Charged particle radiography.

New applications of charged particle radiography have been developed over the past two decades that extend the range of radiographic techniques providing high-speed sequences of radiographs of thicker objects with higher effective dose than can be obtained with conventional radiographic techniques. In this paper, we review the motivation and the development of flash radiography and in particular, charged particle radiography.

Shot noise suppression at room temperature in atomic-scale Au junctions.

Shot noise encodes additional information not directly inferable from simple electronic transport measurements. Previous measurements in atomic-scale metal junctions at cryogenic temperatures have shown suppression of the shot noise at particular conductance values. This suppression demonstrates that transport in these structures proceeds via discrete quantum channels. Using a high-frequency technique, we simultaneously acquire noise data and conductance histograms in Au junctions at room temperature and ambient conditions. We observe noise suppression at up to three conductance quanta, with possible indications of current-induced local heating and 1/f noise in the contact region at high biases. These measurements demonstrate the quantum character of transport at room temperature at the atomic scale. This technique provides an additional tool for studying dissipation and correlations in nanodevices.

A spatially resolved ion temperature diagnostic for the National Ignition Facility.

The concepts and initial development efforts for a spatially resolved ion temperature diagnostic are described. The diagnostic is intended for Inertial Confinement Fusion experiments at the National Ignition Facility and is an integration of neutron aperture imaging and ion temperature techniques. The neutron imaging technique is extended by recording tomographic projections of the radiation-to-light converter on a streak camera. The streak record is used to calculate images at multiple times during the arrival of the thermally broadened 14.1 MeV neutron flux. The resulting set of images is used to determine the spatially resolved ion temperature.

Early prediction of persisting post-concussion symptoms following mild and moderate head injuries.

OBJECTIVES: King (1996) reported that a combination of emotional, organic and neuropsychological measures taken at 7-10 days following mild and moderate head injury may significantly help predict patients most likely to suffer persisting post-concussion symptoms (PCS) at three months post-injury. This study investigated a cross-validation sample (N = 57) to determine whether the results would be replicated for the early prediction of longer-term sufferers (i.e. those with persisting symptoms at 6 months post-injury). DESIGN: Multiple regression analyses were used in which scores on the Hospital Anxiety and Depression Scale, Impact of Event Scale, Short Orientation Memory and Concentration Test, Rivermead Post-Concussion Symptoms Questionnaire and Post-Traumatic Amnesia taken at 7-10 days post-injury were the independent measures. Scoring on the Rivermead Post-Concussion Symptoms Questionnaire taken at 6 months post-injury was the dependent measure. METHODS: Sixty-six consecutive patients admitted to any trauma ward in Oxfordshire with a mild or moderate head injury were recruited from a largescale randomized controlled sample. The assessment measures were administered at 7-10 days post-injury and the Rivermead Post-Concussion Symptoms Questionnaire at 6 months post-injury. Nine patients were unable to be followed up, leaving an active sample of 57. RESULTS: The cross-validation data confirmed that a similar combination of measures to that found in the original study best predicted persisting PCS but that the strength of prediction diminished for the longer term prediction (i.e. 6 months post-injury). CONCLUSIONS: The Hospital Anxiety and Depression Scale, Impact of Even Scale and Post-Traumatic Amnesia in combination are recommended as useful prognostic screening instruments for predicting persisting PCS, but great caution is required if they are used to aid predictions beyond 3 months post-injury.

The effect of weight loss intervention on antihypertensive medication requirements in the hypertension Optimal Treatment (HOT) study.

Obesity is a significant risk factor for hypertension and the cardiovascular sequelae of hypertension. Weight loss has been shown to be effective in lowering blood pressure in overweight individuals. The purpose of this study was to show the impact of a weight loss intervention on overall medication requirements for obese, hypertensive patients. This was a substudy of the Hypertension Optimal Treatment (HOT) study. HOT study patients who had a body mass index > or =27 kg/m2 were randomized to receive either the weight loss intervention, which included dietary counseling and group support, or to serve as the control group. Patients' weights and number of medication steps (per HOT protocol) required to achieve target diastolic blood pressure were measured at 3, 6, 12, 18, 24, and 30 months. Patients in the weight loss group lost significantly more weight than the control group only at 6 months (-3.2+/-4.3 v. -1.8+/-2.7 kg [mean +/- SD] for weight loss group versus control, respectively, P = .05). The weight loss group tended to regain weight after the first 6 months of the study. However, patients in the weight loss group used a significantly fewer number of medication steps than the control group at all time intervals except 3 months. Weight loss appears to be a useful tool in blood pressure management in patients who require medication to control their blood pressure.

Routine follow up after head injury: a second randomised controlled trial.

OBJECTIVE: To confirm that patients admitted to hospital with a head injury benefit from a routinely offered early intervention service. PATIENTS AND METHODS: A mixed rural and urban Health District of 560000 people with two accident and emergency departments provided the setting. Existing routine services for most patients with head injury are minimal. All patients aged 16-65 years admitted to hospital after a head injury of any severity, with or without other injuries entered the trial. Prospective randomisation, with a block randomisation procedure was used to allocate all eligible patients to either: a group offered an additional service by a specialist team; or a group receiving existing standard services. Patients were assessed at follow up six months after injury. The primary outcome measure was the Rivermead head injury follow up questionnaire, a validated and reliable measure of social disability. The Rivermead post-concussion symptoms questionnaire was used to estimate severity of post-concussion symptoms. Each patient in the trial group was contacted 7-10 days after injury, and offered assessment and interventions as needed. These initially focused on the provision of information, support, and advice. Forty six per cent of patients in the trial group also received further outpatient intervention or additional support by telephone. RESULTS: 314 patients were registered: 184 were randomised into the trial group, 130 into the control group. For prognostic data, the groups were comparable at randomisation, and remained comparable when assessed at six months. 132 trial and 86 control patients were followed up at six months after injury. Patients' posttraumatic amnesia ranged from mild (n=79, 40%), and moderate (n=62, 32%), to severe (n=38, 19%) and very severe (n=17, 9%). The trial group patients had significantly less social disability (p=0.01) and significantly less severe post-concussion symptoms (p=0.02) at follow up at six months after injury than the control group patients. CONCLUSIONS: The early interventions offered by a specialist service significantly reduced social morbidity and severity of post-concussion symptoms in trial group patients at six months after head injury. Recommendations about how specialist services should be targeted are made both in the light of these results and those from a previous randomised controlled trial.

Assault, post-traumatic amnesia and other variables related to outcome following head injury.

OBJECTIVE: To estimate how many patients who sustain a head injury might benefit from intervention and support each year and to consider whether relationships can be found between demographic data relating to patients' circumstances at the time of head injury, and their outcomes six months later. DESIGN: Data collected on 625 patients through follow-up interviews and assessments by the Oxford Head Injury Service for a randomized controlled trial of intervention conducted in 1993-94. SETTING: A mixed rural and urban Health District with a population of approximately 560,000. PATIENTS: Patients were aged between 16 and 65 years and resident in Oxfordshire. They presented over 13 months to accident and emergency departments, or were admitted to hospital. All were diagnosed as having suffered a head injury. OUTCOME MEASURES: The Rivermead Head Injury Follow Up Questionnaire and the Rivermead Post Concussion Symptoms Questionnaire. RESULTS: Data are given on age, sex, social circumstances, employment, cause of injury, severity of associated injuries, post-traumatic amnesia (PTA), anticonvulsants, postconcussion symptoms and activities of everyday life. Outcome at six months was significantly worse for those who had been assaulted as against all other causes of injury combined (p = 0.0001); and/or had been admitted to hospital (p = 0.0001)l and/or had sustained more severe additional injuries (p = 0.04); and/or had experienced any PTA (p = 0.00001). The minimum incidence of such injuries in those aged 16-65, calculated for Oxfordshire, is 292 per annum (74/100,000 aged 16-65 per year). CONCLUSIONS: In the general population 52/100,000 patients per annum will experience more serious head injuries as indicated by hospital admission and/or one or more fractures and/or any length of PTA and/or having been assaulted. This group may benefit from monitoring and support and their needs should be considered when planning services.

Does routine follow up after head injury help? A randomised controlled trial.

OBJECTIVE: To evaluate the Medical Disability Society's 1988 recommendation that "every patient attending hospital after a head injury should be registered and offered an outpatient follow up appointment" by determining whether offering a routine follow up service to patients presenting to hospital with a head injury of any severity affects outcome six months later. DESIGN: A randomised controlled trial design with masked assessment of outcome. SETTING: A mixed rural and urban health district with a population of about 560000. PATIENTS: 1156 consecutive patients resident in Oxfordshire aged between 16 and 65 years presenting over 13 months to accident and emergency departments or admitted to hospital and diagnosed as having a head injury of any severity, including those with other injuries. INTERVENTIONS: Patients were registered and randomised to one of two groups. Both groups continued to receive the standard service offered by the hospitals. The early follow up group were approached at 7-10 days after injury and offered additional information, advice, support, and further intervention as needed. All randomised patients were approached for follow up assessment six months after injury by independent clinicians blind to their group. MAIN OUTCOME MEASURES: Validated questionnaires were used to elicit ratings of post-concussion symptoms (the Rivermead postconcussion symptoms questionnaire), and changes in work, relationships, leisure, social, and domestic activities (the Rivermead head injury follow up questionnaire). RESULTS: The two groups were comparable at randomisation. Data was obtained at six months on 226 of 577 "control" patients and 252 of 579 "trial" patients (59% were lost to follow up). There were no significant differences overall between the trial and control groups at follow up, but subgroup analysis of the patients with moderate or severe head injuries (posttraumatic amnesia > or = one hour, or admitted to hospital), showed that those in the early intervention group had significantly fewer difficulties with everyday activities (P = 0.03). CONCLUSIONS: The results from the 41% of patients followed up do not support the recommendation of offering a routine follow up to all patients with head injury, but they do suggest that routine follow up is most likely to be beneficial to patients with moderate or severe head injuries. Some of those with less severe injuries do continue to experience difficulties and need access to services. A further trial is under way to test these conclusions.

Interventions and service need following mild and moderate head injury: the Oxford Head Injury Service.

OBJECTIVE: To describe the interventions given by the Oxford Head Injury Service (OXHIS) to patients seen after head injury, predominantly mild or moderate, over the first six months after their injuries. DESIGN: Descriptive data of the amounts of early intervention provided by OXHIS in relation to severity of head injury and the amount of service need identified at six month follow-up. SETTING: OXHIS aimed to register all patients aged 16-65 with a head injury of any severity, resident in Oxfordshire. It contacted and provided interventions for a random half of those registered at 7-10 days post-injury as part of a randomized controlled trial to investigate the effectiveness of early follow-up. At six months post-injury, independent assessment of all those registered was undertaken to evaluate outcome and identify continuing service needs. SUBJECTS: The data come from the 579 patients (of the 1156 registered), randomized to receive the new service at 7-10 days post-injury. All but eight of these received some form of service, and 252 of the randomized patients were available for interview at six months post-injury to assess their continuing service need. RESULTS: In the first five months after head injury: 240 patients received postal information alone and were not otherwise in contact with the service; 127 had telephone contact, advice and information; 93 were seen in person, assessed and given advice and information; 78 needed more help and support from the OXHIS team over the telephone; and 33 required further face-to-face contact either from OXHIS or other services. Extensive use was made of standardized leaflets but only accompanied by individualized assessment and advice. At six months 252 of the 579 patients were interviewed: 101 had no problems; 136 needed further reassurance; and 15 required further intervention. Patients with longer periods of post-traumatic amnesia (PTA) were more likely to receive a higher level of service, but the majority of patients who received the more extensive services were those with 'mild' and 'moderate' head injuries. CONCLUSIONS: Although the amount of service provided at 7-10 days post-injury increased with severity of head injury, most service was in fact given to patients with milder head injuries which were much more common. The majority of patients seen at six months post-injury needed reassurance, advice or other services, and monitoring of patients for some time after their head injuries does seem warranted. A population of 560,000 people could receive service from three whole-time equivalent (WTE) staff using these assessment and management protocols.

Measurement of post-traumatic amnesia: how reliable is it?

OBJECTIVE: To develop and test a clinical protocol for determining post-traumatic amnesia by retrospective questioning. To establish its limits and factors which influence reliability. DESIGN: Two independent assessments using the Rivermead post-traumatic amnesia protocol were undertaken by separate observers on various groups of patients at various time intervals. Analysis investigated the correlations between assessments, the percentage difference between assessments, the number of patients changing category, and the differences between these analyses in the different patient subgroups. Assessments were undertaken both in hospital and in the patients' homes. Four different patient groups were studied. These were group A: 12 inpatients with very severe head injury late after injury; Group B: 40 patients interviewed at home six months after injury; group C: 22 patients interviewed within a few weeks of injury at home; group D: 116 patients interviewed initially within a few weeks and then at six months, on both occasions at home. The Rivermead post-traumatic amnesia protocol involved clinical questioning of the patient to establish how long after injury (in hours/days/weeks) the patient regained continuous day to day memory. All periods of coma were included. Severity was categorised with standard criteria. RESULTS: Overall correlation was good (Spearman's r 0.79), but the correlation was lower for patients with post-traumatic amnesia < 24 hours and when there was a long delay between assessments. In all groups 19%-25% of patients changed categories between assessments, but only 2% changed by two categories. CONCLUSIONS: The assessment of post-traumatic amnesia with the Rivermead post-traumatic amnesia protocol is reasonably reliable. The misclassification rate however, is significant enough that some caution should be taken in individual cases. Other evidence does show post-traumatic amnesia to be valid, and it probably remains the best simple prognostic item available. In clinical practice one should avoid placing too much weight on post-traumatic amnesia alone.

Post-traumatic stress disorder and head injury as a dual diagnosis: "islands" of memory as a mechanism.

This case study describes post-traumatic stress disorder (PTSD) and head injury after a road traffic accident involving a pedestrian. Previous studies have proposed two mechanisms by which this dual diagnosis may occur: (1) when post-traumatic amnesia and retrograde amnesia are small or non-existent and (2) when non-declarative memory systems for the traumatic event are in operation. This case study demonstrates a third mechanism--"islands" of memory within post-traumatic amnesia.

Emotional, neuropsychological, and organic factors: their use in the prediction of persisting postconcussion symptoms after moderate and mild head injuries.

BACKGROUND: After mild and moderate head injuries a range of postconcussion symptoms (PCS) are often reported by patients. Both organic and psychogenic factors can contribute to these. Full recovery from PCS usually occurs within three months of the injury. A significant minority, however, continue to experience symptoms beyond this time. To date, no means of identifying these patients early after injury has been reported. This study investigates whether a combination of neuropsychological, emotional, and traditional measures of severity of head injury taken early after the injury can help predict severity of PCS three months after injury. METHODS: 50 patients with mild or moderate head injury had a range of measures administered at 7-10 days after injury. These included three tests of divided attention, a PCS rating scale-the Rivermead postconcussion symptoms questionnaire (RPQ), the hospital anxiety and depression scale (HADS), the impact of event scale (IES), and post-traumatic amnesia. An RPQ was then completed by all patients three months after injury. RESULTS: Stepwise multiple regression analysis was performed with the RPQ score at three months as the dependent measure. A combination of eight of the scores from the early measures gave a multiple correlation coefficient of R = 0.86 accounting for 74% of the variance in RPQ scores. The most predictive individual measures were the HADS and IES. Regression analysis with RPQ score at 7-10 days as dependent measure showed that 10 of the scores gave a coefficient of R = 0.84 accounting for 71% of the variance. CONCLUSIONS: A combination of measures may significantly aid the prediction of persistent PCS. Five measures: HADS, post-traumatic amnesia, SOMC, PASAT, and RPQ are recommended for their predictive value and clinical utility. Independent cross validation studies are required before these results can be generally applied. They do, however, provide valuable indications regarding those measures that are most likely to demonstrate utility.

The Rivermead Post Concussion Symptoms Questionnaire: a measure of symptoms commonly experienced after head injury and its reliability.

After head injuries, particularly mild or moderate ones, a range of post-concussion symptoms (PCS) are often reported by patients. Such symptoms may significantly affect patients' psychosocial functioning. To date, no measure of the severity of PCS has been developed. This study presents the Rivermead Post Concussion Symptoms Questionnaire (RPQ) as such a measure, derived from published material, and investigates its reliability. The RPQ's reliability was investigated under two experimental conditions. Study 1 examined its test-retest reliability when used as a self-report questionnaire at 7-10 days after injury. Forty-one head-injured patients completed an RPQ at 7-10 days following their head injury and again approximately 24 h later. Study 2 examined the questionnaire's inter-rater reliability when used as a measure administered by two separate investigators. Forty-six head-injured patients had an RPQ administered by an investigator at 6 months after injury. A second investigator readministered the questionnaire approximately 7 days later. Spearman rank correlation coefficients were calculated for ratings on the total symptom scores, and for individual items. High reliability was found for the total PCS scores under both experimental conditions (Rs = + 0.91 in study 1 and Rs = + 0.87 in study 2). Good reliability was also found for individual PCS items generally, although with some variation between different symptoms. The results are discussed in relation to the major difficulties involved when looking for appropriate experimental criteria against which measures of PCS can be validated.

MEDLINE and PsycLIT on CD-ROM: a survey of users in an academic medical library.

A survey of users of PsycLIT and MEDLINE on CD-ROM was performed at an academic medical library. The questionnaire was designed to gather information about the user population, satisfaction of the users, the assistance needed to use the systems, and the type of searches being performed. The majority of users were graduate students in the schools of medicine, nursing, and pharmacy. In general, users were satisfied with the performance of the systems. Assistance from a librarian, printed documentation, or another patron was required by 85% of users, and they were generally satisfied with this assistance. Most searches were performed to obtain information on a subject. The results were remarkably similar for both databases.

The effect of ouabain on metabolic rate in guinea-pigs: estimation of energy cost of sodium pump activity.

1. The effect of different doses of ouabain, an inhibitor of the sodium pump, or saline (9 g sodium chloride/1; the vehicle) on the metabolic rate of guinea-pigs weighing 500 g was measured by indirect calorimetry for 120 min. 2. Ouabain (0.02-0.07 nmol/g body-weight) decreased the oxygen consumption in a dose-related manner. When higher doses of ouabain (0.10 nmol/g body-weight or greater) were injected the animals were observed to shiver. Ouabain (0.07 nmol/g body-weight) reduced Na+,K+-ATPase (EC 3.6.1.3) activity of liver, kidney and skeletal muscle by 18.0 (SE 6.6), 21.5 (SE 6.0) and 21.9 (SE 6.8)% respectively. An Eadie-Hofstee plot of percentage decrease in O2 consumption v. percentage inhibition divided by dose of ouabain showed that maximal inhibition of O2 consumption was 39.4%. 3. It is concluded that Na pump activity contributed to about 40% of the resting O2 consumption.