Landscape characteristics influence ranging behavior of Asian elephants at the human-wildlands interface in Myanmar

CONTEXT

Asian elephant numbers are declining across much of their range driven largely by serious threats from land use change resulting in habitat loss and fragmentation. Myanmar, holding critical range for the species, is undergoing major developments due to recent sociopolitical changes. To effectively manage and conserve the remaining populations of endangered elephants in the country, it is crucial to understand their ranging behavior.

OBJECTIVES

Our objectives were to (1) estimate the sizes of dry, wet, and annual ranges of wild elephants in Myanmar; and quantify the relationship between dry season (the period when human-elephant interactions are the most likely to occur) range size and configurations of agriculture and natural vegetation within the range, and (2) evaluate how percentage of agriculture within dry core range (50% AKDE range) of elephants relates to their daily distance traveled.

METHODS

We used autocorrelated kernel density estimator (AKDE) based on a continuous-time movement modeling (ctmm) framework to estimate dry season (26 ranges from 22 different individuals), wet season (12 ranges from 10 different individuals), and annual range sizes (8 individuals), and reported the 95%, 50% AKDE, and 95% Minimum Convex Polygon (MCP) range sizes. We assessed how landscape characteristics influenced range size based on a broad array of 48 landscape metrics characterizing aspects of vegetation, water, and human features and their juxtaposition in the study areas. To identify the most relevant landscape metrics and simplify our candidate set of informative metrics, we relied on exploratory factor analysis and Spearman's rank correlation coefficient. Based on this analysis we adopted a final set of metrics into our regression analysis. In a multiple regression framework, we developed candidate models to explain the variation in AKDE dry season range sizes based on the previously identified, salient metrics of landscape composition.

RESULTS

Elephant dry season ranges were highly variable averaging 792.0 km² and 184.2 km² for the 95% and 50% AKDE home ranges, respectively. We found both the shape and spatial configuration of agriculture and natural vegetation patches within an individual elephant's range play a significant role in determining the size of its range. We also found that elephants are moving more (larger energy expenditure) in ranges with higher percentages of agricultural area.

CONCLUSION

Our results provide baseline information on elephant spatial requirements and the factors affecting them in Myanmar. This information is important for advancing future land use planning that takes into account space-use requirements for elephants. Failing to do so may further endanger already declining elephant populations in Myanmar and across the species' range.

Biallelic variants in KARS1 are associated with neurodevelopmental disorders and hearing loss recapitulated by the knockout zebrafish

PURPOSE

Pathogenic variants in Lysyl-tRNA synthetase 1 (KARS1) have increasingly been recognized as a cause of early-onset complex neurological phenotypes. To advance the timely diagnosis of KARS1-related disorders, we sought to delineate its phenotype and generate a disease model to understand its function in vivo.

METHODS

Through international collaboration, we identified 22 affected individuals from 16 unrelated families harboring biallelic likely pathogenic or pathogenic in KARS1 variants. Sequencing approaches ranged from disease-specific panels to genome sequencing. We generated loss-of-function alleles in zebrafish.

RESULTS

We identify ten new and four known biallelic missense variants in KARS1 presenting with a moderate-to-severe developmental delay, progressive neurological and neurosensory abnormalities, and variable white matter involvement. We describe novel KARS1-associated signs such as autism, hyperactive behavior, pontine hypoplasia, and cerebellar atrophy with prevalent vermian involvement. Loss of kars1 leads to upregulation of p53, tissue-specific apoptosis, and downregulation of neurodevelopmental related genes, recapitulating key tissue-specific disease phenotypes of patients. Inhibition of p53 rescued several defects of kars1^-/- knockouts.

CONCLUSION

Our work delineates the clinical spectrum associated with KARS1 defects and provides a novel animal model for KARS1-related human diseases revealing p53 signaling components as potential therapeutic targets.

An exploratory study of self-reported complicated grief symptoms in parentally bereaved adults with intellectual disability

BACKGROUND

Complicated grief involves the experience of grief-related symptoms at a time, and severity, beyond which could be considered adaptive, while persistent complex bereavement disorder (PCBD) has been identified as a condition that requires further study in the typical population. The aims of this study are to (1) explore the symptoms of complicated grief associated with parental bereavement as self-reported by adults with intellectual disabilities (IDs) who have experienced a parental bereavement and (2) conduct an initial examination of how the existing criteria for PCBD apply to this group.

METHODS

This study uses a comparative group design, assessing self and staff (proxy) reports for a group of parentally bereaved individuals and a matched group of non-bereaved individuals using the Complicated Grief Questionnaire - ID Self-Report. Participants were 46 individuals with ID, 30 (65%) of whom who had experienced a parental bereavement within the previous 2 years. The age range was 23-67 years (mean = 43.8; SD = 10.3).

RESULTS

The results highlight the presence of a range of symptoms of complicated grief in individuals' self-reports, although there was some evidence that separation distress-related symptoms were more apparent. An analysis of individual symptoms showed patterns of higher reports among the bereaved group as would be expected. Comparing staff and self-reports, key criteria showed higher levels in self-reports among the bereaved group.

CONCLUSIONS

This study has demonstrated the capacity of people with ID to self-report personal experience of symptoms of complicated grief, when appropriate and accessible assessment tools are used. Some symptoms were more evident among bereaved individuals (compared with non-bereaved participants), and they tended to be from separation distress criteria. This may indicate the relevance of these symptoms for people with ID and question the existing criteria for PCBD in this population, which may have clinical implications for supporting people with ID experiencing a more complicated bereavement response.

Maternal effects obscure condition-dependent sex allocation in changing environments

Climate change increases environmental fluctuations which thereby impact population demography. Species with temperature-dependent sex determination may experience more extreme sex ratio skews, but this has not been considered in species with chromosomally determined sex. However, anticipatory maternal effects cause lifelong physiological changes impacting sex ratios. Here we show, in mice, that more sons were born to mothers in good condition when their breeding environment matched their gestational environment, consistent with theoretical predictions, but mothers in mismatched environments have no condition-sex ratio relationship. Thus, the predicted effect of condition on sex ratio was obscured by maternal effects when the environment changed. This may explain extreme sex ratio skews in reintroduced or translocated populations, and sex ratio skews may become more common and less predictable with accelerating environmental change.

Do men and women with intellectual disabilities understand death?

BACKGROUND

Individuals with ID are often withheld information about the death of their loved ones as it has often been thought that they do not understand death or cannot grieve. This grief exacerbates the stress of individuals with ID as they often encounter secondary losses such as transitioning to a care facility. The aim of this study is to investigate men and women with ID understanding death concepts and to what extent.

METHOD

Adopting a stratified random sampling method, 156 Chinese people with ID were invited to join the study. One hundred and ten participants were interviewed using simple death related vignettes expanding upon and replicating a published study carried out in Ireland. The understanding of the five death concepts: causality, irreversibility, nonfunctionality, universality and inevitability was examined. The correlates of demographics, bereavement experiences and comprehension were explored.

RESULTS

The majority of the participants did understand concepts such as death is irreversible and that the deceased no longer function. One third of the participants understood causality and the universality of death. One fifth understood the inevitability of death. Previous bereavement experiences were correlated with higher understanding. Communication and community skills were correlated with all concepts of death except universality.

CONCLUSION

The results indicate that individuals with ID do have a partial to full understanding of the concepts of death. The culture of Hong Kong is one that considers death to be a taboo or unlucky subject. Therefore, the results mirror the the lack of understanding of universality and inevitability concepts as it is forbidden to speak of these concepts. An open and honest environment is encouraged to educate individuals with ID about death and bereavement.

A matter of life and death: knowledge about the body and concept of death in adults with intellectual disabilities

BACKGROUND

An increased awareness of how people with intellectual disabilities (ID) understand death and dying is necessary in supporting life-long learning, post-bereavement support and planning end-of-life care. Previous research suggests that adults with ID have a limited or 'patchy' understanding of the basic biological components of death. However, the relationship between biological understanding of how the body works and conceptualisation of death remains unexplored in this population.

METHOD

Thirty adults with ID were interviewed to assess their knowledge of human body function and their understanding of the concept of death. Using pictures, participants were asked if they recognised certain organs, asked to explain the function of various body parts and what would happen if certain body parts were missing or did not work. Participants who referred to 'life' or 'not dying' as the goal of body function were categorised as 'Life Theorisers'. In addition, participants were asked about the causes of death, whether all things die and the status of the body after death.

RESULTS

The results support previous studies suggesting that understanding of death in adults with ID varies from partial to full comprehension and is associated with level of ID. Also, death comprehension was positively correlated with total body interview scores and 'Life Theorisers' who understood that body parts maintain life and who spontaneously appealed to 'vitalistic' concepts when reasoning about the human body were also more sophisticated in their understanding of death.

CONCLUSION

The study highlights the relationship between knowledge about the goal of human body functioning and death comprehension in adults with ID. The potential that learning to adopt a 'vitalistic' approach to human functioning may have on the acquisition of a greater understanding of death and dying, understanding illness and supporting end-of-life planning is discussed.

Electrophysiological validation of STN-SNr boundary depicted by susceptibility-weighted MRI

BACKGROUND

Direct targeting of subthalamic nucleus (STN) without secondary electrophysiological verification during deep brain stimulation (DBS) is replacing atlas-based indirect targeting techniques. Recent groups have reported increased contrast and better delineation of STN and substantia nigra (SNr) in susceptibility-weighted imaging protocols (SWI). We aim to validate the STN-SNr boundary seen in MRI- SWI by correlating with intraoperative microelectrode recordings (MER) as a part of developing a multi-contrast DBS MRI planning protocol.

METHODS

Prospective service evaluation involving electrophysiological verification by correlation of MER trajectory and STN-SNr boundary seen in SWI in seven consecutive patients undergoing DBS surgery were analyzed. The angle of inclination of the STN-SNr boundary and DBS trajectory in the coronal plane were calculated. Considering 4-mm dispersion of a coronal 3 MER array, we predicted, measured, and correlated the depths at which each electrode engaged the boundary.

RESULTS

All central microelectrodes identified the STN-SNr boundary within 1 mm of the predicted depth with 100 % accuracy. Ninety percent of the lateral MER identified the STN-SNr boundary as predicted from SWI and angle of the encounter of the MER front.

CONCLUSIONS

The study demonstrates that STN morphology can be depicted using SWI MRI and coincides reliably with the electrophysiological MER boundary. Thus, this imaging modality can be used to refine STN direct targeting protocols in DBS surgery for PD.

Safety and efficacy of motor mapping utilizing short pulse train direct cortical stimulation

BACKGROUND/AIMS

A major goal of intracranial surgery is to maximize resection while minimizing neurological morbidity, particularly motor dysfunction. Direct cortical stimulation (DCS) is a common intraoperative adjunct used to identify functional motor cortex. In this study, we report on the safety/efficacy of short pulse train DCS (direct cortical stimulation motor-evoked potential, dcMEP) for motor mapping and monitoring during intracranial surgery.

METHODS

A retrospective analysis of 29 patients undergoing elective craniotomy for lesions near the motor cortex was performed. dcMEP mapping (40-120 V, 500-1,000 Hz, 5-9 pulses/s, 1- to 3-ms interstimulus interval, monopolar, 50-μs pulse width) was performed either alone (n = 29) or in addition to standard DCS (n = 6). Outcome measures were positive MEPs and the presence of seizures during stimulation. dcMEP-based continuous corticospinal tract (CST) monitoring was also performed. Changes in stimulation threshold and new postoperative neurological deficits were recorded.

RESULTS

dcMEP mapping success was 96% and was not affected by preoperative motor status. Intraoperative seizure rates for dcMEP were 3% and were not related to preoperative seizure status. CST monitoring success rate was 96%, and changes in stimulation threshold were predictive of new permanent motor deficits.

CONCLUSIONS

dcMEP is an effective method for mapping motor function and may prove useful for continuous CST monitoring.

Concept of death and perceptions of bereavement in adults with intellectual disabilities

BACKGROUND

Bereavement is potentially a time of disruption and emotional distress. For individuals with an intellectual disability (ID), a limited understanding of the concept of death may exacerbate this distress. The aim of the present study was to investigate how individuals with ID understand and explain death and make sense of life without the deceased.

METHOD

Thirty-four people with ID were interviewed using simple vignettes describing death-related incidents. Participants were asked about the causes of death, the status of the body after death and whether all living things die. In addition, participants were asked about reactions to death and for their views on post-bereavement support.

RESULTS

Nearly one quarter of participants had a full understanding and over two-thirds a partial understanding of the concept of death. Death comprehension was positively correlated with cognitive ability and adaptive functioning. While cause of death was predominantly associated with illness and old age, participants viewed death as final and understood that all living things die. The role of religious beliefs was also found to be important for many participants.

CONCLUSIONS

The results support earlier findings that suggest people with ID have only a partial understanding of the concept of death leaving them vulnerable to factually incorrect thoughts. The study highlights the considerable scope for making sense of death using religious and spiritual themes and emphasises the need for teaching individuals biological explanations of the life cycle. The results also provide some insight into the views of individuals with ID for carers involved in providing post-bereavement support.

Altered interactions of tryptophan metabolites in first-episode neuroleptic-naive patients with schizophrenia

Schizophrenia is characterized by complex and dynamically interacting perturbations in multiple neurochemical systems. In the past, evidence for these alterations has been collected piecemeal, limiting our understanding of the interactions among relevant biological systems. Earlier, both hyper- and hyposerotonemia were variously associated with the longitudinal course of schizophrenia, suggesting a disturbance in the central serotonin (5-hydroxytryptamine (5-HT)) function. Using a targeted electrochemistry-based metabolomics platform, we compared metabolic signatures consisting of 13 plasma tryptophan (Trp) metabolites simultaneously between first-episode neuroleptic-naive patients with schizophrenia (FENNS, n=25) and healthy controls (HC, n=30). We also compared these metabolites between FENNS at baseline (BL) and 4 weeks (4w) after antipsychotic treatment. N-acetylserotonin was increased in FENNS-BL compared with HC (P=0.0077, which remained nearly significant after Bonferroni correction). N-acetylserotonin/Trp and melatonin (Mel)/serotonin ratios were higher, and Mel/N-acetylserotonin ratio was lower in FENNS-BL (all P-values<0.0029), but not after treatment, compared with HC volunteers. All three groups had highly significant correlations between Trp and its metabolites, Mel, kynurenine, 3-hydroxykynurenine and tryptamine. However, in the HC, but in neither of the FENNS groups, serotonin was highly correlated with Trp, Mel, kynurenine or tryptamine, and 5-hydroxyindoleacetic acid (5HIAA) was highly correlated with Trp, Mel, kynurenine or 3-hydroxykynurenine. A significant difference between HC and FENNS-BL was further shown only for the Trp-5HIAA correlation. Thus, some metabolite interactions within the Trp pathway seem to be altered in the FENNS-BL patients. Conversion of serotonin to N-acetylserotonin by serotonin N-acetyltransferase may be upregulated in FENNS patients, possibly related to the observed alteration in Trp-5HIAA correlation. Considering N-acetylserotonin as a potent antioxidant, such increases in N-acetylserotonin might be a compensatory response to increased oxidative stress, implicated in the pathogenesis of schizophrenia.

Atrazine degradation by stable mixed cultures enriched from agricultural soil and their characterization

AIMS

The aim of this work was to enrich stable mixed cultures from atrazine-contaminated soil. The cultures were examined for their atrazine biodegradation efficiencies in comparison with J14a, a known atrazine-degrading strain of Agrobacterium radiobacter. The cultures were also characterized to identify community structure and bacterial species present.

METHODS AND RESULTS

The cultures were enriched and then stabilized in bacterial media. The stable mixed cultures and J14a were tested in a medium containing 100 microg l(-1) of atrazine. For all cultures, atrazine was removed 33-51% within 7 days and the cell optical density increased from 0.05 to between 0.50 and 0.70. Four isolates designated ND1, ND2, ND3 and ND4 were purified from the mixed cultures and identified based on sequence analysis of the 16 S rRNA gene as Alcaligenes faecalis, Klebsiella ornithinolytica, Bacillus megaterium and Agrobacterium tumefaciens, respectively. An atrazine-degrading gene, atzA, was present in ND2 and ND4.

CONCLUSIONS

The stable mixed cultures obtained could degrade atrazine. Klebsiella ornithinolytica ND2 and Ag. tumefaciens ND4 are atrazine degraders.

SIGNIFICANCE AND IMPACT OF THE STUDY

The novel stable mixed cultures could be used for bioremediating crop fields contaminated with atrazine. This is the first report of the atzA gene in Kl. ornithinolytica.

A study of complicated grief symptoms in people with intellectual disabilities

INTRODUCTION

Previous studies have shown a significant association between familial bereavement and the onset of challenging behaviours and psychopathology in people with intellectual disabilities (ID). However, little work has been done to accurately describe the specific symptoms of grief, in particular symptoms of complicated grief in this population. Consensus criteria for the diagnosis of complicated grief have been drawn up and tested for validity in the general population.

AIMS

To examine the occurrence of symptoms of complicated grief, and to explore the relationships between complicated grief and bereavement experience.

METHOD

A bereavement history questionnaire and a newly developed measure examining for symptoms of complicated grief were administered to a group of carers of people with mild or moderate ID, who had experienced a parental bereavement within the previous 2 years. The questionnaires were also administered to a matched comparison group, who had not been bereaved.

RESULTS/CONCLUSIONS

This carer-based comparison study has revealed that bereaved individuals with ID experience complicated grief symptoms following the death of a parent, with one-third of the bereaved group experiencing 10 or more clinically apparent symptoms. In addition, complicated grief symptoms were more likely to occur with higher rates of bereavement ritual involvement. These findings have both clinical and research implications.

The prevalence of features of attention deficit hyperactivity disorder in a special school in Ireland

BACKGROUND

The prevalence of features of attention deficit hyperactivity disorder (ADHD) in children with intellectual disabilities (ID) in Irish schools is unknown. The aim of this study was to examine the prevalence of features of ADHD in a special school, in order to ascertain the number of children who may need further assessment for ADHD. The study also explores the reliability of the Conners Teachers Rating Scale in this population.

METHOD

All teachers in a special school for children with ID were asked to complete the Conners Teachers Rating Scale and the Attention-Distractibility, Inhibition-Excitation Classroom Assessment Rating Scale, for those children whose parents had consented for them to take part in this study. Consent was obtained for 84 children a response rate of 71%, between the ages of 5 and 18 (mean = 10.5 years; SD = 3.7).

RESULTS

The Conners Teachers Rating Scale was found to be internally reliable and had a normal distribution with our results. Overall, 55.9% of participants (47/84) had markedly elevated scores (T > 69) for at least one of the target subscales, which were the 'Hyperactivity', 'Inattention' and the 'ADHD Index' subscales of the Conners Teachers Rating Scales. In addition, the findings would suggest that the Conners Teachers Rating Scale can be a useful screening tool in the population of school children with ID.

CONCLUSIONS

The study suggests that ADHD may be under diagnosed in children with ID. This has practical implications for the mental health needs of these children. It is recommended that further studies are carried out to determine the prevalence of ADHD in this population.

Metabolomic mapping of atypical antipsychotic effects in schizophrenia

Schizophrenia is associated with impairments in neurotransmitter systems and changes in neuronal membrane phospholipids. Several atypical antipsychotic drugs induce weight gain and hypertriglyceridemia. To date, there has not been a comprehensive evaluation and mapping of global lipid changes in schizophrenia, and upon treatment with antipsychotics. Such mapping could provide novel insights about disease mechanisms and metabolic side effects of therapies used for its treatment. We used a specialized metabolomics platform 'lipidomics' that quantifies over 300 polar and nonpolar lipid metabolites (across seven lipid classes) to evaluate global lipid changes in schizophrenia and upon treatment with three commonly used atypical antipsychotics. Lipid profiles were derived for 50 patients with schizophrenia before and after treatment for 2-3 weeks with olanzapine (n=20), risperidone (n=14) or aripiprazole (n=16). Patients were recruited in two cohorts (study I, n=27 and study II, n=23) to permit an internal replication analyses. The change from baseline to post-treatment was then compared among the three drugs. Olanzapine and risperidone affected a much broader range of lipid classes than aripiprazole. Approximately 50 lipids tended to be increased with both risperidone and olanzapine and concentrations of triacylglycerols increased and free fatty acids decreased with both drugs but not with aripiprazole. Phosphatidylethanolamine concentrations that were suppressed in patients with schizophrenia were raised by all three drugs. Drug specific differences were also detected. A principal component analysis (PCA) identified baseline lipid alterations, which correlated with acute treatment response. A more definitive long-term randomized study of these drugs correlating global lipid changes with clinical outcomes could yield biomarkers that define drug-response phenotypes.

Bile metabolites of polycyclic aromatic hydrocarbons (PAHs) in European eels Anguilla anguilla from United Kingdom estuaries

A total of 94 European eels (Anguilla anguilla) were collected from five estuaries in the UK. The deconjugated metabolites of polycyclic aromatic hydrocarbons (PAHs) in the bile of the eels were separated using HPLC. Six PAH metabolites were identified: 1-hydroxy (1-OH) metabolites of phenanthrene, pyrene and chrysene; and the 1-OH, 3-OH and 7,8 dihydrodiol metabolites of benzo[a]pyrene (BaP). The mean concentration of the six metabolites was greatest in eels from the Tyne (49 microM) followed by the Wear (33 microM), Tees (19 microM), Thames (4 microM) and Severn (2 microM) estuaries. Although 1-OH pyrene was always the dominant compound, there were significant differences (P<0.05) between sites and between estuaries for some metabolites. Normalising the molar concentration of the bile metabolites to the bile biliverdin absorbance reduced sample variation. When the metabolites identified were each expressed as a percentage of the total detected, the metabolite profile was characteristic for each estuary.

Metallothionein in liver of eels Anguilla anguilla from the Thames Estuary: an indicator of environmental quality?

The purpose of this study was to examine the role of the cysteine-rich protein metallothionein (MT) in the detoxification and metabolism of metals in livers of eels Anguilla anguilla from the Thames Estuary, and to assess the value of MT measurements in environmental monitoring. Hepatic MT levels and associated metal concentrations were determined in A. anguilla collected on three occasions during 1998 at sites along the tidal Thames (from freshwater to the sea) and also from a reference site (Tamar Estuary) in southwest England. MT was present at basal levels of 2 mg g(-1) dry weight (dw), predominantly in association with the essential metals Cu and Zn. MT concentrations were variable within each eel 'population' but were generally highest (up to 11 mg g(-1) in individual eels) at the more contaminated upper- and mid-estuarine sites in the Thames (e.g. Brentford and Kew). Lowest MT levels were those in eels from Blythe Sands at the mouth of the estuary. Season, sex, reproductive status and salinity may have influenced MT levels to some extent, although metals were the most significant factor. Hepatic MT concentrations were highly correlated with associated metal burdens (Zn, Cu, Ag and Cd),--notably reflecting Cu and Ag enrichment in the upper- and mid-estuary. With the exception of Zn, metals in the supernatant fraction of eel livers were primarily associated with MT. Proportions of Cu, Ag and Cd bound to MT increased as a function of accumulated metal burdens, with no indication of saturation. Thus, despite causing induction of MT, excess bioavailable Cu, Ag and Cd appear to be successfully detoxified in eels over the range of environmental contamination encountered along the Thames Estuary. Paradoxically, it may be argued from conventional doctrine that the presence of raised levels of MT, at upstream sites, constitutes a response to contamination and, by definition, signals that the fish are affected by metals; however, obvious signs of deleterious effects were not detected. Superficially, from liver MT data, it would seem that eel populations have become biochemically adapted to metal contamination. The approach tested here has proved viable in helping to interpret trends in bioavailability and the toxicological significance of accumulated metal burdens in Thames eels. A. anguilla is a common inhabitant of estuarine and fresh waters throughout Europe, and related species occur world wide. Therefore, determination of hepatic MT (and associated metals) in eels could be useful for monitoring responses to metal exposure and environmental quality on a much broader basis. Ideally these determinations should be performed in tandem with other sublethal-effects measurements to maximise information.

Hepatic 7-ethoxyresorufin O-deethylase activity in eel (Anguilla anguilla) from the Thames Estuary and comparisons with other United Kingdom Estuaries

Hepatic microsomal 7-ethoxyresorufin O-deethylase (EROD) activities (indicative of exposure to polycyclic aromatic hydrocarbons (PAHs) and polychlorobiphenyls (PCBs)) were measured in eel Anguilla anguilla from the Thames Estuary. Fish were collected from up to 13 sites during November 1997, May and August 1998 and October 1999. Throughout this period no clear seasonal variation could be identified at every site along the Thames. However, during the summer months, fish sampled from sites in the middle to the upper estuary (Woolwich, Greenhithe and West Thurrock) reported up to 3-fold higher EROD activities compared to sites either at the upper reaches (Richmond and Brentford) at the same time of the year, or fish sampled in winter, along the entire length of the estuary. A laboratory exposure experiment demonstrated a 3-fold elevation of EROD activity 2 days after injection with beta-naphthoflavone (beta-NF). However, higher levels of activity could be determined in fish sampled from the Weston canal near the Merseyside. The lowest levels of A. anguilla EROD activity were observed in fish sampled from the upper reaches of the River Tamar, Devon, and were comparable to activities determined in fish from the Wear and Humber estuaries. A. anguilla sampled along the Thames, Tyne and Tees estuaries reported between 2.5- and 7-fold higher EROD activities compared to fish collected from the Tamar. These results indicate that a low to moderate induction of A. anguilla CYP1A had occurred (indicative of low to moderate exposure to PAHs and planar PCBs) in fish collected from the Thames, Tyne, Wear, Tees, Humber and Tamar estuaries. However, the highest level of EROD activity was observed in fish from the Weston Canal (Merseyside).

Investigations of cholesterol transformation during sewage treatment: relevance to estrogen formation pathways?

There is currently a great deal of concern over the observation of so-called estrogenic effects (specifically increases in the concentrations of the egg yolk precursor, vitellogenin) in male fish living in some UK rivers. The effects have been attributed to chemicals, including estrogenic steroids, which enter the rivers via sewage effluents. The origins of these estrogenic steroids in sewage may include contributions from the influents and possibly in situ transformation processes of other steroids occurring during sewage treatment. The present study examined the latter possibility. The bacterial metabolism of radiolabelled cholesterol during laboratory-simulated aerobic sewage treatment was studied by reverse phase radio-high performance liquid chromatography (rHPLC) and radio-gas chromatography (rGC) to examine the hypothesis that cholesterol could undergo A-ring aromatisation to form first, 19-norcholest-1,3,5(10)-trien-3-ol (NCT) and hence, by known bacterial pathways, the estrogenic steroid, estrone. The results showed that, to the contrary, much of the cholesterol (approx. 50% in 96 h) underwent rapid mineralisation to carbon dioxide, consistent with A-ring rupture (rather than aromatisation) and beta-oxidation of the alkyl side chain as major transformation routes. Some polar (early-eluting) rHPLC products were observed, possibly steroidal conjugates and/or fatty acids. Among the minor metabolites detected by rGC and GC-mass spectrometry (GC-MS) were cholest-3,5-diene and a second cholestadiene isomer. However, since alkenes were unexpected in this rHPLC fraction, they may arise as artefacts from thermal decomposition of cholesteryl esters, indicating that some cholesterol esterification had also occurred. In the alcohol rHPLC fractions, cholestadienol was identified by GC and GC-MS but neither NCT or estrone were detected. This suggests that, at least under these simulated conditions, in situ aromatisation of cholesterol to NCT and formation of estrone from NCT were not major processes.

Seasonal variation and estradiol-dependent elevation of Thames estuary eel Anguilla anguilla plasma vitellogenin levels and comparisons with other United Kingdom estuaries

Eel Anguilla anguilla plasma vitellogenin was investigated as a biomarker of exposure to environmental compounds with estrogenic activity, along the tidal course of the Thames Estuary, UK. A. anguilla was chosen as a sentinel species because of their wide distribution, robustness in field and laboratory studies and also because they have a characterised normal intersex' condition where the gonad contains both developing male and female gonadal cells termed a Syrski organ. Following laboratory exposure to 17beta-estradiol (intraperitoneal injection), a plasma protein (approx. 211 kDa apparent molecular weight) was detected by monoclonal antibodies to vitellogenin of striped bass (Morone saxatilis). Western and dot blot analyses were developed and vitellogenin was isolated from 17beta-estradiol-treated fish to calibrate the quantification of the blots by image analysis. The limits of sensitivity for the Western and dot blots were 100 and 10 ng vitellogenin/ml, respectively. Levels of vitellogenin in Thames estuary samples were below the detection limits of the Western but not the dot blot, and showed no statistically significant site-specific (10 sites) and seasonal-specific (May, August, November) differences. Values were observed to be low, between 11 and 165 ng/ml, compared with 17-50 mg/ml for 17beta-estradiol-treated eels. Similar low levels of plasma vitellogenin were determined in fish sampled along the Tyne, Wear, Tees or Humber estuaries, or the Weston canal Liverpool, with mean plasma vitellogenin levels varying between 44 and 82 ng/ml. These levels of vitellogenin in A. anguilla plasma were observed to be consistent with the known biology of the eel. Immature females, or fish with syrski organs, reported both lower levels and smaller variation of plasma vitellogenin concentrations whereas the highest plasma vitellogenin concentrations were determined in fish above 45 cm consistent with female fish. These results indicate inter-species variation between the plasma vitellogenin concentrations of A. anguilla and other published fish studies undertaken along the same estuaries.

Effects of clozapine, olanzapine, risperidone, and haloperidol on hostility among patients with schizophrenia

OBJECTIVE

This study compared the specific antiaggressive effects of clozapine with those of olanzapine, risperidone, and haloperidol.

METHODS

A total of 157 inpatients with schizophrenia or schizoaffective disorder and a history of suboptimal treatment response were randomly assigned to receive clozapine, olanzapine, risperidone, or haloperidol in a double-blind 14-week trial. The trial was divided into two periods: eight weeks during which the dosage was escalated and then fixed, and six weeks during which variable dosages were used. The hostility item of the Positive and Negative Syndrome Scale (PANSS) was the principal outcome measure. Covariates included the items that reflect positive symptoms of schizophrenia (delusions, suspiciousness or feelings of persecution, grandiosity, unusual thought content, conceptual disorganization, and hallucinations) and the sedation item of the Nurses Observation Scale for Inpatient Evaluation (NOSIE).

RESULTS

Patients differed in their treatment response as measured by the hostility item of the PANSS. The scores of patients taking clozapine indicated significantly greater improvement than those of patients taking haloperidol or risperidone. The effect on hostility appeared to be independent of the antipsychotic effect of clozapine on other PANSS items that reflect delusional thinking, a formal thought disorder, or hallucinations and independent of sedation as measured by the NOSIE. Neither risperidone nor olanzapine showed superiority to haloperidol.

CONCLUSION

Clozapine has a relative advantage over other antipsychotics as a specific antihostility agent.

Analysis of estrogens in river water and effluents using solid-phase extraction and gas chromatography-negative chemical ionisation mass spectrometry of the pentafluorobenzoyl derivatives

A procedure was developed for the analysis of estrogens in environmental water and effluents. Samples were extracted by passing through polymer-impregnated solid-phase extraction discs or C18 cartridges, followed by gas chromatography-negative chemical ionisation mass spectrometry of the pentafluorobenzoyl derivatives. The derivatives were stable and gave diagnostic negative molecular ions as the base peak for each of the major estrogens studied. The absolute recovery of estrogens spiked into clean groundwater using the disc procedure was 84-116% at the 10 ng l(-1) level (calculation not based on use of internal standards). Using doubly deuterated estradiol as internal standard added prior to extraction, the % relative standard deviation of estrogen extraction and analysis in spiked groundwater at the 10 ng(-1) level was 2.6-9.8%. Detection limits were 0.2 ng l(-1) or below for the major estrogens, based on a 2.5 litre sample. The most abundant estrogen was estrone, with concentrations over the range 6.4-29 ng l(-1) in effluents, and 0.2 to 17 ng l(-1) in water from the River Thames.

Replacement of fish oil with rapeseed oil in diets of Atlantic salmon (Salmo salar) affects tissue lipid compositions and hepatocyte fatty acid metabolism

Duplicate groups of Atlantic salmon post-smolts were fed five practical-type diets in which the added lipid was 100% fish oil [FO; 0% rapeseed oil (0% RO)], 90% FO + 10% RO (10% RO), 75% FO + 25% RO (25% RO), 50% FO + 50% RO (50% RO) or 100% RO, for a period of 17 wk. There were no effects of diet on growth rate or feed conversion nor were any histopathological lesions found in liver, heart, muscle or kidney. The greatest accumulation of muscle lipid was in fish fed 0% RO, which corresponded to significantly lower muscle protein in this group. The highest lipid levels in liver were found in fish fed 100% RO. Fatty acid compositions of muscle lipid correlated with RO inclusion in that the proportions of 18:1(n-9), 18:2(n-6) and 18:3(n-3) all increased with increasing dietary RO (r = 0.98-1.00, P < 0.013). The concentrations of eicosapentaenoic acid [20:5(n-3)] and docosahexaenoic acid [22:6(n-3)] in muscle lipid were significantly reduced (P < 0.05), along with total saturated fatty acids, with increasing dietary RO. Diet-induced changes in liver fatty acid compositions were broadly similar to those in muscle. Hepatic fatty acid desaturation and elongation activities, measured using [1-(14)C] 18:3(n-3), were increased with increasing dietary RO. Limited supplies of marine fish oils require that substitutes be found if growth in aquaculture is to be maintained such that fish health and product quality are not compromised. Thus, RO can be used successfully as a substitute for fish oil in the culture of Atlantic salmon in sea water although at levels of RO >50% of dietary lipid, substantial reductions occur in muscle 20:5(n-3), 22:6(n-3) and the (n-3)/(n-6) polyunsaturated fatty acid (PUFA) ratio, which will result in reduced availability of the (n-3) highly unsaturated fatty acids that are beneficial for human health.

Seasonal export of phosphorus from a lowland catchment: upper River Cherwell in Oxfordshire, England

The export of phosphorus from a lowland catchment, the River Cherwell in southern England, was measured over a period of 1 year. The results describe total phosphorus concentrations in the water and river discharge at 4-day intervals. These were used to estimate the load of total phosphorus exported from the catchment. These annual loads were compared with exports estimated from sewage inputs and diffuse inputs calculated from land-coverage data, with assigned phosphorus export coefficients for particular land uses. The method was further developed to examine seasonal changes in phosphorus exports by predicting monthly losses using annual export coefficients normalised with respect to the relative hydraulic runoff for a particular month. The results show a strong seasonal dependence of total exports, with retention of phosphorus in the river system in the spring to early autumn and release of stored material during the winter. This pattern remained true, even with 50% increase in the main land-cover export and a similar increase in treated sewage exports.

Investigations of the origins of estrogenic A-ring aromatic steroids in UK sewage treatment works effluents

The present preliminary study describes an investigation of a putative aromatisation pathway in sewage from cholesterol through the corresponding A-ring aromatic steroid, norcholest-1,3,5(10)-trienol (NCT) to estrone. The synthesis and analytical characterisation of NCT and of the trimethyl silyl ether by gas chromatography-mass spectrometry, is described. The analytical properties of synthetic NCT were used to direct a search for the compound over several months in 1998 in the effluents of two sewage treatment works (STW; Deephams and Harpenden, north London). The study was prompted by the earlier findings that increased vitellogenin concentrations in the plasma of caged male rainbow trout held in the STW effluents (so-called fish 'feminisation') could be attributed to the presence of A-ring steroids such as estrone. Until now it has been assumed that these steroids originate from the STW influents and it is not clear to what extent, if at all, aromatisation of steroids might occur during STW operation. NCT was only detected in the solid particles associated with the effluents on one occasion in 8 months. This suggests that the hypothesised pathway is not a major one. Confirmation of previous reports of estrone and 17 beta-estradiol was also obtained using a published analytical method and by a simple modification of the method these reports were extended to include a regular occurrence of the weaker estrogen, 16 alpha-estriol in the case of Harpenden STW effluents in 1998.

Postpositivist interpretations of the chemical revolution

Expressing the growing interest of historians of science in “the history of science as history,” this study offers a critical account of recent developments in the historiography of the Chemical Revolution. It explores the philosophical and historiographical dimensions of the “postpositivist” (or “theoreticist”) interpretations of the Chemical Revolution, which displaced the positivist-whig historiographical hegemony in the 1960s and 1970s, only to be challenged by the sociology of knowledge in the 1980s and 1990s. Despite its brief ascendancy in the pantheon of interpretive styles, postpositivism had a profound influence on the historiography of the Chemical Revolution, and this study will enable us to better appreciate its complex, variegated, and important results. Besides providing future specialists in the field with useful information, this study is designed to solicit the interest and input of more general historians in the history of science.

Depletion of alpha-tocopherol and astaxanthin in Atlantic salmon (Salmo salar) affects autoxidative defense and fatty acid metabolism

Duplicate groups of Atlantic salmon post-smolts were fed four purified diets supplemented with both vitamin E and the carotenoid astaxanthin (Ax) (+E, +Ax), or supplemented with either vitamin E or Ax (-E, +Ax and +E, -Ax) or deficient in both vitamin E and Ax (-E, -Ax) for 22 wk. There were no effects of diet on growth rate, but an extensive lipoid liver degenerative lesion was observed in 15% of fish fed diets deficient in vitamin E. Tissue vitamin E concentrations varied in accordance with dietary vitamin E in liver, muscle, heart, plasma, brain and eye; levels were reduced to approximately 3% in liver but only to 40% in eye of fish fed diets deficient in vitamin E compared with those fed diets supplemented with vitamin E. An interactive sparing of Ax supplementation on tissue vitamin E concentration was observed, but only in brain. Dietary deficiency of both vitamin E and Ax significantly increased the recovery of desaturated and elongated products of both [1-(14)C] 18:3(n-3) and [1-(14)C] 20:5(n-3) in isolated hepatocytes, suggesting that conversion of fatty acids to their long-chain highly unsaturated products can be stimulated by a deficiency of lipid-soluble antioxidants. The antioxidant synergism of vitamin E and Ax was supported by their ability to reduce malondialdehyde formation in an in vitro stimulation of microsomal lipid peroxidation and to reduce plasma levels of 8-isoprostane. The results of this study suggest that both vitamin E and the carotenoid Ax have antioxidant functions in Atlantic salmon.

Development of hepatic CYP1A and blood vitellogenin in eel (Anguilla anguilla) for use as biomarkers in the Thames Estuary, UK

The potential of eel (Anguilla anguilla) as a monitoring species for the Thames Estuary, UK, was examined. Hepatic cytochrome P4501A [7-ethoxyresorufin O-deethylase (EROD) activity] and blood vitellogenin (Western analysis) were investigated as biomarkers of exposure to, respectively, organic contaminants and to contaminants showing estrogenic activity. Hepatic microsomal EROD activities in A. anguilla from seven sites in the Thames Estuary in May 1998 varied three-fold (111 +/- 24 to 355 +/- 42 pmol min-1 mg protein-1) (mean +/- S.E.M.) and showed correlation with salinity; however, the latter relationship was not maintained at other times of the year. The range of EROD activities was two- to eight-fold higher than the 37 +/- 8 pmol min-1 mg-1 for A. anguilla from the relatively clean Tamar Estuary. beta-Naphthoflavone treatment (5 mg kg-1 wet wt.; 2 days) of Thames A. anguilla produced a two-fold increase in hepatic microsomal EROD activity. Comparing the Thames EROD data with those for A. anguilla from well-characterised contaminated sites in the Netherlands (Van der Oost, R., Goksøyr, A., Celander, M., Heida, H., & Vermeulen, N. P. E. 1996. Aquatic Toxicology, 36, 189-222), the Thames is suggested to be moderately impacted by polycyclic aromatic hydrocarbons and related contaminants. 17-beta-Estradiol treatment produced the appearance of a plasma protein of 211 Kd app. mol. wt. (recognised by antibodies to vitellogenin of Morone saxatilis), but putative vitellogenin could not be detected in A. anguilla from selected sites in the Thames Estuary.

Development of a fish in vitro cell culture model to investigate oxidative stress and its modulation by dietary vitamin E

When cultured in Dulbecco's minimal essential medium the established epithelioma papulosum cyprini cell line from carp was found to be vitamin E-deficient due to the very low level of vitamin E in the medium and the foetal calf serum used as supplement. The toxicity of oxidative stressors to this cell line was evaluated by means of the neutral red cytotoxicity assay and it was found that an organic hydroperoxide, t-butylhydroperoxide was extremely cytotoxic and that the redox-cycling agents diquat and menadione were less toxic. When grown under vitamin E supplementation (25 microM), the toxicity of these chemicals was reduced by at least an order of magnitude in concentration demonstrating the protective effect of vitamin E. These data show the importance of vitamin E status for interpretation of in vitro and in vivo data and that this in vitro system is useful for mechanistic studies.

Flesh Lipid and Carotenoid Composition of Scottish Farmed Atlantic Salmon (Salmo salar)

Samples of steaks from market-size salmon (2.5-5 kg), produced under the requirements of the Product Certification Scheme for Scottish Quality Farmed Salmon, were obtained from five Scottish salmon producers on a weekly basis for over 2 years. Samples were assayed for total lipid content, lipid class composition, fatty acid composition, vitamin E content, and carotenoid pigment [astaxanthin (AX) and canthaxanthin (CX)] content. In addition, samples were obtained from the same producers to assess loss of carotenoid pigment in the period up to 120 h post-harvest and to measure lipid and pigment content of different body regions. The analyses showed a positive correlation between dietary lipid and deposition of lipid in flesh, although there was great variation in flesh lipid content within each dietary lipid level. The average lipid content of Scottish salmon was 10.1 +/- 2.9% (n = 495). Salmon flesh was rich in the n-3 highly unsaturated fatty acids, 22:6n-3 and 20:5n-3, with average values of 11.3 and 5.4% of total fatty acids or 10.2 and 4.8 g/kg flesh, respectively. Vitamin E content of salmon flesh was around 30 mg/kg but was significantly higher in fish fed the lowest dietary lipid level. Studies investigating changes in carotenoid pigmentation up to 120 h post-harvest suggested that fish fed AX alone showed a loss of pigment over time that did not occur in fish fed either CX alone or a combination of AX and CX. Measurement of lipid content of different body regions showed that the highest levels were found in the region immediately in front of the dorsal fin and that the lowest lipid levels were in the tail region. Total lipid content of all five body zones was positively correlated with dietary lipid. Carotenoid pigment levels were the same across all body zones and were not affected by dietary lipid.

The second finger of Urbs1 is required for iron-mediated repression of sid1 in Ustilago maydis

The urbs1 gene encodes a transcriptional regulator of siderophore biosynthesis in Ustilago maydis. Biological and DNA-binding activities of the two putative zinc-finger motifs of Urbs1 were studied by analyzing mutants containing altered finger domains. The mutated urbs1 alleles from three previously described N'-methyl-N'-nitro-N-nitrosoguanidine (NTG) mutants were mapped and cloned by a gap-repair procedure. Sequence analyses revealed single amino acid substitutions in two of the NTG mutants. Both mutations (G-507 to D in urbs1-1 and P-491 to L in urbs1-3), which are located in the Urbs1 C-terminal finger domain, reduced DNA-binding activity by 10-fold and were sufficient to confer a urbs1-minus phenotype. The third NTG urbs1 mutant (urbs1-2) also contained a mutation in one of the conserved amino acids (P-518 to S) in the C-terminal finger domain, but this mutation alone was not sufficient to confer a urbs1-minus phenotype. A second frame shift mutation was identified in urbs1-2 and is necessary for the urbs1-minus phenotype. In an analysis of the function of the N-terminal finger of Urbs1, the conserved amino acid Arg-350 was mutated to leucine. A Urbs1 protein with this mutation complemented a urbs1 null mutant strain. By contrast, a similar mutation in the C-terminal domain abolished the ability of Urbs1 to regulate siderophore biosynthesis and greatly reduced its ability to bind target DNA.

Nicotine-haloperidol interactions and cognitive performance in schizophrenics

Nearly 90% of schizophrenics smoke cigarettes, considerably higher than the general population's rate of 25%. There is some indication that schizophrenics may smoke as a form of self-medication. Nicotine has a variety of pharmacologic effects that may both counteract some of the cognitive deficits of schizophrenia and counteract some of the adverse side effects of antipsychotic drugs. In the current study, we assessed the interactions of haloperidol and nicotine on cognitive performance of a group of schizophrenics. These patients were in a double-blind study, randomly assigning them to low, moderate, and high dose levels of haloperidol. The subjects, all smokers, came to the laboratory on four different mornings after overnight deprivation from cigarettes. In a double-blind fashion, they were administered placebo, low (7 mg/day), medium (14 mg/day), or high (21 mg/day) dose nicotine skin patches. Three hours after administration of the skin patch, the subjects were given a computerized cognitive test battery including: simple reaction time, complex reaction time (spatial rotation), delayed matching to sample, the Sternberg memory test, and the Conners continuous performance test (CPT). With the placebo nicotine patch, there was a haloperidol dose-related impairment in delayed matching to sample choice accuracy and an increase in response time on the complex reaction time task. Nicotine caused a dose-related reversal of the haloperidol-induced impairments in memory performance and complex reaction time. In the CPT, nicotine reduced the variability in response that is associated with attentional deficit. These results demonstrate the effects of nicotine in reversing some of the adverse side effects of haloperidol and improving cognitive performance in schizophrenia.

Sequences and proteins required for iron-regulated expression ofsid1ofUstilago maydis

The molecular biology of the high affinity, siderophore-mediated iron uptake system of the basidiomycete fungus Ustilago maydis is under investigation. Ustilago maydis produces two cyclic peptide siderophores, ferrichrome and ferrichrome A. Biosynthesis of both siderophores is initiated by ornithine-N5-oxygenase, the product of sid1. sid1 mRNA accumulates only during growth under iron starvation conditions in wild-type cells or constitutively in urbs1 mutants, urbs1 encodes a 100-kDa protein with putative Zn finger domains that share sequence identity with those of the GATA family of transcription factors. The promoter region of sid1 was defined by deletion analysis of a 3.0-kb region 5′ to the translational start of sid1 using the Escherichia coli GUS gene as a reporter. Three regions were defined by this analysis to be critical to expression of sid1. These include (i) a 306-bp region containing two GATA sequences and mapping 2.4 kb from the start of translation; (ii) a 439-bp region immediately 5′ to the start of transcription; and (iii) a region encompassing the first intron of sid1. Deletion of the GATA sequences resulted in deregulated expression of sid1, while elimination of the latter two sequences ablated expression of the gene under all circumstances. Current efforts are focused on determining whether Urbsl interacts directly with the sid1 promoter via the GATA sequences and whether this interaction is dependent upon iron. Key words: GATA, transcription factor, siderophore, ferrichrome, iron, Urbs1.

Bioaccumulation of the lipophilic metabolites of nonionic surfactants in freshwater organisms

Nonylphenol (NP), nonlyphenol monoethoxylate (NP1EO) and nonylphenol diethoxylate (NP2EO) were determined in different freshwater organisms from the surface waters in the Glatt Valley, Switzerland. Rather high concentrations of the compounds investigated have been found to occur in macrophytic algae, particularly Cladophora glomerata (up to 38 mg kg(-1), 80 mg kg(-1), and 28 mg kg(-1) of NP, NP1EO and NP2EO, respectively), the bioconcentration factors of NP reaching up to 10,000. The concentrations in fish were much lower (NP: < 0.03-1.6 mg kg(-1), NP1EO: 0.06-7.0 mg kg(-1), and NP2EO: <0.03-3.1 mg kg(-1) indicating that biomagnification did not take place. Similar concentrations to those in the fish were determined in different tissues of a wild duck. The estimated bioconcentration factors in fish tissues ranged from 13 to 410 for NP, 3 to 300 for NP1EO and 3 to 330 for NP2EO.

Feeding ecology of green catbirds (Ailuroedus crassirostris) in subtropical rainforests of south-eastern Queensland

Foraging data for green catbirds were collected over an 8-year period in lowland (dry) and upland (wet) subtropical rainforests of the Jimna and Conondale Ranges. The fruits of 104 species of trees, palms and vines comprised the bulk of the diet. Catbirds foraged the fruits of a similar number of species (56) in lowland forest as in upland forest (60). Lowland forest was distinctive, however, in that almost 77% of the food plants occurring in upland forest were rare or absent in lowland forest. Catbirds also foraged flowers, various plant material, insects and millipedes, and these were also significant components of the diet during spring and summer. Different species of asynchronous fruiting figs (Ficus spp.) occurred in lowland and upland forest, and these were the most important foods in each forest type. In lowland forest, catbirds seldom ventured beyond their home ranges (average size 1.9+/-O.2 ha) to forage, and bred from December to March when figs were the only reliable fruit that figured prominently in the diet. Insects also appeared to be an important (perhaps essential) component of the nestling diet during this period. Long-term (5-10 years) data on the fruiting phenology of 94 of the food plants enabled the relationship between the fruiting reliability of food plants and their importance in the diet to be evaluated. Availability of most (79% in lowland forest, 77% in upland forest) species of fruit was irregular and foraging by catbirds was therefore mostly opportunistic.

Vasectomy and nonfatal myocardial infarction: continued observation indicates no elevation of risk

The incidence of nonfatal myocardial infarction among 4,733 vasectomized men followed for 33,969 man-years was 1.3 cases per 1,000 man-years. This incidence was nearly identical in a 5-fold larger series of comparable nonvasectomized men. These data represent a substantially increased long-term followup over that reported previously for these groups and provide continued assurance of the lack of an association between vasectomy and myocardial infarction, particularly 10 or more years after vasectomy.

Play activities of mentally handicapped children at home and mothers' perception of play

Reviewers have frequently commented on the meagre literature that is available on the play of mentally handicapped children, especially play at home. This study involved 67 families with a moderately or severely handicapped child aged mainly between 2 and 12 years, living in Dublin city. Details were obtained on who the children played with; the activities they engaged in and aspects of the home environment conducive to play. Furthermore mothers' perception of play are reported along with their reactions to playing with their child. It was found that the children's play was immotive and lacking in variety and that it invariably occurred within the family. Mothers viewed play as very important and saw it as an enjoyable and beneficial experience for themselves as well as the child. It is argued that parents should be given opportunities to learn how best they could nurture their child's development through play.