Randomised controlled trial comparing marksmanship following application of a tourniquet or haemostatic clamp in healthy volunteers.

BACKGROUND: In a care under fire situation, a first line response to haemorrhage is to apply a tourniquet and return fire. However, there is little understanding of how tourniquets and other haemorrhage control devices impact marksmanship. METHODS: We compared the impact of the iTClamp and the Combat Application Tourniquet (CAT) on marksmanship. Following randomisation (iTClamp or CAT), trained marksmen fired an AR15 at a scaled silhouette target in prone unsupported position (shooting task). Subjects then attempted to complete the shooting task at 5, 10, 15, 30 and 60 min post-haemorrhage control device application. RESULTS: All of the clamp groups (n=7) completed the 60 min shooting task. Five CAT groups (n=6) completed the 5 min shooting task and one completed the 5 and 10 min shooting task before withdrawing. Four CAT groups were stopped due to unsafe handling; two stopped due to pain. When examining hits on mass (HOM) for the entire shooting task, there was no significant difference between tourniquet and iTClamp HOM at 5 min (p=0.18). However, there was a significant difference at 10 min, p=0.003 with tourniquet having significantly fewer HOM (1.7±2.7 HOM) than the iTClamp (8.1±3.3 HOM) group. The total effective HOM for the entire 60 min shooting task showed that the iTClamp group achieved significantly (p=0.001) more HOM than the tourniquet group. Over the entire 60 min shooting exercise, the iTClamp group achieved a median 72% (52/72) of available HOM while the tourniquet group obtained 19% (14/72). CONCLUSIONS: Application of a tourniquet to the dominant arm negates effective return of fire in a care under fire setting after a brief time window. Haemorrhage control devices that preserve function may have a role in care under fire situations, as preserving effectiveness in returning fire has obvious operational merits.

Plant growth regulators control ozone damage to wheat yield.

• Tropospheric ozone (O3 ) is damaging to plants and decreases crop yields. This study investigated the role of two plant growth regulators in affecting wheat-yield responses to elevated [O3 ]. In a controlled factorial experiment, wheat plants were treated with combinations of Ethephon, which releases ethene, Chlormequat, which blocks gibberellin synthesis, and elevated [O3 ]. • Spring-wheat plants were subjected to lifelong exposures to ambient or moderately elevated [O3 ]. At flag-leaf emergence, the plants were treated with Ethephon and/or Chlormequat, or untreated (controls). Gas-exchange measurements were made at anthesis; morphology, biomass, and yield components were recorded at harvest. • Elevated [O3 ] accelerated development and decreased the number of grains per ear and ears per plant. Chlormequat abolished these O3 effects, protecting against yield reduction though not biomass loss. Ethephon treatment partially protected against O3 -induced biomass loss though not yield reduction. • This study suggests that the effects of elevated [O3 ] on development and allocation are more important in determining the yield response of wheat than the accompanying decline in photosynthesis and biomass accumulation.

Enhanced ozone-tolerance in wheat grown at an elevated CO2 concentration: ozone exclusion and detoxification.

Elevated [CO2 ] has been shown to protect photosynthesis and growth of wheat against moderately elevated [O3 ]. To investigate the role of ozone exclusion and detoxification in this protection, spring wheat (Triticum aestivum L. ev. Wembley) was grown from seed, in controlled-environment chambers, under reciprocal combinations of [CO2 ] at 350 or 700 µmol mol-1 and [O3 ] peaking at < 5 or 60 nmol mol-1 , respectively. Cumulative ozone dose to the mesophyll and antioxidant status were determined throughout flag leaf development. Catalase activity correlated with rates of photorespiration and declined in response to elevated [CO2 ] and/or [O3 ]. Superoxide dismutase activity was not significantly affected by either condition. Neither ascorbate nor glutathione content was enhanced by elevated [CO2 ]. In wheat, at moderately elevated [O3 ], our results show that stomatal exclusion plays a major role in the protective effect of elevated [CO2 ] against O3 damage.

The effect of vertical and horizontal head positioning in panoramic radiography on mesiodistal tooth angulations.

The purposes of this study were to examine the effect of potentially common patient positioning errors in panoramic radiography on imaged mesiodistal tooth angulations and to compare these results with the imaged mesiodistal tooth angulations present at an idealized head position. A human skull served as the matrix into which a constructed typodont testing device was fixed according to anteroposterior and vertical cephalometric normals. The skull was then repeatedly imaged and repositioned five times at each of the following five head positions: ideal head position, 5 degrees right, 5 degrees left, 5 degrees up, and 5 degrees down. The images were scanned and digitized with custom software to determine the image mesiodistal tooth angulations. Results revealed that the majority of image angles from the five head positions were statistically significantly different than image angles from the idealized head position. Maxillary teeth were more sensitive to 5 degrees up/down head rotation, with 5 degrees up causing mesial projection and 5 degrees down causing distal projection of maxillary roots. Mandibular anterior teeth were more sensitive to 5 degrees right/left head rotation, with the projected mesiodistal angular difference between 5 degrees right and 5 degrees left rotation ranging from 4.0 degrees to 22.3 degrees. Maxillary teeth were relatively unaffected by 5 degrees right/left head rotation, and mandibular teeth were relatively unaffected by 5 degrees up/down head rotation. It was concluded that the clinical assessment of mesiodistal tooth angulation with panoramic radiography should be approached with extreme caution with an understanding of the inherent image distortions that can be further complicated by the potential for aberrant head positioning.

Patients' accounts of calling the doctor out of hours: qualitative study in one general practice.

OBJECTIVE: To investigate patients' accounts of calling the doctor out of hours. DESIGN: Qualitative analysis of semi-structured interviews with two groups of patients who called their doctors out of hours from one general practice. SUBJECTS: 23 people who had called the doctor on their behalf or on behalf of another adult and 23 people who had called on behalf of a child between 6 pm and 8 am on a week day (omitting the weekend from 6 pm on Friday to 8 am on Monday). RESULTS: although respondents described symptoms as the main reason for the call, they also described a range of other factors that led to the call, including their feelings, concerns about specific illnesses, their responsibility for others, and their previous attempts to manage the problem themselves. They also described past experiences with health services that were important in explaining the current out of hours call or explaining their general approach to using services. CONCLUSIONS: The pursuit of a model of out of hours care based on medical necessity that neglects the psychosocial context of illness may not be appropriate. The importance of previous experiences of health services and contacts with health professionals in explaining current service use requires wider acknowledgement by health professionals across sectors. Separate educational programmes to encourage patients to use out of hours services more appropriately that neglect these issues may be too simplistic.

Dimensions and classes of psychosis in a population cohort: a four-class, four-dimension model of schizophrenia and affective psychoses.

BACKGROUND: Classification of psychosis lacks a biological basis and current diagnostic categories may obscure underlying continuities. Data reduction methods of symptom profiles within a population-based cohort of people with a wide range of affective and non-affective psychoses may permit an empirical classification of psychosis. METHOD: OPCRIT (operational criteria) analysis was performed on 387 adults aged 18-65 years in an attempted ascertainment of all patients with psychosis from a geographical area with a stable population. The data were analysed firstly using principal components analysis with varimax rotation to identify factors, and secondly to establish latent classes. Information relating to key variables known to be of relevance in schizophrenia was coded blind to the establishment of the classes and dimensions. RESULTS: Striking correspondence was obtained between the two methods. The four dimensions emerging were labelled 'depression', 'reality distortion', 'mania' and 'disorganization'. Latent classes identified were 'depression', 'bipolar', 'reality distortion/depression' and 'disorganization'. The latent classes corresponded well with DSM-III-R diagnoses, but also revealed groupings usually obscured by diagnostic boundaries. The latent classes differed on gender ratio, fertility, age of onset and self-harming behaviour, but not on substance misuse or season of birth. CONCLUSIONS: Both dimensional and categorical approaches are useful in tapping the latent constructs underlying psychosis. Broad agreement with other similar studies suggests such findings could represent discrete pathological conditions. The four classes described appear meaningful, and suggest that the term non-affective psychosis should be reserved for the disorganization class, which represents only a subgroup of those with schizophrenia.

An alternate procedure for making a remount cast for a locking type removable partial denture.

This procedure describes the use of silicone impression material to make an index that will correctly position a hinge and latch removable partial denture when a remount cast is being made. This procedure ensures that the partial denture can be retrieved with the index without stressing the retentive components of the partial denture and the remaining dentition. Recovering the remount cast is easier because the latch can be released before the impression index is separated from the cast.

The interactive effects of elevated CO2 and O 3 concentration on photosynthesis in spring wheat.

This study investigated the interacting effects of carbon dioxide and ozone on photosynthetic physiology in the flag leaves of spring wheat (Triticum aestivum L. cv. Wembley), at three stages of development. Plants were exposed throughout their development to reciprocal combinations of two carbon dioxide and two ozone treatments: [CO2] at 350 or 700 µmol mol(-1), [O3] at < 5 or 60 nmol mol(-1). Gas exchange analysis, coupled spectrophotometric assay for RuBisCO activity, and SDS-PAGE, were used to examine the relative importance of pollutant effects on i) stomatal conductance, ii) quantum yield, and iii) RuBisCO activity, activation, and concentration. Independently, both elevated [CO2] and elevated [O3] caused a loss of RuBisCO protein and Vcmax. In combination, elevated [CO2] partially protected against the deleterious effects of ozone. It did this partly by reducing stomatal conductance, and thereby reducing the effective ozone dose. Elevated [O3] caused stomatal closure largely via its effect on photoassimilation.

Possible parent-of-origin effect of Dopa decarboxylase in susceptibility to bipolar affective disorder.

Dopa decarboxylase (DDC) catalyses the synthesis of both dopamine and serotonin as well as trace amines suggested to possess neuromodulating capabilities. We have previously reported evidence suggesting an association between DDC and bipolar affective disorder (BPAD) [Børglum et al., 1999]. To further investigate the possible role of DDC in BPAD, we analyzed a 1- and a 4-bp deletion variant-both of putative functional significance-in two new samples: a case-control sample with 140 cases and 204 controls, and 100 case-parents trios. We also tested for association in subjects with familial disease in both the new and the previously investigated samples. The previously reported association was not replicated in either of the new samples. However, a preponderance of the 1-bp deletion was increased by analysis of the familial cases separately for all case-control samples investigated, indicating a possible association with familial disease (combined analysis, P = 0.02). In the trio sample, a preferential paternal transmission of the 4-bp deletion was observed (P = 0.006). DDC is located next to the imprinted gene GRB10, which is expressed specifically from the paternal allele in fetal brains. Increased transmission of paternal DDC alleles has also been suggested in attention deficit hyperactivity disorder. We suggest that DDC might confer susceptibility to BPAD predominantly when paternally transmitted.