Socioeconomic inequalities and the equity impact of population-level interventions for adolescent health: an overview of systematic reviews

OBJECTIVES

Despite robust evidence on health inequalities in adulthood, less attention has been paid to inequalities in adolescence. The aim of this overview was to examine systematic review (SR) evidence on the equity impact of population-level interventions intended to improve health, happiness and wellbeing for adolescents.

STUDY DESIGN

An overview (review of systematic reviews).

METHODS

Eleven electronic databases were systematically searched to identify SRs of population-level interventions for adolescent health. A secondary data analysis of socioeconomic inequality was conducted to identify whether SRs reported on primary studies in terms of disadvantage, by measures of socioeconomic status (SES) and by differential effects.

RESULTS

35,310 review titles were screened; 566 full texts were retrieved and 140 SRs met the predefined selection criteria. Differential intervention effects were considered in 42/140 (30%) SRs, 18/140 (13%) reported primary studies using an SES measure and 16/140 (11%) explicitly reported differential effects. 15/140 SRs (11%) explicitly focused on socioeconomic inequalities; of these 4/15 reported differential intervention effects in more detail, 7/15 concluded there was insufficient primary evidence to identify the impact of interventions on socioeconomic inequalities and 4/15 planned to examine differential effects by SES, but this was not reported further.

CONCLUSIONS

Our overview identifies that there is limited SR evidence on the equity impact of population-level interventions for adolescent health. Strengthening the evidence on whether interventions narrow or widen inequalities for adolescents must be a priority for public health research.

Contrasting arsenic cycling in strongly and weakly stratified contaminated lakes: Evidence for temperature control on sediment-water arsenic fluxes

Arsenic contamination of lakebed sediments is widespread due to a range of human activities, including herbicide application, waste disposal, mining, and smelter operations. The threat to aquatic ecosystems and human health is dependent on the degree of mobilization from sediments into overlying water columns and exposure of aquatic organisms. We undertook a mechanistic investigation of arsenic cycling in two impacted lakes within the Puget Sound region, a shallow weakly-stratified lake and a deep seasonally-stratified lake, with similar levels of lakebed arsenic contamination. We found that the processes that cycle arsenic between sediments and the water column differed greatly in shallow and deep lakes. In the shallow lake, seasonal temperature increases at the lakebed surface resulted in high porewater arsenic concentrations that drove larger diffusive fluxes of arsenic across the sediment-water interface compared to the deep, stratified lake where the lakebed remained ~10#x00B0;C cooler. Plankton in the shallow lake accumulated up to an order of magnitude more arsenic than plankton in the deep lake due to elevated aqueous arsenic concentrations in oxygenated waters and low phosphate: arsenate ratios in the shallow lake. As a result, strong arsenic mobilization from sediments in the shallow lake was countered by large arsenic sedimentation rates out of the water column driven by plankton settling.

A Root-Colonizing Pseudomonad Lessens Stress Responses in Wheat Imposed by CuO Nanoparticles

Nanoparticle (NPs) containing essential metals are being considered in formulations of fertilizers to boost plant nutrition in soils with low metal bioavailability. This paper addresses whether colonization of wheat roots by the bacterium, Pseudomonas chlororaphis O6 (PcO6), protected roots from the reduced elongation caused by CuO NPs. There was a trend for slightly elongated roots when seedlings with roots colonized by PcO6 were grown with CuO NPs; the density of bacterial cells on the root surface was not altered by the NPs. Accumulations of reactive oxygen species in the plant root cells caused by CuO NPs were little affected by root colonization. However, bacterial colonization did reduce the extent of expression of an array of genes associated with plant responses to stress induced by root exposure to CuO NPs. PcO6 colonization also reduced the levels of two important chelators of Cu ions, citric and malic acids, in the rhizosphere solution; presumably because these acids were used as nutrients for bacterial growth. There was a trend for lower levels of soluble Cu in the rhizosphere solution and reduced Cu loads in the true leaves with PcO6 colonization. These studies indicate that root colonization by bacterial cells modulates plant responses to contact with CuO NPs.

Pesticidal activity of metal oxide nanoparticles on plant pathogenic isolates of Pythium

CuO and ZnO nanoparticles (NPs) have antimicrobial effects that could lead to formulations as pesticides for agriculture or medicine. The responses of two soil-borne plant pathogenic Pythium isolates to the NPs were studied to determine the potential of these metal oxide NPs as pesticides. Growth of the P. ultimum isolate was more sensitive to CuO NPs than the P. aphanidermatum isolate. Growth in liquid medium with CuO NPs eliminated culturability whereas exposure to ZnO NPs resulted in stasis with growth resuming on transfer to medium lacking NPs. The citrate in the medium used for the growth assays was involved in enhanced release of the toxic metals from the NPs. Both CuO and ZnO NPs affected processes involved in Fe uptake. The NPs reduced levels of Fe-chelating siderophore-like metabolites produced by Pythium hyphae. CuO NPs inhibited, but ZnO NPs increased, ferric reductase activity detected at the mycelial surface. These findings illustrate that the toxicity of the metal oxide NPs towards Pythium was influenced by the medium, especially by the presence of a metal chelator. Environmental factors are likely to alter the pesticide potential of the metal oxide NPs when formulated for agricultural use in soils.

Household food insecurity and dietary diversity as correlates of maternal and child undernutrition in rural Cambodia

OBJECTIVES

To assess household food insecurity and dietary diversity as correlates of maternal and child anthropometric status and anemia in rural Cambodia.

METHODS

Trained interviewers administered a survey to 900 households in four rural districts of Prey Veng, Cambodia. The Household Food Insecurity Access Scale (HFIAS) and Household Dietary Diversity Score (HDDS) were used to assess household food insecurity and dietary diversity. The height, weight and hemoglobin concentration of the mother and youngest child under 5 years in each household were measured. Multivariate logistic regression models were constructed to assess the association between household food insecurity and dietary diversity, and child stunting and wasting, maternal thinness, maternal and child anemia.

RESULTS

The mean (s.d.) HFIAS and HDDS scores were 5.3 (3.9) and 4.7 (1.6), respectively. The respective prevalences of mild, moderate and severe food insecurity were 33, 37 and 12%. Maternal thinness, child stunting and child wasting were present in 14.6, 25.4 and 8.1% of respondents, respectively. The risk of maternal thinness, but not child stunting or wasting, increased as the severity of household food insecurity increased. Household food insecurity was also positively associated with maternal, but not child, anemia. Household dietary diversity status was not significantly associated with any of the outcomes we assessed.

CONCLUSIONS

Efforts to improve household food security are important as a means of promoting maternal nutritional status; however, additional research is needed to better understand the role of other factors that are driving the burden of child undernutrition in Cambodia.

Survival of 3T3 cells expressing or co-expressing bFGF and/or IGF-I and/or IGF-II in low serum and serum free media

The aim of this study was to improve the survival ofNIH3T3 cells in low serum or serum-free media by theendogenous expression of recombinant bFGF (basicfibroblast growth factor) and/or IGF (insulin-likegrowth factor) -I and II. Expression was detected byWestern blotting, and the growth characteristics ofdifferent transfected cell lines investigated in bothserum-free and low serum conditions and also in softagar. Morphological changes and the growth rate werecompared with growth in normal serum-containingmedium. The experimental data suggested that theexpression of either bFGF alone, or the co-expressionof bFGF and either IGF-I or II could improve thesurvival of NIH3T3 cells in low serum or serum-freemedia. The use of such lines could decrease the use ofserum in cell culture and thus both reduce the costsinvolved in this technique and simplify thedown-stream purification procedure in protein harvest.Hence, such lines may be of value in both experimentaland industrial applications.

Peak shift as a function of multiple schedules of reinforcement

Pigeons were trained to respond to two stimuli on the wavelength continuum, 550 nm and 570 nm, each correlated with an independent schedule of reinforcement. The multiple schedule component in effect during 550 nm (S1) was always a variable-interval 1-min. During the 570-nm stimulus (S2) the second component of the schedule was either variable-interval 30-sec, 1-min, 2-min, 5-min, or extinction for different groups of birds. Generalization gradients were obtained after this training, with the following results: (1) response rate to S1 during training was related to the reinforcement frequency associated with S2; the distribution of responding during generalization testing was a function of the schedules of reinforcement used during training and the response rates they produced. Decreases in the relative frequency of reinforcement correlated with S2 resulted in increases in the distribution shift of responses away from S2 during generalization testing.

Genetic variation in the structural pattern of osteoclast activity during post-natal growth of mouse femora

While the spatial activity of osteoblasts has been associated with modeling of bones during development, few studies have examined if variation in the spatial activity of osteoclasts also contributes to the morphogenesis of skeletal tissues. We examined this question by histomorphometric analysis and reconstructing the three-dimensional spatial distribution of osteoclasts in the femora of three inbred strains of male mice (A/J, C57BL/6J [B6], and C3H/HeJ [C3H]) that have differing skeletal, structural, and material properties. Our data show that total osteoclast surface area and osteoclast numbers are related to the overall bone density, but not related to the development of bone diameter or overall cortical area. The analysis of the spatial distribution of the osteoclasts showed that the asymmetrical mid-diaphyseal distribution of osteoclasts in A/J and B6 compared to the more uniform distribution of these cells around the circumference in the C3H mice was consistent with the more ellipsoid shape of A/J and B6 femora compared to the more circular mid-diaphyseal shape of the femora in the C3H mice. The statistically 2- to 3-fold fewer cells on the periosteal surface in the C3H compared to either the B6 or A/J mice is also consistent with the greater cortical thickness that is seen for the C3H mice compared to either B6 or A/J strains. In vitro studies of osteoclastogenesis and the expression of numerous phenotypic properties of osteoclasts prepared from the three strains of mice showed that A/J and B6 mice developed statistically greater numbers of tartrate resistant acid phosphatase (TRAP) positive cells and expressed statistically higher levels of multiple mRNAs that are unique to differentiated osteoclasts than those isolated from the C3H strain. In summary, the 3D reconstructions and histomorphometric analysis suggest that genetic differences lead to spatial variation in the distribution of osteoclasts. These variations in spatial distribution of osteoclasts in turn contribute in part to the development of the structural variations of the femora that are seen in the three strains of mice. In vitro studies suggest that intrinsic genetic variation in osteoclastogenesis and their phenotypic expression may contribute to the differences in their functional activities that give rise to the unique spatial distributions of these cells in bones.

Redox-reactive membrane vesicles produced by Shewanella

This manuscript is dedicated to our friend, mentor, and coauthor Dr Terry Beveridge, who devoted his scientific career to advancing fundamental aspects of microbial ultrastructure using innovative electron microscopic approaches. During his graduate studies with Professor Robert Murray, Terry provided some of the first glimpses and structural evaluations of the regular surface arrays (S-layers) of Gram-negative bacteria (Beveridge & Murray, 1974, 1975, 1976a). Beginning with his early electron microscopic assessments of metal binding by cell walls from Gram-positive bacteria (Beveridge & Murray, 1976b, 1980) and continuing with more than 30 years of pioneering research on microbe-mineral interactions (Hoyle & Beveridge, 1983, 1984; Ferris et al., 1986; Gorby et al., 1988; Beveridge, 1989; Mullen et al., 1989; Urrutia Mera et al., 1992; Mera & Beveridge, 1993; Brown et al., 1994; Konhauser et al., 1994; Beveridge et al., 1997; Newman et al., 1997; Lower et al., 2001; Glasauer et al., 2002; Baesman et al., 2007), Terry helped to shape the developing field of biogeochemistry. Terry and his associates are also widely regarded for their research defining the structure and function of outer membrane vesicles from Gram-negative bacteria that facilitate processes ranging from the delivery of pathogenic enzymes to the possible exchange of genetic information. The current report represents the confluence of two of Terry's thematic research streams by demonstrating that membrane vesicles produced by dissimilatory metal-reducing bacteria from the genus Shewanella catalyze the enzymatic transformation and precipitation of heavy metals and radionuclides. Under low-shear conditions, membrane vesicles are commonly tethered to intact cells by electrically conductive filaments known as bacterial nanowires. The functional role of membrane vesicles and associated nanowires is not known, but the potential for mineralized vesicles that morphologically resemble nanofossils to serve as palaeontological indicators of early life on Earth and as biosignatures of life on other planets is recognized.

A comparative evaluation of the Adaptive knee and Catech knee joints: a preliminary study

The Adaptive knee joint is a microprocessor-controlled prosthetic knee that incorporates both pneumatic and hydraulic control in one electronic unit. Pneumatic control is said to provide control during swing phase and the hydraulic control during the stance phase of the gait. This hybrid controller is triggered by a computer contained within the knee that responds to input from force, time and angle sensors. The microprocessor then selects an appropriate speed and stability setting. The Catech knee joint is a conventional hydraulic knee joint. The aim of this study was to compare the Adaptive and Catech knee joints in established trans-femoral amputees. The patients meeting the inclusion criteria were all established trans-femoral amputees using the Catech knee joint. The study was carried out by performing gait analysis, assessing energy requirements using the Physiological Cost Index (PCI) and using questionnaires. There was no significant benefit gained from the use of the Adaptive knee over the Catech knee joint in our small study group.

Outcomes of intervention programs using flatscreen virtual reality

Virtual reality (VR) has the potential to offer experiences which are engaging and rewarding. In VR, the focus is shifted from the person's efforts in producing a movement or completing a task to that of interaction with the virtual environment. We have found that participants place value and meaning on and enjoy the activities programmed. Virtual reality interventions have been shown to improve cognitive function and concentration through an individual's interaction with a pleasant activity. Importantly, the enjoyment experienced while working with VR may increase the level of participation. In addition to generating realistic situations for testing, intervention and collection of data, the provision of immediate and positive feedback through VR has been shown to increase self esteem and empowerment. We will report outcomes from several intervention and feasibility trials using a flat screen virtual reality system with survivors of traumatic brain injury, community living older adults and children with spastic cerebral palsy. Gross motor movements were elicited through various game-like VR applications without the need for head-mounted displays or other peripherals. The impact of VR exercise participation ranged from improvements in clinical measures of functional balance and mobility, time on task, as well as participant and care provider perceptions of enjoyment, independence and confidence. Although still preliminary, our data suggest that simple applications of virtual reality have significant impacts on physical and psychosocial variables. Possibilities for and benefits of home and community-based access to virtual reality based programs will be explored.

Method Modification (2004.08) to Field Testing of Visible Powders on a Variety of Nonporous Environmental Surfaces: Field Study

The RAMP® Anthrax Test Cartridge for detecting Bacillus anthracis was validated for use in the field for detection of B. anthracis spores in visible powder residues on 7 nonporous environmental surfaces. Six teams of trained first responders and civil support personnel in Class C personal protective equipment sampled visible powder residues on plastic, stainless steel, ceramic tile, wood, rubber, sealed concrete, and food-grade painted wood and analyzed the samples on the RAMP Anthrax Test System. The accuracy for each surface was at least 97% and the overall average was 98.8%. The overall average false-positive rate was 1.79% and false-negative rate was 1.07% for all surfaces. There were no significant differences between surfaces or between spore levels.

Feasibility, Motivation, and Selective Motor Control: Virtual Reality Compared to Conventional Home Exercise in Children with Cerebral Palsy

Children with cerebral palsy (CP) have difficulty controlling and coordinating voluntary muscle, which results in poor selective control of muscle activity. Children with spastic CP completed ankle selective motor control exercises using a virtual reality (VR) exercise system and conventional (Conv) exercises. Ankle movements were recorded with an electrogoniometer. Children and their parents were asked to comment on their interest in the exercise programs. Greater fun and enjoyment were expressed during the VR exercises. Children completed more repetitions of the Conv exercises, but the range of motion and hold time in the stretched position were greater during VR exercises. These data suggest that using VR to elicit or guide exercise may improve exercise compliance and enhance exercise effectiveness.

Do contrast agents affect ultrasound flow measurements?

The use of iodine contrast agents during angiography can put patients at risk. The replacement of angiography through duplex ultrasound methods would, therefore, be of great interest. Even when duplex sonography is used however, an x-ray angiography is often performed afterwards to verify the diagnosis. This causes complications in an unacceptable number of patients. The safety of duplex ultrasound sonography diagnosis can be improved by using low-risk Doppler contrast agents. Slow blood flow through vessels with a high degree stenosis and intracerebral flow can be more easily and accurately detected using these agents. However, amplification of the Doppler echo alters the measurements during both high and low flow, so that the flow rate cannot be recorded very precisely. Our goal was to study the effect of a contrast agent on velocity measurements with color-coded Doppler ultrasonography and on pulsed, one-goal measurements. We used a laser-Doppler-anemometer (LDA) with high temporal and spatial resolution as a reference method to compare the measurements.

Differential impact of audiogenic stressors on Lewis and Fischer rats: behavioral, neurochemical, and endocrine variations

Exposure to intense noise can trigger a cascade of neuroendocrine events reminiscent of a stress response, including activation of the hypothalamic-pituitary-adrenocortical (HPA) axis. Using male Fischer and Lewis rats, which exhibit differences in their corticosterone response to stressors, this investigation assessed effects of acute noise exposure on neurochemical and neuroendocrine responses. In response to the noise exposure, Fischer rats displayed greater plasma adrenocorticotropin-releasing hormone (ACTH) and corticosterone responses than their Lewis counterparts. However, both strains responded with similar increases of plasma prolactin, suggesting that strain differences in the HPA response were not likely because of differences in noise perception. Post-mortem analyses revealed that noise exposure induced strain-dependent variations of corticotropin-releasing hormone (CRH) across several brain regions. These effects were evident irrespective of whether the rats were noise exposed in a familiar (home cage) or unfamiliar environment. In vivo, dynamic assessment of immunoreactive (ir)-CRH at the pituitary gland revealed that noise exposure elicited an immediate rise in ir-CRH among Fischer rats, relative to the delayed response in Lewis rats. Similarly, the rise in local interstitial corticosterone was more rapid and pronounced in Fischer rats. In contrast to these differences, ir-CRH released at the central nucleus of the amygdala (CeA) was gradual and protracted following noise exposure in both strains. Behaviorally, the Fischer rats displayed an active stress response, whereas the Lewis strain adopted freezing as a defensive style. The role of CRH in the genesis of the overall strain-dependent response to stressors is discussed.

Comparison of 5% povidone-iodine solution against 1% povidone-iodine solution in preoperative cataract surgery antisepsis: a prospective randomised double blind study

BACKGROUND/AIM

Povidone-iodine (PI, Betadine) is routinely used as a preoperative topical antiseptic in cataract surgery as it has been shown to reduce the incidence of postoperative endophthalmitis. However, the concentration used clinically is variable. In vitro studies have shown that PI is paradoxically more effective at lower concentration. This study was undertaken to determine if this effect was reproducible in vivo.

METHODS

A prospective randomised double blind study was carried out in the ophthalmic theatre in a district general hospital. 105 patients attending for routine cataract surgery were randomly allocated to have their conjunctival fornices irrigated preoperatively with either PI 1% (group A) or PI 5% (group B). Conjunctival swabs were taken, in identical fashion, both before and 1 minute after irrigation. The number and species of bacterial colonies cultured from each swab was counted. The difference in the median number of bacterial colonies from pre-irrigation to post-irrigation cultures was then compared between the groups.

RESULTS

Bacterial cultures were gained from 100 patients (33 male, 67 female, mean age 74 years, range 30-95 years). Group B (5% PI) showed a decrease in median colony forming units (CFU) pre-irrigation from 100 to 40 CFU post-irrigation (a drop of 60%). This was greater than in group A (1% PI) where the reduction was 120 CFU pre-irrigation to 100 CFU post-irrigation (a drop of 16.7%) (Mann-Whitney test, p<0.05). At higher initial bacterial loads (CFU pre-irrigation >1000), the difference in median between the two groups became larger as the number of pre-irrigation bacteria increased. In group B pre-irrigation CFU reduced from 3340 to 110 post-irrigation (a drop of 96.7%) compared with group A: 5000 CFU pre-irrigation to 3000 post-irrigation (a drop of 40%) (Mann-Whitney test, p=0.0014).

CONCLUSION

Despite in vitro evidence of higher bactericidal efficacy of PI at more dilute concentrations, 5% PI is more effective than 1% PI in decreasing the human conjunctival bacterial flora in vivo, particularly in the presence of heavier initial bacterial load.

Sequence of Plasmodium falciparum chromosomes 1, 3-9 and 13

Since the sequencing of the first two chromosomes of the malaria parasite, Plasmodium falciparum, there has been a concerted effort to sequence and assemble the entire genome of this organism. Here we report the sequence of chromosomes 1, 3-9 and 13 of P. falciparum clone 3D7--these chromosomes account for approximately 55% of the total genome. We describe the methods used to map, sequence and annotate these chromosomes. By comparing our assemblies with the optical map, we indicate the completeness of the resulting sequence. During annotation, we assign Gene Ontology terms to the predicted gene products, and observe clustering of some malaria-specific terms to specific chromosomes. We identify a highly conserved sequence element found in the intergenic region of internal var genes that is not associated with their telomeric counterparts.

The genome sequence of Schizosaccharomyces pombe

We have sequenced and annotated the genome of fission yeast (Schizosaccharomyces pombe), which contains the smallest number of protein-coding genes yet recorded for a eukaryote: 4,824. The centromeres are between 35 and 110 kilobases (kb) and contain related repeats including a highly conserved 1.8-kb element. Regions upstream of genes are longer than in budding yeast (Saccharomyces cerevisiae), possibly reflecting more-extended control regions. Some 43% of the genes contain introns, of which there are 4,730. Fifty genes have significant similarity with human disease genes; half of these are cancer related. We identify highly conserved genes important for eukaryotic cell organization including those required for the cytoskeleton, compartmentation, cell-cycle control, proteolysis, protein phosphorylation and RNA splicing. These genes may have originated with the appearance of eukaryotic life. Few similarly conserved genes that are important for multicellular organization were identified, suggesting that the transition from prokaryotes to eukaryotes required more new genes than did the transition from unicellular to multicellular organization.

Chromate reduction by a pseudomonad isolated from a site contaminated with chromated copper arsenate

A pseudomonad (CRB5) isolated from a decommissioned wood preservation site reduced toxic chromate [Cr(VI)] to an insoluble Cr(III) precipitate under aerobic and anaerobic conditions. CRB5 tolerated up to 520 mg of Cr(VI) liter(-1) and reduced chromate in the presence of copper and arsenate. Under anaerobic conditions it also reduced Co(III) and U(VI), partially internalizing each metal. Metal precipitates were also found on the surface of the outer membrane and (sometimes) on a capsule. The results showed that chromate reduction by CRB5 was mediated by a soluble enzyme that was largely contained in the cytoplasm but also found outside of the cells. The crude reductase activity in the soluble fraction showed a K(m) of 23 mg liter(-1) (437 microM) and a V(max) of 0.98 mg of Cr h(-1) mg of protein(-1) (317 nmol min(-1) mg of protein(-1)). Minor membrane-associated Cr(VI) reduction under anaerobiosis may account for anaerobic reduction of chromate under nongrowth conditions with an organic electron donor present. Chromate reduction under both aerobic and anaerobic conditions may be a detoxification strategy for the bacterium which could be exploited to bioremediate chromate-contaminated or other toxic heavy metal-contaminated environments.

Flow cytometric enumeration of micronucleated reticulocytes: high transferability among 14 laboratories

This laboratory previously described a single-laser flow cytometric method, which effectively resolves micronucleated erythrocyte populations in rodent peripheral blood samples. Even so, the rarity and variable size of micronuclei make it difficult to configure instrument settings consistently and define analysis regions rationally to enumerate the cell populations of interest. Murine erythrocytes from animals infected with the malaria parasite Plasmodium berghei contain a high prevalence of erythrocytes with a uniform DNA content. This biological model for micronucleated erythrocytes offers a means by which the micronucleus analysis regions can be rationally defined, and a means for controlling interexperimental variation. The experiments described herein were performed to extend these studies by testing whether malaria-infected erythrocytes could also be used to enhance the transferability of the method, as well as control intra- and interlaboratory variation. For these studies, blood samples from mice infected with malaria, or treated with vehicle or the clastogen methyl methanesulfonate, were fixed and shipped to collaborating laboratories for analysis. After configuring instrumentation parameters and guiding the position of analysis regions with the malaria-infected blood samples, micronucleated reticulocyte frequencies were measured (20,000 reticulocytes per sample). To evaluate both intra- and interlaboratory variation, five replicates were analyzed per day, and these analyses were repeated on up to five separate days. The data of 14 laboratories presented herein indicate that transferability of this flow cytometric technique is high when instrumentation is guided by the biological standard Plasmodium berghei.

Groin hernia repair in Scotland

BACKGROUND

The use of mesh for groin hernia repair has dramatically changed the way this common operation is performed. The aim of this study was to survey the methods of groin hernia repair in Scotland and to assess patient satisfaction with the operation.

METHODS

Between 1 April 1998 and 31 March 1999 all patients who underwent groin hernia repair in the National Health Service in Scotland were identified. As well as looking at the type of hernia repair performed and postoperative morbidity, patients were sent a Short Form-36 about 3 months after the operation to assess satisfaction and return to normal activity.

RESULTS

Information was obtained on 5506 (97 per cent) of patients who underwent groin hernia repair during the study period. Eighty-five per cent of patients had an open mesh repair and 4 per cent had a laparoscopic repair. Most operations (85 per cent) were performed using general anaesthesia on an inpatient basis (78 per cent), and 8 per cent were for repair of a recurrent hernia. Potentially serious intraoperative complications were rare (seven patients), although they were significantly (P < 0. 001) more likely to be associated with a laparoscopic approach or repair of a femoral hernia: relative risk compared with open inguinal hernia repair 33 (95 per cent confidence interval (c.i.) 6-197) and 22 (95 per cent c.i. 3-152) respectively. Wound complications were common and 10 per cent of patients required a district nurse to attend the wound. Patients expressed a high degree of satisfaction; 94 per cent would recommend the same operation to someone else if required.

CONCLUSION

An open mesh repair using general anaesthesia has become the repair of choice for a groin hernia in Scotland. Despite a high incidence of wound complications, patients are satisfied with this operation.

Community leader education to increase epilepsy attendance at clinics in Epworth, Zimbabwe

OBJECTIVE

To determine whether educating community leaders about epilepsy would lead to an increase in epilepsy cases being diagnosed and treated at primary health centers.

METHODS

This was a single-arm cohort study performed in Epworth, a periurban township outside Harare, Zimbabwe. The subjects were Epworth community leaders (Local Board members, teachers, nurses, police officers, traditional healers, prophets). Educational workshops were given on epilepsy, its cause, and its management, and the number of new epilepsy cases on local primary health clinic registers 6 months after the workshops was measured.

RESULTS

Six new cases were recorded, all among patients previously diagnosed with epilepsy. This was a significant increase (p = 0.02) compared with the null hypothesis.

CONCLUSION

Although there was a significant increase in new cases, these did not represent newly diagnosed patients. Significant prejudice within the community may still prevent identified patients with epilepsy from seeking treatment. Alternative methods must be sought to increase the awareness of epilepsy within low-income communities and to reach "hidden" people with epilepsy.

The complete nucleotide sequence of chromosome 3 of Plasmodium falciparum

Analysis of Plasmodium falciparum chromosome 3, and comparison with chromosome 2, highlights novel features of chromosome organization and gene structure. The sub-telomeric regions of chromosome 3 show a conserved order of features, including repetitive DNA sequences, members of multigene families involved in pathogenesis and antigenic variation, a number of conserved pseudogenes, and several genes of unknown function. A putative centromere has been identified that has a core region of about 2 kilobases with an extremely high (adenine + thymidine) composition and arrays of tandem repeats. We have predicted 215 protein-coding genes and two transfer RNA genes in the 1,060,106-base-pair chromosome sequence. The predicted protein-coding genes can be divided into three main classes: 52.6% are not spliced, 45.1% have a large exon with short additional 5' or 3' exons, and 2.3% have a multiple exon structure more typical of higher eukaryotes.

Deciphering the biology of Mycobacterium tuberculosis from the complete genome sequence

Countless millions of people have died from tuberculosis, a chronic infectious disease caused by the tubercle bacillus. The complete genome sequence of the best-characterized strain of Mycobacterium tuberculosis, H37Rv, has been determined and analysed in order to improve our understanding of the biology of this slow-growing pathogen and to help the conception of new prophylactic and therapeutic interventions. The genome comprises 4,411,529 base pairs, contains around 4,000 genes, and has a very high guanine + cytosine content that is reflected in the biased amino-acid content of the proteins. M. tuberculosis differs radically from other bacteria in that a very large portion of its coding capacity is devoted to the production of enzymes involved in lipogenesis and lipolysis, and to two new families of glycine-rich proteins with a repetitive structure that may represent a source of antigenic variation.

Representing doctors: discourses and images in the Australian press

Reports of incidents and issues related to members of the medical profession and the practice of medicine often feature in the western news media. Such intense coverage has incited the interest of both medical sociologists and members of the profession themselves. Thus far, however, very few detailed studies addressing the tenor of news reporting on the medical profession have been published, particularly in relation to the Australian media. This article presents the findings of a systematic and comprehensive analysis of the representation of doctors and the medical practice over a period of 15 months (January 1994 to March 1995) in metropolitan Australian newspapers and major news magazines. The method of critical discourse analysis was employed, including both quantitative analysis and interpretive analysis of the language and visual imagery of the news texts. The study revealed that negative portrayals of doctors were countered by positive representations. While cases of medical negligence, sexual assault and avarice on the part of doctors were often reported, medical successes were also frequently covered. Doctors were overwhelmingly reported as the major authorities on medical matters and as active agents in interacting with patients and other groups such as government officials. It is concluded that while the nature of reporting would suggest that members of the medical profession may be constantly under the spotlight of media scrutiny, they enjoy a significant degree of cultural and social authority in the Australian press.

Plasticity of neuronal response properties in adult cat striate cortex

We have utilized an associative conditioning paradigm to induce changes in the receptive field (RF) properties of neurons in the adult cat striate cortex. During conditioning, the presentation of particular visual stimuli were repeatedly paired with the iontophoretic application of either GABA or glutamate to control postsynaptic firing rates. Similar paradigms have been used in kitten visual cortex to alter RF properties (Fregnac et al., 1988, 1992; Greuel et al., 1988; Shulz & Fregnac, 1992). Roughly half of the cells that were subjected to conditioning with stimuli differing in orientation were found to have orientation tuning curves that were significantly altered. In general, the modification in orientation tuning was not accompanied by a shift in preferred orientation, but rather, responsiveness to stimuli at or near the positively reinforced orientation was increased relative to controls, and responsiveness to stimuli at or near the negatively reinforced orientation was decreased relative to controls. A similar proportion of cells that were subjected to conditioning with stimuli differing in spatial phase were found to have spatial-phase tuning curves that were significantly modified. Conditioning stimuli typically differed by 90 deg in spatial phase, but modifications in spatial-phase angle were generally 30-40 deg. An interesting phenomenon we encountered was that during conditioning, cells often developed a modulated response to counterphased grating stimuli presented at the null spatial phase. We present an example of a simple cell for which the shift in preferred spatial phase measured with counterphased grating stimuli was comparable to the shift in spatial phase computed from a one-dimensional Gabor fit of the space-time RF profile. One of ten cells tested had a significant change in direction selectivity following associative conditioning. The specific and predictable modifications of RF properties induced by our associative conditioning procedure demonstrate the ability of mature visual cortical neurons to alter their integrative properties. Our results lend further support to models of synaptic plasticity where temporal correlations between presynaptic and postsynaptic activity levels control the efficiency of transmission at existing synapses, and to the idea that the mature visual cortex is, in some sense, dynamically organized.

Magnetic field effects on the behavior of radicals in protein and DNA environments

We have examined the behavior of radical pairs derived by hydrogen abstraction of triplet benzophenone and some of its derivatives from bovine serum albumin, human serum albumin and calf thymus DNA. They have been investigated by means of nanosecond laser flash photolysis techniques. The dynamics of radical pair behavior are shown to be sensitive to external magnetic fields; these effects are interpreted using the established model for the influence of magnetic fields on radical pairs in micellar aggregates, in which intersystem crossing of the radical pair is slowed by the external magnetic field. Our results indicate that proteins and DNA can confine the radicals for a sufficiently long period of time for spin evolution to be affected by external fields. In proteins the radical pair retains its geminate character (i.e. remains confined) for about 0.5-1 microsecond. Interestingly, the magnetic field effects observed in proteins and in DNA seem to occur in distinct timescales; for example, for 2,3,4,5,6-pentafluorobenzophenone bound to DNA, the magnetic field alters the radical reactivity only over times < or = 50 ns, suggesting poor confinement. The timescale for these effects can be increased by promoting Coulombic attraction between DNA and the radical precursor. Electron transfer interactions play a role in the case of DNA.

Axonal injury in falls

Amyloid precursor protein (APP) immunocytochemistry was used as a marker for axonal injury (AI) in a series of 16 cases of head trauma associated with fatal falls. Nine cases were falls from not more than the person's own height (falls from < or = own height) and seven cases were falls from a distance greater than the person's own height (falls from > own height). AI was recorded on a series of line diagrams of standard brain sections divided into 116 sectors. AI around focal lesions (infarcts, hemorrhages, contusions) was distinguished from nonfocal axonal injury that was distant from any focal area of damage. The percentage of sectors showing focal AI provided the Focal Axonal Injury Score (FAIS) and the percentage showing nonfocal AI the Non-Focal Axonal Injury Score (NFAIS). The FAIS is a measure of secondary AI and the NFAIS of diffuse axonal injury (DAI). The percentage of sectors involved with AI (focal and nonfocal) provided the cumulative Axonal Injury Score (AIS). A semiquantitative grading system was also used to assess the severity of axonal injury in each sector and the sum of the grades from all sectors was expressed as a percentage to provide the Axonal Injury Severity Score (AISS). Widespread AI was present in all cases irrespective of the height of the fall. AI was present in the midbrain (94%), pons (94%), corpus callosum (100%), central grey matter (100%), and cerebral hemispheric white matter (94%). AIS ranged from 10 to 94 in falls from < or = own height (mean 73) and from 38 to 92 in falls from > own height (mean 82). AISS ranged from 6 to 95 in falls from < or = own height (mean 65) and 28 to 95 in falls from > own height (mean 72). There was no statistically significant difference in AIS or AISS between the two groups. The extent and severity of AI cannot be predicted from biomechanical data, such as the height of the fall, as the total AI in a given case is a variable mixture of Nonfocal AI (DAI) and Focal AI arising by secondary mechanisms, and APP immunostaining is unable to distinguish primary from secondary AI. However, the combination of the Hypoxic-Ischemic Score (HIS) defined as the percentage of sectors showing any hypoxic-ischemic damage ranging from neuronal "red cell change" to infarction in conjunction with the FAIS and NFAIS provided a measure of the relative contribution of primary and secondary AI in a given brain.

Contrast adaptation and excitatory amino acid receptors in cat striate cortex

We have employed two paradigms to investigate the mechanisms of contrast gain control in cat striate cortex. In the first paradigm, optimal drifting gratings were presented in three consecutive periods. The contrast was near threshold in the first and third periods and accompanied by iontophoretic pulses of glutamate or glutamate receptor (GluR) agonists. The contrast was set to evoke a higher firing rate in the second period. Although both visual and iontophoretic conditions were identical in the first and third periods, responses to glutamate, N-methyl-D-aspartic acid (NMDA), and (IS,3R)-1-Aminocyclopentane-1,3-dicarboxylic acid (ACPD) were reduced following the adapting interval. (S)-alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) responses were not reduced. Administration of ionotropic GluR antagonists did not affect adaptation to the high-contrast grating. The metabotropic GluR antagonist (+/-)-alpha-Methyl-4-carboxyphenylglycine (MCPG), which acts at presynaptic glutamate autoreceptors, decreased the degree of adaptation exhibited by striate cells. In a second paradigm, contrast response functions (CRFs) were obtained at various adapting contrasts and least-squares fits to a hyperbolic ratio equation generated for each adapting level. Similar to previous reports, DL-2-amino-5-phosphonovaleric acid (APV) reduced the slope of the CRF and increased the responsiveness of the cells but did not affect the semisaturation constant, sigma, or the exponent of the CRF, n. Only MCPG significantly altered the distribution of sigma and n for 19 cells. The effect on sigma suggests that this drug can interfere with the cell's ability to shift its operating point to match the adapting contrast. These results suggest the involvement of a presynaptic mechanism for contrast adaptation. The decrease in neuronal responsiveness immediately following the high-contrast period may reflect an additional, postsynaptic effect in which there is a decrease in the NMDA-mediated component of the visual response.