A Data-Driven Approach in an Unbiased Sample Reveals Equivalent Sex Ratio of Autism Spectrum Disorder-Associated Impairment in Early Childhood

BACKGROUND

Sex differences in the prevalence of neurodevelopmental disorders are particularly evident in autism spectrum disorder (ASD). Heterogeneous symptom presentation and the potential of measurement bias hinder early ASD detection in females and may contribute to discrepant prevalence estimates. We examined trajectories of social communication (SC) and restricted and repetitive behaviors (RRBs) in a sample of infant siblings of children with ASD, adjusting for age- and sex-based measurement bias. We hypothesized that leveraging a prospective elevated familial likelihood sample, deriving data-driven behavioral constructs, and accounting for measurement bias would reveal less discrepant sex ratios than are typically seen in ASD.

METHODS

We conducted direct assessments of ASD symptoms at 6 to 9, 12 to 15, 24, and 36 to 60 months of age (total nobservations = 1254) with infant siblings of children with ASD (n = 377) and a lower ASD-familial-likelihood comparison group (n = 168; nobservations = 527). We established measurement invariance across age and sex for separate models of SC and RRB. We then conducted latent class growth mixture modeling with the longitudinal data and evaluated for sex differences in trajectory membership.

RESULTS

We identified 2 latent classes in the SC and RRB models with equal sex ratios in the high-concern cluster for both SC and RRB. Sex differences were also observed in the SC high-concern cluster, indicating that girls classified as having elevated social concerns demonstrated milder symptoms than boys in this group.

CONCLUSIONS

This novel approach for characterizing ASD symptom progression highlights the utility of assessing and adjusting for sex-related measurement bias and identifying sex-specific patterns of symptom emergence.

Decoupling anthropogenic vs. natural impacts at a wastewater treatment plant situated on acid sulfate soils

Decoupling natural and anthropogenic impacts on the subsurface environment can be difficult, particularly when it has been subject to a wide range of influences over time and space. In this work we show how the use of hydrogeochemical plotting tools, time-series analysis of key contaminants of concern, and targeted isotopic analysis can be used to better understand the contamination sources/processes in a complex environment - a Wastewater Treatment Plant (WWTP) located on coastal acid sulfate soils (ASS). Analysis of soil profiles for potential oxidisable sulfur, acid neutralising capacity (ANC), and pH_fox along with groundwater chemistry, revealed that oxidation of pyritic sediments, initially deposited during the mid-Holocene, have led to significant pH declines and the secondary mobilisation of metals into the groundwater environment. This is further complicated by historic anthropogenic inputs associated with the WWTP (e.g., effluent leakages) and the surrounding agricultural land uses. There is distinct separation between spatial and temporal trends in the nutrient and heavy metals data in groundwater, suggesting these reflect different contaminant sources and/or processes. Isotopic data indicate nutrients are largely derived from the WWTP, whereas time-series analysis of key contaminants of concern and hydrogeochemical plotting tools indicate metals are largely derived from the secondary mobilisation of ASS due to acidity generated during sulfide oxidation. This work highlights the importance of understanding the hydrogeological environment and need for careful planning and ongoing management of WWTP sites, particularly those constructed on potential acid sulfate soils (PASS), which, if disturbed or exposed, can lead to impacts beyond the area of ASS via groundwater discharge to nearby surface water bodies (in this case the site is adjacent to a Ramsar-listed wetland). The outcomes of this work have significant global application in the identification, assessment, and control of ASS, the practice of contaminant source attribution, and the siting and design of future WWTPs, which will continue to be sited in coastal areas to meet population needs.

Management of Acute Lower Gastrointestinal Bleeding: Principles and Current Practice in the United Kingdom

Acute lower gastrointestinal bleeding (ALGIB) is a common cause for hospital admission that results in significant morbidity and mortality. The major objectives of all involved in the management of ALGBI patients are to reduce mortality and the need for major surgery. A secondary objective is to prevent unnecessary hospital admission for patients presenting with bleeding that is not life-threatening. The management of ALGBI has evolved over last decade with the changing modalities of diagnostic facilities. On review of the published literature, there is paucity of randomised control trials in relation to the diagnostic tools and management of ALGBI. The aim of this review is to summarise the principles and current methods available for the diagnosis and treatment of ALGIB and based on the available evidence and the current practice in the United Kingdom, outline an algorithm for the management of ALGIB.

A therapeutic workplace for the long-term treatment of drug addiction and unemployment: eight-year outcomes of a social business intervention

This study evaluated the long-term effects of a therapeutic workplace social business on drug abstinence and employment. Pregnant and postpartum women (N = 40) enrolled in methadone treatment were randomly assigned to a therapeutic workplace or usual care control group. Therapeutic workplace participants could work weekdays in training and then as employees of a social business, but were required to provide drug-free urine samples to work and maintain maximum pay. Three-year outcomes were reported previously. This paper reports 4- to 8-year outcomes. During year 4 when the business was open, therapeutic workplace participants provided significantly more cocaine- and opiate-negative urine samples than controls; reported more days employed, higher employment income, and less money spent on drugs. During the 3 years after the business closed, therapeutic workplace participants only reported higher income than controls. A therapeutic workplace social business can maintain long-term abstinence and employment, but additional intervention may be required to sustain effects.

The apelin receptor inhibits the angiotensin II type 1 receptor via allosteric trans-inhibition

BACKGROUND AND PURPOSE

The apelin receptor (APJ) is often co-expressed with the angiotensin II type-1 receptor (AT1) and acts as an endogenous counter-regulator. Apelin antagonizes Ang II signalling, but the precise molecular mechanism has not been elucidated. Understanding this interaction may lead to new therapies for the treatment of cardiovascular disease.

EXPERIMENTAL APPROACH

The physical interaction of APJ and AT1 receptors was detected by co-immunoprecipitation and bioluminescence resonance energy transfer (BRET). Functional and pharmacological interactions were measured by G-protein-dependent signalling and recruitment of β-arrestin. Allosterism and cooperativity between APJ and AT1 were measured by radioligand binding assays.

KEY RESULTS

Apelin, but not Ang II, induced APJ : AT1 heterodimerization forced AT1 into a low-affinity state, reducing Ang II binding. Likewise, apelin mediated a concentration-dependent depression in the maximal production of inositol phosphate (IP(1) ) and β-arrestin recruitment to AT1 in response to Ang II. The signal depression approached a limit, the magnitude of which was governed by the cooperativity indicative of a negative allosteric interaction. Fitting the data to an operational model of allosterism revealed that apelin-mediated heterodimerization significantly reduces Ang II signalling efficacy. These effects were not observed in the absence of apelin.

CONCLUSIONS AND IMPLICATIONS

Apelin-dependent heterodimerization between APJ and AT1 causes negative allosteric regulation of AT1 function. As AT1 is significant in the pathogenesis of cardiovascular disease, these findings suggest that impaired apelin and APJ function may be a common underlying aetiology.

LINKED ARTICLE

This article is commented on by Goupil et al., pp. 1101-1103 of this issue. To view this commentary visit http://dx.doi.org/10.1111/bph.12040.

A randomized clinical trial of a Therapeutic Workplace for chronically unemployed, homeless, alcohol-dependent adults

AIMS

To assess the efficacy of the Therapeutic Workplace, a substance abuse intervention that promotes abstinence while simultaneously addressing the issues of poverty and lack of job skills, in promoting abstinence from alcohol among homeless alcoholics.

METHODS

Participants (n = 124) were randomly assigned to conditions either requiring abstinence from alcohol to engage in paid job skills training (Contingent Paid Training group), offering paid job skills training with no abstinence contingencies (Paid Training group) or offering unpaid job skill training with no abstinence contingencies (Unpaid Training group).

RESULTS

Participants in the Contingent Paid Training group had significantly fewer positive (blood alcohol level ≥ 0.004 g/dl) breath samples than the Paid Training group in both randomly scheduled breath samples collected in the community and breath samples collected during monthly assessments. The breath sample results from the Unpaid Training group were similar in absolute terms to the Contingent Paid Training group, which may have been influenced by a lower breath sample collection rate in this group and fewer reported drinks per day consumed at intake.

CONCLUSION

Overall, the results support the utility of the Therapeutic Workplace intervention to promote abstinence from alcohol among homeless alcoholics, and support paid training as a way of increasing engagement in training programs.

Asymptomatic isolated coccygeal metastasis in low rectal carcinoma

As well as being relatively rare, osseous metastases from colorectal cancer are frequently asymptomatic and represent a late manifestation of disease. We report a case of an unidentified, asymptomatic coccygeal metastasis discovered on histological processing of the resection specimen from a patient with locally advanced rectal cancer treated with neoadjuvant chemoradiotherapy followed by radical abdomino-perineal resection with coccygectomy. The anatomical explanation for this finding may involve passage of tumour cells via the vertebral venous plexus.

Prevalence of depression, sleep-related disturbances, and anxiety and their effect on quality of life in patients with adenocarcinoma of the pancreas

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Purpose: To evaluate the prevalence of depression, sleep related disturbances and anxiety and their effect on quality of life in patients with recently diagnosed adenocarcinoma of the pancreas who present to a multidisciplinary pancreatic cancer clinic. Methods: Cross-sectional and longitudinal psychosocial distress was assessed utilizing Personal Health Questionnaire 9 (PHQ9) to screen for depression and monitor symptoms during the course of care, the Penn State Worry Questionnaire (PSWQ) for generalized anxiety, and the Sleep Problems Questionnaire 4 (SPQ4)/ University of Michigan Sleep Questionnaire to monitor sleep symptoms. Patients were evaluated at their intake consultation and at subsequent follow up visits. Results: 24 patients (pts; mean age 66 years, 48% females) consented to participate during the 6 month pilot study with longitudinal follow up for 13. The PHQ9 scores on presentation revealed mild to moderate depressive symptoms in 54% (13 pts) of pts and moderately severe depressive symptoms in only 8% (2 pts). A minority (2 pts, 8%) had PSWQ scores characteristic of an anxiety disorder, while 33% (8 pts) had moderate anxiety scores. Only 3 pts (12.5%) scores revealed a clear sleep problem; 10 pts, (41.67%) had no sleep problem and 10 pts had a potential sleep problem. Due to the limited follow up, a statistical difference in scores over time was not observed. Conclusions: Our results indicate that mild to moderate depressive symptoms, anxiety and potential sleep problems are common in patients referred to a multidisciplinary pancreatic cancer clinic. Moderately severe depressive symptoms, severe anxiety and clear sleep problems are not as prevalent as is generally believed. To better characterize the relationship of depression (and potential causes) with pancreatic cancer, additional prospective longitudinal studies are needed.

No significant financial relationships to disclose.

A randomized controlled trial of the therapeutic workplace for community methadone patients: a partial failure to engage

The Therapeutic Workplace is an employment-based treatment for drug addiction that uses wages for work to reinforce drug abstinence. The Therapeutic Workplace has promoted abstinence from heroin and cocaine in treatment-resistant mothers in methadone treatment. This study attempted to replicate that effect in crack cocaine users recruited from community-based methadone programs. Participants were randomly assigned to a Therapeutic Workplace (n=22) or usual care control (n=25) group. Therapeutic Workplace participants were invited to work in the workplace and earn vouchers every weekday for 9 months contingent on documented opiate and cocaine abstinence. The two groups did not differ significantly on measures of cocaine or opiate use collected during study participation. Daily attendance and urinalysis results of the Therapeutic Workplace group were analyzed, and only 7 of the 22 participants initiated consistent periods of abstinence and workplace attendance. Two individuals gained access to the workplace on a few days, and 9 participants attempted to gain access to the workplace but never provided a drug-negative urine sample. Possible reasons for differences between the current study and the previous Therapeutic Workplace study are considered. Procedures that increase participant contact with the Therapeutic Workplace and its reinforcement contingencies might increase the likelihood of these individuals being successful in the treatment program.

A web-based therapeutic workplace for the treatment of drug addiction and chronic unemployment

This article describes a Web-based therapeutic workplace intervention designed to promote heroin and cocaine abstinence and train and employ participants as data entry operators. Patients are paid to participate in training and then to perform data entry jobs in a therapeutic workplace business. Salary is linked to abstinence by requiring patients to provide drug-free urine samples to gain access to the workplace. Prior data show that a prototype of the intervention could promote drug abstinence. Preliminary data on the Web-based intervention suggest that it should be able to teach adults with histories of chronic unemployment and drug addiction to become skilled data entry operators in about 3 to 6 months. Early experience in the business provides preliminary evidence that it might become financially successful. The therapeutic workplace intervention may serve as an effective and practical long-term treatment for chronic unemployment and heroin and cocaine addiction.

Colonic pouchography is not routinely required prior to stoma closure

BACKGROUND

Colonic pouch formation with pouch-anal anastomosis is now regarded as the procedure of choice for restoration of intestinal continuity following anterior resection for low rectal cancers. The aim of this study was to review the necessity for routine colonic pouchography prior to closure of a diverting loop stoma.

METHODS

This was a prospective study of 52 consecutive patients who underwent colonic pouch formation between 1 June 1999 and 31 May 2002, four of whom have subsequently died. Each pouch was assessed clinically and radiologically prior to stoma closure.

RESULTS

There were no clinical anastomotic leaks. Forty-six of 48 surviving patients have had a colonic pouchogram and in no case was either a pouch or pouch-anal anastomotic defect identified. To date 40 patients have undergone stoma closure without an anastomosis-related complication.

CONCLUSION

Following successful colonic pouch formation, routine study of the pouch by contrast radiology does not add to clinical assessment. As a consequence radiological imaging is unnecessary and can be omitted.

The heart failure revascularisation trial (HEART): rationale, design and methodology

BACKGROUND

Most patients with heart failure due to left ventricular systolic dysfunction (LVSD) secondary to coronary artery disease (CAD) have evidence of myocardium in jeopardy (reversible ischaemia and/or stunning hibernation). It is not known whether revascularisation in such cases is safe or beneficial.

AIMS

To determine whether revascularisation will improve the survival of patients with LVSD and heart failure secondary to CAD and myocardium in jeopardy.

METHODS

This is a randomised controlled trial comparing revascularisation or not, in addition to optimal medical therapy with ACE inhibitors, beta-blockers, aldosterone antagonists and an anti-thrombotic agent. Patients must have heart failure requiring treatment with diuretics, a left ventricular ejection fraction <35% and evidence of coronary disease. Myocardial viability and ischaemia are assessed by a broad range of techniques including stress echocardiography and nuclear imaging. All imaging tests are reviewed in core laboratories to ensure uniform reporting. Any conventional revascularisation technique is permitted. The primary outcome measure is all cause mortality. Symptoms, quality of life and health economic issues will also be explored. Assuming an annual mortality of 10% in the control group and allowing for substantial cross-over rates, a study of 800 patients followed for 5 years has 80% power with an alpha of 0.05 (two-sided) to show a 25% reduction in mortality with revascularisation.

RESULTS

At the time of writing 180 patients have been screened for inclusion, 111 have consented to participate and 70 have been randomised. The results of viability testing are awaited in 22 patients. Twenty-six patients had been investigated for myocardial viability and/or by angiography prior to consent, as part of the routine practice in that cardiology department. Of 68 patients who have completed assessment only after consent, 47 (69%) were included. The principal reason for drop-out between consent and randomisation was lack of evidence of myocardial ischaemia or hibernation.

CONCLUSION

The HEART trial will help to determine whether investigation of myocardial ischaemia and/or viability with a view to revascularisation should become part of the routine care of patients with heart failure due to LVSD and CAD.

A reinforcement-based therapeutic workplace for the treatment of drug abuse: three-year abstinence outcomes

Long-term Therapeutic Workplace effects were evaluated in heroin- and cocaine-dependent, unemployed, treatment-resistant young mothers. Participants were paid to work or to train in the Therapeutic Workplace but had to provide drug-free urine samples to gain daily access. Participants (N = 40) were randomly assigned to a Therapeutic Workplace or usual care control group. Therapeutic Workplace participants could work for 3 years. Relative to controls, Therapeutic Workplace participants increased cocaine (28% vs. 54% negative; p = .04) and opiate (37% vs. 60% negative; p = .05) abstinence on the basis of monthly urine samples collected until 3 years after intake. The Therapeutic Workplace can be an effective long-term treatment of cocaine and heroin addiction in poor and chronically unemployed young mothers.

Changing the diagnostic criteria for myocardial infarction in patients with a suspected heart attack affects the measurement of 30 day mortality but not long term survival

OBJECTIVES

To explore the effects of alternative methods of defining myocardial infarction on the numbers and survival patterns of patients identified as having sustained a confirmed myocardial infarct.

DESIGN

An inclusive historical cohort of patients admitted with a suspected heart attack. Patients were recoded from raw clinical data (collected at the index admission) to the epidemiological definitions of myocardial infarction used by the Nottingham heart attack register (NHAR), the World Health Organization (MONICA), and the UK heart attack study.

SETTING

Single health district.

PATIENTS

The NHAR identified all patients admitted in 1992 with suspected myocardial infarction.

OUTCOME MEASURES

Survival at 30 days and four year postdischarge.

RESULTS

2739 patients were identified, of whom 90% survived to discharge. Recoding increased the numbers of patients defined as having confirmed myocardial infarction from 26% under the original NHAR classification to 69%, depending on the classification system used. In confirmed myocardial infarction, subsequent 30 day survival from admission varied from 77-86% depending on the classification system; four year survival after discharge was not affected. The distribution of important prognostic variables differed significantly between groups of patients with confirmed myocardial infarction defined by different systems. Patients with suspected but unconfirmed myocardial infarction under all classification systems had a worse postdischarge mortality.

CONCLUSIONS

The classification system used had a substantial effect on the numbers of patients identified as having had a myocardial infarct, and on the 30 day survival. There were significant numbers of patients with more atypical presentations, not labelled as myocardial infarction, who did badly following discharge. More research is needed on these patients.

Long-term efficacy of simple behavioral therapy for daytime wetting in children

PURPOSE

Behavioral therapy has proved benefit for children with daytime wetting but most studies have used biofeedback techniques and provide no long-term assessment of results. We previously reported similar results using simple behavioral therapy without biofeedback. We report the long-term efficacy of behavioral therapy for daytime wetting.

MATERIALS AND METHODS

Our program of behavioral therapy included timed voiding, modification of fluid intake, positive reinforcement techniques and pelvic floor (Kegel) exercises to promote pelvic floor strengthening and relaxation. Questionnaires to assess therapeutic efficacy were mailed to patients who had completed therapy more than 1 year previously.

RESULTS

A total of 48 patients responded. Mean ages at the time of the initial clinic visit and questionnaire were 8.2 and 12.9 years, respectively. Improvement in symptoms was noted in approximately 74% of the cases during the first year following therapy. At a mean of 4. 7 years after treatment 59.4% of the patients had improved daytime urinary control, 51.1% improved daytime urinary frequency and 45.6% improved daytime urinary urgency. The frequency of urinary tract infections decreased in 56.4% of the cases. Measures of psychological well-being were also noted to be improved in a majority of patients. A total of 77.3% of the patients stated that they would recommend the program to others.

CONCLUSIONS

Simple behavioral therapy without biofeedback techniques is an effective and durable first line therapy for children with daytime wetting.

Mortality of patients admitted with a suspected acute myocardial infarction in whom the diagnosis is not confirmed

AIMS

To examine the survival of patients admitted with a suspected acute myocardial infarction in whom the diagnosis was not confirmed ('possible myocardial infarction').

METHODS AND RESULTS

A cohort study based on the Nottingham Heart Attack Register of 1716 sequential patients discharged alive from two acute teaching hospitals following admission in 1992. The main outcome was mortality following hospital discharge after 5 years of follow-up. Survival of the cohort of patients in whom myocardial infarction was suspected but not confirmed was 58% (95% C.I. 56 to 60%) after 5 years of follow-up, compared with an expected survival of 76% in an age/sex matched general population. Patients with ECG abnormalities that were not diagnostic of myocardial infarction had a 5-year survival of 56%, compared with 77% in those without such changes (P<0.00001). In the 703 patients who died in the first 5 years of follow-up, the cause of death was cardiovascular in at least 53% of cases. Survival following hospital discharge was worse than that in patients discharged alive in the same year following a confirmed myocardial infarction (63% vs 69% after 4 years of follow-up P=0.0016).

CONCLUSION

Patients in this study had a substantially increased risk of death in the 5 years after discharge from hospital, compared with an age- and sex-matched population, and worse than patients discharged following a confirmed myocardial infarction. Almost half of those with ECG changes at the time of their admission died over the next 5 years. As over half of all deaths in this cohort were due to cardiovascular causes, further work is needed to identify patients at high and low risk of subsequent mortality who may warrant investigation and treatment following hospital discharge.

Identifying the risk of death following hospital discharge in patients admitted with a suspected acute myocardial infarction in whom the diagnosis is not confirmed

AIMS

To describe clinical factors, available at the time of discharge, that predicted survival of patients admitted with a suspected acute myocardial infarction in whom the diagnosis was not confirmed.

METHODS AND RESULTS

A cohort study based on the Nottingham Heart Attack Register of 1716 sequential patients discharged alive from two acute teaching hospitals following admission in 1992. The main outcome was identification of high and low mortality risk groups over 5 years of follow-up. Overall 5-year survival was 58% (95% CI 56 to 60%). Having abnormal cardiac enzyme changes or an abnormal ECG that was insufficient to meet established diagnostic criteria of myocardial infarction, or both, identified three groups with a 5 year survival of 77%, 60% or 51%. Multivariate methods were used to develop a risk score from seven variables available at the time of discharge (age, sex, past history of myocardial infarction, ECG abnormalities, cardiac enzyme abnormalities, Killip score of 2 or 3 on admission and being discharged on a diuretic). Quartiles of this risk score then identified four groups with 5 year survival ranging from 89% to 25%.

CONCLUSION

Among the study cohort, it was possible to identify subgroups with a markedly different risk of subsequent mortality from clinical indicators that were readily available at the time of hospital discharge. Risk stratification has the potential to improve targeting of subsequent secondary preventive efforts, but further work is required to ascertain whether cardiovascular risk can be modified through a more intensive approach to management.

Persistent dominant follicle alters pattern of oviductal secretory proteins from cows at estrus

The experimental objective was to compare synthesis of oviductal secretory proteins of dairy cows bearing a persistent dominant follicle (PDF) versus a fresh dominant follicle (FDF) at estrus. On Day 7 after synchronized estrus (Day 0), cows received an intravaginal progesterone device and injection of prostaglandin F2alpha (PGF2alpha). On Day 9, cows received an injection of a GnRH agonist (FDF group; n = 3) or received no injection (PDF group, n = 3). On Day 16, all cows received PGF2alpha, and progesterone devices were removed. At slaughter on Day 18 or Day 19, oviducts ipsilateral and contralateral to the dominant follicle were divided into infundibulum, ampulla, and isthmus regions. Explants from oviductal regions were cultured in minimal essential medium supplemented with [3H]leucine for 24 h. Two-dimensional fluorographs of proteins in conditioned media were analyzed by densitometry. Rate of incorporation of [3H]leucine into macromolecules was greater in the infundibulum, ampulla, and isthmus of FDF cows (p < 0.01). Overall, intensities of radiolabeled secretory protein (P) 2 and P13 were greater for FDF than for PDF. In the ampulla, P14 was more intense for FDF while P7 was more intense for PDF. Abundance of P1 in the isthmus was greater for PDF cows. Across regions, P5, P6, P8, P9, and P11 were more intense for PDF than for FDF in the ipsilateral side. In the contralateral side, P19 was more intense for PDF than for FDF, whereas P6, P8, P9, and P11 were more intense for FDF. Differences in biosynthetic activity and in secreted oviductal proteins from cows bearing a PDF may contribute to the decrease in fertility associated with a PDF.

Tumor versus vascular photodamage in a rat tumor model

The [4-(5-nitro-2-furyl)-2-thiazoyl] formamide (FANFT)-induced urothelial tumor in the rat is found to express the mdr gene. The resulting multidrug resistance (MDR) phenotype results in the expression of an outward transport system that prevents cellular accumulation of certain weakly cationic agents. Among the latter is a photosensitizer with known efficacy for the FANFT tumor, the copper benzochlorin iminium salt. FANFT cells are protected from direct cell kill mediated by this drug, suggesting that the substantial delay in tumor regrowth from this tumor/sensitizer combination can be attributed to vascular effects.

Retinal changes associated with tamoxifen treatment for breast cancer

PURPOSE

This study was undertaken to estimate the incidence of retinal changes and determine the prevalence of ocular toxicity associated with tamoxifen treatment in a breast cancer population.

METHODS

The study was based on a population cross-sectional survey, including 290 patients taking tamoxifen from 6 months to 12 years; 274 patients were analysed. The main outcome measures were the incidence of retinal changes and visual impairment.

RESULTS

The incidence of retinal changes was 0.9% (3 of 274 patients). All 3 patients were asymptomatic. The length of tamoxifen treatment ranged from 39 months to 120 months in the affected patients, with cumulative tamoxifen doses ranging from 23.7 g to 73 g.

CONCLUSIONS

Retinopathy in patients receiving low doses of tamoxifen is rare and, in our study, did not result in changes in visual acuity. We found no retinopathy in patients receiving tamoxifen within the first 3 years of treatment or in patients receiving a total tamoxifen dosage of less than 23.7 g. Although retinopathy can occur in a tamoxifen-treated population, its low incidence and an associated good prognosis for vision does not merit special screening for this problem.

Occupational exposure to permethrin during its use as a public hygiene insecticide

Permethrin is an active ingredient found in many public hygiene insecticide products and exposure to it was assessed in a survey of 45 professional users. The exposures measured were over a wide range, with more than a 100-fold difference between average levels and the highest levels. Dermal contamination was evident on 93% of the operators, the highest contamination resulting from the use of leaking application equipment, demonstrating that proper maintenance of equipment is vital. Where the insecticide was applied at ground level most contamination was on the legs, indicating the importance of appropriate footwear. Contamination of the hands occurred despite the use of protective gloves, higher levels of contamination occurring when liquids were used. Dermal contamination was not always the principle route of exposure, and high airborne concentrations were linked with use in confined areas. Airborne concentrations were also associated with the physical form of the product used and the treatment method. To help in assessing the effectiveness of protective clothing and control measures, biological monitoring was carried out. Monitoring of metabolites in urine showed that systemic uptake occurred but evidence from toxicological studies indicates that the levels found were well below those considered to cause harm.

Essentialism, word use, and concepts

The essentialist approach to word meaning has been used to undermine the fundamental assumptions of the cognitive psychology of concepts. Essentialism assumes that a word refers to a natural kind category in virtue of category members possessing essential properties. In support of this thesis, Kripke and Putnam deploy various intuitions concerning word use under circumstances in which discoveries about natural kinds are made. Although some studies employing counterfactual discoveries and related transformations appear to vindicate essentialism, we argue that the intuitions have not been investigated exhaustively. In particular, we argue that discoveries concerning the essential properties of whole categories (rather than simply of particular category members) are critical to the essentialist intuitions. The studies reported here examine such discovery contexts, and demonstrate that words and concepts are not used in accordance with essentialism. The results are, however, consistent with "representational change" views of concepts, which are broadly Fregean in their motivation. We conclude that since essentialism is not vindicated by ordinary word use, it fails to undermine the cognitive psychology of concepts.

Cardiac rupture associated with thrombolytic therapy: impact of time to treatment in the Late Assessment of Thrombolytic Efficacy (LATE) study

OBJECTIVES

This prospective ancillary study was conducted to determine the association between the time from symptom onset to treatment and cardiac rupture in patients with acute myocardial infarction.

BACKGROUND

There is strong evidence that the time window for thrombolytic therapy should be extended to at least 12 h; however, many clinicians are concerned that late treatment may cause an excessive occurrence of death from cardiac rupture. Because up to 30% of patients with acute myocardial infarction arrive in the hospital > 6 h from symptom onset, resolving this issue is of paramount clinical importance.

METHODS

A total of 5,711 patients with acute myocardial infarction were randomized to receive intravenous recombinant tissue-type plasminogen activator (rt-PA) (100 mg over 3 h) or matching placebo, within 6 and 24 h from symptom onset. Both groups received immediate oral aspirin, and a majority of patients received intravenous heparin during the initial 48 h.

RESULTS

By 35 days, 177 patients had died, with the cause of death specified as cardiac rupture (53 patients), electromechanical dissociation (42 patients) or asystole (82 patients). An additional 370 patients had died of other causes. In patients treated within 12 h, the proportion of rupture deaths in the group given rt-PA was higher than that observed in those who received placebo, but the difference was not statistically significant. In patients treated after 12 h, there was no evidence of an increased incidence of rupture with rt-PA, and the proportion of deaths due to rupture in this group was lower than that in patients given placebo. However, there was evidence of a difference between rt-PA and placebo with respect to the time that rupture became clinically manifest (treatment by time to death interaction, p = 0.03).

CONCLUSIONS

This study provides unequivocal evidence that late treatment (6 to 24 h after symptom onset) with rt-PA is not associated with an increased risk of cardiac rupture. However, for reasons that are unclear, coronary thrombolysis appears to accelerate rupture events, typically to within 24 h of treatment.

The role of lipoproteins in the distribution of tin etiopurpurin (SnET2) in the tumor-bearing rat

The role of plasma lipoproteins in the distribution of the photosensitizing agent tin etiopurpurin (SnET2) was examined in male rats bearing the N-[4-(5-nitro-2-furyl)-2- thiazolyl1bdformamide-induced tumor. Treatment with 17 alpha-ethinyl estradiol resulted in the depletion of total plasma cholesterol by > 70% and a corresponding decrease in plasma lipoproteins. To both control and estradiol-treated animals, a therapeutic dose (1.5 mg/kg) of SnET2 was administered and biodistribution measured 24 h later. Estradiol treatment was not associated with differences in the distribution of SnET2 to liver, skin or tumor, or in the pattern of affinity of SnET2 to plasma albumin and lipoprotein. These results indicate that a substantial decrease in circulating lipoprotein levels does not alter patterns of SnET2 biodistribution.