol (KM = 68.5 microM, Vmax = 1056.2 mU/mg protein, Vmax/Km = 15.4), 2-hydroxyoestrone (KM = 38.0 microM, Vmax = 795.0 mU/mg protein, Vmax/KM = 20.9) or 4-hydroxyoestrone (KM = 12.8 microM, Vmax = 159.7, Vmax/KM = 12.5). This efficient methylation of the principal metabolite of ethynyloestradiol substantiates the implications of the studies of Bolt et al.[1] that O-methylation is a major route of ethynyloestradiol metabolism. Furthermore, this also implies that catechol-O-methyltransferase in involved in the protection, by S-adenoysylmethionine, against the impairment of bile secretion by ethynyloestradiol, observed in female rats [2].

Substrate stereospecificity and selectivity of catechol-O-methyltransferase for DOPA, DOPA derivatives and alpha-substituted catecholamines.

The substrate specificity of highly purified pig liver catechol-O-methyltransferase has been investigated kinetically. This enzyme shows stereospecificity towards the naturally occurring L-isomer of 3,4-dihydroxyphenylalanine (DOPA) which has a higher affinity and maximal velocity as a substrate than the D-form. We have confirmed the implication of the in vivo study of Ito et al. [1], that methylation of 5-S-L-cysteinyl-L-DOPA is catalysed extremely slowly by catechol-O-methyltransferase, despite the comparatively high affinity of the enzyme for the substrate. Salbutamol is not a substrate for the enzyme and DL-threo-3,4-dihydroxyphenylserine (DOPS) is such a poor substrate that accurate kinetic analysis proved impossible. Alpha-substitution of DOPA, noradrenaline and isoprenaline causes a decrease in the affinity of catechol-O-methyltransferase for these compounds. However, the "suicide' inhibitors of aromatic-L-amino acid decarboxylase (DOPA decarboxylase), fluoro- and difluoro-alpha-methyl DOPA are more superior catechol-O-methyltransferase substrates than alpha-methyl DOPA, presumably because the electron-withdrawing effect of the presence of fluorine in their structure overcomes the steric influence of the alpha-methyl group. A DOPA decarboxylase inhibitor in clinical use, benserazide, is, however, a much superior catechol-O-methyltransferase substrate and may have the therapeutic advantage of decreasing methylation of L-DOPA [2]. Alpha-Methyl dopamine has a lower Km and higher Vmax than the parent compound.

Whole brain tyrosine hydroxylase activity during the development of deoxycorticosterone acetate-1% sodium chloride-induced hypertension in rats.

Water was chosen as the optimal medium for the extraction of tyrosine hydroxylase (TH) from rat brain. Determination of TH activity in crude homogenates failed to exhibit a linear relationship between enzyme concentration and measured activity, however, when a supernatant was used, a linear relationship existed. At a time when TH activity is maximally increased in the locus coeruleus after reserpine treatment (Reis et al 1975; Zigmond.1979) (2.5 mg kg-1 day-1 for 3 days, kill 24 h after last dose) we could detect no alterations in whole brain TH, however if treatment continued for 4 days and animals were killed 72 h after the last dose it was possible to detect increases in TH activity in various brain regions. These results suggest that local changes in brain TH activity are not revealed in measurements made on whole brain. The early rise in blood pressure, following the administration of deoxycorticosterone acetate (doca) and 1% NaCl to male Wistar rats, was accompanied by bradycardia. Whole brain Th activity was determined in these hypertensive animals 6-21 days after the commencement of treatment and the results failed to confirm the reported elevation of TH activity (Rylett et al 1976). The results are discussed with reference to the TH assay employed.