Organ donation after cardiac death from withdrawal of life support in patients with amyotrophic lateral sclerosis

OBJECTIVE

Donation after cardiac death (DCD) or donation of organs after removal of life support is an accepted means of organ retrieval that usually occurs in the setting of sudden illness but has not been described in people with progressive neurologic illness. We report DCD in two people with progressive amyotrophic lateral sclerosis (ALS).

METHODS

Case series at an academic medical center of two men with progressive ALS who underwent withdrawal of artificial life support, rapid cardiac death, and subsequent organ donation. The primary outcome was donation of organs in concordance with patient and family wishes.

RESULTS

Both patients underwent peaceful withdrawal of life support in the presence of family, and multiple organs were donated.

CONCLUSIONS

Patients may legally and ethically refuse life-sustaining care. These patients considered their lives to be more burdensome than beneficial near the end of their lives, both carefully planned the time and circumstance of their deaths, and both fulfilled a long-standing desire to donate their organs. This study describes a potential opportunity for patients with progressive neurologic illness.

Risk assessment of polycyclic aromatic hydrocarbons in aquatic ecosystems

A probability risk assessment of anthracene, benzo(a)pyrene, chrysene, fluorene, phenanthrene and pyrene was carried out to examine the ecological risk of these six polycyclic aromatic hydrocarbons (PAHs) in aquatic ecosystems in China. The literature on PAH concentrations in surface water in China was collected to evaluate the environmental exposure concentrations (EEC). The 10th percentile of predicted no observed effect concentration (PNEC(10%)) of PAHs, calculated according to the data from the USEPA AQUIRE database and regulatory reviews, was applied as the toxicity assessment endpoint. The ratio of EEC and PNEC(10%), expressed as a risk quotient (RQ), was used to characterize the risk value. Bootstrapping method and Monte Carlo simulation were utilized to calculate the distribution of EEC, PNEC(10%), RQ and associated uncertainties. Risk assessment showed that reliable maximum RQs of anthracene, benzo(a)pyrene, chrysene, fluorene and phenanthrene were in the range of 0.064-0.755, lower than the acceptable value of 1. However, the reliable maximum RQ of pyrene was 1.39, indicating its potential ecological risk. Notwithstanding the uncertainty, these results suggest that the aquatic ecosystems with high PAH concentrations might pose potential ecological risks, and concerted efforts are required to ensure that surface water is protected.

Computational studies of interactions between endocrine disrupting chemicals and androgen receptor of different vertebrate species

Homology modeling and molecular docking were used to in silico analyze the interactions between six endocrine disrupting chemicals (EDCs) and 11 androgen receptors (ARs) of different vertebrate species. The MODELLER 9V7 program was employed to construct the homology models of AR ligand binding domains (LBDs) from birds, amphibians, bony fishes and cartilaginous fishes. The Surflex-Dock program was applied to calculate and analyze the binding affinities between the six EDCs and AR LBDs. The docking experiment showed that AR LBDs had high affinities with nonyl phenol (NP) and butyl benzyl phthalate (BBP), but low affinities with the 2,2',4,4',5,5'-hexabromodiphenyl ether (BDE153). The results of cluster analysis suggested that predicted binding affinities were species-specific, which was consistent with the phylogenetic analysis of AR LBDs. The difference of binding affinities could be mainly due to the different hydrogen bonds and the orientation of ligands in the binding pockets. Our results suggest that integrated methods of phylogenetic analysis, homology modeling and molecular docking might be a potential tool to predict the different interactions between contaminants and associated receptors in different trophic levels.

Widefield fluorescence sectioning with HiLo microscopy

HiLo microscopy is a widefield fluorescence imaging technique that provides depth discrimination by combining two images, one with non-uniform illumination and one with uniform illumination. We discuss the theory of this technique and a variety of practical implementations in brain-tissue imaging and fluorescence endomicroscopy.

Children's specific fears

BACKGROUND

Most children experience some degree of fear during their development. Specific fears are considered as an appropriate response provided that they are proportionate to the intensity of the perceived threat. Our aim is to present the prevalence of specific fears among children in the Great Britain, their socio-demographic correlates, in particular their association with ethnicity.

METHODS

Data on the child's experience of specific fears were obtained from parents of a national representative sample of 5- to 16-year-olds using the Development and Well-Being Assessment. Biographic, socio-demographic and socioeconomic characteristics of the child and the family were included in the questionnaire.

RESULTS

About one-third of children were assessed by their parents as having at least one of 12 specific fears. The most commonly reported fears were animals (11.6%), blood/injections (10.8%) and the dark (6.3%). Just less than 1% of all children were assessed according to International Classification of Diseases research diagnostic criteria as having a specific phobia. Biographic, socio-demographic and socioeconomic factors were independently associated with a greater likelihood of a child having particular fears. The most marked associations were fears of the dark, loud noises, imagined supernatural beings in younger children and fear of animals among girls and all non-white groups.

CONCLUSIONS

Although fears are only labelled as phobias when they impair functioning and interfere with life, they can cause personal distress to children and also can interfere with their daily activities. Children's fears differ in nature across different ethnic groups. Culturally mediated beliefs, values and traditions may play a role in their expression.

Can early intake of dietary omega-3 predict childhood externalizing behaviour?

AIM

To determine whether maternal and child intake of dietary omega-3 (n-3) fatty acids (FA), together with the presence or absence of breast-feeding, predicted psychiatric diagnosis of externalizing disorders in childhood.

METHODS

Data concerning childhood externalizing disorders were collected from 8242 children aged 7.9 years in a large British cohort. Intake of n-3 FA was measured for the study mother during pregnancy and for the child at 3 years. Duration of breast-feeding was examined to account for moderating effects. Adjustment was made for a variety of potential confounders.

RESULTS

Maternal intake of n-3 and breast-feeding predicted oppositional/conduct disorder and comorbid externalizing disorder before adjustment for confounding factors. However, there was no association between intake of n-3 by mother or child and any type of externalizing disorder once socio-demographic factors were taken into account.

CONCLUSIONS

Any association between intake of n-3 and childhood externalizing disorders appears to be strongly confounded with socio-demographic factors. This is important to note given the current popularity of n-3 as a possible treatment for behaviour problems related to inattention and impulsivity. Care must be taken that studies investigating this relationship account fully for factors associated with both behaviour and diet.

Pharmacodynamic effects of a novel prokinetic 5-HT receptor agonist, ATI-7505, in humans

ATI-7505, an investigational 5-HT(4) receptor agonist, was designed to have similar activity as cisapride without the cardiac adverse effects, i.e. without QT prolongation. In addition, ATI-7505 is not metabolized by CYP450. The aim of the study was to assess the effect of ATI-7505 on gastrointestinal (GI) and colonic transit in healthy humans. A randomized, parallel-group, double-blind, placebo-controlled study evaluated effects of 9-day treatment with ATI-7505 (3, 10 or 20 mg t.i.d.) on scintigraphic GI and colonic transit in healthy volunteers (12 per group). Primary endpoints were gastric-emptying (GE) T(1/2), colonic geometric centre (GC) at 24 h and ascending colon (AC) emptying T(1/2). Daily stool diaries were kept. Analysis of covariance assessed overall treatment group differences, followed by post hoc unadjusted pairwise comparisons. There were borderline overall treatment effects (decrease) on GE T(1/2) (P = 0.154); the 20 mg t.i.d. of ATI-7505-accelerated GE vs placebo (P = 0.038). ATI-7505 increased colonic transit (GC24, P = 0.031) with fastest transit at 10 mg t.i.d. vs placebo (P = 0.065). ATI-7505 accelerated AC emptying T(1/2) (overall P = 0.075) with 10 mg dose vs placebo (P = 0.042). There was looser stool (Bristol stool form scale, overall P = 0.056) with the 10 and 20 mg t.i.d. doses. No safety issues were identified. ATI-7505 accelerates overall colonic transit and tends to accelerate GE and AC emptying and loosen stool consistency.

Use of ecotoxicological tools to evaluate the health of New Bedford Harbor sediments: a microbial biomarker approach

We have been investigating microbial communities in sediments from New Bedford Harbor (NBH), Massachusetts, USA, for a number of years. NBH is a U.S. Environmental Protection Agency-designated Superfund site heavily contaminated with polychlorinated biphenyls, polycyclic aromatic hydrocarbons, and heavy metals. Microorganisms are thought to contribute to the fate and distribution of contaminants in NBH through a variety of mechanisms, including direct transformations and formation of soluble and insoluble species. Our more recent research has focused on changes in microbial community structure and function in response to exposure to toxic contaminants, with the ultimate goal of using microbes as ecotoxicological tools. Microbial diversity, as measured by restriction fragment-length polymorphism analysis, changes along pollution gradients, with an apparent increase in diversity at the most contaminated sites, concomitant with an increase in genetic relatedness. Current work on microbial communities examines the presence of arsenic-resistance genes in NBH isolates. In collaboration with the Plymouth Environmental Research Center, Plymouth University, United Kingdom, we have also used more conventional ecotoxicological approaches to examine the health of the NBH biota.

Serological evidence of Cryptosporidium infections in a Russian city and evaluation of risk factors for infections

PURPOSE

Assess the relative frequency of Cryptosporidium infections and risk factors for infection in Cherepovets, Russia.

METHODS

In June 1999, data on demographic, socioeconomic, hygienic characteristics, and recent gastrointestinal illness were collected on 50 community-recruited adults and 50 blood donors. The community group then maintained daily diaries of exposures and gastrointestinal symptoms for 5 months. Sera samples at the inception and conclusion of the study were tested for antibody responses to the 15/17 kDa and 27 kDa Cryptosporidium antigens using mini-immunoblots.

RESULTS

At the inception, 68% and 88% of study participants had detectable serological responses to 15/17 kDa and 27 kDa antigens. Older age was associated with stronger antibody responses to both antigens. Attendance at swimming pools was associated with stronger responses to both antigens in predominantly male blood donors. Over the follow-up period, drinking non-boiled water from shallow draw-wells was associated with an increase in serological response to the 27 kDa antigen. Self-reported gastrointestinal illness was not associated with an increase in serological response.

CONCLUSIONS

The prevalence of positive serological responses in Cherepovets was higher than in most prior Cryptosporidium serosurveys in non-outbreak communities. Drinking water is an important pathway for infection.

Prevalence of obsessive-compulsive disorder in the British nationwide survey of child mental health

Obsessive-compulsive disorder (OCD) is a disorder that appears to be under-diagnosed and under-treated, despite the evidence for effective treatments. There are variable estimates of OCD prevalence in the under-16s and published rates give little indication of age trends. The aim of this study was to establish the prevalence and associates of OCD in young people aged 5-15 years. The method was a nationwide (UK) epidemiological study of rates of psychiatric disorder in 5-15 year olds (1999 British Child Mental Health Survey): 10,438 children were assessed. Twenty-five children with OCD were identified (weighted overall prevalence 0.25%; 95% CI 0.14-0.35), with prevalence rising exponentially with increasing age. Compared with normal controls, children with OCD were more likely to be from lower socio-economic class and of lower intelligence. Only three of these children had been seen by specialist children's services. Although OCD is rare in young children, the rate increases towards the adult rates at puberty. Children with OCD have additional psychosocial disadvantage. The majority of the childhood cases identified in this survey appear to have been undetected and untreated.

Mental health of children and adolescents in Great Britain

The findings described in this report and summarized here focus on the prevalence of mental disorders among 5-15 year olds and on the associations between the presence of a mental disorder and biographic, sociodemographic, socio-economic, and social functioning characteristics of the child and the family. Causal relationships should not be assumed for any of the results presented in this report.

Prevalence of pervasive developmental disorders in the British nationwide survey of child mental health

The prevalence of pervasive developmental disorders (PDD) is not well established and needs monitoring. We investigated the prevalence of PDDs in the 1999 nationwide British survey of child and adolescent mental health. A randomized stratified sample of children (n = 12,529) aged 5-15 was generated from Child Benefit Records. Trained interviewers interviewed parents and youths aged 11 or older with a standardized diagnostic interview (Development and Well-Being Assessment) and questionnaire data (Strengths and Difficulties Questionnaire) were obtained from teachers and parents who also completed self-report measures of psychological distress. A team of experienced clinicians using all data sources achieved final diagnostic determination. A total of 10,438 (83%) interviews were conducted. There were two girls with Rett syndrome (weighted prevalence: 3.8/10,000 girls) and 27 children with other PDDs (weighted prevalence: 26.1/10,000). Compared to children with a psychiatric disorder other than PDD, social but not behavioural problems were more frequent in the PDD group. Parents of children with PDDs had higher rates of psychological distress than those from the two comparison groups. Consistent with other recent surveys, PDD rates are higher than those reported 30 years ago. The burden associated with PDDs is very high.

Mental health of children and adolescents in Great Britain

The findings described in this report and summarized here focus on the prevalence of mental disorders among 5-15 year olds and on the associations between the presence of a mental disorder and biographic, sociodemographic, socio-economic, and social functioning characteristics of the child and the family. Causal relationships should not be assumed for any of the results presented in this report.

Using the Strengths and Difficulties Questionnaire (SDQ) to screen for child psychiatric disorders in a community sample

Child psychiatric disorders are common and treatable, but often go undetected and therefore remain untreated. To assess the Strengths and Difficulties Questionnaire (SDQ) as a potential means for improving the detection of child psychiatric disorders in the community, SDQ predictions and independent psychiatric diagnoses were compared in a community sample of 7984 5-15 year olds from the 1999 British Child Mental Health Survey. Multi-informant (parents, teachers, older children) SDQs identified individuals with a psychiatric diagnosis with a specificity of 94.6% (95% Cl, 94.1-95.1%) and a sensitivity of 63.3% (59.7-66.9%). The questionnaires identified over 70% of individuals with conduct, hyperactivity, depressive, and some anxiety disorders, but fewer than 50% of individuals with specific phobias, separation anxiety and eating disorders. Sensitivity was substantially poorer with single-informant rather than multi-informant SDQs. Community screening programmes based on multi-informant SDQs could potentially increase the detection of child psychiatric disorders, thereby improving access to effective treatments.

Deterioration of drinking water quality in the distribution system and gastrointestinal morbidity in a Russian city

Few studies have been conducted in Russia to assess the relationship between drinking water quality and gastrointestinal (GI) infections. In the city of Cherepovets, effluent water at the treatment plant usually meets the country's hygienic standards. To provide protection against secondary water contamination in the distribution system, concentrations of total residual chlorine in effluent water are maintained#10; at levels from 1 to 2 mg x l(-1). However, residual chlorine concentrations rapidly decline in the distribution system and rechlorination is not practiced. Some areas of the city routinely have very low residual chlorine at taps and little protection against secondary microbiological contamination of water in pipelines. A cross-sectional epidemiological study was conducted in Cherepovets to assess an association between decline in residual chlorine concentrations and risk of GI illness. This study included water quality monitoring and an extensive questionnaire survey of city residents. The results demonstrated a consistent spatial pattern of free chlorine decline in the distribution system. An interquartile range variability in free residual chlorine decline (0.22 mg x l(-1)) was associated with 1.42 (95% confidence interval (CI) = 1.05, 1.91) relative risk of self-reported gastrointestinal illness after control for socioeconomic, hygienic and demographic parameters.

Contamination of water supplies with Cryptosporidium parvum and Giardia lamblia and diarrheal illness in selected Russian cities

Cryptosporidium parvum and Giardia lamblia are important agents of waterborne diarrheal illness worldwide. While giardiasis is routinely diagnosed in Russia with a chemical staining technique, data on the prevalence of cryptosporidiosis are scarce. Monitoring of the respective parasites in water supplies in Russia is very limited. A health survey conducted in the city of Cherepovets and three other cities in the European part of Russia using enzyme-linked immunosorbent assays (ELISA) demonstrated that 6.9% of diarrheal patients tested had C. parvum antigens in their fecal samples; 9.4% had G. lamblia antigens. A survey of occurrence of these parasites in water supplies in Cherepovets and seven other cities demonstrated that source and finished water samples from several of these cities were contaminated with either C. parvum oocysts or G. lamblia cysts. The surveys were not designed to assess associations between presence or concentrations of C. parvum and G. lamblia in water and related gastrointestinal diseases in exposed populations. Rather, the goals were to demonstrate the presence of disinfection-resistant protozoan parasites in untreated and treated waters, and the importance of these pathogens as causative agents of diarrheal illnesses in a number of Russian cities.

Prevalence of obsessive-compulsive disorder in the British nationwide survey of child mental health

BACKGROUND

Obsessive-compulsive disorder (OCD) is a disorder that appears to be underdiagnosed and undertreated, despite the evidence for effective treatments. There are variable estimates of OCD prevalence in the under-16s and published rates give little indication of age trends.

AIMS

To establish the prevalence and associates of OCD in young people aged 5-15 years.

METHOD

A nationwide (UK) epidemiological study of rates of psychiatric disorder in 5- to 15-year-olds (1999 British Child Mental Health Survey): 10 438 children were assessed.

RESULTS

Twenty-five children with OCD were identified (weighted overall prevalence 0.25%; 95% CI 0.14-0.35), with prevalence rising exponentially with increasing age. Compared with normal controls, children with OCD were more likely to be from lower socio-economic class and of lower intelligence. Only three of these children had been seen by specialist children's services.

CONCLUSIONS

Although OCD is rare in young children, the rate increases towards the adult rates at puberty. Children with OCD have additional psychosocial disadvantage. The majority of the childhood cases identified in this survey appear to have been undetected and untreated.

Prevalence of pervasive developmental disorders in the British nationwide survey of child mental health

OBJECTIVE

The prevalence of pervasive developmental disorders (PDD) is not well established and needs monitoring. The prevalence of PDD in the 1999 nationwide British survey of child and adolescent mental health was investigated.

METHOD

A randomized, stratified sample of children (N= 12,529) aged 5 to 15 years was generated from the Child Benefit Register. Trained interviewers interviewed parents and youths aged 11 or older with a standardized diagnostic interview (Development and Well-Being Assessment), and questionnaire data (Strengths and Difficulties Questionnaire) were obtained from teachers and parents, who also completed self-report measures of psychological distress. Final diagnostic determination was achieved by a team of experienced clinicians using all data sources.

RESULTS

A total of 10,438 (83%) interviews were conducted. There were 2 girls with Rett syndrome (weighted prevalence: 3.8/10,000 girls) and 27 children with other PDD (weighted prevalence: 26.1/10,000). Compared with children with a psychiatric disorder other than PDD, social but not behavioral problems were more frequent in the PDD group. Parents of children with PDD had higher rates of psychological distress than those from the two comparison groups.

CONCLUSIONS

Consistent with other recent surveys, PDD rates are higher than those reported 30 years ago. The burden associated with PDD is very high.

Marine swimming-related illness: implications for monitoring and environmental policy

There is increasing evidence that environmental degradation may be contributing to an increase in marine-related diseases across a wide range of taxonomic groups. This includes a growing number of reports of both recreational and occupational users of marine waters developing gastrointestinal, respiratory, dermatologic, and ear, nose, and throat infections. The duration and type of exposure, concentration of pathogens, and host immunity determine the risk of infection. Public health authorities may not be able to accurately predict the risk of waterborne disease from marine waters due to the limitations of conventional monitoring, as well as erroneous perceptions of pathogen life span in marine systems. Pathogens undetectable by conventional methods may remain viable in marine waters, and both plankton and marine sediments may serve as reservoirs for pathogenic organisms, which can emerge to become infective when conditions are favorable. In this paper we address the environmental factors that may contribute to illness, the types of associated economic costs, the issues of water quality monitoring and the policy implications raised by the apparent rise in incidence of marine water-related illnesses.

Using the Strengths and Difficulties Questionnaire (SDQ) to screen for child psychiatric disorders in a community sample

BACKGROUND

Child psychiatric disorders are common and treatable, but often go undetected and therefore remain untreated.

AIMS

To assess the Strengths and Difficulties Questionnaire (SDQ) as a potential means for improving the detection of child psychiatric disorders in the community.

METHOD

SDQ predictions and independent psychiatric diagnoses were compared in a community sample of 7984 5- to 15-year-olds from the 1999 British Child Mental Health Survey.

RESULTS

Multi-informant (parents, teachers, older children) SDQs identified individuals with a psychiatric diagnosis with a specificity of 94.6% (95% Cl 94.1-95.1%) and a sensitivity of 63.3% (59.7-66.9%). The questionnaires identified over 70% of individuals with conduct, hyperactivity, depressive and some anxiety disorders, but under 50% of individuals with specific phobias, separation anxiety and eating disorders. Sensitivity was substantially poorer with single-informant rather than multi-informant SDQs.

CONCLUSIONS

Community screening programmes based on multi-informant SDQs could potentially increase the detection of child psychiatric disorders, thereby improving access to effective treatments.

Effects of losartan and captopril on left ventricular volumes in elderly patients with heart failure: results of the ELITE ventricular function substudy

BACKGROUND

The mechanism by which angiotensin-converting enzyme inhibitors reduce mortality rates and disease progression in patients with heart failure is likely mediated in part through prevention of adverse ventricular remodeling. This study examined the effects of the angiotensin-converting enzyme inhibitor captopril and the angiotensin II type 1 receptor antagonist losartan on ventricular volumes and function in elderly patients with heart failure and reduced left ventricular ejection fraction (< or =40%).

METHODS

Patients underwent radionuclide ventriculograms (RVG) at baseline and were randomized to either captopril (n = 16) or losartan (n = 13). After 48 weeks, another RVG was obtained. Therapy was then withdrawn for at least 5 days, and the RVG was repeated while the patient was not receiving the drug.

RESULTS

At 48 weeks both captopril and losartan significantly reduced left ventricular (LV) end-diastolic volume index (135 +/- 26 to 128 +/- 23 mL/m(2) for losartan, P <.05 vs baseline; 142 +/- 25 to 131 +/- 20 mL/m(2) for captopril, P <.01; mean (SD). Captopril also reduced LV end-systolic volume index (98 +/- 24 to 89 +/- 21 mL/m(2), P <.01 vs. baseline), whereas a nonsignificant trend was observed for the losartan group (97 +/- 23 to 90 +/- 16 mL/m(2), P = not significant). The between-group differences in the changes in LV volumes were not statistically significant. After drug withdrawal, LV end-diastolic volume index remained significantly lower than baseline in the captopril group (P <.01).

CONCLUSIONS

Both captopril and losartan prevent LV dilation, representing adverse ventricular remodeling, previously seen with placebo treatment. Reverse remodeling was observed in the captopril group. On the basis of these results, the relative effects on LV remodeling do not provide a rationale for a survival benefit of losartan over captopril.

Case study: bipolar disorder after head injury

A case of bipolar disorder subsequent to a mild head injury in a 15-year-old girl is reported. Review of the literature indicates that this is an extremely rare outcome. Lack of adequate follow-up studies makes it difficult to accurately predict type and severity of psychiatric outcome. Assessment and management involves ongoing consideration of both organic and psychosocial factors even after initial negative investigations.

Interactions between metals and microbial communities in New Bedford Harbor, Massachusetts

The fate of toxic metals in marine sediments depends on a combination of the physical, chemical, and biologic conditions encountered in any given environment. These conditions may vary dramatically, both spatially and temporally, in response to factors ranging from seasonal changes and storm events to human activities such as dredging or remediation efforts. This paper describes a program designed to evaluate the interrelationships between the microbial community and pollutants in the New Bedford Harbor, Massachusetts, area, a U.S. Environmental Protection Agency designated Superfund site. Research has focused on establishing distributional relationships between contaminant metals, fluxes of metals between sediments and the overlying water, changes in microbial diversity in response to metals, and potential use of the microbial community as a biomarker of contaminant availability. This research has shown that a significant flux of metals to the water column is mediated by benthic biologic activity, and that microbial communities may be a responsive marker of contaminant stress. A combination of biogeochemical studies and the use of molecular tools can be used to improve our understanding of the fate and effect of heavy metals released to aquatic systems.

A novel method for the rapid separation of plasma lipoproteins using self-generating gradients of iodixanol

We describe a new method for the rapid fractionation of plasma lipoproteins, which makes use of a new non-ionic, iodinated, density gradient medium, iodixanol, commercially available as Optiprep(TM). The method is simple: plasma or serum is mixed with iodixanol followed by centrifugation in a vertical or near vertical rotor. Separation of VLDL, LDL and HDL can be achieved in 3 h and the lipoprotein fractions are comparable in density and composition with those prepared using conventional salt based gradients. Each class of lipoprotein can be removed in a single fraction, or a profile of lipoprotein distribution can be obtained using a gradient fractionator. Because the medium is inert, fractions from the gradient can be analysed by agarose gel electrophoresis or assayed for lipid content or apolipoprotein composition by SDS-PAGE without removing the iodixanol. Small differences in electrophoretic mobility of HDL and LDL across several gradient fractions suggest that subfractionation of these classes may occur. The new method is simple, rapid and versatile with potential application for preparation of lipoproteins and for analysis of lipoprotein profiles in the research or clinical laboratory.

Phospholipase A2-activating protein induces the synthesis of IL-1 and TNF in human monocytes

Phospholipase A2-activating protein (PLAP) is an important mediator of eicosanoid generation. PLAP can also be found in high concentrations in synovial fluid from patients with rheumatoid arthritis, and injection of PLAP into animal joints results in an inflammatory, rheumatoid-like lesion. We have demonstrated previously that TNF-alpha and IL-1 beta stimulate formation of PLAP before phospholipase A2 (PLA2) enzyme activation and production of eicosanoids. To further explore the mechanisms found in the inflammatory response, we examined the ability of PLAP to stimulate release of TNF and IL-1 from human peripheral blood monocytes. TNF and IL-1 protein levels were measured by ELISA, and IL-1 and TNF mRNA were determined by Northern blotting. PLAP, PLAP peptide, and melittin, a bee venom PLA2 activator with homology with PLAP, all increased IL-1 and TNF production in a time- and dose-dependent manner. Heat-denatured PLAP and actin (an irrelevant protein) failed to exert this effect. PLAP stimulation of TNF and IL-1 could be enhanced with co-treatment of cells with free fatty acids, such as arachidonic or linoleic acid, but it was not blocked completely by PLA2 inhibitors. These results demonstrate not only that synthesis of PLAP can be stimulated by cytokines, but also that PLAP may regulate cytokine synthesis and thus perpetuate an immune or inflammatory response.

Phospholipase A2-activating protein induces the synthesis of IL-1 and TNF in human monocytes

Phospholipase A2-activating protein (PLAP) is an important mediator of eicosanoid generation. PLAP can also be found in high concentrations in synovial fluid from patients with rheumatoid arthritis, and injection of PLAP into animal joints results in an inflammatory, rheumatoid-like lesion. We have demonstrated previously that TNF-alpha and IL-1 beta stimulate formation of PLAP before phospholipase A2 (PLA2) enzyme activation and production of eicosanoids. To further explore the mechanisms found in the inflammatory response, we examined the ability of PLAP to stimulate release of TNF and IL-1 from human peripheral blood monocytes. TNF and IL-1 protein levels were measured by ELISA, and IL-1 and TNF mRNA were determined by Northern blotting. PLAP, PLAP peptide, and melittin, a bee venom PLA2 activator with homology with PLAP, all increased IL-1 and TNF production in a time- and dose-dependent manner. Heat-denatured PLAP and actin (an irrelevant protein) failed to exert this effect. PLAP stimulation of TNF and IL-1 could be enhanced with co-treatment of cells with free fatty acids, such as arachidonic or linoleic acid, but it was not blocked completely by PLA2 inhibitors. These results demonstrate not only that synthesis of PLAP can be stimulated by cytokines, but also that PLAP may regulate cytokine synthesis and thus perpetuate an immune or inflammatory response.

Toxic metals in aquatic ecosystems: a microbiological perspective

Microbe-metal interactions in aquatic environments and their exact role in transport and transformations of toxic metals are poorly understood. This paper will briefly review our understanding of these interactions. Ongoing research in Lake Chapala, Mexico, the major water source for the City of Guadalajara, provides an opportunity to study the microbiological aspects of metal-cycling in the water column. Constant resuspension of sediments provides a microbiologically rich aggregate-based system. Data indicate that toxic metals are concentrated on aggregate material and bioaccumulate in the food chain. A provisional model is presented for involvement of microbial aggregates in metal-cycling in Lake Chapala.

Molecular and genetic characterization of elite transgenic rice plants produced by electric-discharge particle acceleration

The recovery of transgenic rice plants expressing a number of exogenous genes was reported previously. Using immature embryo explants as the target tissue, plasmids containing both selectable and screenable marker genes were introduced into elite rice varieties via electric-discharge particle acceleration. Co-integration, copy number, expression, and inheritance of these genes were analyzed. A 100% co-integration frequency was confirmed by Southern-blot analyses of R0 plants. The majority of transgenic plants contained between one and ten copies of exogenous DNA and molecular and genetic analyses of progeny indicated that all copies in almost all R0 plants were inherited as a single dominant hemizygous locus. Co-expression of unselected genes ranged from 30-66% for gus/hmr constructs, depending on the promotor used, and up to 90% for bar/hmr constructs. The integrative structures of two unlinked transgenic loci of a rare R0 plant were analyzed in detail by Southern-blot analysis of its progeny.

Genetic and molecular ecotoxicology: a research framework

Participants at the Napa Conference on Genetic and Molecular Ecotoxicology assessed the status of this field in light of heightened concerns about the genetic effects of exposure to hazardous substances and recent advancements in our capabilities to measure those effects. We present here a synthesis of the ideas discussed throughout the conference, including definitions of important concepts in the field and critical research needs and opportunities. While there were many opinions expressed on these topics, there was general agreement that there are substantive new opportunities to improve the impact of genetic and molecular ecotoxicology on prediction of sublethal effects of exposure to hazardous substances. Future studies should emphasize integration of genetic ecotoxicology, ecological genetics, and molecular biology and should be directed toward improving our understanding of the ecological implications of genotoxic responses. Ecological implications may be assessed at either the population or ecosystem level; however, a population-level focus may be most pragmatic. Recent technical advancements in measuring genetic and molecular responses to toxicant exposure will spur rapid progress. These new techniques have considerable promise for increasing our understanding of both mechanisms of toxicity on genes or gene products and the relevance of detrimental effects to individual fitness.

Pollutant effects on the microbial ecosystem

Genetic diversity of a microbial community will inevitably be affected by environmental stress. However, our understanding of the implications of these effects is limited. Genetic exchange between natural microbial communities appears to be a common phenomenon, mediated by a number of microbial processes (conjugation, transformation, and transduction). These mechanisms of change are presumably adaptations to natural environmental perturbation, e.g., the low levels of antibiotics produced by other organisms. However, anthropogenic influences on the environment may be accelerating genetic change within microbiologic ecosystems, beyond these natural adaptation rates. This article highlights some of the perceived risks to ecosystem health and research questions that need to be addressed.

The preparation of subcellular organelles from mouse liver in self-generated gradients of iodixanol

This paper reports the use of a new density gradient compound, Iodixanol, for the resolution of the major organelles from mouse liver. A major advantage of Iodixanol over other iodinated density gradient media is its ready ability to form self-generated gradients. Gradient-forming conditions have been modulated to provide optimal recoveries of Golgi membranes, lysosomes, mitochondria, and peroxisomes. The organelles were isolated in high yield (80-90% of gradient input) and high purity. Nycodenz and Iodixanol were compared using preformed gradients. Iodixanol provided resolution superior to that of Nycodenz, notably of peroxisomes and mitochondria and the separation of lysosomes from endoplasmic reticulum. Because Iodixanol does not interfere significantly with marker enzyme activities, gradient fractions can be analyzed without removal of the gradient medium.

Iodixanol: a nonionic iso-osmotic centrifugation medium for the formation of self-generated gradients

The physical and biological properties of Iodixanol, a new nonionic density gradient medium, are described in this paper. It is effectively a dimer of Nycodenz and it exhibits two significant advantages over previous iodinated density gradient media--its aqueous solutions are iso-osmotic up to a density of 1.32 g/ml and it is capable of forming self-generating gradients in 1 to 3 h. It has a very low toxicity toward biological material and enzyme assays can be carried out in its presence.

Airborne environmental endotoxin: a cross-validation of sampling and analysis techniques

A standard method for measurement of airborne environmental endotoxin was developed and field tested in a fiberglass insulation-manufacturing facility. This method involved sampling with a capillary-pore membrane filter, extraction in buffer using a sonication bath, and analysis by the kinetic-Limulus assay with resistant-parallel-line estimation (KLARE). Cross-validation of the extraction and assay method was performed by comparison with methanolysis of samples followed by 3-hydroxy fatty acid (3-OHFA) analysis by gas chromatography-mass spectrometry. Direct methanolysis of filter samples and methanolysis of buffer extracts of the filters yielded similar 3-OHFA content (P = 0.72); the average difference was 2.1%. Analysis of buffer extracts for endotoxin content by the KLARE method and by gas chromatography-mass spectrometry for 3-OHFA content produced similar results (P = 0.23); the average difference was 0.88%. The source of endotoxin was gram-negative bacteria growing in recycled washwater used to clean the insulation-manufacturing equipment. The endotoxin and bacteria become airborne during spray cleaning operations. The types of 3-OHFAs in bacteria cultured from the washwater, present in the washwater and in the air, were similar. Virtually all of the bacteria cultured from air and water were gram negative composed mostly of two species, Deleya aesta and Acinetobacter johnsonii. Airborne countable bacteria correlated well with endotoxin (r2 = 0.64). Replicate sampling showed that results with the standard sampling, extraction, and Limulus assay by the KLARE method were highly reproducible (95% confidence interval for endotoxin measurement +/- 0.28 log10). These results demonstrate the accuracy, precision, and sensitivity of the standard procedure proposed for airborne environmental endotoxin.

Biofilms and the survival of opportunistic pathogens in recycled water

Microorganisms are likely to develop an organic film on pipes, water reservoirs and filters used for waste water reclamation during extended missions in space. These biofilms can serve to protect and concentrate potentially pathogenic microorganisms. Our investigation has emphasized the survival strategy of opportunistic pathogenic bacteria in distilled water. Pseudomonas aeruginosa and Staphylococcus aureus were used as test organisms. Cultures were incubated at 10 degrees, 25 degrees, and 37 degrees C. No viable Staphylococcus cells were detected after the first week of incubation. P. aeruginosa, however, survived in distilled water up to 5 months at all three temperatures tested. The starved cells were able to form a biofilm layer on stainless steel. The cells exhibited a negative surface charge. The charge may be involved in the adhesion of this bacterium to metal substrata. We are currently investigating the importance of adhesion in the survival of this and other potential human pathogens found in water recycling systems.

Characterization of exopolymers of aquatic bacteria by pyrolysis-mass spectrometry

Exopolymers from a diverse collection of marine and freshwater bacteria were characterized by pyrolysis-mass spectrometry (Py-MS). Py-MS provides spectra of pyrolysis fragments that are characteristic of the original material. Analysis of the spectra by multivariate statistical techniques (principal component and canonical variate analysis) separated these exopolymers into distinct groups. Py-MS clearly distinguished characteristic fragments, which may be derived from components responsible for functional differences between polymers. The importance of these distinctions and the relevance of pyrolysis information to exopolysaccharide function in aquatic bacteria is discussed.

Umbilical keloid: an early start

A case of umbilical keloid formation following cord separation in an infant is described. Treatment involved excision of the mass and reconstruction of the umbilicus with histological confirmation of the excised lesion. To our knowledge, this is the first report of an umbilical keloid occurring at such an early age.

Isolation of the major subcellular organelles from mouse liver using Nycodenz gradients without the use of an ultracentrifuge

Commonly, subcellular organelles such as nuclei, mitochondria, lysosomes, and Golgi membranes are isolated first by differential centrifugation in low-speed or high-speed centrifuges and then purified by gradient centrifugation in ultracentrifuges. We have prepared these organelles using a new high-speed centrifuge (28,000 rpm max) which allows the generation of higher radial centrifugal forces (rcfs) than are available in standard machines. We have shown that most subcellular organelles can be purified by using low-viscosity Nycodenz gradients at rcfs lower than those normally used in ultracentrifuges, without increasing the time of centrifugation. Use of Nycodenz also allows rapid harvesting of material from gradients and we have adapted a number of enzyme assays to facilitate gradient analysis.