Clinical Outcomes of Third-Generation Cephalosporin Definitive Therapy for Bloodstream Infections Due to Enterobacterales with Potential AmpC Induction: A Single-Center Retrospective Study

The recommended therapy for severe infections caused by AmpC-inducible Enterobacterales (AmpC-E) typically involves cefepime or carbapenems. In an era of emerging resistance to these antimicrobials, we aim to assess the impact of third-generation cephalosporins (3GCs) vs. alternative antibiotics on clinical outcomes in bloodstream infections (BSIs) due to AmpC-E. We retrospectively included hospitalized adult patients with BSIs caused by 3GC-susceptible AmpC-E between 2012 and 2022, comparing the outcomes of 3GC and non-3GC definitive therapies. The primary outcome was overall treatment failure (OTF), encompassing 90-day all-cause mortality, 90-day reinfection, and 90-day readmission. Secondary outcomes comprised components of the OTF, in-hospital all-cause mortality, and length-of-stay. Within a total cohort of 353 patients, OTF occurred in 46.5% and 41.5% in the 3GC- and non-3GC-therapy groups, respectively (p = 0.36). The 3GC-therapy group exhibited a longer length-of-stay (38 vs. 21 days, p = 0.0003) and higher in-hospital mortality (23.3% vs. 13.4%, p = 0.019). However, the 90-day mortality, 90-day reinfection, and 90-day readmission were comparable between the therapy groups. Subgroup analyses involving high-risk AmpC-E and 3GC vs. standard-of-care yielded similar conclusions. Overall, our findings suggest that 3GC definitive therapy may not result in poorer clinical outcomes for the treatment of BSIs caused by AmpC-E.

Airflow obstruction as a marker of adverse prognosis in rheumatoid arthritis

Objectives

In our study, we explored the specific subgroup of patients with rheumatoid arthritis (RA) suffering from obstructive lung disease (OLD) and its impact on morbi-mortality.

Methods

Our retrospective study included 309 patients suffering from RA with either obstructive (O-RA) or non-obstructive patterns (non-O-RA). OLD was defined based on the Tiffeneau index at the first available pulmonary functional test (PFT). Survival was then calculated and represented by a Kaplan–Meier curve. The comparison between the populations considered was performed by the Log-Rank test.

Results

Out of the 309 RA patients, 102 (33%) had airway obstruction. The overall survival time was significantly lower in the O-RA group than in the non-O-RA group (n = 207) (p < 0.001). The median survival time was 11.75 years in the O-RA group and higher than 16 years in the non-O-RA group. Multivariate analysis identified OLD as an independent risk factor for mortality (HR 2.20; 95% CI 1.21–4.00, p < 0.01).

Conclusion

Airway obstruction can be an independent risk factor of mortality in RA and should be considered as an early marker of poor prognosis. Further prospective longitudinal studies are required in order to determine the best clinical management for O-RA patients.

Progressive fibrosing interstitial lung disease in rheumatoid arthritis: A retrospective study

BACKGROUND AND OBJECTIVE

Rheumatoid arthritis associated-interstitial lung disease (RA-ILD) is the most common pulmonary manifestation of rheumatoid arthritis (RA) and an important cause of mortality. In patients suffering from interstitial lung diseases (ILD) from different etiologies (including RA-ILD), a significant proportion is exhibiting a fibrotic progression despite immunosuppressive therapies, defined as progressive fibrosing interstitial lung disease (PF-ILD). Here, we report the frequency of RA-ILD and PF-ILD in all RA patients' cohort at University Hospital of Liège and compare their characteristics and outcomes.

METHODS

Patients were retrospectively recruited from 2010 to 2020. PF-ILD was defined based on functional, clinical and/or iconographic progression criteria within 24 months despite specific anti-RA treatment.

RESULTS

Out of 1,500 RA patients, about one third had high-resolution computed tomography (HRCT) performed, 89 showed RA-ILD and 48 PF-ILD. RA-ILD patients were significantly older than other RA patients (71 old of median age vs. 65, p < 0.0001), with a greater proportion of men (46.1 vs. 27.7%, p < 0.0001) and of smoking history. Non-specific interstitial pneumonia pattern was more frequent than usual interstitial pneumonia among RA-ILD (60.7 vs. 27.0%) and PF-ILD groups (60.4 vs. 31.2%). The risk of death was 2 times higher in RA-ILD patients [hazard ratio 2.03 (95% confidence interval 1.15-3.57), p < 0.01] compared to RA.

CONCLUSION

We identified a prevalence of PF-ILD of 3% in a general RA population. The PF-ILD cohort did not seem to be different in terms of demographic characteristics and mortality compared to RA-ILD patients who did not exhibit the progressive phenotype yet.

Increased KL-6 levels in moderate to severe COVID-19 infection

BACKGROUND

The global coronavirus disease 2019 (COVID-19) has presented significant challenges and created concerns worldwide. Besides, patients who have experienced a SARS-CoV-2 infection could present post-viral complications that can ultimately lead to pulmonary fibrosis. Serum levels of Krebs von den Lungen 6 (KL-6), high molecular weight human MUC1 mucin, are increased in the most patients with various interstitial lung damage. Since its production is raised during epithelial damages, KL-6 could be a helpful non-invasive marker to monitor COVID-19 infection and predict post-infection sequelae.

METHODS

We retrospectively evaluated KL-6 levels of 222 COVID-19 infected patients and 70 healthy control. Serum KL-6, fibrinogen, lactate dehydrogenase (LDH), platelet-lymphocytes ratio (PLR) levels and other biological parameters were analyzed. This retrospective study also characterized the relationships between serum KL-6 levels and pulmonary function variables.

RESULTS

Our results showed that serum KL-6 levels in COVID-19 patients were increased compared to healthy subjects (470 U/ml vs 254 U/ml, P <0.00001). ROC curve analysis enabled us to identify that KL-6 > 453.5 U/ml was associated with COVID-19 (AUC = 0.8415, P < 0.0001). KL-6 level was positively correlated with other indicators of disease severity such as fibrinogen level (r = 0.1475, P = 0.0287), LDH level (r = 0,31, P = 0,004) and PLR level (r = 0.23, P = 0.0005). However, KL-6 levels were not correlated with pulmonary function tests (r = 0.04, P = 0.69).

CONCLUSIONS

KL-6 expression was correlated with several disease severity indicators. However, the association between mortality and long-term follow-up outcomes needs further investigation. More extensive trials are required to prove that KL-6 could be a marker of disease severity in COVID-19 infection.

Automatized lung disease quantification in patients with COVID-19 as a predictive tool to assess hospitalization severity

The pandemic of COVID-19 led to a dramatic situation in hospitals, where staff had to deal with a huge number of patients in respiratory distress. To alleviate the workload of radiologists, we implemented an artificial intelligence (AI) - based analysis named CACOVID-CT, to automatically assess disease severity on chest CT scans obtained from those patients. We retrospectively studied CT scans obtained from 476 patients admitted at the University Hospital of Liege with a COVID-19 disease. We quantified the percentage of COVID-19 affected lung area (% AA) and the CT severity score (total CT-SS). These quantitative measurements were used to investigate the overall prognosis and patient outcome: hospital length of stay (LOS), ICU admission, ICU LOS, mechanical ventilation, and in-hospital death. Both CT-SS and % AA were highly correlated with the hospital LOS, the risk of ICU admission, the risk of mechanical ventilation and the risk of in-hospital death. Thus, CAD4COVID-CT analysis proved to be a useful tool in detecting patients with higher hospitalization severity risk. It will help for management of the patients flow. The software measured the extent of lung damage with great efficiency, thus relieving the workload of radiologists.

Bone Marrow-Derived Mesenchymal Stromal Cell Therapy in Severe COVID-19: Preliminary Results of a Phase I/II Clinical Trial

Background

Treatment of acute respiratory distress syndrome (ARDS) associated with COronaVIrus Disease-2019 (COVID-19) currently relies on dexamethasone and supportive mechanical ventilation, and remains associated with high mortality. Given their ability to limit inflammation, induce immune cells into a regulatory phenotype and stimulate tissue repair, mesenchymal stromal cells (MSCs) represent a promising therapy for severe and critical COVID-19 disease, which is associated with an uncontrolled immune-mediated inflammatory response.

Methods

In this phase I-II trial, we aimed to evaluate the safety and efficacy of 3 intravenous infusions of bone marrow (BM)-derived MSCs at 3-day intervals in patients with severe COVID-19. All patients also received dexamethasone and standard supportive therapy. Between June 2020 and September 2021, 8 intensive care unit patients requiring supplemental oxygen (high-flow nasal oxygen in 7 patients, invasive mechanical ventilation in 1 patient) were treated with BM-MSCs. We retrospectively compared the outcomes of these MSC-treated patients with those of 24 matched control patients. Groups were compared by paired statistical tests.

Results

MSC infusions were well tolerated, and no adverse effect related to MSC infusions were reported (one patient had an ischemic stroke related to aortic endocarditis). Overall, 3 patients required invasive mechanical ventilation, including one who required extracorporeal membrane oxygenation, but all patients ultimately had a favorable outcome. Survival was significantly higher in the MSC group, both at 28 and 60 days (100% vs 79.2%, p = 0.025 and 100% vs 70.8%, p = 0.0082, respectively), while no significant difference was observed in the need for mechanical ventilation nor in the number of invasive ventilation-free days, high flow nasal oxygenation-free days, oxygen support-free days and ICU-free days. MSC-treated patients also had a significantly lower day-7 D-dimer value compared to control patients (median 821.0 µg/L [IQR 362.0-1305.0] vs 3553 µg/L [IQR 1155.0-6433.5], p = 0.0085).

Conclusions

BM-MSC therapy is safe and shows very promising efficacy in severe COVID-19, with a higher survival in our MSC cohort compared to matched control patients. These observations need to be confirmed in a randomized controlled trial designed to demonstrate the efficacy of BM-MSCs in COVID-19 ARDS.

Clinical Trial Registration

(www.ClinicalTrials.gov), identifier NCT04445454

The Role of Imaging in the Detection of Non-COVID-19 Pathologies during the Massive Screening of the First Pandemic Wave

During the COVID-19 pandemic induced by the SARS-CoV-2, numerous chest scans were carried out in order to establish the diagnosis, quantify the extension of lesions but also identify the occurrence of potential pulmonary embolisms. In this perspective, the performed chest scans provided a varied database for a retrospective analysis of non-COVID-19 chest pathologies discovered de novo. The fortuitous discovery of de novo non-COVID-19 lesions was generally not detected by the automated systems for COVID-19 pneumonia developed in parallel during the pandemic and was thus identified on chest CT by the radiologist. The objective is to use the study of the occurrence of non-COVID-19-related chest abnormalities (known and unknown) in a large cohort of patients having suffered from confirmed COVID-19 infection and statistically correlate the clinical data and the occurrence of these abnormalities in order to assess the potential of increased early detection of lesions/alterations. This study was performed on a group of 362 COVID-19-positive patients who were prescribed a CT scan in order to diagnose and predict COVID-19-associated lung disease. Statistical analysis using mean, standard deviation (SD) or median and interquartile range (IQR), logistic regression models and linear regression models were used for data analysis. Results were considered significant at the 5% critical level (p < 0.05). These de novo non-COVID-19 thoracic lesions detected on chest CT showed a significant prevalence in cardiovascular pathologies, with calcifying atheromatous anomalies approaching nearly 35.4% in patients over 65 years of age. The detection of non-COVID-19 pathologies was mostly already known, except for suspicious nodule, thyroid goiter and the ascending thoracic aortic aneurysm. The presence of vertebral compression or signs of pulmonary fibrosis has shown a significant impact on inpatient length of stay. The characteristics of the patients in this sample, both from a demographic and a tomodensitometric point of view on non-COVID-19 pathologies, influenced the length of hospital stay as well as the risk of intra-hospital death. This retrospective study showed that the potential importance of the detection of these non-COVID-19 lesions by the radiologist was essential in the management and the intra-hospital course of the patients.

Combined obstructive airflow limitation associated with interstitial lung diseases (O-ILD): the bad phenotype ?

Background

Patients suffering from combined obstructive and interstitial lung disease (O-ILD) represent a pathological entity which still has to be well clinically described. The aim of this descriptive and explorative study was to describe the phenotype and functional characteristics of a cohort of patients suffering from functional obstruction in a population of ILD patients in order to raise the need of dedicated prospective observational studies and the evaluation of the impact of anti-fibrotic therapies.

Methods

The current authors conducted a retrospective study including 557 ILD patients, with either obstructive (O-ILD, n = 82) or non-obstructive (non O-ILD, n = 475) pattern. Patients included were mainly males (54%) with a mean age of 62 years.

Results

Patients with O-ILD exhibited a characteristic functional profile with reduced percent predicted forced expired volume in 1 s (FEV1) [65% (53–77) vs 83% (71–96), p < 0.00001], small airway involvement assessed by maximum expiratory flow (MEF) 25/75 [29% (20–41) vs 81% (64–108), p < 0.00001], reduced sGaw [60% (42–75) vs 87% (59–119), p < 0.01] and sub-normal functional residual capacity (FRC) [113% (93–134) vs 92% (75–109), p < 0.00001] with no impaired of carbon monoxide diffusing capacity of the lung (DLCO) compared to those without obstruction. Total lung capacity (TLC) was increased in O-ILD patients [93% (82–107) vs 79% (69–91), p < 0.00001]. Of interest, DLCO sharply dropped in O-ILD patients over a 5-year follow-up. We did not identify a significant increase in mortality in patients with O-ILD. Interestingly, the global mortality was increased in the specific sub-group of patients with O-ILD and no progressive fibrosing ILD phenotype and in those with connective tissue disease associated ILD especially in case of rheumatoid arthritis.

Conclusions

The authors individualized a specific functional-based pattern of ILD patients with obstructive lung disease, who are at risk of increased mortality and rapid DLCO decline over time. As classically those patients are excluded from clinical trials, a dedicated prospective study would be of interest in order to define more precisely treatment response of those patients.

Long-term clinical follow-up of patients suffering from moderate-to-severe COVID-19 infection: a monocentric prospective observational cohort study

Objectives

Various symptoms and considerable organ dysfunction persist following infection with severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). Uncertainty remains about the potential mid- and long-term health sequelae. This prospective study of patients hospitalized with coronavirus disease 2019 (COVID-19) in Liège University Hospital, Belgium aimed to determine the persistent consequences of COVID-19.

Methods

Patients admitted to the University Hospital of Liège with moderate-to-severe confirmed COVID-19, discharged between 2 March and 1 October 2020, were recruited prospectively. Follow-up at 3 and 6 months after hospital discharge included demographic and clinical data, biological data, pulmonary function tests (PFTs) and high-resolution computed tomography (CT) scans of the chest.

Results

In total, 199 individuals were included in the analysis. Most patients received oxygen supplementation (80.4%). Six months after discharge, 47% and 32% of patients still had exertional dyspnoea and fatigue. PFTs at 3-month follow-up revealed a reduced diffusion capacity of carbon monoxide (mean 71.6 ± 18.6%), and this increased significantly at 6-month follow-up (P<0.0001). Chest CT scans showed a high prevalence (68.9% of the cohort) of persistent abnormalities, mainly ground glass opacities. Duration of hospitalization, intensive care unit admission and mechanical ventilation were not associated with the persistence of symptoms 3 months after discharge.

Conclusion

The prevalence of persistent symptoms following hospitalization with COVID-19 is high and stable for up to 6 months after discharge. However, biological, functional and iconographic abnormalities improved significantly over time.

MO523PATIENTS FROM COVID-19 MOSTLY RECOVER FROM TUBULAR PROTEINURIA AND ACUTE KIDNEY INJURY AFTER HOSPITAL DISCHARGE

Background and Aims

Proteinuria, hematuria and acute kidney injury (AKI) are frequently observed in hospitalized patients with COVID-19. However, few data are available on these parameters after hospital discharge.

Method

This retrospective, observational and monocentric study included 153 hospitalized patients, in whom urine total proteinuria and α1-microglobulin (a marker of tubular injury) were measured. Thirty patients died. Among the 123 survivors, follow-up urine and creatinine analyses were available for 72 patients (after a median of 51 [19;93] days following hospital discharge).

Results

The median proteinuria at hospitalization and follow-up (n=72) was 419 [239; 748] and 79 [47; 129] mg/g, respectively (p&lt;0.0001). The median concentrations of urinary α1-microglobulin (n=66) were 50 [25; 81] and 8 [0; 19] mg/g, respectively (p&lt;0.0001). Estimating glomerular filtration rate (eGFR) was lower during the hospitalization compared to the follow-up: 81 [62; 92] versus 87 [66; 98] mL/min/1.73m² (p=0.0222). At follow-up, a decreased renal function was observed in 10/72 (14%) of patients, with 50% of them presenting decreased renal function before COVID-19 hospitalization and others developing severe AKI and/or proteinuria during hospitalization.

Conclusion

In most hospitalized patients with COVID-19, proteinuria and eGFR significantly improved after hospital discharge. Only patients who developed severe AKI and/or heavy proteinuria will require a specific follow-up by nephrologists.

Proteinuria in COVID-19: prevalence, characterization and prognostic role

BACKGROUND

Proteinuria has been commonly reported in patients with COVID-19. However, only dipstick tests have been frequently used thus far. Here, the quantification and characterization of proteinuria were investigated and their association with mortality was assessed.

METHODS

This retrospective, observational, single center study included 153 patients, hospitalized with COVID-19 between March 28th and April 30th, 2020, in whom total proteinuria and urinary α1-microglobulin (a marker of tubular injury) were measured. Association with mortality was evaluated, with a follow-up until May 7th, 2020.

RESULTS

According to the Kidney Disease Improving Global Outcomes staging, 14% (n = 21) of the patients had category 1 proteinuria (< 150 mg/g of urine creatinine), 42% (n = 64) had category 2 (between 150 and 500 mg/g) and 44% (n = 68) had category 3 proteinuria (over 500 mg/g). Urine α1-microglobulin concentration was higher than 15 mg/g in 89% of patients. After a median follow-up of 27 [14;30] days, the mortality rate reached 18%. Total proteinuria and urinary α1-microglobulin were associated with mortality in unadjusted and adjusted models. This association was stronger in subgroups of patients with normal renal function and without a urinary catheter.

CONCLUSIONS

Proteinuria is frequent in patients with COVID-19. Its characterization suggests a tubular origin, with increased urinary α1-microglobulin. Tubular proteinuria was associated with mortality in COVID-19 in our restropective, observational study.

Development and Validation of an Automated Radiomic CT Signature for Detecting COVID-19

The coronavirus disease 2019 (COVID-19) outbreak has reached pandemic status. Drastic measures of social distancing are enforced in society and healthcare systems are being pushed to and beyond their limits. To help in the fight against this threat on human health, a fully automated AI framework was developed to extract radiomics features from volumetric chest computed tomography (CT) exams. The detection model was developed on a dataset of 1381 patients (181 COVID-19 patients plus 1200 non COVID control patients). A second, independent dataset of 197 RT-PCR confirmed COVID-19 patients and 500 control patients was used to assess the performance of the model. Diagnostic performance was assessed by the area under the receiver operating characteristic curve (AUC). The model had an AUC of 0.882 (95% CI: 0.851-0.913) in the independent test dataset (641 patients). The optimal decision threshold, considering the cost of false negatives twice as high as the cost of false positives, resulted in an accuracy of 85.18%, a sensitivity of 69.52%, a specificity of 91.63%, a negative predictive value (NPV) of 94.46% and a positive predictive value (PPV) of 59.44%. Benchmarked against RT-PCR confirmed cases of COVID-19, our AI framework can accurately differentiate COVID-19 from routine clinical conditions in a fully automated fashion. Thus, providing rapid accurate diagnosis in patients suspected of COVID-19 infection, facilitating the timely implementation of isolation procedures and early intervention.

[Role of physical and rehabilitation medicine in the aftermath of SARS-CoV-2 disease]

2020 will be remembered as the year of SARS-CoV-2 pandemic which confined most of the world's population at home. Rehabilitation units will have to face specific challenges to protect the vulnerable in-patients. Moreover, they must prepare for post-COVID-19 patients who might suffer from illness consequences or present a post intensive care syndrome secondary to the increased ICU length of stay. The purpose of this paper is to highlight the deficiencies of post-COVID-19 patients and suggest a decision algorithm to best match their needs.

[The COVID-19 breaker : PCR to the rescue !]

Chronicle of a crisis management at the Clinical Microbiology Laboratory of CHU Liège The SARS-CoV-2 outbreak in December 2019 in China and its expansion across the world and Europe have requested the participation of clinical laboratories as major players in the diagnosis of COVID-19, to perform PCR tests mainly on nasopharyngeal swabs. In Belgium, the first confirmed COVID-19 patient was diagnosed in early February, the first of many, especially travelers returning from winter sports. In order to meet the ever-increasing demands for testing, the Clinical Microbiology Laboratory of the CHU of Liege had to adapt to this situation: firstly, by developing manual PCR tests and then automated solutions, permitting to increase the number of analyzes by ensuring a short turnaround time of results. Then, a system for the communication of results on a large scale has been set up, and finally solutions to deal with the lack of sampling devices have been found. This first wave of the pandemic has also highlighted an unprecedented solidarity within the institution. In this article, we recount the chronology of the management of this unprecedented health crisis within the Clinical Microbiology Laboratory of the CHU of Liege.

A snapshot of European neurosurgery December 2019 vs. March 2020: just before and during the Covid-19 pandemic

Background

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2 or Covid-19), which began as an epidemic in China and spread globally as a pandemic, has necessitated resource management to meet emergency needs of Covid-19 patients and other emergent cases. We have conducted a survey to analyze caseload and measures to adapt indications for a perception of crisis.

Methods

We constructed a questionnaire to survey a snapshot of neurosurgical activity, resources, and indications during 1 week with usual activity in December 2019 and 1 week during SARS-CoV-2 pandemic in March 2020. The questionnaire was sent to 34 neurosurgical departments in Europe; 25 departments returned responses within 5 days.

Results

We found unexpectedly large differences in resources and indications already before the pandemic. Differences were also large in how much practice and resources changed during the pandemic. Neurosurgical beds and neuro-intensive care beds were significantly decreased from December 2019 to March 2020. The utilization of resources decreased via less demand for care of brain injuries and subarachnoid hemorrhage, postponing surgery and changed surgical indications as a method of rationing resources. Twenty departments (80%) reduced activity extensively, and the same proportion stated that they were no longer able to provide care according to legitimate medical needs.

Conclusion

Neurosurgical centers responded swiftly and effectively to a sudden decrease of neurosurgical capacity due to relocation of resources to pandemic care. The pandemic led to rationing of neurosurgical care in 80% of responding centers. We saw a relation between resources before the pandemic and ability to uphold neurosurgical services. The observation of extensive differences of available beds provided an opportunity to show how resources that had been restricted already under normal conditions translated to rationing of care that may not be acceptable to the public of seemingly affluent European countries.

Electronic supplementary material

The online version of this article (10.1007/s00701-020-04482-8) contains supplementary material, which is available to authorized users.

The importance of adequate fixation for immunofluorescent staining of bovine embryos

Immunofluorescent staining is often used to investigate the expression of specific proteins in pre-implantation embryos. The success of this method is determined by the specificity of the antibodies, but also by the protocol used for fixation and permeabilization of the samples. In this study, different fixatives are compared in combination with immunofluorescent staining of caudal-type homeobox 2 (CDX2), fibronectin 1 (FN1) and integrins (ITGs) on bovine blastocysts. For both CDX2 and the ITGs, the outcome of the staining was largely dependent on the fixation methods. Paraformaldehyde fixation was best for the intracellular CDX2 protein, whereas acetone fixation gave the best results for the transmembrane ITGs. No difference was observed for the FN1 staining between samples fixed with paraformaldehyde or acetone. These examples demonstrate that the choice of fixation and permeabilization agents is very important for the outcome of the experiment, and this choice is dictated by the (extra)cellular location of the protein under investigation. Inappropriate fixation and/or permeabilization methods can lead to erroneous conclusions regarding the site and amount of protein expression.

Short-term exposure to hydrogen peroxide during oocyte maturation improves bovine embryo development

Recent studies have shown that short-term exposure of oocytes to a stressor such as hydrostatic pressure or osmotic stress might induce stress tolerance in embryos. The aim of the present study was to investigate the consequences of short-term hydrogen peroxide (H(2)O(2)) exposure to bovine in vitro matured cumulus-oocyte complexes (COCs) on subsequent preimplantation embryo development and apoptosis. In the first experiment, mature COCs were incubated in H(2)O(2) at concentrations ranging between 0.01 and 100 micromol/l, and subsequently fertilized and cultured. Oocyte incubation with 50-100 micromol/l of H(2)O(2) resulted in a significantly higher blastocyst yield (47.3%) in comparison with control medium (31.8%), while apoptotic cell ratio was inversely related with H(2)O(2) concentration. In the second experiment, we showed that the stress tolerance after H(2)O(2) exposure was not mediated by increased glutathione content in treated oocytes nor by enhanced fertilization or penetration. Further research should concentrate on the potential role of players that have been associated with stress tolerance in somatic cell lines.

Single-nucleotide polymorphisms in the COL1A1 regulatory regions are associated with otosclerosis

Otosclerosis (MIM 166800) has a prevalence of 0.2-1% among white adults, making it the single most common cause of hearing impairment in this ethnic group. Although measles virus, hormones, human leukocyte antigen alleles and genetic factors have been implicated in the development of otosclerosis, its etiology remains unknown. In a focused effort to identify genetic factors in otosclerosis, we have mapped four disease loci (MIM 166800/605727/608244/608787); however, cloning the disease-causing genes in these intervals has not been successful. Here, we used a case-control study design to investigate the association between collagen type I genes and otosclerosis. We identified susceptibility and protective haplotypes in COL1A1 that are significantly associated with otosclerosis in the Caucasian population. These haplotypes alter reporter gene activity in an osteoblast cell line by affecting binding of transcription factors to cis-acting elements. Our data suggest that increased amounts of collagen alpha1(I) homotrimers are causally related to the development of otosclerosis. Consistent with this hypothesis, mouse mutants homozygous for a Col1a2 frameshift mutation on a C57BL/6J background that deposit only homotrimeric type I collagen have hearing loss.

113 EFFECT OF SPERM COATING ON THE QUALITY OF BOVINE FROZEN - THAWED SPERMATOZOA

The substantial decrease of sperm quality after cryopreservation remains an important issue in the artificial insemination industry. Sperm coating with Triladyl® (Minitübe, Tiefenbach, Germany) during ejaculation can preserve sperm characteristics and oocyte penetrating capacity of fresh bovine spermatozoa stored in egg yolk diluent for up to 6 days (De Pauw et al. 2003 Theriogenology 59, 1109–1122). Since collecting semen in a tube containing egg yolk-Tris extender (sperm coating) limits the period of contact between spermatozoa and seminal plasma, the present experiment was conducted to assess if this slightly adjusted method of sperm collection could also have a significant effect on bovine sperm quality after cryopreservation. Semen of five young Holstein Friesian bulls was collected by means of an artificial vagina connected to an empty tube (Group 1; five ejaculates per bull) or a tube containing 4 mL of an egg yolk-Tris extender (Groups 2 and 3; each five ejaculates per bull). The semen samples of Group 1 were conventionally diluted in straws (60 × 106 sperm/mL), frozen, and stored in liquid nitrogen. The samples of Group 3 were centrifuged, and after removing diluent and seminal plasma, the sperm pellet was conventionally diluted and processed. The samples of Group 2 were processed without removal of the supernatant. After thawing each ejaculate was analyzed for average path velocity (VAP), beat cross frequency (BCF), and progressive motility (PROG) using CASA (Minitübe, Tiefenbach, Germany). Furthermore, the membrane integrity of each sample was evaluated using fluorescent SYBR®–14/PI staining (BD Biosciences, Erembodegem, Belgium). All parameters were compared among the three groups of sperm using univariate analysis of variance (SPSS 12.0; SPSS, Inc., Chicago, IL, USA). No significant differences could be observed among the three groups for all of the evaluated sperm characteristics (Table 1). A significant effect of the bull could be determined for all analyzed parameters (P ≤ 0.02), except for the percentage of moribund cells. Nevertheless, the group-bull interaction was never statistically significant. Coating bovine sperm with an egg yolk-Tris extender during ejaculation cannot prevent the substantial deterioration of the spermatozoa that occurs during freezing and thawing since this method of sperm collection does not significantly influence the motility parameters or the membrane integrity after thawing. Table 1. VAP, BCF, PROG, and percentage of membrane-intact, dead, and moribund spermatozoa for the three groups of sperm This research was supported by IWT (no. IWT/020727).

Attitude of laboratory personnel towards accreditation

A multiple choice questionnaire was submitted to medical technologists in three medical laboratories, at varying times after obtaining an EN 45001 accreditation. A large majority (85-90 per cent) considered that their workload was increased by the accreditation process. In two laboratories, the technologists did not think that the accreditation process had improved the quality of the results. The major advantages were the fact that everything was traceable, that the technologists felt more sure about the procedures to follow, received more responsibilities and had a better knowledge of the tests they performed. The major disadvantages were the increased paperwork, discrepancies between the procedures and the reality, the fact that more attention is paid to the formalities than to the quality of the results and that the accreditation process decreased the adaptability. The number of advantages mentioned seemed to increase with the interval since the accreditation. A small majority of the technologists preferred working in an accredited laboratory than in a non accredited one.

Evaluation of dowel space preparation on the apical seal using an image processing system

The effect of post preparation on the apical seal of endodontically treated specimens was studied. The canals prepared in bovine bone were instrumented and obturated using five obturation techniques: the silver point technique, the lateral condensation of gutta-percha technique, the warm vertical condensation of gutta-percha technique, the Hygenic Ultrafil injection system and the Obtura technique. In addition to these five control groups, the five experimental groups were also subjected to post preparation. In the latter group, the gutta-percha was removed with an engine-driven root canal reamer 48 hours after obturation. Both the control and experimental groups were suspended in a 0.5 per cent crystal violet solution for 48 hours. After dye penetration, the specimens were immersed in liquid nitrogen and then split longitudinally. Linear measurements of the resultant apical dye leakage were determined by image processing. For each obturation technique, all specimens in both the control and experimental groups were recorded if they showed leakage. Using Fisher's exact probability test, it was shown that there was no significant difference between the obturation techniques used.