Cutting seton for the treatment of cryptoglandular fistula-in-ano: a systematic review and meta-analysis

BACKGROUND

The use of cutting seton (CS) for the management of cryptoglandular fistula-in-ano has remained controversial because of reports of fecal incontinence, postoperative pain, and extended healing time. The aim of this review was to provide the first synthesis of studies investigating the use of CS for the treatment of cryptoglandular fistula-in-ano.

METHODS

MEDLINE, Embase, and CENTRAL were searched up to October 2022. Randomized controlled trials and observational studies comparing CS with alternative interventions were included, along with single-arm studies evaluating CS alone. The primary outcome was fistula-in-ano recurrence, and secondary outcomes included incontinence, healing time, proportion with complete healing, and postoperative pain. Inverse variance random-effects meta-analyses were used to pool effect estimates.

RESULTS

After screening 661 citations, 29 studies were included. Overall, 1513 patients undergoing CS (18.8% female, mean age: 43.1 years) were included. Patients with CS had a 6% (95% CI: 3-12%) risk of recurrence and a 16% (95% CI: 5-38%) risk of incontinence at 6 months. CS patients had an average healing time of 14.6 weeks (95% CI: 10-19 weeks) with 73% (95% CI: 48-89%) of patients achieving complete healing at 6 months postoperatively. There was no difference in recurrence between CS and fistulotomy, advancement flap, two-stage seton fistulotomy, or draining seton.

CONCLUSIONS

Overall, this analysis shows that CS has comparable recurrence and incontinence rates to other modalities. However, this may be at the expense of more postoperative pain and extended healing time. Further comparative studies between CS and other modalities are warranted.

Differences in in-hospital outcomes and healthcare utilization for laparoscopic versus open approach for emergency inguinal hernia repair: a nationwide analysis

PURPOSE

There has been a growing debate of whether laparoscopic or open surgical techniques are superior for inguinal hernia repair. For incarcerated and strangulated inguinal hernias, the laparoscopic approach remains controversial. This study aims to be the first nationwide analysis to compare clinical and healthcare utilization outcomes between laparoscopic and open inguinal hernia repair in an emergency setting.

METHODS

A retrospective analysis of the National Inpatient Sample was performed. All patients who underwent laparoscopic inguinal hernia repair (LIHR) and open inguinal hernia repair (OIHR) between October 2015 and December 2019 were included. The primary outcome was mortality, and secondary outcomes include post-operative complications, ICU admission, length of stay (LOS), and total admission cost. Two approaches were compared using univariate and multivariate logistic and linear regression.

RESULTS

Between the years 2015 and 2019, 17,205 patients were included. Among these, 213 patients underwent LIHR and 16,992 underwent OIHR. No difference was observed between laparoscopic and open repair for mortality (odds ratio [OR] 0.80, 95% CI [0.25, 2.61], p = 0.714). Additionally, there was no significant difference between groups for post-operative ICU admission (OR 1.11, 95% CI [0.74, 1.67], p = 0.614), post-operative complications (OR 1.09, 95% CI [0.76, 1.56], p = 0.647), LOS (mean difference [MD]: -0.02 days, 95% CI [- 0.56, 0.52], p = 0.934), or total admission cost (MD: $3,028.29, 95% CI [$- 110.94, $6167.53], p = 0.059).

CONCLUSION

Laparoscopic inguinal hernia repair is comparable to the open inguinal hernia repair with respect to low rates of morbidity, mortality as well as healthcare resource utilization.

Outcomes in pediatric studies of medium-chain acyl-coA dehydrogenase (MCAD) deficiency and phenylketonuria (PKU): a review

BACKGROUND

Inherited metabolic diseases (IMDs) are a group of individually rare single-gene diseases. For many IMDs, there is a paucity of high-quality evidence that evaluates the effectiveness of clinical interventions. Clinical effectiveness trials of IMD interventions could be supported through the development of core outcome sets (COSs), a recommended minimum set of standardized, high-quality outcomes and associated outcome measurement instruments to be incorporated by all trials in an area of study. We began the process of establishing pediatric COSs for two IMDs, medium-chain acyl-CoA dehydrogenase (MCAD) deficiency and phenylketonuria (PKU), by reviewing published literature to describe outcomes reported by authors, identify heterogeneity in outcomes across studies, and assemble a candidate list of outcomes.

METHODS

We used a comprehensive search strategy to identify primary studies and guidelines relevant to children with MCAD deficiency and PKU, extracting study characteristics and outcome information from eligible studies including outcome measurement instruments for select outcomes. Informed by an established framework and a previously published pediatric COS, outcomes were grouped into five, mutually-exclusive, a priori core areas: growth and development, life impact, pathophysiological manifestations, resource use, and death.

RESULTS

For MCAD deficiency, we identified 83 outcomes from 52 articles. The most frequently represented core area was pathophysiological manifestations, with 33 outcomes reported in 29/52 articles (56%). Death was the most frequently reported outcome. One-third of outcomes were reported by a single study. The most diversely measured outcome was cognition and intelligence/IQ for which eight unique measurement instruments were reported among 14 articles. For PKU, we identified 97 outcomes from 343 articles. The most frequently represented core area was pathophysiological manifestations with 31 outcomes reported in 281/343 articles (82%). Phenylalanine concentration was the most frequently reported outcome. Sixteen percent of outcomes were reported by a single study. Similar to MCAD deficiency, the most diversely measured PKU outcome was cognition and intelligence/IQ with 39 different instruments reported among 82 articles.

CONCLUSIONS

Heterogeneity of reported outcomes and outcome measurement instruments across published studies for both MCAD deficiency and PKU highlights the need for COSs for these diseases, to promote the use of meaningful outcomes and facilitate comparisons across studies.

Family History Taking in Pediatric Practice: A Qualitative Interview Study

BACKGROUND

Family history (FH) is a risk factor for many conditions in pediatric practice. There is no standard of care regarding FH taking, and only a few published studies about current practice.

OBJECTIVES

To explore in depth pediatricians' perceptions, attitudes, beliefs, and practices regarding FH taking.

METHODS

The Theoretical Domains Framework (TDF) was used to develop a comprehensive interview scheme. Semi-structured interviews were conducted with community pediatricians. Interviews were audio-recorded, transcribed, and analyzed using a thematic approach and the constant comparison method.

RESULTS

Eleven pediatricians were interviewed. FH was found to be a firmly embedded, complex, and important aspect of pediatric practice. Participants described FH as part of regular holistic care. FH and social history were linked and often appeared to be part of the same concept to participants. FH was used for a range of purposes. In addition to risk assessment, FH information helped clarify diagnosis and select medication, tailor overall patient management based on family circumstance, and provide psychosocial support for parents. Participants expressed confidence in their FH skills and reported tailoring their approach with experience. Most were not concerned about formal evidence for FH and would not change their practice except for "good reason."

CONCLUSIONS

The use of the TDF helped ensure a comprehensive approach to FH taking in pediatric practice. The findings suggest that FH taking in this setting is a complex activity, embedded in routine care. Efforts to make FH taking more systematic may founder if they fail to take into account pediatricians' attitudes, perspectives, and practices.

What is in a Name? Parent, Professional and Policy-Maker Conceptions of Consent-Related Language in the Context of Newborn Screening

Newborn bloodspot screening programs are some of the longest running population screening programs internationally. Debate continues regarding the need for parents to give consent to having their child screened. Little attention has been paid to how meanings of consent-related terminology vary among stakeholders and the implications of this for practice. We undertook semi-structured interviews with parents (n = 32), healthcare professionals (n = 19) and policy decision makers (n = 17) in two Canadian provinces. Conceptions of consent-related terms revolved around seven factors within two broad domains, decision-making and information attainment. Decision-making comprised: parent decision authority; voluntariness; parent engagement with decision-making; and the process of enacting choice. Information ascertainment comprised: professional responsibilities (including disclosure of information and time to review); parent responsibilities; and the need for discussion and understanding prior to a decision. Our findings indicate that consent-related terms are variously understood, with substantive implications for practice. We suggest that consent procedures should be explained descriptively, regardless of approach, so there are clear indications of what is expected of parents and healthcare professionals. Support systems are required both to meet the educational needs of parents and families and to support healthcare professionals in delivering information in a manner in keeping with parent needs.

Targeted metabolomics reveals reduced levels of polyunsaturated choline plasmalogens and a smaller dimethylarginine/arginine ratio in the follicular fluid of patients with a diminished ovarian reserve

STUDY QUESTION

Does the metabolomic profile of the follicular fluid (FF) of patients with a diminished ovarian reserve (DOR) differ from that of patients with a normal ovarian reserve (NOR)?

SUMMARY ANSWER

The metabolomic signature of the FF reveals a significant decrease in polyunsaturated choline plasmalogens and methyl arginine transferase activity in DOR patients compared to NOR patients.

WHAT IS KNOWN ALREADY

The composition of the FF reflects the exchanges between the oocyte and its microenvironment during its acquisition of gametic competence. Studies of the FF have allowed identification of biomarkers and metabolic pathways involved in various pathologies affecting oocyte quality, but no large metabolomic analysis in the context of ovarian ageing and DOR has been undertaken so far.

STUDY DESIGN, SIZE, DURATION

This was an observational study of the FF retrieved from 57 women undergoing in vitro fertilization at the University Hospital of Angers, France, from November 2015 to September 2016. The women were classified in two groups: one including 28 DOR patients, and the other including 29 NOR patients, serving as controls.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Patients were enrolled in the morning of oocyte retrieval after ovarian stimulation. Once the oocytes were isolated for fertilization and culture, the FF was pooled and centrifuged for analysis. A targeted quantitative metabolomic analysis was performed using high-performance liquid chromatography coupled with tandem mass spectrometry, and the Biocrates Absolute IDQ p180 kit. The FF levels of 188 metabolites and several sums and ratios of metabolic significance were assessed by multivariate and univariate analyses.

MAIN RESULTS AND THE ROLE OF CHANCE

A total of 136 metabolites were accurately quantified and used for calculating 23 sums and ratios. Samples were randomly divided into training and validation sets. The training set, allowed the construction of multivariate statistical models with a projection-supervised method, i.e. orthogonal partial least squares discriminant analysis (OPLS-DA), applied to the full set of metabolites, or the penalized least absolute shrinkage and selection operator with logistic regression (LASSO-LR), applied to the ratios and sums of the metabolites. Both multivariate models showed good predictive performances when applied to the validation set. The final penalized model retained the three most significant variables, i.e. the total dimethylarginine-to-arginine ratio (Total DMA/Arginine), the sum of the polyunsaturated choline plasmalogens (PUFA ae), and the patient's age. The negative coefficients of Total DMA/Arginine and PUFA ae indicated that these FF variables had lower values in DOR patients than in NOR patients.

LARGE SCALE DATA

N/A.

LIMITATIONS REASONS FOR CAUTION

This study presents two limitations. First, with this targeted metabolomics analysis, we have explored only a limited portion of the FF metabolome. Second, although the signature found was highly significant, the mechanism underlying the dysfunction remains undetermined.

WIDER IMPLICATIONS OF THE FINDINGS

The understanding of the mechanisms implied in ovarian ageing is essential for providing an adequate response to affected women desiring pregnancy. Our study proposes an incoming signature that may open new paths towards this goal.

STUDY FUNDING/COMPETING INTEREST(S)

This study was supported by the University Hospital of Angers, the University of Angers, and the French national research centers, INSERM and the CNRS. There were no competing interests.

Establishing core outcome sets for phenylketonuria (PKU) and medium-chain Acyl-CoA dehydrogenase (MCAD) deficiency in children: study protocol for systematic reviews and Delphi surveys

BACKGROUND

Inherited metabolic diseases (IMD) are a large group of rare single-gene disorders that are typically diagnosed early in life. There are important evidence gaps related to the comparative effectiveness of therapies for IMD, which are in part due to challenges in conducting randomized controlled trials (RCTs) for rare diseases. Registry-based RCTs present a unique opportunity to address these challenges provided the registries implement standardized collection of outcomes that are important to patients and their caregivers and to clinical providers and healthcare systems. Currently there is no core outcome set (COS) for studies evaluating interventions for paediatric IMD. This protocol outlines a study that will establish COS for each of two relatively common IMD in children, phenylketonuria (PKU) and medium-chain acyl-CoA dehydrogenase (MCAD) deficiency.

METHODS

This two-part study is registered with the Core Outcome Measures in Effectiveness Trials (COMET) initiative. Part 1 includes a rapid review and development of an evidence map to identify a comprehensive listing of outcomes reported in past studies of PKU and MCAD deficiency. The review follows established methods for knowledge synthesis, including a comprehensive search strategy, two stages of screening citations against inclusion/exclusion criteria by two reviewers working independently, and extraction of important data elements from eligible studies, including details of the outcomes collected and outcome measurement instruments. The review findings will inform part 2 of our study, a set of Delphi surveys to establish consensus on the highest priority outcomes for each condition. Healthcare providers, families of children with PKU or MCAD deficiency, and health system decision-makers will be invited to participate in two to three rounds of Delphi surveys. The design of the surveys will involve parents of children with IMD who are part of a family advisory forum.

DISCUSSION

This protocol is a crucial step in developing the capacity to launch RCTs with meaningful outcomes that address comparative effectiveness questions in the field of paediatric IMD. Such trials will contribute high-quality evidence to inform decision-making by patients and their family members, clinicians, and policy-makers.

Experiences of caregivers of children with inherited metabolic diseases: a qualitative study

Background

We sought to understand the experiences of parents/caregivers of children with inherited metabolic diseases (IMD) in order to inform strategies for supporting patients and their families. We investigated their experiences regarding the management of disease, its impact on child and family life, and interactions with the health care system.

Methods

From four Canadian centres, we conducted semi-structured telephone interviews with parents/caregivers of children with an IMD who were born between 2006 and 2015 and who were participating in a larger cohort study. Participants were selected with the aim of achieving a diverse sample with respect to treatment centre, IMD, and age of the child. Interviews emphasized the impacts of the disease and its treatment on the child and family and explicitly queried perceptions of interactions with the health care system. We identified emergent themes from the interview data.

Results

We completed interviews with 21 parents/caregivers. The 21 children were aged <1 to 7 years old with IMD that included amino acid disorders, urea cycle disorders, fatty acid oxidation disorders, and organic acid disorders or ‘other’ IMD. Most parents reported that they and their families had adapted well to their child’s diagnosis. Parents used proactive coping strategies to integrate complex disease management protocols into routine family life. An important source of stress was concern about the social challenges faced by their children. Participants reported positive interactions with their most involved health care providers within the metabolic clinic. However, they reported challenges associated with the health care system outside of disease-specific metabolic care, when encountering systems and providers unfamiliar with the child’s disease.

Conclusions

The successful use of proactive coping strategies among parents of children with IMD in this study suggests the potential value of promoting positive coping and is an important direction for future study. Parents’ social concerns for their children were important stressors that warrant consideration by health care providers positioned to support families. Our results with respect to experiences with care highlight the important role of specialized metabolic clinics and point to a need for better coordination of the care that takes place outside the disease-specific management of IMD.

Consent for newborn screening: parents' and health-care professionals' experiences of consent in practice

Consent processes for newborn bloodspot screening (NBS) are variable, with a lack of descriptive research that depicts how the offer of NBS is made to parents. We explored the experience, in practice, of consent for NBS. Semistructured interviews in two Canadian provinces were held with: (1) parents of children offered NBS (n=32); and (2) health-care professionals involved in the NBS process (n=19). Data on recollections of NBS, including consent processes, were utilized to identify emerging themes using the method of constant comparison. Three themes were relevant to NBS consent: (1) The 'offer' of NBS; (2) content and timing of information provision; and (3) the importance of parental experiences for consent decisions. Recollections of consent for NBS were similar between jurisdictions. Excepting midwives and their patients, NBS was viewed as a routine part of giving birth, with little evidence of an informed consent process. Although most parents were satisfied, all respondents suggested information about NBS be provided long before the birth. Accounts of parents who declined screening highlight the influence of parental experiences with the heel prick process in screening decisions. Findings further our understanding of consent in practice and highlight areas for improvement in parent-provider interactions.

Family History-Taking in Paediatrics: It’s Much More Than Just A Checklist

BACKGROUND: Family history (FH) is a risk factor for many conditions in pediatric practice; interest has increased in supporting systematic FH taking in this area by identifying core conditions for enquiry and developing point of care tools. There is little published about current practice to inform implementing such changes.

OBJECTIVES: To inform future FH taking interventions by identifying pediatricians' perceptions, attitudes, beliefs, and current practices.

DESIGN/METHODS: The Theoretical Domains Framework (TDF) was used to develop a comprehensive interview scheme. Semi-structured interviews were conducted with community and hospital-based pediatricians Analysis was by the constant comparison method, using a thematic approach. This study was funded by the Canadian Institutes of Health Research.

RESULTS: The data revealed FH taking to be a firmly embedded, but complex aspect of pediatric practice. Participants described FH as part of regular, holistic care, extending to social and interpersonal, as well as clinical purposes; in addition to disease risk assessment, FH information helped clarify diagnosis, and select medication; tailor the overall patient management based on family circumstances; and provide psychosocial support for parents. It was also used as a method to build a relationship with parents/carers. FH and social history information were inextricably linked and often appeared to be the same concept in participants’ minds. Participating pediatricians generally expressed confidence in their FH skills and reported tailoring their approach according to experience, after initial training early in their career. While acknowledging some challenges in ensuring accuracy, they were attuned to nuances in their interactions with parents and children which would affect whether, and what, they were told about illness in the family. Most were not concerned about formal evidence, and would not change their practice except for “good reason”.

CONCLUSION: The use of the TDF helped ensure a comprehensive approach to FH taking in pediatric practice. The findings suggest that FH taking in this setting is a complex activity, embedded in routine care. Recommendations for systematic enquiry about specific conditions cannot be seen as a simple additional activity to current practice. Efforts to make FH taking more systematic may founder if they fail to take into account pediatricians’ attitudes, perspectives, and practices. Further studies should explore and seek to confirm and expand our observations.

Stakeholder attitudes towards the role and application of informed consent for newborn bloodspot screening: a study protocol

INTRODUCTION

Newborn bloodspot screening (NBS) involves testing a small sample of blood taken from the heel of the newborn for a number of serious and life-limiting conditions. In Canada, newborn screening programmes fall under provincial and territorial jurisdiction with no federal coordination. To date, we know very little about the underlying beliefs around different consent practices or how terminology is interpreted by different individuals. Differences in attitudes may have important healthcare consequences. This study will provide empirical data comparing stakeholder opinions on their understanding of consent-related terminology, the perceived applicability of different consent approaches to newborn screening, and the requirements of these different approaches.

METHODS AND ANALYSIS

Parents, healthcare professionals and policymakers will be recruited in the provinces of Ontario and Newfoundland and Labrador. Parents will be identified through records held by each provincial screening programme. Healthcare professionals will be purposively sampled on the basis of engagement with newborn screening. Within each province we will identify policymakers who have policy analysis or advisory responsibilities relating to NBS. Data collection will be by qualitative interviews. We will conduct 20 interviews with parents of young children, 10 interviews with key healthcare professionals across the range of appropriate specialties and 10 with policymakers at each site (40 per site, total, N=80). The examination of the transcripts will follow a thematic analysis approach. Recruitment started in June 2014 and is expected to be complete by June 2015.

ETHICS AND DISSEMINATION

This study received ethics approval from the Ottawa Health Science Network Research Ethics Board, the Children's Hospital of Eastern Ontario Research Ethics Board (both Ontario), and the Health Research Ethics Authority (Newfoundland and Labrador).

RESULTS

These will be reported in peer-reviewed publications and conference presentations. The results will have specific application to the development of parent education materials for newborn screening.

Control of Listeria monocytogenes in raw-milk cheeses

The development of Listeria monocytogenes in cheeses made with raw-milk originating from six different farms and according to the Saint-Nectaire cheesemaking technology was studied. Milk was inoculated with two strains of L. monocytogenes at 5 to 10 CFU/25 ml. Microbial and chemical analyses were carried out at appropriate intervals during ripening. L. monocytogenes did not grow in the cores of cheeses prepared with milk originating from three farms. That inhibition could be partially attributed to the pH values and L-lactate content. There was no growth in cheeses with pH below 5.2 and lactate content around 14 mg/g. In all cheeses, L. monocytogenes stopped growing in the cores of cheeses after eight days and some other factors may be involved in the inhibition. No relation was found between L. monocytogenes count and other microbial counts. Growth occurred on cheese surfaces between eight and eighteen days, when the pH significantly increased. The lowest L. monocytogenes growth was found on the surface of cheeses with the lowest pH and without any core growth. Further studies will be performed to clarify the involvement of the microbial community in L. monocytogenes inhibition, in particular during the ripening period.

Diversity, dynamics and activity of bacterial populations in 'Registered Designation of Origin' Salers cheese by single-strand conformation polymorphism analysis of 16S rRNA genes

AIMS

The aim of this work was to measure the dynamic global metabolic activities of the microbial community during ripening of RDO Salers cheese by using a direct molecular approach.

METHODS AND RESULTS

A culture-independent approach including PCR, reverse transcriptase PCR (RT-PCR) and single strand conformation polymorphism (SSCP) analysis of 16S rRNA genes was applied on 'Registered Designation of Origin' Salers cheese samples collected in three farms. The evolution of the global structure of the microbial community in terms of structure or global activities was assessed using ecological indices. The diversity of the global population was higher on RNA patterns than on DNA patterns, because of less dominance and greater richness. Comparison of the SSCP patterns derived from RNA and DNA analysis indicated that the dominant population was not necessarily the most active. The metabolic activities of each bacterial group changed significantly during ripening. Besides lactic acid bacteria that were dominant on both DNA and RNA patterns, the dynamics of the presence and activity of microbial groups rarely studied in the core of cheese, such as corynebacteria, or of unidentified peaks were reported.

CONCLUSIONS

By using SSCP RNA analysis, we were able to obtain information about the activity of bacterial population in cheese, which varied a lot between cheeses and was changing perpetually during ripening.

SIGNIFICANCE AND IMPACT OF THE STUDY

Double DNA-RNA SSCP analysis opens up future prospects in the microbial ecology of cheeses. It will have many applications for controlling of microbial community during cheese processing.

Separation and purification of benzylpenicillin produced by fermentation using coupled ultrafiltration and nanofiltration technologies

The purpose of this study was to evaluate the capacity of using coupled ultrafiltration-nanofiltration technologies for separation and purification of benzylpenicillin (BP). More specifically, we verified the efficiency of three ultrafiltration (UF) membranes (cut-off of 5000, 30,000 and 100,000 Da) to remove impurities that cause stable emulsion during the chemical extraction of the antibiotic. We also tested the effectiveness of a nanofiltration (NF) membrane (cut-off of 300 Da) to concentrate the benzylpenicillin recovered from permeates and to decrease the osmotic pressure by reducing the ionic charge of the broth. Results have shown that high recovery (89.0-91.0%) can be obtained in permeate generated by the 30,000 and 100,000 UF membranes, but a slight emulsion will be formed during phase separation. With the 5000 UF membrane, lower recovery is obtained (81.0%) but no emulsion is produced, leading to a high solvent extraction yield (94.6%). The nanofiltration of 30,000 and 100,000 UF permeates leads to very high recovery (98.0%), but stable emulsions are formed, reducing the chemical extraction yield (80.0-82.6%). For the nanofiltration of 5000 UF permeate, excellent recovery of the antibiotic is noted (97.4%) leading to high extraction yield (92.4%) with no emulsion formed. Diafiltration step should be applied during UF procedure in order to increase the antibiotic recovery in the generated permeates.

Identification of selenomethionine in selenized yeast using two-dimensional liquid chromatography-mass spectrometry based proteomic analysis

Selenium-enriched yeast has been commonly used as a nutritional supplement. Here we describe a protocol used to investigate the metabolic fate of inorganic selenium in yeast. We provide definitive, mass spectrometry based evidence for the non-specific incorporation of selenomethionine in the yeast proteome involving the replacement of about 30% of all methionine with selenomethionine.

[Impact of the climatic scenario of global warming on the growth of trees]

The climatic impact on tree radial growth resulting from an atmospheric CO2 doubling was studied for 24 populations of five tree species in the French Alps and the French Mediterranean area. The Arpege AGCM, which predicts a 3 degrees C increase in mean temperature and a light increase of precipitation, is used to estimate the climatic perturbation. The method is based on the integration of estimated climate in an empirical tree-ring to climate model, involving artificial neural networks. Only a few populations are sensitive to the climatic change; all are located on the boundaries of their ecological area and can be divided in two groups. The first one is composed of high altitude populations which show a growth increase induced by the warmer climate during the growing season. The second one, composed of a single Mediterranean Scots pine population, reacts with a severe growth reduction induced by the stronger water stress in summer.

Anomalies on capture nets of Hydropsyche slossonae larvae (Trichoptera; Hydropsychidae), a potential indicator of chronic toxicity of malathion (organophosphate insecticide)

A laboratory study on the sublethal effects of malathion on the net-spinning behavior of the caddisfly larvae Hydropsyche slossonae was conducted in order to assess the potential of net anomalies as an indicator of chronic exposure to organophosphorus insecticides. Two anomalies were identified after chronic exposure to 0.01, 0.05, 0.1, 0.5 and 1.0 µg l(-1) malathion. The first was a distortion of the midline meshes where the normal diamond shape structure was disrupted and the meshes were separated by extra strands (called 'midline' anomaly). The second aberration observed was a significant decrease in net symmetry. Both anomalies were highly correlated to the toxic action of malathion, i.e. inhibition of the acetylcholinesterase enzyme (AChE). Sodium dodecyl sulfate-polyacrylamide gel electrophoresis analyses of capture nets did not show any modification of silk polypeptides after exposure to malathion, indicating that net distortions were not related to silk composition. Both anomalies seem to represent the symptoms of the specific toxic action of malathion; nevertheless, they can serve as an index of the physiological condition of the larvae, especially the midline anomaly. The symmetry of the nets decreased significantly after exposure to 0.5 and 1.0 µg l(-1). However, the toxicity curves (EC(50)) showed that the sensitivity threshold for the midline anomaly ranged from 0.11 to 0.28 µg l(-1), which reflect more realistic exposure to concentrations expected to occur in the field. Hence, the use of capture net anomalies of hydropsychid larvae could represent a valuable indicator of sublethal toxicity induced by malathion and other organophosphorus insecticides in running waters.

Effects of 2,4-dichlorophenol on the net-spinning behavior of hydropsyche slossonae larvae (Trichoptera; Hydropsychidae), an early warning signal of chronic toxicity

In order to assess the potential of hydropsychid capture net anomalies as a bioindicator of chronic toxicity in streams and rivers, the effects of 2,4-dichlorophenol (2,4-DCP) exposure on the net-spinning behavior of Hydropsyche slossonae were examined for anomalies after 0, 5, 10, 15, and 20 exposure days to gradient concentration of 2,4-dichlorophenol. The net-spinning behavior was significantly affected when larvae were exposed to 1.0, 10, 25, and 50 microg small middle dotL(-1), as expressed by the occurrence of two distinct abnormalities. The first one was a distortion of the midline meshes, where the normal diamond-shape structure is disrupted and the meshes are separated by extra strands (called "midline anomaly). The second aberration observed was called "chaotic net, where the nets are highly irregular without any real structure or well-defined areas. A good correlation was found between the chaotic net frequencies and the reduction of ATP concentrations in the larvae, indicating possible uncoupling effects of 2,4-DCP on the oxidative phosphorylation process. Toxicity curves demonstrate that the sensitivity threshold of chaotic net frequencies ranged from 3.5 to 7 microg small middle dotL(-1), which is highly sensitive compared with other sublethal effects of 2,4-DCP on other aquatic species.

Anomalies on capture nets of Hydropsyche slossonae larvae (Trichoptera; Hydropsychidae) following a sublethal chronic exposure to cadmium

A laboratory study on the sublethal effects of cadmium (Cd) on the net-spinning process of the larvae of Hydropsyche slossonae was conducted in order to assess the potential of net anomalies as an indicator of chronic exposure to Cd. Two major anomalies with different frequency levels were identified after chronic exposure to 0.37, 1.2, 11.6, 21.4 and 43.3 microg l(-1) of Cd. The first was a distortion of the midline meshes where the diamond-shape structure is disrupted and the meshes are separated by extra strands (called 'midline' anomaly). The second aberration consisted of a distortion of the rectilinear structure of net opening by strands being fused or added over the meshes (called 'crossover' anomaly). The midline distortion may be linked to a physiological stress caused by Cd, which can affect the control of the net-spinning process. It was not possible to relate the crossover aberrations to a specific toxic action of Cd, but data indicated that both anomalies are independent from each other and that two modes of action could be implicated. Protein analyses of capture nets have revealed silk polypeptide modifications at the highest Cd concentration tested, indicating a possible effect of Cd interaction with silk proteins. However, neither a gradient-concentration nor a time-dependent response could be established with both aberration frequencies. Silk protein modifications would rather play a secondary role in the appearance of both net anomalies, and mostly at a high concentration level. Finally, the toxicity curves (EC(50)) show that the sensitivity threshold for both types of aberration ranged from 1 to 5 microg l(-1) which is highly sensitive compared with other sublethal effects of Cd on other macroinvertebrate species. Hence, the use of capture-net anomalies of hydropsychid larvae would represent a valuable indicator of sublethal toxicity induced by Cd and possibly by other metals in running waters.

Mass sensitivity of acoustic plate mode in liquids

In this paper, the concept of electrical effective permittivity function is used to calculate the eigen-frequencies and the particle displacements of piezoelectric acoustic plate modes (APM). These results allowed us to determine the mass sensitivities of the first order vibration modes using a first order perturbation theory. Theoretical results are discussed and compared to those of a variational method and isotropic two-layer composite analysis in the case of a shear horizontal APM sensor on a singly rotated cut quartz substrate. Experimental measurements by a copper electrodeposition are carried out and show that the perturbation method leads to a better understanding of the APM behavior.

Comparative performance of piezoceramic and crystal SAW filters

Bulk elastic, piezoelectric, and dielectric constants of four lead zirconate titanate piezoceramics, Pz24, Pz26, Pz27, Pz28, and a modified lead titanate, PTS, are measured and used to theoretically compute the effective permittivity curve of each material from which the surface acoustic wave (SAW) properties are deduced. In parallel, experimental measurements of the SAW properties are carried out by using a curve fitting algorithm on the real and imaginary parts of the electrical input impedance of an unapodised single electrode SAW transducer. The SAW propagation losses are also measured using a SAW delay line. For these ceramics, the effects of a hot isostatic pressing (HIP) post sintering process on the performances of the device are also studied. All these results are discussed and show that ceramic materials, particularly PTS, have potential for SAW applications.

Comparative study of the cadmium and mercury kinetics between the short-lived gastropod Viviparus georgianus (Lea) and pelecypod Elliptio complanata (Lightfoot), under laboratory conditions

A laboratory study of the cadmium and mercury accumulation and elimination kinetics was conducted on the pelecypod Elliptio complanata (Lightfoot) and the short-lived gastropod Viviparus georgianus (Lea), according to age-classes. Preliminary results (metal concentration vs time of exposure) have demonstrated that uptake of Cd and Hg, in the two molluscs studied, follow a biphasic pattern, whereby a steady state is reached after approximately 16 days' exposure and then accumulation increases again for the rest of exposure period. The elimination of the two metals is also characterized in a biphasic way: fast excretion for the first four days followed by a slower depuration for the rest of exposure time. A two-compartment bioaccumulation model has been used to described the different kinetic parameters: (1) the rate constant for depuration; (2) the rate constant for uptake; (3) the theoretical bioconcentration factor extrapolated to steady-state conditions; and (4) the biological half-life of the metals.

Spatio-temporal analysis of climate-tree ring relationships

This paper is concerned with the value of the ecological information provided by response functions. Two questions are considered. The first deals with the spatial reproducibility of response functions depending on the tree population and the location of the meteorological station that yielded the climatic data. The second concerns the temporal stability of the response function. The climate-ring-width relationships are calculated for six Populations of Pinus silvestris (L.). Twelve meteorological stations are involved in this calculation, over the period 1890-1980, divided in five sequences of 50 years. Analogies and differences between response functions are investigated using multi-dimensional analysis (principal component analysis and cluster analysis). Spatial analysis reveals that the climate ring-width relationship mainly depends on the population habitat. The temporal analysis shows that instability is linked with the evolution of the habitat, more especially with the expansion of the forest cover.

A two-year follow-up of a comparative trial of the cost-effectiveness of home and hospital psychiatric treatment

The manpower and operating cost of home-based treatment was compared with the manpower and operating cost of hospital-based treatment during the second year and at the end of two years of treatment. Of the 155 patients destined to receive inpatient treatment, 76 were randomly assigned to home treatment, 79 to hospital treatment. The two groups were similar as to important social, demographic, and clinical characteristics, including psychiatric diagnosis. The manpower and operating cost of treatment, measured in two ways, was similar in the two groups during the second year. However, over the 2-year period hospital-based treatment of patients in each of the three diagnostic groups was more expensive than home-based treatment. Also, regardless of which treatment was given, the cost of treating schizophrenics was higher than the cost of treating manic-depressives which, in turn, was higher than the cost of treating individuals with depressive neurosis. Treatment failures were discussed. Over the 2-year period, failures in home-based treatment accounted for 39.1% of the total manpower and operating cost of home-based treatment, calculated according to Cost Model 1, and for 67.1% of the cost calculated according to Cost Model 2. The concept of failure in hospital-based treatment is also discussed.

A comparative trial of home and hospital psychiatric treatment: financial costs

The financial costs of community-based treatment, stressing home treatment, were compared with the cost of hospital-based treatment during one year. Of 155 patients destined to receive inpatient treatment, 76 were randomly assigned to home treatment, 79 to hospital treatment; the two groups were similar as to important social, demographic, and clinical characteristics. The principal differences between the two treatments concerned the focus of treatment, the locale of treatment, the degree to which continuity of treatment was maintained, and the roles of the respective treatment staffs. Manpower and operating costs, measured in dollars, were estimated in two ways. Either way, hospital-based treatment was more expensive during the year: 64.1% more expensive (+3,250 vs. +1,980 per patient) in the first instance, 108.9% more expensive (+6,750 vs. +3,230 per patient) in the second. With two exceptions during the first month of treatment, the proportions of patients and families receiving either treatment who incurred other costs of treatment were low, and the differences between groups were not significantly different. A higher proportion of patients and families receiving home-based treatment defrayed the cost of the patient's psychotropic drugs; second, a higher proportion of families of patients receiving hospital-based treatment defrayed transportation costs. The proportions of patients and families incurring costs of the consequences of illness were low, and the differences between treatment groups were not significant. We compared this study with similar studies, discussed the generalizability of the results of this study and similar studies, and identified issues for future research.

Isolation and characterization of polysomes and polyadenylated polysomal RNA from Vicia faba meristematic root cells

Undegraded Vicia faba polysomes from meristematic root cells were obtained after homogenization in a medium of low ionic strength provided that the pH was equal to 9.0. By minimizing the shearing forces during the homogenization step, polysomes were obtained free of mitochondrial and nuclear contaminants, measured by differential spectrophotometry and CsCl gradient centrifugation respectively. Poly(A)-containing RNA was obtained by poly(U)-Sepharose chromatography and shown to be virtually free of rRNA and its average size was 13-15 S. Approximately 9% of the purified preparation was annealed by [3H]-poly(U). Sucrose gradient analysis under denaturing conditions showed that the poly(A)-CONtaining RNA were non-degraded. This RNA was used to direct the synthesis of proteins in a heterologous cell-free system from wheat germ.

A comparative trial of home and hospital psychiatric care. One-year follow-up

The effectiveness of community-based treatment stressing home care was compared with hospital-based psychiatric care. One hundred and fifty-five patients destined for inpatient psychiatric care were randomly assigned to Home Care (76 patients) and to Hospital Care (79 patients). Symptoms, role functioning, and psychosocial burden on the family were similar at admission, one month, three months, six months, and one year. The mean in-hospital stay of Hospital Care patients was 41.7 days compared with a mean stay of 14.5 days for Home Care patients. The difference in the amount of ambulatory care received by patients in the two groups was not significant. The evidence is consistent: community-based psychiatric care is an effective alternative to hospital-based care for many but not all severely disabled patients. The active ingredients of successful community treatment are known, yet the lag in implementing these programs persists.

Home care treatment of acutely ill psychiatric patients. A one year follow-up

This paper presents the results of one year of Home Care treatment of 77 acutely ill psychiatric patients. Home Care treatment was successful in 83.1% of 77 patients during the first year. Since only four patients failed during the second six months of treatment, hospitalization was effectively prevented, and not delayed, during the first year of treatment.

Finally, a history of previous psychiatric hospitalization is not an accurate predictor of success or failure in the patients receiving Home Care treatment in this study. It appears more likely that the psychosocial supports available to the patient, and the relationship between the patient, his family and the Home Care treatment team, are more important in determining the success or failure of treatment at home.