Avoiding falsely low creatinine concentrations measured in patients treated with N-acetylcysteine for acetaminophen intoxication using enzymo-amperometric method - An in vitro and in vivo study

BACKGROUND

Circulating creatinine is a biomarker of paramount importance in clinical practice. In cases of acetaminophen (APAP) intoxication, the antidote, N-acetylcysteine (NAC), interferes with commonly used creatininase-peroxidase methods. This study aimed to assess whether creatininase-amperometric methods were affected in this context.

METHODS

This study includes in vitro interference tests, involving four creatinine assays using NAC-spiked plasma pools and an in vivo retrospective study comparing creatininase-peroxidase and creatininase-amperometric measurements in patients presenting with NAC-treated APAP poisoning.

RESULTS

Creatininase-peroxidase method was impacted by NAC interference in a clinically-significant manner at therapeutic NAC levels (basal value recovery of 80 % and 70 % for 500 and 1000 mg.L-1 of NAC, respectively), surpassing the desirable Reference Change Value (RCV%). Enzymo-amperometric methods were not impacted. Among patients, a mean bias of -45.2 ± 28.0 % was observed for the peroxidase detection method compared to the amperometric in those who received NAC prior plasma sampling and -2.7 ± 5.4 % in those who did not.

CONCLUSIONS

Our findings indicate that enzymo-amperometric creatinine assays remain unaffected by NAC interference due to the absence of the peroxidase step in the analytical process. Therefore, these methods are suitable to prevent spurious hypocreatininemia in APAP intoxicated patients undergoing NAC therapy.

Early detection of plasma d-lactate: Toward a new highly-specific biomarker of bacteraemia?

Background

Bloodstream infections are a leading cause of mortality. Their detection relies on blood cultures (BCs) but time to positivity is often between tens of hours and days. d-lactate is a metabolite widely produced by bacteria but very few in human. We aimed to evaluate d-lactate, d-lactate/l-lactate ratio and d-lactate/total lactate ratio in plasma as potential early biomarkers of bacteraemia on a strictly biological standpoint.

Methods

A total of 228 plasma specimens were collected from patients who had confirmed bacteraemia (n = 131) and healthy outpatients (n = 97). Specific l-lactate and d-lactate analyses were performed using enzymatic assays and analytical performances of d-lactate, d-lactate/total lactate and d-lactate/l-lactate ratios for the diagnosis of bacteraemia were assessed.

Results

A preliminary in vitro study confirmed that all strains of Escherichia coli, Klebsiella pneumoniae and Staphylococcus aureus were able to produce d-lactate at significant levels. In patients, plasma d-lactate level was the most specific biomarker predicting a bacteraemia profile with a specificity and predictive positive value of 100% using a cut-off of 131 μmol.L^-1. However, sensitivity and negative predictive value were rather low, estimated at 31% and 52%, respectively. d-lactate displayed an Area Under Receiver Operating Characteristic (AUROC) curve of 0.696 with a P value < 0.0001. There was no difference of d-lactate levels between BCs bottles positive for Gram-positive or Gram-negative bacteria (p = 0.55).

Conclusion

d-lactate shows promise as a specific early biomarker of bacterial metabolism. The development of rapid automated assays could raise clinical applications for infectious diseases diagnosis including early bacteraemia prediction.

Nurses' perception on social network of children with chronic illness: qualitative study, Brazil

Introduction

The high prevalence of chronic diseases in childhood is a serious public health problem in Brazil. The family life of children with chronic illness is marked by numerous determinant and conditioning factors, whether they are biological, psychological, cultural and social. Such factors are more relevant in the absence of a social support network for care. Therefore, the greater the support offered by health professionals, the greater the resources available for the family to face vulnerability.

Objectives

describing primary care nurses' perception of the social network approach for children with chronic diseases.

Methods

Qualitative research conducted in October 2019 through an interview with ten nurses from family health units in the city of Rio de Janeiro, Brazil. The project was approved by the Ethics and Research Committees of the participating institutions. Thematic content analysis was used.

Results

For nurses, social network meant support from family members and from secondary and tertiary level services. In their practice, these professionals are often unaware of the health situation of children with chronic diseases, and they perceive lack of articulation in referral those children to other services of the Health Care Network.

Conclusions

There are gaps between knowledge and practice of these professionals on the social network approach. It is important to highlight frailties in comprehensive care of children with chronic illness and the service counter-referral to the family health unit. It is necessary to carry out training courses for professionals, helping them to belong to the social network of the family of the child with chronic disease. This strategy could implement effective approach of support, surveillance and health promotion of children.

Key messages

There is a gap in the knowledge of social network approach among primary care nurses. The social network approach of children with chronic diseases favors comprehensive care and implementation of effective strategies focused on supporting, monitoring and promoting child health.

Doubling immunochemistry laboratory testing efficiency with the cobas e 801 module while maintaining consistency in analytical performance

OBJECTIVES

The new immunochemistry cobas e 801 module (Roche Diagnostics) was developed to meet increasing demands on routine laboratories to further improve testing efficiency, while maintaining high quality and reliable data.

DESIGN AND METHODS

During a non-interventional multicenter evaluation study, the overall performance, functionality and reliability of the new module was investigated under routine-like conditions. It was tested as a dedicated immunochemistry system at four sites and as a consolidator combined with clinical chemistry at three sites.

RESULTS

We report on testing efficiency and analytical performance of the new module. Evaluation of sample workloads with site-specific routine request patterns demonstrated increased speed and almost doubled throughput (maximal 300 tests per h), thus revealing that one cobas e 801 module can replace two cobas e 602 modules while saving up to 44% floor space. Result stability was demonstrated by QC analysis per assay throughout the study. Precision testing over 21 days yielded excellent results within and between labs, and, method comparison performed versus the cobas e 602 module routine results showed high consistency of results for all assays under study. In a practicability assessment related to performance and handling, 99% of graded features met (44%) or even exceeded (55%) laboratory expectations, with enhanced reagent management and loading during operation being highlighted.

CONCLUSION

By nearly doubling immunochemistry testing efficiency on the same footprint as a cobas e 602 module, the new module has a great potential to further consolidate and enhance laboratory testing while maintaining high quality analytical performance with Roche platforms.

Bioinformatic software for cerebrospinal fluid spectrophotometry in suspected subarachnoid haemorrhage

Background

Diagnosis of subarachnoid haemorrhage (SAH) is firstly based on imaging and secondly on spectrophotometry. Bilirubin may be detected in the cerebrospinal fluid (CSF) for up to two weeks after SAH. CSF pigment analysis is commonly performed according to the Chalmers manual technique but may be prone to operator error. We propose an online software solution, based on the United Kingdom National External Quality Assessment Service (UKNEQAS) recommendations, to support the interpretation of CSF pigment analysis.

Methods

Based on the manual Chalmers technique, we have developed a web application (in Personal Home Page language including JpGraph module and an Oracle database®) that enables the calculation of net oxyhaemoglobin absorbance and net bilirubin absorbance. It uses data from the CSF spectrophotometry, CSF and serum protein concentrations, and serum bilirubin concentration to provide an interpretation based on the NEQAS decision tree. The application was retrospectively validated using the spectra from 350 patients, previously analysed by the manual method.

Results

In total, 91.1% interpretations from spectra analysed with the web application were in accordance with the results obtained manually. The 8.9% discordant results were mostly related to an incorrect interpretation using the manual technique.

Conclusions

The software developed in our laboratory to interpret CSF pigment analysis results is a precise, robust and useful tool that allows reproducible conclusions to be drawn. This software is available through a web interface.

[The neutrophil gelatinase-associated lipocalin, or LCN 2, marker of aggressiveness in clear cell renal cell carcinoma]

OBJECTIVE

To determine the prognostic significance of the neutrophil gelatinase-associated lipocalin (NGAL) and the matrix metalloproteinase 9 (MMP-9) in clear cell renal cell carcinoma (CCRCC).

PATIENTS AND METHODS

NGAL and MMP-9 expression were quantified by immunohistochemistry in clear renal cell carcinoma tissues and in sera by Enzyme Linked Immunosorbent Assay (Elisa). Results were associated with clinicopathologic data.

RESULTS

Seventy-four patients operated for CCRCC in Rennes between 2003 and 2009 were included. High concentrations of NGAL-MMP-9 complex in serum were associated with short progression free survival (PFS) (33.3 months versus 47.3 months, P=0.016) and poor overall survival (42.5 months versus 51.9 months, P<0.047). High NGAL concentrations in serum were also associated with shorter PFS (13.6 months versus 41.6 months, P=0.04). However, no NGAL expression was observed in renal tumor cells. Interestingly, NGAL was expressed by neutrophils infiltrating CCRCC and we showed that the density of NGAL expressing neutrophils was associated with pejorative PFS and survival (36.9months versus 56.1 months, P<0.006).

CONCLUSION

In this study, we showed the pejorative significance of NGAL-MMP-9 complex and NGAL rates in serum of CCRCC. We also confirmed that density of NGAL expressing neutrophils in CCRCC was associated with poor outcome.

PPARγ is functionally expressed in clear cell renal cell carcinoma

Peroxisome proliferator-activated receptor gamma (PPARγ) agonists have been demonstrated to exert an inhibitory effect on cell growth in several tumor models, including clear cell renal cell carcinoma (CCRCC). PPARγ has therefore been proposed to be a potential therapeutic target. Thus, the PPARγ gene must be expressed and not altered in cancer cells. We have therefore analyzed tumor specimens collected from 63 patients with CCRCC who underwent partial or total nephrectomy. The multiplex ligation-dependent probe amplification (MLPA) assay was used to detect deletions in the PPARγ gene. The majority of the tumors (48/63; 76.2%) did not present alterations. Two samples (3.2%) presented a deletion of the non-coding exon A1. Nine samples (14.3%) showed large heterozygous deletions in chromosome 3p including PPARγ. Potential mutations were analyzed by DNA sequencing of the 6 coding exons of the PPARγ gene. No mutation was found in exons 1-5. In exon 6, a silent polymorphism was detected in 14 samples (22.2%). CCRCC were found to express the PPARγ1 isoform. The expression level of PPARγ was measured by real-time quantitative PCR. A significantly reduced transcript level was associated with an elevated Fuhrman grade. Finally, we analyzed the expression of angiopoietin-like 4, a known PPARγ target gene, in CCRCC cell lines cultured in the presence of rosiglitazone, a PPARγ agonist. A strong induction was found in the 3 cell lines tested, indicating that PPARγ is functional in all these cell lines. In conclusion, we show here that PPARγ is expressed and functional in CCRCC, prerequisites for being a potential target for CCRCC treatment.

Determination of daptomycin in human plasma by liquid chromatography-tandem mass spectrometry. Clinical application

BACKGROUND

Daptomycin is a recently developed cyclic lipopeptide antibiotic active against most Gram-positive pathogens including vancomycin-resistant enterococci and methicillin-resistant Staphylococcus aureus. To optimize treatment efficacy and safety, especially in patients undergoing multiple drug regimens and/or co-morbidities, a specific liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed for the quantification of daptomycin in plasma.

METHODS

A C18 column was used for separation, with a mobile phase initially consisting of 0.1% formic acid, water, and acetonitrile (ACN) in a linear gradient from 20% to 70%. After protein precipitation with ACN, the clear upper layer was diluted in water:ACN (50:50, v/v) before injection. Detection was performed using an electrospray ionization technique. MS/MS transitions, monitored in the positive ion mode were m/z 811.1 → m/z 313.1 for daptomycin, and m/z 609.4 → m/z 194.9 for reserpine, used as internal standard.

RESULTS

Elution of daptomycin and reserpine occurred at 4.5 and 3.9 min, respectively. The method was validated over a range of concentrations from 1 mg/L to 120 mg/L. The assay met recommended acceptance criteria: coefficients of variation were <6.3% and <7.4%, and accuracies were between -5.9% and +11.2% and between -3.5% and +3.7%, for intra- and inter-day validations, respectively.

CONCLUSIONS

This method appears well-adapted to routine hospital practice for therapeutic drug monitoring of daptomycin considering its time of analysis, range of concentrations measured, precision and accuracy.

Absence of VHL gene alteration and high VEGF expression are associated with tumour aggressiveness and poor survival of renal-cell carcinoma

Background:

The von Hippel–Lindau gene (VHL) alteration, a common event in sporadic clear-cell renal-cell carcinoma (CCRCC), leads to highly vascularised tumours. Vascular endothelial growth factor (VEGF) is the major factor involved in angiogenesis, but the prognostic significance of both VHL inactivation and VEGF expression remain controversial. The aims of this study were to analyse the relationship between VHL genetic and epigenetic alterations, VHL expression and VEGF tumour or plasma expression, and to analyse their respective prognostic value in patients with CCRCC.

Methods:

A total of 102 patients with CCRCC were prospectively analysed. Alterations in VHL were determined by sequencing, Multiplex Ligation-dependent Probe Amplification (MLPA) and methylation-specific MLPA. Expression of pVHL and VEGF was determined by immunohistochemistry. Plasma VEGF was measured by enzyme-linked immunosorbent assay (ELISA).

Results:

VHL mutation, deletion and promoter methylation were identified in 70, 76 and 14 cases, respectively. Overall, at least one VHL-gene alteration occurred in 91 cases (89.2%). Both VEGF tumour and plasma expression appeared to be decreased in case of VHL alteration. Median progression-free survival and CCRCC-specific survival were significantly reduced in patients with wild-type VHL or altered VHL and high VEGF expression, which, therefore, represent two markers of tumour aggressiveness in CCRCC.

Conclusion:

Stratifying CCRCCs according to VHL and VEGF status may help tailor therapeutic strategy.

[Pilot epidemiologic study of transmission of cytomegalovirus from mother to preterm infant by breastfeeding]

Transmission of cytomegalovirus (CMV) infection from mothers to preterm infants during breastfeeding may be symptomatic and long term consequences are unknown. This study evaluated the kinetics of CMV load in breastmilk and the rate of postnatal CMV transmission via breastmilk from mothers to their preterm infants.

METHODS

Prospective study of mother-child pairs after preterm delivery before 33 weeks. Exclusion of donor breast milk and of CMV-seropositive blood products. Material used was maternal CMV serostatus, ear swab of the infant at birth, weekly screened breast milk and children's urine by rapid viral culture.

RESULTS

During a 5-month period 28 mother-infant pairs with 34 preterm infants were studied. Eighteen women (64.3%) were CMV-seronegative at birth; breastmilk samples and the infants' urine remained CMV-negative. Eight of the 10 seropositive mothers, who had 11 preterm infants, excreted CMV into breast milk (80%). CMV excretion into breast milk was detected during the first week after delivery in 66% cases and was at its peaked between 3 to 5 weeks after delivery. Out of the 7 CMV-exposed infants, CMV transmission was confirmed in only one asymptomatic case. Total quantity of breast milk intake did not seem discriminative for CMV transmission.

CONCLUSION

In CMV-seropositive mothers of preterm infants a high incidence of CMV excretion into breast milk was detected. Despite this high rate, symptomatic infection did not occur. However, potential risk and severity of infection may be difficult to establish. Because breastfeeding is beneficial, new procedures for gentle virus inactivation of seropositive breast milk should be assessed.

[Methodological issues of health research]

This work aims at presenting a reflection on the method of research in the health field. Some questions are presented which involve the use of the method of natural sciences and that of social sciences in an attempt at understanding some methodological problems concerning the former and the latter. Problems related to the methodological issues in the elaboration of investigation projects in this field and the need for continuous discussion are pointed out as to: the differentiation of the nature of the object of investigation; the context in which a determined problem is identified; the type of question which is asked when it is problematized; technical procedures, the theory and the interpretative scheme on which it is founded; the dichotomy concerning the subject/object of knowledge; the researcher's neutrality; the concept of casualty.

[Interprofessional and interinstitutional relations of power at a hospital]

The purpose of this article is to make a critical analysis about power relationships, which permeate daily professional and/or institutional actions in the hospital environment. This reflection is based on a concrete situation experienced by a group of nursing professors from a state university in Paraná, which unleashed conflicts concerning interprofessional and interinstitutional power relationships. This study focuses on power relationships in the hospital emphasizing the interrelations that characterize nursing practice. We believe that these relationships can only be understood, reflected upon and rebuilt in the context of daily practice, as new ways of collective action are sought.

[Nursing research: progress and challenges]

The objective of this study is to reflect on the organization and development of nursing research in Brazil, pointing out some knowledge advances and limits until the moment, as well as indicating some of the challenges for the research in nursing. One of these challenges would be establishing the relation between nursing and care.

[Hospitalized children: mothers' perception of the affective bond between child and family]

This purpose of this research was to verify the perception of the mother who has her child sick and hospitalized, about the importance of her permanence during the hospitalization time for the maintenance of the affective child-family link. Empiric data were collected with mother's of hospitalized children, who were accompanying the hospitalization of their children in a public hospital at the Cascavel city in the West of Paraná, Brazil, through semi-structured interviews. The analysis of these data demonstrated that the mothers recognize the importance of staying with their children in such a stress time like the hospitalization time, however, the external facts that influence their daily life, often do not allow them to stay with their children.

[Care-research interface in nursing]

In this study, the authors have as a goal to discuss the care-investigation interface in the caring practice of Nursing in the hospital ambit, starting from their professional experiences. The bases of the discussion is the career/cared being. We surpass care as the object of research and the importance of investigation for the improvement of care quality. Interdisciplinarity is pointed out as one of the possible resources for the construction of integral care and of a therapeutical action that exceeds the biological, in a perspective of co-participation, as well as the need of promoting and stimulating the accomplishment of investigations in the units of hospital care. The meaning of the investigation about care goes beyond its internality, requiring technical competence, ethical compromise and coherence among the different areas of knowledge which involves it. We enlighten the need of overcoming the dichotomies of caring/investigating, researching while caring, and caring while researching. We stress out the importance of creating research groups in Universities; the stimulus to the accomplishment of graduation courses with leave-out time from work; the availability of financial resources; and the incentive to subscribe periodicals and to acquire books.

[Dialectic hermeneutics: a way of thinking in nursing research]

This paper is a theoretical study about dialectic and hermeneutics union and the possibility of its application as a "way of thinking" in nursing research. For this, we retake its origin and discussion at the present time, as well as the theoretical postulates that gives it foundation, looking forward on expanding the horizons in nursing investigation.

[Nurses' aides and the practice of nursing research: study of a reality in hospitals]

The present study aims at demonstrating the situation of nurses of a particular hospital institution with respect to nursing research, focusing their previous and actual research, the limited and favourable elements to elaborate scientific works and the meaning of research to nursing, according to this study participant's opinion. The data collection were made through questionnaire and semi-structured interview.

[Philosophy of nursing education. Various considerations]

The study has objective to promote a reflection about the importance of philosophy for nurse's formation. For this purpose, we search of questions in the literature that could give foundations about the theme, focusing on the importance for scientific nursing research.

[Public health nursing, pedagogical and agricultural advice in a rural community of landless settled people: report of an experience]

O estudo relata uma experiência no acompanhamento de Enfermagem, assessoramento pedagógico e agrícola desenvolvido em uma comunidade de assentados sem-terra na zona rural da cidade de Cascavel, estado do Paraná, que teve como premissa básica a integração docente/discente, oferecendo oportunidade de socialização do saber, integração teoria e prática e contato direto com a comunidade. Aponta para a necessidade da enfermagem compreender melhor este tipo de realidade buscando, através da observação e vivência, uma visão crítica com possibilidades de intervenção.

[Reflections on a controversial topic: nursing ethics]

The present study does a reflection on the ethics in nursing, considering the context in which it is introduced. The authors approaches it in a broad manner and its historic evolution, going through a discussion inside the health care area, until the nursing related questions emerged, establishing relations between them. The questions and the doubts, much more than answers, are the focus of this study, whose main concern is to contribute to nurse's critical thought necessary to the effective practice of the profession.

[Teacher-student communication across the Tizadora pedagogical problem]

Report of experience in the use of a social-cultural approach during the development of a work done by graduate students of Ribeiräo Preto School of Nursing-USP. As a form of reference for the didactic strategy, it was used the scheme of arch proposed by Charles Maguerez and presented by BORDENAVE, in an attempt to systematize the communication teacher-student talking about "Aspects related to the Undergraduate Teaching Problems".