A qualitative exploration of undergraduate nursing students' experience of emotional safety for learning during their clinical practice

BACKGROUND

During their clinical practice, nursing students learn to manage patient safety through their experiences, emotions, and interpersonal relationships.

OBJECTIVES

To explore contextual and mechanistic factors that facilitate a sense of emotional safety for learning in nursing students, particularly regarding patient safety events experienced during their placements.

DESIGN

A descriptive qualitative study using narratives and thematic analysis.

SETTINGS

A university in Northern Italy.

PARTICIPANTS

Undergraduate nursing students recruited through purposive sampling.

METHODS

Twenty cases relevant to the present study were selected from the "Sharing LearnIng from Practice for Patient Safety" (SLIPPS) project database containing 100 narratives collected using the patient safety learning Event Recording Tool. The data were analysed using thematic analysis according to Braun & Clarke's methodology. The themes that emerged from the thematic analysis were rearranged in Context-Mechanism-Outcomes.

RESULTS

Students identified clinical practice experiences as important occasions for their personal and professional development. Emotional safety and tutoring were the elements that effectively "govern" the students' learning and development process.

CONCLUSIONS

Emotional safety is key for nursing students because it enables them to constructively overcome any relational and emotional tensions that may develop during their clinical placements.

Modelling approaches for histology-independent cancer drugs to inform NICE appraisals: a systematic review and decision-framework

BACKGROUND

The first histology-independent marketing authorisation in Europe was granted in 2019. This was the first time that a cancer treatment was approved based on a common biomarker rather than the location in the body at which the tumour originated. This research aims to explore the implications for National Institute for Health and Care Excellence appraisals.

METHODS

Targeted reviews were undertaken to determine the type of evidence that is likely to be available at the point of marketing authorisation and the analyses required to support National Institute for Health and Care Excellence appraisals. Several challenges were identified concerning the design and conduct of trials for histology-independent products, the greater levels of heterogeneity within the licensed population and the use of surrogate end points. We identified approaches to address these challenges by reviewing key statistical literature that focuses on the design and analysis of histology-independent trials and by undertaking a systematic review to evaluate the use of response end points as surrogate outcomes for survival end points. We developed a decision framework to help to inform approval and research policies for histology-independent products. The framework explored the uncertainties and risks associated with different approval policies, including the role of further data collection, pricing schemes and stratified decision-making.

RESULTS

We found that the potential for heterogeneity in treatment effects, across tumour types or other characteristics, is likely to be a central issue for National Institute for Health and Care Excellence appraisals. Bayesian hierarchical methods may serve as a useful vehicle to assess the level of heterogeneity across tumours and to estimate the pooled treatment effects for each tumour, which can inform whether or not the assumption of homogeneity is reasonable. Our review suggests that response end points may not be reliable surrogates for survival end points. However, a surrogate-based modelling approach, which captures all relevant uncertainty, may be preferable to the use of immature survival data. Several additional sources of heterogeneity were identified as presenting potential challenges to National Institute for Health and Care Excellence appraisal, including the cost of testing, baseline risk, quality of life and routine management costs. We concluded that a range of alternative approaches will be required to address different sources of heterogeneity to support National Institute for Health and Care Excellence appraisals. An exemplar case study was developed to illustrate the nature of the assessments that may be required.

CONCLUSIONS

Adequately designed and analysed basket studies that assess the homogeneity of outcomes and allow borrowing of information across baskets, where appropriate, are recommended. Where there is evidence of heterogeneity in treatment effects and estimates of cost-effectiveness, consideration should be given to optimised recommendations. Routine presentation of the scale of the consequences of heterogeneity and decision uncertainty may provide an important additional approach to the assessments specified in the current National Institute for Health and Care Excellence methods guide.

FURTHER RESEARCH

Further exploration of Bayesian hierarchical methods could help to inform decision-makers on whether or not there is sufficient evidence of homogeneity to support pooled analyses. Further research is also required to determine the appropriate basis for apportioning genomic testing costs where there are multiple targets and to address the challenges of uncontrolled Phase II studies, including the role and use of surrogate end points.

FUNDING

This project was funded by the National Institute for Health Research (NIHR) Evidence Synthesis programme and will be published in full in Health Technology Assessment; Vol. 25, No. 76. See the NIHR Journals Library website for further project information.

Full field dependence of primary aberrations in perturbed double-plane symmetric systems with a circular pupil

This paper deals with the theory of primary aberrations for perturbed double-plane symmetric optical systems consisting of a combination of tilted and decentered surfaces and a circular pupil. First, the analytical expressions describing the full field behavior of Zernike polynomials are derived from the fourth-order wavefront aberration function for this class of optical systems. Then, such expressions are combined to retrieve the full field dependence of primary coma, primary astigmatism, and field curvature. They are described by an elliptical conic-shaped surface with a variable apex location over the field of view, by a binodal surface with two nodes over the field of view, and by a general elliptical surface with one node. The proposed analytical expressions provide a better understanding of the primary aberration behavior for these systems and can be of great use in their optical design and aberration correction. An optical system constituted by a pair of tilted and decentered biconic lenses is studied to validate the proposed expressions.

Antimicrobial-impregnated central venous catheters for preventing neonatal bloodstream infection: the PREVAIL RCT

BACKGROUND

Clinical trials show that antimicrobial-impregnated central venous catheters reduce catheter-related bloodstream infection in adults and children receiving intensive care, but there is insufficient evidence for use in newborn babies.

OBJECTIVES

The objectives were (1) to determine clinical effectiveness by conducting a randomised controlled trial comparing antimicrobial-impregnated peripherally inserted central venous catheters with standard peripherally inserted central venous catheters for reducing bloodstream or cerebrospinal fluid infections (referred to as bloodstream infections); (2) to conduct an economic evaluation of the costs, cost-effectiveness and value of conducting additional research; and (3) to conduct a generalisability analysis of trial findings to neonatal care in the NHS.

DESIGN

Three separate studies were undertaken, each addressing one of the three objectives. (1) This was a multicentre, open-label, pragmatic randomised controlled trial; (2) an analysis was undertaken of hospital care costs, lifetime cost-effectiveness and value of information from an NHS perspective; and (3) this was a retrospective cohort study of bloodstream infection rates in neonatal units in England.

SETTING

The randomised controlled trial was conducted in 18 neonatal intensive care units in England.

PARTICIPANTS

Participants were babies who required a peripherally inserted central venous catheter (of 1 French gauge in size).

INTERVENTIONS

The interventions were an antimicrobial-impregnated peripherally inserted central venous catheter (coated with rifampicin-miconazole) or a standard peripherally inserted central venous catheter, allocated randomly (1 : 1) using web randomisation.

MAIN OUTCOME MEASURE

Study 1 - time to first bloodstream infection, sampled between 24 hours after randomisation and 48 hours after peripherally inserted central venous catheter removal. Study 2 - cost-effectiveness of the antimicrobial-impregnated peripherally inserted central venous catheter compared with the standard peripherally inserted central venous catheters. Study 3 - risk-adjusted bloodstream rates in the trial compared with those in neonatal units in England. For study 3, the data used were as follows: (1) case report forms and linked death registrations; (2) case report forms and linked death registrations linked to administrative health records with 6-month follow-up; and (3) neonatal health records linked to infection surveillance data.

RESULTS

Study 1, clinical effectiveness - 861 babies were randomised (antimicrobial-impregnated peripherally inserted central venous catheter, n = 430; standard peripherally inserted central venous catheter, n = 431). Bloodstream infections occurred in 46 babies (10.7%) randomised to antimicrobial-impregnated peripherally inserted central venous catheters and in 44 (10.2%) babies randomised to standard peripherally inserted central venous catheters. No difference in time to bloodstream infection was detected (hazard ratio 1.11, 95% confidence interval 0.73 to 1.67; p = 0.63). Secondary outcomes of rifampicin resistance in positive blood/cerebrospinal fluid cultures, mortality, clinical outcomes at neonatal unit discharge and time to peripherally inserted central venous catheter removal were similar in both groups. Rifampicin resistance in positive peripherally inserted central venous catheter tip cultures was higher in the antimicrobial-impregnated peripherally inserted central venous catheter group (relative risk 3.51, 95% confidence interval 1.16 to 10.57; p = 0.02) than in the standard peripherally inserted central venous catheter group. Adverse events were similar in both groups. Study 2, economic evaluation - the mean cost of babies' hospital care was £83,473. Antimicrobial-impregnated peripherally inserted central venous catheters were not cost-effective. Given the increased price, compared with standard peripherally inserted central venous catheters, the minimum reduction in risk of bloodstream infection for antimicrobial-impregnated peripherally inserted central venous catheters to be cost-effective was 3% and 15% for babies born at 23-27 and 28-32 weeks' gestation, respectively. Study 3, generalisability analysis - risk-adjusted bloodstream infection rates per 1000 peripherally inserted central venous catheter days were similar among babies in the trial and in all neonatal units. Of all bloodstream infections in babies receiving intensive or high-dependency care in neonatal units, 46% occurred during peripherally inserted central venous catheter days.

LIMITATIONS

The trial was open label as antimicrobial-impregnated and standard peripherally inserted central venous catheters are different colours. There was insufficient power to determine differences in rifampicin resistance.

CONCLUSIONS

No evidence of benefit or harm was found of peripherally inserted central venous catheters impregnated with rifampicin-miconazole during neonatal care. Interventions with small effects on bloodstream infections could be cost-effective over a child's life course. Findings were generalisable to neonatal units in England. Future research should focus on other types of antimicrobial impregnation of peripherally inserted central venous catheters and alternative approaches for preventing bloodstream infections in neonatal care.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN81931394.

FUNDING

This project was funded by the National Institute for Health Research Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 24, No. 57. See the NIHR Journals Library website for further project information.

Cost-effectiveness of strategies preventing late-onset infection in preterm infants

OBJECTIVE

Developing a model to analyse the cost-effectiveness of interventions preventing late-onset infection (LOI) in preterm infants and applying it to the evaluation of anti-microbial impregnated peripherally inserted central catheters (AM-PICCs) compared with standard PICCs (S-PICCs).

DESIGN

Model-based cost-effectiveness analysis, using data from the Preventing infection using Antimicrobial Impregnated Long Lines (PREVAIL) randomised controlled trial linked to routine healthcare data, supplemented with published literature. The model assumes that LOI increases the risk of neurodevelopmental impairment (NDI).

SETTING

Neonatal intensive care units in the UK National Health Service (NHS).

PATIENTS

Infants born ≤32 weeks gestational age, requiring a 1 French gauge PICC.

INTERVENTIONS

AM-PICC and S-PICC.

MAIN OUTCOME MEASURES

Life expectancy, quality-adjusted life years (QALYs) and healthcare costs over the infants' expected lifetime.

RESULTS

Severe NDI reduces life expectancy by 14.79 (95% CI 4.43 to 26.68; undiscounted) years, 10.63 (95% CI 7.74 to 14.02; discounted) QALYs and costs £19 057 (95% CI £14 197; £24697; discounted) to the NHS. If LOI causes NDI, the maximum acquisition price of an intervention reducing LOI risk by 5% is £120. AM-PICCs increase costs (£54.85 (95% CI £25.95 to £89.12)) but have negligible impact on health outcomes (-0.01 (95% CI -0.09 to 0.04) QALYs), compared with S-PICCs. The NHS can invest up to £2.4 million in research to confirm that AM-PICCs are not cost-effective.

CONCLUSIONS

The model quantifies health losses and additional healthcare costs caused by NDI and LOI during neonatal care. Given these consequences, interventions preventing LOI, even by a small extent, can be cost-effective. AM-PICCs, being less effective and more costly than S-PICC, are not likely to be cost-effective.

TRIAL REGISTRATION NUMBER

NCT03260517.

Determinants, consequences and potential solutions to poor adherence to anti-osteoporosis treatment: results of an expert group meeting organized by the European Society for Clinical and Economic Aspects of Osteoporosis, Osteoarthritis and Musculoskeletal Diseases (ESCEO) and the International Osteoporosis Foundation (IOF)

Many patients at increased risk of fractures do not take their medication appropriately, resulting in a substantial decrease in the benefits of drug therapy. Improving medication adherence is urgently needed but remains laborious, given the numerous and multidimensional reasons for non-adherence, suggesting the need for measurement-guided, multifactorial and individualized solutions.

INTRODUCTION

Poor adherence to medications is a major challenge in the treatment of osteoporosis. This paper aimed to provide an overview of the consequences, determinants and potential solutions to poor adherence and persistence to osteoporosis medication.

METHODS

A working group was organized by the European Society on Clinical and Economic Aspects of Osteoporosis, Osteoarthritis and Musculoskeletal diseases (ESCEO) to review consequences, determinants and potential solutions to adherence and to make recommendations for practice and further research. A systematic literature review and a face-to-face experts meeting were undertaken.

RESULTS

Medication non-adherence is associated with increased risk of fractures, leading to a substantial decrease in the clinical and economic benefits of drug therapy. Reasons for non-adherence are numerous and multidimensional for each patient, depending on the interplay of multiple factors, suggesting the need for multifactorial and individualized solutions. Few interventions have been shown to improve adherence or persistence to osteoporosis treatment. Promising actions include patient education with counselling, adherence monitoring with feedback and dose simplification including flexible dosing regimen. Recommendations for practice and further research were also provided. To adequately manage adherence, it is important to (1) understand the problem (initiation, implementation and/or persistence), (2) to measure adherence and (3) to identify the reason of non-adherence and fix it.

CONCLUSION

These recommendations are intended for clinicians to manage adherence of their patients and to researchers and policy makers to design, facilitate and appropriately use adherence interventions.

Runaway electron imaging spectrometry (REIS) system

A portable Runaway Electron Imaging and Spectrometry System (REIS) was developed in ENEA-Frascati to measure synchrotron radiation spectra from in-flight runaway electrons in tokamaks. The REIS is a wide-angle optical system collecting simultaneously visible and infrared emission spectra using an incoherent bundle of fibers, in a spectral range that spans from 500 nm to 2500 nm, and visible images using a CCD color microcamera at a rate of 25 frames/s. The REIS system is supervised and managed using a dedicated LabVIEW program to acquire data simultaneously from three spectrometers every 20 ms (configurable down to 10 ms). An overview of the REIS architecture and acquisition system and resulting experimental data obtained in FTU are presented and discussed in this paper.

Brodalumab for the Treatment of Moderate-to-Severe Plaque Psoriasis: An Evidence Review Group Evaluation of a NICE Single Technology Appraisal

As part of the National Institute for Health and Care Excellence single technology appraisal process, brodalumab was assessed to determine the clinical and cost effectiveness of its use in the treatment of moderate-to-severe plaque psoriasis. The Centre for Reviews and Dissemination and the Centre for Health Economics Technology Assessment Group at the University of York were commissioned to act as the independent Evidence Review Group. This article provides a summary of the Evidence Review Group's review of the company's submission, the Evidence Review Group report and the National Institute for Health and Care Excellence Appraisal Committee's subsequent guidance issued in March 2018. The main clinical effectiveness data were derived from three well-conducted, multicentre, double-blind randomised controlled trials. The trials demonstrated that brodalumab statistically significantly reduced the severity of psoriasis and its impact on health-related quality of life, compared with placebo, at 12 weeks. In comparison with ustekinumab, statistically significantly more patients taking brodalumab had reduced psoriasis severity at 12 weeks. Psoriasis severity and quality of life also appeared improved at 52 weeks, although statistical significance was not assessed. Withdrawal rates were comparable to drug survival rates of other biological therapies and rates of adverse events were similar between brodalumab and ustekinumab. A network meta-analysis was presented, comparing brodalumab with other therapies available at the same point in the treatment pathway (i.e. in patients for whom standard systemic therapy or phototherapy is inadequately effective, not tolerated or contraindicated). The network meta-analysis ranked treatments in order of effectiveness, in terms of achieving different levels of Psoriasis Area and Severity Index response. The results indicated that brodalumab had a similar probability of response to ixekizumab, secukinumab and infliximab and a higher probability of response than ustekinumab, adalimumab, etanercept, apremilast, dimethyl fumarate and placebo. The company's economic model compared nine treatment sequences that included three lines of active therapy, consisting of brodalumab and other comparators recommended by the National Institute for Health and Care Excellence, followed by best supportive care. The sequence with brodalumab in the first-line position dominated sequences that started with adalimumab, infliximab, secukinumab and ustekinumab. The incremental cost-effectiveness ratio of the brodalumab sequence compared to less effective and non-dominated sequences ranged from £7145 (vs. the etanercept sequence) to £13,353 (vs. the dimethyl fumarate sequence) per quality-adjusted life-year gained. The incremental cost-effectiveness ratio for the more costly and effective ixekizumab sequence was £894,010 per quality-adjusted life-year gained compared to the brodalumab sequence. At a threshold of £20,000 per quality-adjusted life-year gained, the brodalumab sequence had the highest probability of being cost effective (96%). The main limitation of the company's economic model was the restrictive nature of the sequences compared. Twelve separate scenarios based on key uncertainties were explored by the Evidence Review Group. The only scenarios where brodalumab was ranked lower than first were not considered to be more appropriate or plausible than the assumptions or scenarios included in the company's base case. The treatment rankings identified in the Evidence Review Group's alternative base case were identical to those derived from the company's base case model. At the first National Institute for Health and Care Excellence Appraisal Committee meeting, the Committee concluded that brodalumab appears to be as effective as other anti-interleukin-17 agents and is cost effective, based on the discount agreed in the patient access scheme. Brodalumab is recommended as an option for treating adults with severe plaque psoriasis (defined by a total Psoriasis Area and Severity Index score of 10 or more and a Dermatology Life Quality Index score of more than 10) who have not responded to other systemic non-biological therapies. Brodalumab should be stopped at 12 weeks if the psoriasis has not responded adequately.

The course of asthma during pregnancy in a recent, multicase-control study on respiratory health

Background

Over the years it has been widely stated that approximately one-third of asthmatic women experience worsening of the disease during pregnancy. However, the literature has not been reviewed systematically and the meta-analytic reviews include old studies. This study aimed to examine whether the prevalence of worsening asthma during pregnancy is still consistent with prior estimate or it has been reduced.

Methods

A detailed Clinical Questionnaire on respiratory symptoms, medical history, medication, use of services, occupation, social status, home environment and lifestyle was administered to random samples of the Italian population in the frame of the Gene Environment Interactions in Respiratory Diseases (GEIRD) study. Only clinical data belong to 2.606 subjects that completed the clinical stage of the GEIRD study, were used for the present study.

Results

Out of 1.351 women, 284 self-reported asthma and 92 of them had at least one pregnancy. When we considered the asthma course during pregnancy, we found that 16 women worsened, 31 remained unchanged, 25 improved. Seven women had not the same course in the different pregnancies and 13 did not know. The starting age of ICS use almost overlaps with that of asthma onset in women with worsening asthma during pregnancy (19 years ± 1.4), unlike the other women who started to use ICS much later (30.3 years ± 12). In addition, the worsening of asthma was more frequent in women with an older age of onset of asthma (18 years ± 9 vs 13 years ± 10). Among women who completed the ACT during the clinical interview, the 50% of women who experienced worsening asthma during pregnancy (6/12) had an ACT score below 20.

Conclusion

Asthma was observed to worsen during pregnancy in a percentage much lower to that generally reported in all the previous studies. There is still room in clinical practice to further reduce worsening of asthma during pregnancy by improving asthma control, with a more structured approach to asthma education and management prepregnancy.

Poplar woody taproot under bending stress: the asymmetric response of the convex and concave sides

Background and Aims Progress has been made in understanding the physiological and molecular basis of root response to mechanical stress, especially in the model plant Arabidopsis thaliana, in which bending causes the initiation of lateral root primordia toward the convex side of the bent root. In the case of woody roots, it has been reported that mechanical stress induces an asymmetric distribution of lateral roots and reaction wood formation, but the mechanisms underlying these responses are largely unknown. In the present work, the hypothesis was tested that bending could determine an asymmetric response in the two sides of the main root axis as cells are stretched on the convex side and compressed on the concave side. Methods Woody taproots of 20 seedlings were bent to an angle of 90° using a steel net. Changes in the anatomy, lignin and phytohormone content and proteome expression in the two sides of the bent root were analysed; anatomical changes, including dissimilarities and similarities to those found in poplar bent woody stem, were also considered. Key Results Compression forces at the concave side of poplar root induced the formation of reaction wood which presented a high lignin content and was associated with the induction of cambium cell activity. Auxin seemed to be the main hormone triggering lignin deposition and cell wall strengthening in the concave sides. Abscisic acid appeared to function in the water stress response induced by xylem structures and/or osmotic alterations in the compression sides, whereas gibberellins may control cell elongation and gravitropisms. Conclusions Poplar root reaction wood showed characteristics different from those produced in bent stem. Besides providing biomechanical functions, a bent root ensures water uptake and transport in the deforming condition induced by tension and compression forces by two different strategies: an increase in xylem thickness in the compressed side, and lateral root formation in the tension side.

Effect of short-term cadmium stress on Populus nigra L. detached leaves

Pollution by toxic metals, accumulating into soils as result of human activities, is a worldwide major concern in industrial countries. Plants exhibit different degrees of tolerance to heavy metals, as a consequence of their ability to exclude or accumulate them in particular tissues, organs or sub-cellular compartments. Molecular information about cellular processes affected by heavy metals is still largely incomplete. As a fast-growing, highly tolerant perennial plant species, poplar has become a model for environmental stress response investigations. To study the short-term effects of cadmium accumulation in leaves, we analyzed photosystem II (PSII) quantum yield, hydrogen peroxide (H2O2) generation, hormone levels variation, as well as proteome profile alteration of 50μM CdSO4 vacuum-infiltrated poplar (Populus nigra L.) detached leaves. Cadmium management brought about an early and sustained production of hydrogen peroxide, an increase of abscisic acid, ethylene and gibberellins content, as well as a decrease in cytokinins and auxin levels, whereas photosynthetic electron transport was unaffected. Proteomic analysis revealed that twenty-one proteins were differentially induced in cadmium-treated leaves. Identification of fifteen polypeptides allowed to ascertain that most of them were involved in stress response while the remaining ones were involved in photosynthetic carbon metabolism and energy production.

Auditory cortex involvement in emotional learning and memory

Emotional memories represent the core of human and animal life and drive future choices and behaviors. Early research involving brain lesion studies in animals lead to the idea that the auditory cortex participates in emotional learning by processing the sensory features of auditory stimuli paired with emotional consequences and by transmitting this information to the amygdala. Nevertheless, electrophysiological and imaging studies revealed that, following emotional experiences, the auditory cortex undergoes learning-induced changes that are highly specific, associative and long lasting. These studies suggested that the role played by the auditory cortex goes beyond stimulus elaboration and transmission. Here, we discuss three major perspectives created by these data. In particular, we analyze the possible roles of the auditory cortex in emotional learning, we examine the recruitment of the auditory cortex during early and late memory trace encoding, and finally we consider the functional interplay between the auditory cortex and subcortical nuclei, such as the amygdala, that process affective information. We conclude that, starting from the early phase of memory encoding, the auditory cortex has a more prominent role in emotional learning, through its connections with subcortical nuclei, than is typically acknowledged.

Pulmonary involvement in patients with Marfan Syndrome

AIM

Pulmonary involvement is not generally considered a main feature of Marfan syndrome, an autosomal connective tissue disorder caused by mutations in fibrillin 1. Thanks to the substantial progress in treatments, life expectation of these patients has been dramatically improved determining changes in different organ systems. The number of patients with pulmonary pathology may be higher than expected. Objective of the study was to evaluate the pulmonary involvement in all the patients referring to the largest Italian center for Marfan syndrome, assessing clinical examination and lung function tests.

METHODS

Clinical history, spirometry, lung volumes and diffusing capacity have been assessed in 64 patients of our national referral center.

RESULTS

None of the patients reported chronic respiratory symptoms. Fourteen percent reported a previous pneumothorax and 3 blebs and 45% had moderate to severe rib cage abnormalities. Twenty-three percent had cardiothoracic surgery. Two of the 19 patients with chest TC performed at our hospital were diagnosed with emphysema and were both non smoker; 7 had subpleural apical blebs. Only 37% of patients had normal lung function; 19% showed a restrictive pattern and 44% an obstructive pattern or an isolated diffusion impairment or an isolated hyperinflation. All patients with pneumothorax showed an obstructive pattern and diffusion impairment.

CONCLUSION

In the absence of early respiratory symptoms, pulmonary abnormalities should be detected and monitored before they aggravate. Particular attention should be paid to prevent pneumothorax. Our results support the importance of lung volume determination to identify patients in which pulmonary parenchyma require a careful chest CT evaluation.

Involvement of lignin and hormones in the response of woody poplar taproots to mechanical stress

Mechanical stress is a widespread condition caused by numerous environmental factors that severely affect plant stability. In response to mechanical stress, plants have evolved complex response pathways able to detect mechanical perturbations and inducing a suite of modifications in order to improve anchorage. The response of woody roots to mechanical stresses has been studied mainly at the morphological and biomechanical level, whereas investigations on the factors triggering these important alterations are still at the initial stage. Populus has been widely used to study the response of stem to different mechanical stresses and, since it has the first forest tree genome to be decoded, represents a model woody plant for addressing questions on the mechanisms controlling adaptation of woody roots to changing environments. In this study, a morphological and physiological analysis was used to investigate factors controlling modifications in Populus nigra woody taproots subjected to mechanical stress. An experimental model analyzing spatial and temporal mechanical force distribution along the woody taproot axis enabled us to compare the events occurring in its above-, central- and below-bending sectors. Different morphogenetic responses and local variations of lignin and plant hormones content have been observed, and a relation with the distribution of the mechanical forces along the stressed woody taproots is hypothesized. We investigated the differences of the response to mechanical stress induction during the time; in this regard, we present data referring to the effect of mechanical stress on plant transition from its condition of winter dormancy to that of full vegetative activity.

What defines airflow obstruction in asthma?

Asthma guidelines from the Global Initiative for Asthma (GINA) and from the National Heart, Lung, and Blood Institute provide conflicting definitions of airflow obstruction, suggesting a fixed forced expiratory volume in 1 s (FEV(1))/forced vital capacity (FVC) cut-off point and the lower limit of normality (LLN), respectively. The LLN was recommended by the recent American Thoracic Society/European Respiratory Society guidelines on lung function testing. The problem in using fixed cut-off points is that they are set regardless of age and sex in an attempt to simplify diagnosis at the expense of misclassification. The sensitivity and specificity of fixed FEV(1)/FVC ratios of 0.70, 0.75 and 0.80 versus the LLN were evaluated in 815 subjects (aged 20-44 yrs) with a diagnosis of asthma within the framework of the European Community Respiratory Health Survey. In males, the 0.70 ratio showed 76.5% sensitivity and 100.0% specificity, the 0.75 ratio 100.0% sensitivity and 92.4% specificity, and the 0.80 ratio 100.0% sensitivity but 58.1% specificity. In females, the 0.70 ratio showed 57.3% sensitivity and 100.0% specificity, the 0.75 ratio 91.5% sensitivity and 95.9% specificity, and the 0.80 ratio 100.0% sensitivity but 72.9% specificity. The fixed cut-off points cause a lot of misidentification of airflow obstruction in young adults, with overestimation with the 0.80 ratio and underestimation with the 0.70 ratio. In conclusion, the GINA guidelines should change their criteria for defining airflow obstruction.

A histochemical approach to the evaluation of the in vivo cytotoxicity of the nitrobutadienes (1E,3E)-1,4-bis(1-naphthyl)-2,3-dinitro-1,3-butadiene and methyl (2Z,4E)-2-methylsulfanyl-5-(1-naphthyl)-4-nitro-2,4-pentadienoate in mice liver and kidney

Two new molecules (1E,3E)-1,4-bis(1-naphthyl)-2,3-dinitro-1,3-butadiene (1-Naph-DNB) and (2Z,4E)-2-methylsulfanyl-5-(1-naphthyl)-4-nitro-2,4-pentadienoate (1-Naph-NMCB) in previous studies showed interesting antiproliferative activity in vitro. Furthermore, toxicological tests and histological analysis provided promising results, in particular for 1-Naph-NMCB that displayed lower toxic activity both in terms of lethal effect and tissue damage of the main organs. Finally, studies of the antitumour activity in vivo confirmed the efficacy of both molecules, though with some differences in tumour selectivity and levels of activity. In this investigation the activities of some specific enzymes, acid phosphatase (AcPase), alkaline phosphatase (AlkPase), catalase (Cat), succinic dehydrogenase (SDH), glucose-6-phosphatase (G6Pase) and K+ p-nitrophenyl phosphatase (K+ pNPPase) were studied in the liver and kidney as histopathological biomarkers, to assess the effects of the two compounds in organs generally involved in the metabolism and excretion of different drugs. As oxidative stress may also develop as a consequence of the toxic effect of chemicals, reactive oxygen species (ROS) production was evaluated by a histochemical method. The results indicated that some enzyme activities and ROS expression changed in a dose-related manner. Nevertheless, neither in the liver nor in the kidney were dramatic toxic effects evident. By contrast, the variations of some enzyme activities (AlkPase, AcPase, Cat, K+ pNPPase) were interpreted as possible defensive mechanisms for tolerating high dosage of the compounds.

Morphofunctional evidence of changes in principal and mitochondria-rich cells in the epidermis of the frog Rana kl. esculenta living in a polluted habitat

The epidermis of vertebrates is the body's principal barrier against environment and its possible contaminants. The presence of keratins, as well as specific detoxifying molecules or enzyme activities, in the various epidermis layers is believed to be involved in providing protection from harmful environmental influences. Anuran integument is poorly hornified and thus permeable to some endogenous and exogenous compounds and thus serves as a good bioindicator of overall environmental conditions. In the present investigation, we studied the epidermis of Rana kl. esculenta adult specimens collected at two different rice fields, relatively unpolluted and heavily polluted, respectively. Environmental pollution was assayed by chemical analysis performed on both sediments and animals. We evaluated the structural aspects of the epidermis at both light and electron microscopy levels and the pattern of keratinization by immunohistochemistry. Furthermore, we studied the activities of some enzymes (acid and alkaline phosphatase, nitric oxide synthase-related nicotinamide adenine dinucleotide phosphate dehydrogenase, glucose-6-phosphate dehydrogenase, catalase, nonspecific esterases, and succinic dehydrogenase) involved mainly in membrane transport, xenobiotics, and oxidative metabolism. Compared with controls, in polluted animals we found the following results: (1) an increase in pollutant levels (i.e., cadmium, mercury, and lead); (2) less keratinized superficial cells in the epidermis; and (3) changes in most enzyme activities in keratinocytes and mitochondria-rich cells (particularly glucose-6-phosphate dehydrogenase and esterases, both important to counteract oxidative and toxic stress). Taken as a whole, the present data indicate the morphofunctional plasticity of the frog epidermis in response to environmental contamination.

Hypertensive retinopathy revisited: some answers, more questions

Hypertension is associated with cardiovascular risk and systemic target organ damage. Retinopathy is considered one of the indicators of target organ damage. This review focuses on recent studies on hypertensive retinopathy and their implications for clinical care. Early recognition of hypertensive retinopathy signs remains an important step in the risk stratification of hypertensive patients.

Direct demonstration of iron in a term placenta in two cases of beta-thalassemia

The aim of this study was to quantify iron in the placentas at the end of pregnancy in two patients suffering from beta-thalassemia and compare the data to that recorded from the placentas of healthy women. Iron was quantified in placental specimens taken after the delivery. The specimens were subjected to chemical treatments in order to remove extracellular iron and leave the intracellular iron intact. After coloration, each specimen was subjected to quantitative analysis of images in order to identify and quantify iron. Our results demonstrated that in beta-thalassemia there is an accumulation of iron in the outer basal cytoplasm of the epithelial cells of placental cotyledons.

GB virus C/hepatitis G virus exposure in Italian pediatric and young adult thalassemic patients

BACKGROUND

The aim was to estimate the prevalence and the persistence of GB virus C/hepatitis G virus (GBV-C/HGV) exposure markers in a group at high risk for transfusion-transmitted agents.

PATIENTS AND METHODS

Serum samples from 37 thalassemic patients were screened for GBV-C/HGV RNA by reverse transcription PCR (RT-PCR) and for antibodies to the envelope protein E2 of GBV-C/HGV (anti-E2).

RESULTS AND DISCUSSION

GBV-C/HGV RNA and anti-E2 were detected in 13 (35%) and 12 (32%) sera, respectively. Contemporary presence of both markers was found in one patient. GBV-C/HGV exposure was found in 24 patients (64.8%). Mean levels of liver enzymes were similar in both exposed and unexposed GBV-C/HGV groups. 33 out of 35 patients showed no change in GBV-C/HGV RNA and anti-E2 status in sera taken 6 months apart. The rate of persistent infection was 92.3% and the anti-E2 seroconversion rate was 23% for sera taken at least 6 months apart. The temporal overlap between anti-E2 seroconversion and loss of detectable GBV-C/HGV RNA may last more than 6 months.

[Laparoscopic appendectomy. Retrospective analysis of our experience compared with the literature]

BACKGROUND

The benefits of laparoscopic appendectomy (LA) remain controversial. This study reports a critical examination of our experience in a peripheral hospital.

METHODS

A total of 128 appendectomies have been performed since January 1996, of which 63 (49%) were laparoscopic. The patients included 52 (82.5%) females and 11 (17.5%) males with a mean age of 20.8 years (range 11-46). Emergency surgery was required in 6 cases (9.5%) and was elective in 57 (90.5%). Appendectomy was performed during another operation in 3 cases (laparoscopic cholecystectomy).

RESULTS

Mortality was nil. Morbidity was 1.7% (1 case). The index of conversion was 0%. Only one major complication occurred. This took the form of perforation of an ileal loop following accidental lesion during adhesiolysis. The intraoperative diagnosis was not confirmed in 12 (19%) cases: 9 ovarian cysts, 1 terminal ilieitis and 2 cases of acute salpingitis. In 10 cases (15%) surgery was associated with adhesiolysis, and in 6 cases (9.3%) the appendix was retrocecal. Mean operating time was 42 min (range 18-105 min). The mean hospitalisation was 3.3 days.

CONCLUSIONS

The authors emphasise the numerous advantages of laparoscopic techniques in their experience, including excellent cosmetic results, reduced PO pain, rapid functional recovery, lower incidence of adhesion, wound infection and laparocele, and more cost-effective when mechanical staplers are not used. Owing to the ability to explore the entire abdominal cavity, the main advantage of this technique consisted in a correct differential diagnostic balance, especially in young women of child-bearing age, between appendectomy and pathologies of the uterus and adnexa.

[Laparoscopic cholecystectomy. Our experience]

BACKGROUND

The many advantages and extreme versatility made laparoscopic cholecystectomy (L.C.) the gold standard for symptomatic cholelithiasis. The aim of this research is a retrospective analysis of personal experience with laparoscopic cholecystectomy in a peripheral hospital compared with the literature on the subject.

METHODS

Since June 1982, a total of 989 L.C. have been performed. The patients were: 691 (68.6%) women and 298 (29.4%) men with a mean age of 56 years (range 17-84). The indications were: 791 symptomatic cholelithiasis, 142 chronic cholecystitis, 45 empyema-hydrops and 11 adenomyomatosis.

RESULTS

No postoperative death have been observed and the conversion rate was of 24 cases (2.3%). The main complications were 3 cases of injury of the biliary tract and 2 cases of postoperative bleeding (1 from cystic artery and 1 from the umbilical wound). Minor complications observed were 12 cases (1.2%) of infections of the umbilical wound and 3 cases of umbilical hernia (0.3%). The elevation of stasis index was observed in 3 cases which solved spontaneously. The length of stay was 2 days in 957 cases (97%), 8 days in 24 cases and 4-5 days in 8 (0.7%).

CONCLUSIONS

No major trochar's lesions occurred, contrary to the percentages quoted in the literature (0.02%-0.9%). The selective use of the open technique and of the multiuse conic section trocar in the "closed" technique is suggested. The 3 cases of bile duct lesions did not occur during the training period, contrary to what quoted in the literature. In personal opinion, a careful surgical technique with a good Calot's triangle preparation, is necessary to prevent these inconveniences. Parietal complications (umbilical wound infections and laparocele) even if lesser than in the laparotomy technique, can be reduced by using the endobag and suturing the abdominal fascia of the 10 mm trocars. Moreover, the use of a systematic subhepatic drainage during the first 24 postoperative hours is suggested, since it can be useful to reveal possible bleeding.

[The correlation between morphology, electrolytic content and risk factors in breast cysts]

Many studies on the biochemical composition of the liquid aspirated from breast cysts have identified three types of cysts: type I (apocrine) cysts, with a high concentration of K+ and low levels of Na+ and C1-; type II (transudate) cysts, with an electrolytic content similar to that of plasma and high Na+ levels and, finally, type III cysts, with intermediate characteristics. The literature data appear to indicate that the women with type I cysts are at higher risk for breast cancer. The authors report the results of a study carried out on 143 women from October, 1991, through October, 1994, in the Radiology Department of the University of Bologna, to investigate the correlations between some risk factors for breast cancer, the characteristics of cyst fluid and the morphology of the cysts after pneumocystography. Of 186 cysts, 104 (55.9%) were type I, 49 (26.4%) were type II, and 33 (17.7%) were type III. Among the risk factors we considered, only the premenopausal state (41 to 45 years of age) exhibited a statistically significant correlation with the presence of type I cysts. The morphological study of the cysts after pneumocystography showed a surprisingly high correlation between the honeycomb pattern and type I cysts. The constant correlation between cyst morphology and electrolytic content may allow the easy identification of the subgroups of patients eligible for a closer follow-up.

Anion-induced dynamic behavior of apical water channels in vasopressin-sensitive epithelia exposed to mercury

We showed recently that, in toad skins preexposed to Hg, water permeability is high in SO4-Ringer and low in Cl-Ringer. This anion effect was further investigated in Hg-treated skins and bladders of toads (Bufo marinus) in a variety of experimental conditions, including glutaraldehyde fixation and stimulation by vasopressin (VP) or isoproterenol (IP). In fixed bladders either unstimulated or stimulated with VP, net water flow (Jw) in SO4-Ringer [Jw (SO4)] was always significantly higher than Jw in Cl [Jw (Cl)]; the same applies to fixed toad skins, either unstimulated or stimulated with IP. In unfixed isolated toad epidermis challenged with IP before Hg exposure, Jw(SO4)/Jw(Cl) >> 1 approaching the ratio Jw (maximally stimulated)/Jw (basal). Therefore, anion-induced Jw changes were present whether Hg acted on epithelial water channels exocytosed by Hg itself or by hydrosomotic agents and suggest a switching between open and closed configurations of the channel protein. This anion effect was not abolished by glutaraldehyde and might be correlated with changes in intracellular chloride.

Mercury blockage of apical water channels in toad skin (Bufo marinus)

1. Net water flow (Jw) was continuously monitored across the abdominal skin of the toad Bufo marinus by means of a volumetric, automatic technique. Jw was either averaged over periods of 2 min or taken cumulatively (10 or 30 min periods). 2. The state of high water permeability induced by vasopressin or isoprenaline was reversed (88-89% inhibition of delta Jw after 1 h) by the addition of 10(-3) M HgCl2 (or CH3ClHg) to the external bathing medium. Similarly, pre-exposure of the skins to Hg2+, totally blocked the induction of the hydrosmotic response to the same agents. By itself, Hg2+ exerted only a minor (26%) stimulation of basal Jw. 3. There was a sigmoidal dose-response relationship between the reduction of the hydrosmotic effect of vasopressin (VP) and the concentration of Hg2+ in the external medium, with a half-maximal effect at 1.2 x 10(-4) M HgCl2. 4. Total replacement of Na+ by K+, Rb+ or Cs+ in the Ringer solution, caused a VP-like, hydrosmotic effect that was reversed, or prevented, by exposure to Hg2+ in a manner indistinguishable from that previously seen with vasopressin or isoprenaline. 5. The data point to the presence of a Hg(2+)-sensitive apical water pathway in stimulated epithelia, very probably constituted by water channels similar to those reported in red blood cells, amphibian bladder and mammalian kidney tubules.

Effects of anions and/or cell volume on the permeance of an apical water pathway induced by Hg in toad skin epithelium

Hg compounds block membrane transport units behaving as water channels. Here we show that Hg induces an apical water pathway in toad skins pretreated with 10(-3) M CH3ClHg or HgCl2, added to the outer bathing medium. Washing with SO4-Ringer caused a several-fold increase in net water flow (Jw) and osmotic permeability coefficient (Pf) that was reversed by re-exposure to Cl- or NO3-Ringer and mimicked by gluconate-Ringer. These Pf changes could be elicited repeatedly and were present if, and only if, anion replacements took place in the inner bathing solution. Such inner polarity was related to the anion permeability of the epidermal basolateral membrane: impermeant anions (SO4, gluconate) increased Pf; permeant anions (Cl, NO3) did not change basal Pf but reversed the high Pf induced by impermeant anions. Hg induced the appearance of aggregates that persisted despite repeated washings of the skins during 4-5 h, and whether Pf was high (SO4-Ringer) or low (Cl-Ringer) before skin fixation. The Hg-induced apical water pathway in toad skin appears to be a unique model for studying the interplay between cell volume, cell ionic composition and water permeability.

The growth response of the green alga Chlorella vulgaris to combined divalent cation exposure

Using the growth response of the green alga Chlorella vulgaris as a model system, the effects of combinations of the environmentally active cations Cd, Co, and Cu were evaluated. The 96-h static EC50 for these cations to C. vulgaris were, respectively, 0.89 microM, 9.0 microM, and 2.8 microM, yielding a toxicity series such that Cd > Cu > Co. The cation combinations of Cd + Cu, and Cu + Co acted synergistically, while Cd + Co, and the tri-metallic combination Cd + Cu + Co resulted in antagonistic interactions. Examination of these toxic combinations at 24, 48, 72, and 96 h indicate that the cellular response is not a uniform one. Failure of energy dispersive X-ray spectrophotometric analysis to demonstrate any intracellular incorporation of these cations (except for a weak cytoplasmic Cu peak at the 8.0 KEV position) suggests that the toxic actions of these cations at EC50 concentrations are exerted at the level of the plasma membrane.