How important are human immunodeficiency virus (HIV) clinical markers to the long-term formal employment among people living with HIV in developing countries? A study in South Africa.

OBJECTIVE: To examine the relationship of Human Immunodeficiency Virus (HIV) clinical markers and socio-demographic characteristics with long-term formal employment among people living with HIV (PLHIV). PARTICIPANTS: 554 adults, 55% females, on HIV treatment for at least two years at two public hospitals in Johannesburg, South Africa. METHODS: A retrospective cohort design, tracing changes in study participants' formal employment status since the first HIV-positive diagnosis. Data collection included historical medical records review and interviewer-administered questionnaires. RESULTS: 44% of all study participants (39% and 49% among males and females, respectively) were formally employed at the time of the study, primarily in low-skilled jobs in the private sector. The majority (83%) of males and 60% of females remained in formal employment since being diagnosed as HIV-positive. Female gender, education to grade 12 or higher, a smaller household size and being married were significantly associated with current formal employment. Formal employment was unrelated to HIV treatment indicators (CD4 count, viral load and duration since diagnosis). Of those in formal employment, 68 (28%) were aware of HIV policies at their workplaces, which was also positively associated with the duration in their current employment. CONCLUSIONS AND RECOMMENDATIONS: PLHIV in developing country contexts can enter into and maintain formal employment, especially when treatment and workplace support are available. Thus, employer organisations should implement effective workplace HIV policies to enhance employment experiences of their workforce living with HIV. Care and support services for people on HIV treatment should also address their career development needs.

Frequency of allergic contact dermatitis to isoeugenol is increasing: a review of 3636 patients tested from 2001 to 2005.

BACKGROUND: Isoeugenol is an important fragrance allergen. The cosmetic industry was recommended voluntarily to reduce concentrations of isoeugenol in finished cosmetic products from 0.2% to 0.02% in 1998. It was suspected that this would reduce the incidence of patch test positivity in individuals undergoing routine patch testing after approximately 2-3 years (the Dillarstone effect). OBJECTIVES: To review our patch test data since the change in practice by industry, to see if there has been an observable decrease in isoeugenol contact sensitivity. METHODS: We retrospectively analysed all subjects patch tested to isoeugenol 1% pet. in the St John's Department of Cutaneous Allergy over a period of 5 years, commencing 3 years after the changes. RESULTS: We identified 3636 subjects, 97 of whom were positive for isoeugenol. Year-on-year incidence shows an increasing trend, with an overall incidence of 2.67%. Using the exact Cochran-Armitage test, this ascending trend is statistically significant (P = 0.0182). Seventy-two of 97 isoeugenol-positive subjects were also positive to fragrance mix I. Other fragrances positive in these 97 patients included Myroxylon pereirae (30%), Evernia prunastri (22%) and eugenol (15%). CONCLUSIONS: We suspect that the increasing trend may be due to allergen substitution with compounds chemically related to isoeugenol, or which hydrolyse to isoeugenol itself.

Developments in electronic portal imaging systems.

Verification of geometric accuracy at the time of treatment delivery has always been a necessary part of the radiotherapy process. Since the introduction of conformal and intensity-modulated radiotherapy, the consequences of patient positioning errors are more serious. Portal imaging has played a large part in fulfilling the need for improved geometric accuracy. This review examines how portal imaging has progressed through the development and evolution of electronic portal imaging devices (EPIDs). Changes in technology, including the current commercial systems, and how image quality has changed are presented. The clinical usage of EPIDs and the technological innovations being devised for further improvements in image quality and systems are considered.

Dosimetric characteristics of the Elekta Beam Modulator.

The dosimetric characteristics of a production pilot multi-leaf collimator (Elekta Beam Modulator, Elekta Oncology Systems, Crawley, UK) having a 4 mm leaf width (at isocentre) have been investigated. Characteristics explored included leaf bank set-up, penumbra width (80-20%) as a function of leaf position, leaf positioning reproducibility, interleaf leakage and leaf transmission. The penumbra values for leaf ends were measured to be between 4.2 and 4.8 mm for various large rectangular fields studied using Kodak X-omat V film at isocentre (1.5 cm deep). Similar films were taken with a standard 1 cm width multi-leaf collimator (MLC) and the penumbra for leaf ends was found to range from 4.3 to 5.2 mm. Other results showed that the rounded leaf tip provided tight control of the penumbra across the leaves' full range of travel. The positioning of the leaves was within a 0.5 mm range when approaching from the same direction. The maximum interleaf leakage was found to be 1.7% and the average leaf transmission less than 1.0%. No major differences were observed in leakage and transmission with changing gantry angle.

Dose-time relationships for elicitation of contact allergy to para-phenylenediamine.

Skin-sensitizing chemicals exhibit dose-response relationships for the elicitation of contact dermatitis. Previously, considerable work has been carried out in which the elicitation of allergic skin reaction has been examined as a function of the applied concentration. However, the relationship between exposure time, dose and response has not been explored in any depth. The present work has extended our initial assessment of the relationship between both exposure time and concentration for para-phenylenediamine (PPD) in a group of 19 PPD-allergic volunteers. The results clearly demonstrate that a relationship exists between both exposure time and concentration. Positive responses to PPD were directly proportional to exposure time: at 5 min 16% responded; at 15 min, 38%; at 30 min, 50%; and at 120 min, 69%. A similar direct relationship was found between concentration of PPD and response: after 120 min, 22% of patients had responded to 0.01%, and 69% to 1% PPD. All exposures for 1 and 2 min were negative. Subsequent evaluation using repeated 5 min open application testing demonstrated a cumulative effect, as after 8 days 39% of the panel reacted, more than double the number that reacted to a single occluded 5-min treatment. It was noted that there was marked subject variability in exposure time and dose required to elicit an allergic response. These results are of relevance for the general interpretation of patch test data, especially with regard to risk assessment.

An audit of the use of self-administered adrenaline syringes in patients with angio-oedema.

BACKGROUND: Self-administered adrenaline syringes may be prescribed for patients at risk of life-threatening episodes of angio-oedema or anaphylaxis. OBJECTIVES: To determine whether patients are able to use these syringes appropriately and adequately. METHODS: Twenty-nine consecutive patients who had been prescribed self-administered adrenaline syringes for severe angio-oedema were recruited. All completed a questionnaire (unsupervised), and were asked to demonstrate how to use a dummy syringe. RESULTS: Three of 29 (10%) patients had been prescribed syringes in the absence of severe angio-oedema or collapse. Seventeen of 29 (59%) patients had been prescribed two syringes, and 21 of 29 (72%) kept a syringe with them at all times. Twenty of 28 (71%) patients had had the use of a syringe demonstrated to them with the initial prescription, but two of 29 (7%) had never been shown how to use it. Only six of 26 (23%) patients had been told to telephone for an ambulance after using a syringe. Only seven of 29 (24%) patients would use a syringe for an episode of collapse, whereas eight of 28 (29%) would use one for an episode of lip swelling. Nine of 21 (43%) patients had not been warned about adverse effects, although 13 of 20 (65%) given adrenaline had had at least one adverse effect. Of the 25 patients asked to demonstrate their use of a syringe, only 14 (56%) were able to perform all steps correctly, and three (12%) were unable to perform any of the steps. Despite this, all 29 patients felt confident about giving themselves an injection, and most felt more secure having been prescribed syringes. CONCLUSIONS: As self-administered adrenaline syringes are prescribed for life-threatening events, it is vital that they are given to appropriate patients with adequate written instructions and proper demonstration at the time of the initial prescription. As a result of this study we have developed a more detailed patient information leaflet, and all patients are shown how to use a syringe for a second time when attending the clinic for follow-up.

Young people in 'drinking' societies? Norwegian, Scottish and Swedish adolescents' perceptions of alcohol use.

The paper studies young people's reported drinking behaviors and their views on various social aspects of alcohol, utilizing a sample of over 4000 rural adolescents aged 11.8-16.5 years in Norway, Scotland and Sweden. The methodology employed includes a common questionnaire and a range of varying qualitative approaches (essays and focus group interviews). The various venues and drinking contexts used by young people, their motives for drinking, and their 'learning' experiences with alcohol are described. Beyond nationality, the most powerful predictors of 'high' drinking are 'involvement with friends' and 'participation in commercial leisure'. The predictors for 'low' drinking are 'involvement in activities with parents' and 'parental concerns about drinking'. Results show that Scottish teenagers drink most, Norwegians least and no differences in the predictor variables are found that can explain this. Results are discussed in relation to social and cultural differences, and illustrated by quotations from rural young people in Scotland and Sweden.

Recording accelerator monitor units during electronic portal imaging: application to collimator position verification during IMRT.

The application of multiple portal image acquisition to collimator position verification during dynamic multileaf collimation (DMLC) using a commercial camera-based electronic portal imaging device (EPID) (Theraview, Cablon Medical BV, Leusden, The Netherlands) mounted on an Elekta SL15i accelerator (Elekta Oncology Systems, Crawley, UK) is described. This is achieved using a custom-built dose acquisition system optically interfaced to both the camera control unit of the EPID and the monitor unit (MU) channel of the accelerator. The method uses the beam blanking camera control signal to trigger the dose acquisition system to read the cumulative accelerator MUs at the beginning and end of each period of image formation. A maximum delay of 15 ms has been estimated for recording of accelerator MUs in the current system. The camera interface was observed to have no effect on the operation of the EPID during normal clinical use and could therefore be left permanently in situ. Use of the system for collimator position verification of a test case is presented. The technique described uses a specific camera-based EPID and accelerator, although the general principle of using an EPID control signal to trigger recording of accelerator MUs may be applicable to other EPIDs/accelerators with suitable knowledge of the accelerator dosimetry system.

Measurement of the response of Gd2O2S:Tb phosphor to 6 MV x-rays.

The phosphor GdO2S:Tb is widely used in camera-based electronic portal imaging devices (EPIDs). There is considerable interest in the application of EPIDs to dosimetry and the verification of intensity modulated radiation therapy produced by dynamic multileaf collimation (DMLC). This paper presents direct measurement of Gd2O2S:Tb phosphor luminescence under 6 MV x-ray irradiation from a linear accelerator using a photomultiplier tube. The luminescence following each radiation pulse (3 micros duration) was observed to decay with a dominant lifetime of 558 micros. Using a specialized electrometer, the temporal variation of the optical signal has been compared with the dose rate incident on the phosphor measured using a semiconductor diode detector. Under dose rates typical of those used in the clinic (1.2 Gy min(-1) to the phosphor), measurements at beam-start confirmed that the optical signal is linear with dose per radiation pulse. Measurements at beam termination following phosphor doses up to 4.4 Gy showed no residual signal associated with long-lived luminescence (afterglow) from the phosphor above the noise level of the optical signal (0.17% standard deviation). This measurement demonstrates that afterglow from Gd2O2S:Tb is not of significance for its application to DMLC verification. Additionally, it was confirmed that the accelerator pulse repetition frequency has no effect on the optical signal from the phosphor in the range 25-400 Hz.

A method for controlling image acquisition in electronic portal imaging devices.

Certain types of camera-based electronic portal imaging devices (EPIDs) which initiate image acquisition based on sensing a change in video level have been observed to trigger unreliably at the beginning of dynamic multileaf collimation sequences. A simple, novel means of controlling image acquisition with an Elekta linear accelerator (Elekta Oncology Systems, Crawley, UK) is proposed which is based on illumination of a photodetector (ORP-12, Silonex Inc., Plattsburgh, NY, USA) by the electron gun of the accelerator. By incorporating a simple trigger circuit it is possible to derive a beam on/off status signal which changes at least 100 ms before any dose is measured by the accelerator. The status signal does not return to the beam-off state until all dose has been delivered and is suitable for accelerator pulse repetition frequencies of 50-400 Hz. The status signal is thus a reliable means of indicating the initiation and termination of radiation exposure, and thus controlling image acquisition of such EPIDs for this application.

Dosimetric properties of the Theraview fluoroscopic electronic portal imaging device.

Electronic portal imaging devices (EPIDs) can be used for non-imaging applications in radiotherapy such as patient dosimetry. Of the systems available, the fluoroscopic camera-based EPID Theraview (InfiMed Inc.) has not been studied to date, and a review of the dosimetric properties of the system is presented here. In the "single set-up" mode of image acquisition, pixel intensity increases sublinearly with applied dose. The response was dependent on the system's video signal gain and showed a threshold dose to the detector in the range 0.05-0.35 cGy, and pixel saturation at detector doses in the range 1.2-1.6 cGy. Repeated exposures of the EPID were observed to be extremely reproducible (standard deviation 0.5%). The sensitivity of the system showed a linear decline of 0.04% day-1 over a 68-day period, during which time the relative off-axis response within 10 x 10 cm2 field was constant to within a standard deviation of 0.56%. The system shows spatial non-uniformity, which requires correction for application to dose measurements in two-dimensions. Warm-up of the camera control unit required a period of at least 40 min and was associated with an enhancement in pixel intensity of up to 12%. A radiation dose history effect was observed at doses as low as 0.2 Gy. Camera dark current was shown to be negligible at normal accelerator operation. No discernible image distortion was found. Mechanical stability on gantry rotation was also assessed and image displacement of up to 5 mm at the isocentre was observed. It was concluded that the device could be used for dosimetry provided necessary precautions were observed and corrections made.

Smoking behaviour in youth: the problem of low self-esteem?

The study considers the relationship between self-esteem and smoking in youth. Research has emphasized the need for ecological perspectives on health behaviours, for example, the context and meaning of cigarette smoking in young people's lives. Recent Scottish research, utilizing a range of methodologies, has examined the peer group context and smoking. The convergence of findings is striking. It would appear that different social groupings exist within the peer context, where these are tied to peer status and associated with distinctive lifestyle practices, and dispositions, including smoking. In the case of self-esteem and smoking the results from conventional, survey-based research have often been inconclusive, the suggestion being that global measures of self-esteem are insufficient, since feelings of self-esteem are domain or context specific. However, the present study analyses survey data from two Scottish samples of 13-14-year-olds, conducted some 10 years apart, one national (n=2100, 1987) and the other rural (n=800, 1996) to show that even with the bluntest of research instruments, i.e. self-report questionnaire survey data and general measures, it is possible to elaborate on the relationship between self-esteem and cigarette smoking in youth.

Adolescent drinking behaviour and the role of family life: a Scottish perspective.

Family socialisation processes have been shown to have a significant influence on a variety of health-related behaviours. In this study two aspects of family life--the family's social position, and patterns of support and control by parents of their adolescent offspring--are examined in relation to young peoples self-reports of levels of drinking by a representative randomly selected sample of more than 600 Scottish young people. The analysis is based on data drawn from a longitudinal study of adolescent socialisation and life-styles. The results initially support the usual negative relationship reported in other studies between family structure and young people's alcohol use, with adolescents from non-intact families tending to drink more. However, adolescent drinking behaviour is found to be largely unrelated to the socio-economic circumstances of the family. In addition, a supportive family environment is associated with lowered prevalences of alcohol use. The work also points to the fact that, from the young person's perspective, an unsupportive family environment where there are also extremes of parental control (irrespective of whether these are high or low levels of control) is associated with raised levels of alcohol use later in adolescence. The results of a multiple linear regression show that these socialisation factors, related to parental support and control, continue to be of significance even when the family's social position is taken into account, and that such family socialisation factors would appear to be of more direct importance to adolescent drinking behaviour than family structure.

Adolescent focal theories: age-trends in developmental transitions

Focal theory is considered as a framework for looking at psychosocial and leisure transitions in middle and later adolescence. Although these transitions are examined from a different perspective in the present study, by utilising cross-sectional survey data from a representative sample of three age groups of young Scots (13-14, 15-16 and 17-18 year-olds), the results confirm and extend the general age-trends in relational issues and leisure involvement reported in original studies. Within this overall picture, few gender differences are found in age-related relational transitions, but gender differences are apparent in shifting focuses of leisure involvement with age. Further, the findings suggest a linkage between relational issues in adolescence and leisure contexts, where psychosocial processes are seen to be associated with contextual changes in young people's lives. Focal theory has been criticised for a failure to take true account of the social circumstances, constraints and contexts affecting adolescent development, but in the present study surprisingly few differences are found with respect to the young person's social class of family background, for example, with age-trends in developmental transitions similar for all social groups. By contrast, in later adolescence aspects of the young person's own socio-economic position, rather than that of their family background, are clearly linked to both relational issues and leisure involvement, for example, creating a disrupting effect on those young people who are currently unemployed or non-employed at this age.

Lifestyle, health and social class in adolescence.

The paper considers mechanisms for indirect health selection in adolescence, as part of the explanation for health inequalities between social groups. Aspects of adolescent lifestyles are identified as potentially important factors for the production of class based differences in adult health status. Survey data from a Scottish longitudinal study of adolescent socialization and lifestyles are utilized in order to locate such health lifestyle factors within the wider contexts of the individual's personal and social environment at this stage of the life cycle. Relationships and attitudes to family, school and peers in middle adolescence at 15-16 years of age are first examined, and distinctive patterns of integration within these contexts are identified. The inter-connections between these broader aspects of lifestyle, social class and individual health behaviours are then examined. Mid-adolescent patterns of social integration are found to have a clear structural basis, and most importantly, they anticipate social position in later adolescence at 17-18 years of age. It is also found that such patterns of integration into the family, peer and school contexts are linked to subsequent health related behaviours and to self assessed health in later adolescence, and that these links are independent of the young person's social class background. Thus, we conclude that behavioural--cultural lifestyle factors, when these are located within a broader social context, provide a clear and plausible mechanism for indirect health selection in adolescence.

Social class and adolescent smoking behaviour.

The paper examines class based differences in smoking behaviour in middle and later adolescence. The analyses are based on questionnaire survey data drawn from a longitudinal study of adolescent socialisation, leisure and lifestyles in Scotland. Perhaps surprisingly, the social class of the family is found to have little relationship to smoking in middle and later adolescence. By contrast, marked variations in smoking are evident with respect to the current socio-economic position occupied by young people themselves in middle and later adolescence. The connections between smoking, social class background, and current social class position are examined through a consideration of inter-generational occupational mobility, and once more a clear pattern of differences is found. Thus, we conclude that there is an emergent pattern of class based differences in adolescent smoking behaviour, as young people make the transition towards adulthood. We consider the possible role that factors from the family, the peer group, and the school contexts may play in the production of these differences in smoking behaviour. We also highlight the importance that our findings may have for the health inequalities debate, and particularly for explanations which link the production of class based differences in health to processes of inter-generational mobility.

Adolescence and health inequalities: extensions to Macintyre and West.

The paper investigates class based health inequalities in mid to late adolescence. Health status is assessed by means of three subjective self-report measures; evaluation of general health, psychological well-being and disability/long-standing illness. Using six measures of social class (three occupationally and three non-occupationally based) which derive from parental characteristics, no evidence for consistent class based differentials in health amongst adolescents is found. However, it is not concluded that class based health inequalities are absent at this stage of the life cycle. Instead, it is argued that the above measures of social class differentiate between young people on the basis of the socio-economic status of their parents. As such they fail to allow for the possibility that variations in the current social position of young people themselves may have important consequences for their health. Current social position is assessed in terms of economic activity status, occupation and educational attainment. Using these measures, class based health inequalities are indeed found. Extending the analysis further, the relationship between social class of origin, current social circumstances and self-assessed health status is investigated by considering inter-generational occupational mobility. Again, evidence for class based health inequalities is found.

Adolescents' perceptions of significant individuals in their lives.

180 adolescents, aged 11-12 years, and 180, aged 15-16 years, from one Scottish secondary school participated in this study. The purposes of the investigation were: to determine the most significant family member and unrelated person in young peoples' lives; and to identify which characteristics rendered these persons important. 'Mother' and '(same sex) friend' emerged as the outstanding choices. Family members (except siblings) were associated with positive characteristics, whilst amongst unrelated adults, youth group leaders were viewed positively. By contrast, school teachers were primarily seen as occupying a challenging role. Where age and sex differences were found, it was invariably those in early adolescence and females who were more likely to attribute positive characteristics. These results are discussed in relation to the concept of 'mentoring' and the role of mentors in adolescents' lives.

Tubular duplication of the rectum with a rectourethral fistula.

An infant with pneumaturia and fecaluria was found to have a rectal duplicatation with a fistula between the duplicated rectum and the urethra. Rectal duplication, although rare, should be considered in cases of bizarre lower bowel symptoms in children. Correction in our case was effected by exclusion of the duplicated segment along with removal of its mucosal lining and division of its urethral fistula. The termination of the duplicated rectum in the urinary tract, as in cases of imperforate anus, suggests a related embryologic mechanism for the 2 types of anomalies.