bluuebunny/crossref_metadata_2025 huggingface dataset:
The Contribution of Remedial Courses on the Academic and Social Lives of Secondary School Students
Authors: Yolak Betül Betina , Kiziltepe Zeynep , Seggie Fatma Nevra
Published: April 2019

This qualitative study investigates the impact of nonformal education, namely remedial courses, on students’ lives and the ways in which it contributes to their academic and social development. The study was conducted via semi-structured interviews with 40 participants (12 students, 12 parents, and 16 teachers and administrators). The findings reveal that these remedial courses had academic, social, psychological, economic, and career development impacts on students’ lives. Moreover, as students’ school success improved, students learned how to spend their leisure time effectively in a secure environment, became socialized, increased their self-confidence, and realized their potential.
‘You Can’t Just Stick with Those You Like’: Why Friendship Practices Threaten Fraternal Life in Cistercian Monasteries
Authors: Sundberg Mikaela
Published: April 2019

Tensions between different relationship forms exist in every organisational setting. Catholic monasteries – as archetypical examples of voluntary total and greedy institutions – provide strategic cases of inquiry for understanding relational conflicts owing to the significance they assign to exclusively fraternal relations, resulting in explicit tensions regarding personal forms of relationships, such as friendship. Based on a multi-sited, qualitative case study of Cistercian monasteries in France, the present article pushes theorising on fraternal relations forward. Fraternal relations as a social form is membership-based and characterised by collectivism, egalitarianism and an imposed level of intimacy. In the monastic setting, it takes the form of prescribed impersonal love. The ideals of fraternal relations pose normative constraints for establishing friendship, but the ambition to minimise verbal interaction, perceived differences between members and the severe limits on joint, extra-organisational activities constitute additional constraints for friendship to form in monasteries.
The geochemical and organic petrological characteristics of coal measures of the Xujiahe formation in the Sichuan Basin, China
Authors: Zhou Guoxiao , Wei Guoqi , Hu Guoyi
Published: April 2019

Upper Triassic coaly and lacustrine source rocks complicate efforts to determine the source of hydrocarbons in Sichuan Basin. Total organic carbon analyses, pyrolysis experiments, petrological examinations, and gas chromatography and gas chromatography–mass spectrometry determinations were conducted on coals, carbonaceous mudstones and mudstones collected from two outcrop sections and cores of nine wells. Results revealed that the abundant organic carbon content will prolong the hydrocarbon generation cycle for coals and then the hydrocarbon generating capacity of coals will be enhanced by salinization, thereby contributing bacteria and algae microorganisms into humic coal of the Xujiahe Formation. Compared with mudstone, coal with the same maturity has a stronger adsorption effect on free hydrocarbons. When Ro is greater than 1.35, coal still has a strong hydrocarbon generation ability. The stable water column stratification and euxinic bottom water conditions are evidenced from the lower Pr/Ph and the higher gammacerane indices. The mixing of sea water has been proven by the existence of 4α,23,24,-trimethylcholestanes.
Transition States in Single Case Experimental Designs
Authors: Brogan Kristen M. , Rapp John T. , Sturdivant Bailey R.
Published: April 2019

The continuation of a baseline pattern of responding into a treatment phase, sometimes referred to as a “transition state,” can obscure interpretation of data depicted in single-case experimental designs (SCEDs). For example, when using visual analysis, transition states may lead to the conclusion that the treatment is ineffective. Likewise, the inclusion of overlapping data points in some statistical analyses may lead to conclusions that the treatment had a small effect size and give rise to publication bias. This study reviewed 20 volumes in a journal that publishes primarily SCEDs studies. We defined a transition state as a situation wherein at least the first three consecutive data points of a treatment phase or condition are within the range of the baseline phase or condition. Results indicate that transitions states (a) were present for 7.4% of graphs that met inclusion criteria and (b) occurred for a mean of 4.9 data points before leading to behavior change. We discuss some implications and directions for future research on transition states.
Cervical Lymphangioma: An Acquired Idiopathic Presentation in an Adult
Authors: Singh Bist Sampan , Varshney Saurabh , Bisht Manisha , Kumar Rajesh
Published: April 2019

Lymphangioma is an uncommon benign pathology, usually reported in children and rarely in adults. In the past, the definitive diagnosis was made intraoperatively and was usually an unexpected finding. However, with today's modern imaging technologies, such as computed tomography and magnetic resonance imaging, the diagnosis can he assumed before intervention, even though the final diagnosis still can be reached only via histopathologic examination. Imaging techniques also can aid in the precise mapping of the lesion and in defining its boundaries with the surrounding vital structures, improving therapeutic success. Various therapeutic options are reported in literature, but complete surgical excision is still considered the best approach. We report a case of cervical lymphangioma of unknown etiology in an 18-year-old man and discuss the presentation, diagnosis, and management of this lesion.
Acute Suppurative Neonatal Parotitis: Case Report
Authors: Khan Sardar U. , O'Sullivan Peter G. , McKiernan John
Published: April 2019

Neonatal suppurative parotitis is very rare. One review of the English-language literature spanning 35 years found only 32 cases. Most cases are managed conservatively with antibiotic therapy; early antibiotic treatment reduces the need for surgery. The predominant organism is Staphylococcus aureus. We report a new case of neonatal suppurative parotitis in a 3-week-old boy. The patient was diagnosed on the basis of parotid swelling, a purulent exudate from a Stensen duct, and the growth of pathogenic bacteria in culture. He responded well to 9 days of intravenous antibiotic therapy. We also discuss the microbiologic and clinical patterns of this disease.
A Primary Clival Defect: Endoscopic Binostril Approach With Nasal Septal Flap Closure and Preservation of Septal Integrity
Authors: Nogueira Joao Flavio , Woodworth Bradford A. , Stamm Aldo , Silva Maria Laura
Published: April 2019

Primary spontaneous cerebrospinal fluid (CSF) rhinorrhea is an unusual phenomenon that may occur anywhere along the skull base. However, CSF leaks originating from clival defects are rarely reported in the literature. The majority of reported cases were managed with microscopic techniques, using free grafts. The present study discusses a case of spontaneous CSF rhinorrhea from a clival defect closed with our transnasal operative approach using endoscopic techniques. The skull base defect was successfully managed with an endoscopic binostril approach to create a nasal septal flap pedicled at the sphenopalatine artery, while also preserving the integrity of the nasal septum.
Radiation Therapy Impact on Lymph Node Yield in Patients With Laryngeal Squamous Cell Carcinoma
Authors: Reyes Camilo , Rios Julian , Groves Michael , Solares C. Arturo , Jackson Lana , Byrd J. Kenneth
Published: April 2019

Background:

A lymph node yield (LNY) over 20 is considered a quality metric for lateral neck dissection to ensure an oncologic representative sample. Anecdotally, however, LNY in patients undergoing neck dissection after radiation therapy (RT) is lower due to atrophy and fibrosis.

Objective:

To determine whether preoperative RT decreases LNY in patients with laryngeal cancers undergoing surgery.

Methods:

Medical record database was queried for patients presenting between 2006 and 2015 with laryngeal cancer. Tabulation was made for location (glottic/supraglottic), stage, and side for the total number of lymph nodes between primary surgery and RT (salvage surgery) groups. Descriptive analysis and a paired Student t test were used for statistical analysis.

Results:

Fifty-nine patients were included in the study for a total of 98 neck dissections. Twenty-six (44%) patients had primary surgery, and 33 (56%) patients had salvage surgery. The mean left and right total LNY in the salvage surgery group was 27.6 and 29.5, respectively, and 32.2 and 33.7 for the primary surgery group. A difference of 4.5 (left) and 4.3 (right) in LNY between the salvage surgery and primary surgery group was found. A Student t test showed no statistically significant difference in LNY between both groups when analyzed per site (glottic and supraglottic), side, and stage (III-IV).

Conclusion:

Although patients with prior RT had a lower mean of LNY, our results did not demonstrate a statistically significant difference. Further studies with a larger number of patients are recommended.
High-Resolution MRI Microscopy Coil Assessment of Parotid Masses
Authors: Ginat Daniel Thomas , Christoforidis Gregory
Published: April 2019

The goal of this study was to determine whether high-resolution magnetic resonance imaging (MRI) microscopy coil imaging can improve the depiction parotid masses. A total of 14 parotid masses, including 7 salivary neoplasms, 2 abnormal lymph nodes, and 5 benign cystic lesions were imaged with T2-weighted and fat-suppressed postcontrast T1-weighted sequences using a 47-mm diameter microscopy coil in addition to conventional MRI sequences acquired with a conventional head and neck neurovascular coil. Compared to conventional parotid MRI sequences, microscopy coil images provided better definition of the margins of neoplasms, provide more detailed definition of lymph node morphology, and better depict certain cyst contents in the superficial portions of the parotid gland. The microscopy coil images provided significantly better definition of lesions and surrounding tissues within the superficial parotid gland with resptect to the deep parotid gland structures due to loss of signal. Furthermore, the fat-suppressed postcontrast T1-weighted microscopy coil images were significantly better than the corresponding T2-weighted images for delineating the superficial parotid gland. Ultimately, the microscopy coil sequences added over 10 minutes to the examination time.
Effect of Body Mass Index on Auricular Morphology and Auditory Functions
Authors: Surmeli Mehmet , Deveci Ildem , Canakci Hasan , Canpolat Mustafa Salih , Karabulut Burak , Yilmaz Ayse Asli Sahin
Published: April 2019

In this study, we aimed to investigate the relationship between the body mass index (BMI) and the morphometric properties of auricula and its acoustic gain characteristics. A total of 45 participants between 18 and 45 years of age were enrolled into the study. Participants’ height and weight measurements were recorded for the BMI calculation. On both sides, the morphometric properties of the auricula were measured and recorded. Additionally, the participants were subjected to multidirectional dynamic real ear measurements (REMs) to specify the intensity and frequency values of the maximum hearing gain. Participants consisted of 24 women and 21 men. The mean BMI was 23.42. The mean auricular area was 22.70 cm2. Statistically significant positive correlation was found between the auricular area and BMI ( r = 0.427, P = .03). The mean postauricular sulcus angle was 20.99°. The mastoid-helix distance was 16.07 mm. There was no statistically significant correlation between BMI level and postauricular sulcus angle and mastoid-helix distance ( P > .05). The mean dynamic REM measurement was evaluated. The maximum acoustic gain at anterior, lateral, and posterior vectorial stimulation was calculated as 20.9, 24.2, and 20.7 dB Sound Presure Level (SPL), respectively. Statistically significant negative correlation was found between the three directions acoustic gain level and BMI in the statistical examination ( r = −0.365, r = −0.386, r = −0.453, respectively, and P < .05 for all). The results of acoustic gain frequency were 2967.4, 2963, and 2934 Hz, respectively. There was no statistically significant correlation between acoustic gain frequency and BMI ( P > .05). When participants were grouped according to their BMI, participants with a BMI >25 had a statistically significantly bigger auricular area and lower maximum acoustic gain when compared with those with BMI <25 ( P < .05). We found that the auricular area increased with BMI. We think that this is related to soft tissue thickening of the auricula related to high BMI. In addition, we found that the acoustic gain level decreased inversely with BMI. We believe that the decrease in acoustic gain is due to the increase of acoustic resistance after the increase of soft tissue thickness. In conclusion, we think that BMI has a negative effect on auditory function according to findings in our study.
Transoral Sialolitectomy as an Alternative to Submaxilectomy in the Treatment of Submaxillary Sialolithiasis
Authors: Saga-Gutierrez Carlos , Chiesa-Estomba Carlos Miguel , Larruscain Ekhiñe , González-García José Ángel , Sistiaga Jon Alexander , Altuna Xabier
Published: April 2019

Introduction:

Sialolithiasis is the most common pathology in the submaxillary gland. The introduction of minimally invasive techniques isolated or associated with sialoendoscopy is replacing glandular resection as a treatment. The conservation of the gland is justified by the recovery of function and a low recurrence rate. The rate of complications is lower in conservative techniques than in submandibular gland resection.

Patients and Methods:

Thirty-three patients with fixed stones in the hilum of the submaxillary gland were treated by transoral sialolitectomy between July 2015 and July 2018, demographic data of the patients such as the number of stones, size, time of hospital stay, complications, pre- and postoperative lingual nerve function, and lithiasis recurrence were collected.

Results:

The average volume of the stones was 1.02 cm. Complete removal of the stone was possible in 32 patients. All the patients were operated in the outpatient clinic. Seven (21%) patients reported some degree of alteration of the lingual nerve function, of which the only one presented a persistence of more than 4 weeks due to an inadvertent injury that required a microsurgical anastomosis.

Conclusions:

Transoral sialolitectomy is a reproducible technique with good results and lower complication rates than submandibular gland resection. Our results in the first 33 cases encourage us to maintain the combined techniques as standard in the treatment of submaxillary sialolithiasis. Current experience guides the definitive substitution of submandibular gland resection by conservative techniques in obstructive pathology.
Intranasal Azelastine and Fluticasone as Combination Therapy for Allergic Rhinitis: Systematic Review and Meta‐analysis
Authors: Debbaneh Peter M. , Bareiss Anna K. , Wise Sarah K. , McCoul Edward D.
Published: April 2019

Objective

Combination therapy with intranasal azelastine and fluticasone propionate is an option for treatment of allergic rhinitis. This systematic review and meta‐analysis examines existing literature to determine efficacy in treating allergic rhinitis compared to monotherapy.

Data Sources

The PubMed, EMBASE, Cochrane, and MEDLINE databases were systematically searched for randomized controlled trials using AzeFlu nasal spray.

Review Methods

Randomized, controlled trials that reported symptom relief of allergic rhinitis in males and females of all ages were included. Results were reported in accordance with the Preferred Reporting Items for Systematic Reviews and Meta‐Analyses (PRISMA) standard.

Results

Systematic review identified 8 articles suitable for review. The risk of bias was generally low. All studies exhibited a greater decrease in patient‐reported symptom scores in patients treated with combination therapy compared to monotherapy or placebo. Meta‐analysis revealed superiority of combination therapy in reducing Total Nasal Symptom Score compared to placebo (mean change from baseline: −2.41; 95% confidence interval [CI], −2.82 to −1.99; P <. 001; I
2 = 60%), azelastine (mean change from baseline: −1.40; 95% CI, −1.82 to −0.98; P <. 001; I
2 = 0%), and fluticasone (mean change from baseline: −0.74; 95% CI, −1.17 to −0.31; P <. 001; I
2 = 12%).

Conclusion

Current evidence supports both efficacy and superiority of combination intranasal azelastine and fluticasone in reducing patient‐reported symptom scores in patients with allergic rhinitis. Combination nasal spray should be considered as second‐line therapy in patients with allergic rhinitis that is not controlled with monotherapy.
Multimodal Analgesia Protocol after Head and Neck Surgery: Effect on Opioid Use and Pain Control
Authors: Du Eugenie , Farzal Zainab , Stephenson Elizabeth , Tanner April , Adams Katherine , Farquhar Douglas , Weissler Mark , Patel Samip , Blumberg Jeffrey , Jowza Maryam , Hackman Trevor , Zanation Adam
Published: April 2019

Objective

To assess the effect that implementation of a multimodal analgesic plan has on opioid requirements and pain control in head and neck (H&N) surgery patients.

Study Design

Prospective cohort.

Setting

Tertiary academic hospital.

Subjects and Methods

An institutional review board (IRB)–approved quality improvement initiative was undertaken to implement a multimodal analgesic protocol for all admitted H&N surgery patients starting November 2017. Postprotocol data from January to May 2018 were compared to preprotocol data from May to October 2017. Data were obtained from the electronic health records as well as through preoperative and postoperative surveys. Average pain scores and opioid use in morphine milligram equivalents (MMEs) before and after protocol implementation were compared.

Results

In total, 139 postprotocol patients were compared to 89 preprotocol patients. The adjusted MMEs in the first 24 hours after surgery decreased significantly from 93.7 mg to 58.6 mg (P =. 026) with protocol implementation. When averaged over the length of stay (MME/hospital day), the change was no longer statistically significant (57.9 vs 46.8 mg, P =. 211). The average pain score immediately after surgery and on day of discharge did not change with protocol implementation.

Conclusion

Implementation of a multimodal analgesia plan reduced opioid use immediately after surgery but not over the course of hospitalization without any change in reported pain scores. This study shows that multimodal opioid‐sparing analgesia after H&N surgery is feasible. Future studies are needed further refine the optimal analgesic strategy for H&N patients and assess the long‐term efficacy, safety, and cost of such regimens.
PART II: Ethics, Environment, and Migration: Immigration and the Ethics of Choice
Authors: Sullivan Teresa A.
Published: April 2019

This paper begins by developing a language for ethical discourse on immigration and then examining the extent to which choices may be made at the micro-level and at the macro-level. States and individuals are examined as actors who are variously described as making choices or being choiceless. The concepts of cultural distance, reciprocity, the role of the individual and of the state and their interrelationships are evaluated in the perspective of choice. Whether an ethics of immigration can be successfully developed hinges on the degree of choice that individuals and states have or perceive themselves to have.

How sad and fraught with trouble is the state of those who yearly emigrate in bodies to America for the means of living…. It is, indeed, piteous that so many unhappy sons of Italy, driven by want to seek another land, should encounter ills greater than those from which they would fly…. When they reach the lands for which they are destined, ignorant as they are of the language and the place, and hired out for daily labor, they fall into the hands of the dishonest, and even into the snares of those powerful men to whom they enslave themselves. (Pope Leo XIII, 1888)

You shall not oppress an alien. You well know how it feels to be an alien since you were once aliens yourselves in the land of Egypt. (Ex 23:9)
Conceptualisation of Diagnostic Agents: From Empirical In Vivo Screening to Rational In Vitro Predictive Parameters
Authors: Belhadj-Tahar Hafid , Boumahdi Rachid , Darbieu Marie-hélène
Published: April 2019

A new rational conceptualisation protocol in new isotopic diagnostic agents has been designed to avoid systematic empirical in vivo screening. This protocol is based on multiple regression analysis, in order to determine the pharmacokinetic model capable of explaining in the best possible way the in vivo behaviour of molecules injected into an organism. Nine technetium complexes (99mTc-L) were synthesised from aminothiol ligand vectors. These complexes were characterised in terms of their physical, chemical and biological in vitro properties, i.e. lipophilicity (P), free fraction unbound to plasmatic proteins (Fup), the fraction unbound to blood cells (FuCb), and membrane adsorption fraction (Fad), an original factor assessed in vitro. Thus, two pharmacokinetic models were tested. The first takes into account the parameters classically used in pharmacokinetics (P, Fup, FuCb), and the second, in parallel with the first, includes the membrane adsorption rate (polar/apolar/polar membrane model). According to the phenomenon of tissular distribution, the explanatory power of the second model, including the Fad, is radically greater than that of the classical model. The comparative adjusted coefficient of determination ([Formula: see text]2) of the model, including the Fad versus [Formula: see text]2 of the first model, are heart (91%/6%), liver (89%/47%), spleen (64%/44%), lung (78%/26%), kidney (70%/33%) and brain (73%/8%), respectively. In addition, as for the myocardium, the membrane adsorption factor seems to be the only predictive factor of the affinity between the myocardium and neutral or cationic molecules. This refutes the generally held view that only cationic molecules could have an affinity with the heart.
Host Plant Effects on Activities of Detoxification Enzymes and Insecticide Tolerance in Western Flower Thrips, Frankliniella occidentalis (Insecta)
Authors: Jensen Sten E. , Brødsgaard Henrik F.
Published: April 2019

The polyphagous western flower thrips, Frankliniella occidentalis, is a severe pest of horticultural crops. Individuals from a laboratory population adapted to bean plants were transferred to new host plants, sweet pepper and chrysanthemum, to establish two new populations. The thrips appeared to perform poorly on the new host plants, as the total protein content of individual adults was lowered in the new populations. The specific activities of two insect detoxification enzyme systems, esterases and glutathione S-transferases, were assayed in vitro in the three populations. Host plant shifts had no effect on the level of general esterase activity to α-naphthyl acetate and only a minor effect on the level of glutathione S-transferase activity to 1-chloro-2,4-dinitrobenzene. The new population on pepper plants had slightly lowered glutathione S-transferase activity. The level of tolerance to the insecticide, methiocarb, was not affected by culturing the thrips on new host plants, nor was the total activity per individual of acetylcholinesterase, the target-site enzyme for methiocarb.
Gill Epithelial Cells as In Vitro Models in Aquatic Toxicology
Authors: Sandbacka Maria , Christianson Inga , Isomaa Boris
Published: April 2019

Gill epithelial cells are less sensitive than fish for most test chemicals, but a high correlation and a slope of the regression line close to 1 support the use of gill epithelial cells for prediction of acute toxicity in fish. Cells in suspension perform as well as cultured cells in the toxicity tests. However, the use of cells in suspension results in a quicker and more cost-effective assay for toxicity screening, but the cells should be used within about 5 hours of isolation. If a longer incubation time is required, cultured cells should be used. Cultured cells re-establish their polarity and contacts with other cells, and retain detectable amounts of enzymes for xenobiotic metabolism for at least 12 days in culture. Epithelial cell layers grown on filters seem to be less suitable for toxicity screening.
Cultured Porcine Urinary Bladder Epithelial Cells as a Screening Model for Genotoxic Effects of Aromatic Amines: Characterisation and Application of the Cell Culture Model
Authors: Föllmann Wolfram , Guhe Christine , Weber Susanne , Birkner Sascha , Mähler Solveigh
Published: April 2019

Isolated epithelial cells from porcine urinary bladders were maintained in dividing long-term monolayer cultures, and were used as a model system for the urinary bladder in toxicological studies in vitro. To examine the state of differentiation during the culture period, the culture system was characterised morphologically by light and transmission electron microscopy and by immune fluorescence labelling with antibodies against cytokeratins 7,13 and pan. The cultured cells were identified as urothelial epithelium by their polarised structure, and by their expression of several uroepithelial specific morphological features, such as fusiform vesicles, tight junctions and an asymmetric apical cell membrane. Additionally, the cells were labelled with anti-cytokeratin 7, 13 and pan antibodies, and negatively with anti-vimentin antibodies. The maintenance of suitable culture conditions was shown by the stable enzyme activities of γ-glutamyltranspeptidase, alkaline phosphatase and acid phosphatase over a culture period of 4 weeks. A good viability of the cultured cells under the chosen culture conditions was shown by the presence of low amounts of lactate dehydrogenase (≤ 5%) in the culture medium. The activities of the chosen marker enzymes for cell differentiation (γ-glutamyltranspeptidase), lysosomes (acid phosphatase) and luminal membranes (alkaline phosphatase) were relatively stable over the observed culture period. Enzyme activities involved in metabolism of xenobiotics were determined, to define the ability for metabolism in cultured cells compared with bladder tissue in situ. Several constitutive phase I and II enzyme activities were found to be stable during the culture period, indicating that the cultured cells should be able to metabolise xenobiotics in a comparable manner to the urothelium in vivo. The cytotoxic effects of xenobiotics were investigated and IC50 values were determined by means of lactate dehydrogenase leakage and inhibition of neutral red uptake. The induction of sister chromatid exchanges was used as a parameter for the genotoxic effects of several xenobiotics. This cell culture system was found to be a very good screening system for the testing of substances that affect the bladder, especially aromatic amines.
Toxic Effects of Chromium Acetate Hydroxide on Cells Cultivated In Vitro
Authors: Rudolf Emil , Peychl Jan , Červinka Miroslav
Published: April 2019

Many human activities, particularly industrial ones, result in an ever-growing production of toxic waste materials. The dynamics of the toxic effects of chromium acetate hydroxide, which is found in high concentrations in a waste sediment produced in the Czech Republic, were assessed by using a battery of in vitro tests carried out on two cell lines: L-929 (mouse fibroblasts) and Hep 2 (human laryngeal cells). Various markers of cell damage were assessed by phase-contrast, video and fluorescence microscopy, fluorometry, and DNA analysis. Chromium acetate hydroxide, over a concentration range of 1–0.02mol/l induced immediate cell death by fixation, whereas, at 0.002mol/l, the treated cells died in a much slower, more discrete manner. All the detected markers of cell damage, whether immediate or slow, clearly demonstrated that the cells died by necrosis. On the other hand, test concentration of 0.001mol/l appeared to constitute a threshold at which no pathological changes of Hep 2 cells were observed over 96 hours. We conclude that chromium acetate hydroxide has a high toxic potential in vitro, which should be considered when studying the toxicity of waste materials containing it.
The Use of Cultured Hepatocytes to Investigate the Metabolism of Drugs and Mechanisms of Drug Hepatotoxicity
Authors: Gómez-Lechón Maria J. , Ponsoda Xavier , Bort Roque , Castell José V.
Published: April 2019

Hepatotoxins can be classified as intrinsic when they exert their effects on all individuals in a dose-dependent manner, and as idiosyncratic when their effects are the consequence of an abnormal metabolism of the drug by susceptible individuals (metabolic idiosyncrasy) or of an immune-mediated injury to hepatocytes (allergic hepatitis). Some xenobiotics are electrophilic, and others are biotransformed by the liver into highly reactive metabolites that are usually more toxic than the parent compound. This activation process is the key to many hepatotoxic phenomena. Mitochondria are a frequent target of hepatotoxic drugs, and the alteration of their function has immediate effects on the energy balance of cells (depletion of ATP). Lipid peroxidation, oxidative stress, alteration of Ca2+ homeostasis, and covalent binding to cell macromolecules are the molecular mechanisms that are frequently involved in the toxicity of xenobiotics. Against these potential hazards, cells have their own defence mechanisms (for example, glutathione, DNA repair, suicide inactivation). Ultimately, toxicity is the balance between bioactivation and detoxification, which determines whether a reactive metabolite elicits a toxic effect. The ultimate goal of in vitro experiments is to generate the type of scientific information needed to identify compounds that are potentially toxic to man. For this purpose, both the design of the experiments and the interpretation of the results are critical.
Protein Precipitation In Vitro as a Measure of Chemical-induced Cytotoxicity: An EDIT Sub-programme
Authors: Novillo Apolonia , Ekwall Barbro , Castaño Argelia
Published: April 2019

As a priority area of the Evaluation-Guided Development of In Vitro Toxicity and Toxicokinetic Tests (EDIT) programme, an in vitro protein precipitation (PP) assay was used on the 50 reference chemicals of the Multicentre Evaluation of In Vitro Cytotoxicity (MEIC) project, to confirm and extend the MEIC results. Dose–response curves were generated for only 30 of the chemicals, and the concentrations causing 10% (EC10) and 50% (EC50) protein precipitation versus the positive control were chosen as endpoints. The number of chemicals with a positive response increased to 46 when a new endpoint, the minimum effect concentration (MEC) that induces protein precipitation with respect to the negative control, was used. When the results were correlated with in vitro cytotoxicity in human cell lines, a similarly good correlation was found between the various endpoints of the PP assay at 5 hours and the 24-hour IC50 average cytotoxicity in human cell lines, even though the number of chemicals included in the correlation was larger for the MEC. Using the prediction error, the endpoint that gave the best correlation between the PP assay and human cell cytotoxicity was once more found to be the 5-hour MEC, and this was chosen for the PP assay. The sensitivity of the PP assay is lower than that of the in vitro cell-line cytotoxicity assay, possibly due to its shorter exposure period and because precipitation is the ultimate event in the sequence of a protein disturbance. It is expected that earlier denaturation steps would give better sensitivity. However, this simple, inexpensive and rapid assay could be useful in the early stages of testing chemicals.
Study of the Environmental Hazard Caused by the Oil Shale Industry Solid Waste
Authors: Põllumaa Lee , Maloveryan Alla , Trapido Marina , Sillak Helgi , Kahru Anne
Published: April 2019

The environmental hazard was studied of eight soil and solid waste samples originating from a region of Estonia heavily polluted by the oil shale industry. The samples were contaminated mainly with oil products (up to 7231mg/kg) and polycyclic aromatic hydrocarbons (PAHs; up to 434mg/kg). Concentrations of heavy metals and water-extractable phenols were low. The toxicities of the aqueous extracts of solid-phase samples were evaluated by using a battery of Toxkit tests (involving crustaceans, protozoa, rotifers and algae). Waste rock and fresh semi-coke were classified as of “high acute toxic hazard”, whereas aged semi-coke and most of the polluted soils were classified as of “acute toxic hazard”. Analysis of the soil slurries by using the photobacterial solid-phase flash assay showed the presence of particle-bound toxicity in most samples. In the case of four samples out of the eight, chemical and toxicological evaluations both showed that the levels of PAHs, oil products or both exceeded their respective permitted limit values for the living zone (20mg PAHs/kg and 500mg oil products/kg); the toxicity tests showed a toxic hazard. However, in the case of three samples, the chemical and toxicological hazard predictions differed markedly: polluted soil from the Erra River bank contained 2334mg oil/kg, but did not show any water-extractable toxicity. In contrast, spent rock and aged semi-coke that contained none of the pollutants in hazardous concentrations, showed adverse effects in toxicity tests. The environmental hazard of solid waste deposits from the oil shale industry needs further assessment.
Cytotoxicity Testing of Wound-Dressing Materials
Authors: Sahlin Herman , Nygren Håkan
Published: April 2019

A method was developed for testing the cytotoxicity of various bandage-like wound dressings and gel wound dressings. In this method, the ability of human polymor-phonuclear neutrophils (PMNs) to initiate a respiratory burst after exposure to the various wound dressings is used as a marker of cytotoxicity. Luminol-amplified chemiluminescence stimulated with opsonised zymosan or phorbol 12-myristate 13-acetate (PMA) is used to measure the degree of activation of the respiratory burst, i.e. the NADPH oxidase activity, after exposure to wound dressings. Opsonised zymosan (material from yeast cell walls) is a phagocytic stimulus that activates the NADPH oxidase by binding to Fc-receptors and complement receptors, and functions as an artificial bacterium, whereas PMA activates the NADPH oxidase by direct activation of protein kinase C. NADPH oxidase activity was inhibited by several wound dressings. The down-regulation of the respiratory burst is detrimental to the bactericial effect of PMNs, and can be used as a marker for the cytotoxicity of wound-dressing materials.
Metabolic Activity in Primary Cultures of Fish Hepatocytes
Authors: Segner Helmut , Cravedi Jean-Pierre
Published: April 2019

In aquatic toxicology, isolated liver cells from fish can be used as a tool to generate initial information on the hepatic metabolism of xenobiotics, and on the mechanisms of xenobiotic activation or deactivation. This isolation of teleost liver cells is achieved by enzymic dissociation, and monolayer cultures of fish hepatocytes in serum-free medium maintain good viability for 3–8 days. During in vitro culture, fish liver cells express stable levels of phase I and phase II enzymes, such as cytochrome P4501A or glutathione S-transferase, and the cells show an induction of biotransformation enzymes after exposure to xenobiotics. The xenobiotic metabolite pattern produced by fish hepatocytes in vitro is generally similar to that observed in vivo. Limitations to more-intensive application of cultured fish hepatocytes as a screen in aquatic hazard assessment are partly due to the rather limited scope of existing studies, i.e. the focus on one particular species (rainbow trout), and on one particular biotransformation enzyme (cytochrome P4501A), as well as a lack of comparative in vitro/in vivo studies.
The ECVAM International Validation Study on In Vitro Embryotoxicity Tests: Results of the Definitive Phase and Evaluation of Prediction Models
Authors: Genschow Elke , Spielmann Horst , Scholz Gabriele , Seiler Andrea , Brown Nigel , Piersma Aldert , Brady Madeleine , Clemann Nicole , Huuskonen Hannele , Paillard Francoise , Bremer Susanne , Becker Klaus
Published: April 2019

From 1996 to 2000, ZEBET (Centre for Documentation and Evaluation of Alternative Methods to Animal Experiments at the BgVV, Berlin, Germany) coordinated the European Centre for the Validation of Alternative Methods (ECVAM) prevalidation and validation study on three embryotoxicity tests: a) a test employing embryonic stem cell lines (EST); b) the micromass (MM) test; and c) the postimplantation rat whole-embryo culture assay (WEC test). The main objectives of the study were to assess the performance of these three in vitro tests in discriminating between non-embryotoxic, weakly embryotoxic and strongly embryotoxic compounds. Phase I of the study (1997) was designed as a prevalidation phase, for test protocol optimisation, and for the establishment of a comprehensive database of in vivo and in vitro data on embryotoxic compounds. Phase II (1998–2000) involved a formal validation trial, conducted under blind conditions on 20 test compounds selected from the database, which were coded and distributed to the participating laboratories. In the preliminary phase of the validation study, six chemicals out of the 20, which showed embryotoxic potential, were tested. These results were used to define new biostatistically based prediction models (PMs) for the MM and WEC tests, and to evaluate those developed previously for the EST. As a next step, the PMs were evaluated by using the results for the remaining 14 chemicals of the definitive phase of the validation study. The three in vitro embryotoxicity tests proved to be applicable to testing a diverse group of chemicals with different embryotoxic potentials (non-embryotoxic, weakly embryotoxic, and strongly embryotoxic). The reproducibility of the three in vitro embryotoxicity tests were acceptable according to the acceptance criteria defined by the Management Team. The concordances between the embryotoxic potentials derived from the in vitro data and from the in vivo data were good for the EST and the WEC (PM2) test, and sufficient for the MM test and the WEC (PM1) tests according to the performance criteria defined by the Management Team before the formal validation study. When applying the PM of the EST to the in vitro data obtained in the definitive phase of the formal validation study, chemicals were classified correctly in 78% of the experiments. For the MM and the WEC tests, the PMs provided 70% and 80% (PM2) correct classifications, respectively. And, very importantly, an excellent predictivity (100%, except for PM1 of the WEC test, with 79%, considered as good) was obtained with strongly embryotoxic chemicals in each of the three in vitro tests.
The Use of Fetal Bovine Serum: Ethical or Scientific Problem?
Authors: Jochems Carlo E. A. , van der Valk Jan B.F. , Stafleu Frans R. , Baumans Vera
Published: April 2019

Fetal bovine serum (FBS) is a common component of animal cell culture media. It is harvested from bovine fetuses taken from pregnant cows during slaughter. FBS is commonly harvested by means of a cardiac puncture without any form of anaesthesia. Fetuses are probably exposed to pain and/or discomfort, so the current practice of fetal blood harvesting is inhumane. Apart from moral concerns, several scientific and technical problems exist with regard to the use of FBS in cell culture. Efforts should be made to reduce the use of FBS or, preferably, to replace it with synthetic alternatives.
In Vitro Phototoxicity Testing: Development and Validation of a New Concentration Response Analysis Software and Biostatistical Analyses Related to the Use of Various Prediction Models
Authors: Peters Björn , Holzhütter Hermann-Georg
Published: April 2019

As demonstrated in several validation studies, the dermal phototoxic potential of chemicals in humans can be effectively assessed by in vitro methods. The core of these methods is to monitor dose–response curves of a chemical in the absence and presence of light, to quantify the difference between these two curves by appropriate measures (either the photo-irritancy factor [PIF], or the mean photo effect [MPE]), and to use these measures as predictors of in vivo phototoxicity. We present new concentration–response analysis software for in vitro phototoxicity testing, which runs on current personal computers, and takes into account all the limitations identified when using a former program. We also demonstrate the validity and robustness of this new software by applying it retrospectively to all data available from two phases of the EU/COLIPA validation trial for the 3T3 neutral red update in vitro phototoxicity test. Some frequently raised questions pertaining to the use of prediction models in phototoxicity testing are addressed, including: the necessity of using prediction models based on a cut-off; whether it is justifiable to use sharp prediction cut-off values; whether there is a biostatistical justification for the highest concentration of the test chemical; and whether repeated testing of a chemical is required.
Three-dimensional Co-culture of Primary Human Liver Cells in Bioreactors for In Vitro Drug Studies: Effects of the Initial Cell Quality on the Long-term Maintenance of Hepatocyte-specific Functions
Authors: Zeilinger Katrin , Sauer Igor M. , Pless Gesine , Strobel Catrin , Rudzitis Jeannette , Wang Aiguo , Nüssler Andres K. , Grebe Alexander , Mao Lei , Auth Stefan H.G. , Unger Juliane , Neuhaus Peter , Gerlach Jörg C.
Published: April 2019

In vitro culture models that employ human liver cells could be potent tools for predictive studies on drug toxicity and metabolism in the pharmaceutical industry. A bioreactor culture model was developed that permits the three-dimensional co-culture of liver cells under continuous medium perfusion with decentralised mass exchange and integral oxygenation. We tested the ability of the system to support the long-term maintenance and differentiation of primary human liver cells. The effects of the initial cell quality were investigated by comparing cultures from resected, non-preserved liver with cultures from liver graft tissue damaged by long-term preservation. In cultures originating from non-preserved liver, protein and urea synthesis, glucose metabolism, and cytochrome (P450) activities were stable over the 2-week culture period, with maximal activities at the end of the first week in culture. Enzyme induction led to increased 7-ethoxyresorufin O-deethylase activities of up to 20 times the basal value. In cultures from preservation-damaged liver, recovery of metabolic activities was detected during bioreactor culture. After two weeks, most biochemical parameters approached those of cultures from non-preserved human liver. Light microscopy demonstrated the three-dimensional reorganisation of hepatocytes and nonparenchymal cells in co-culture. Long-term maintenance, and even the regeneration of specific functional activities of human liver cells, can be achieved in the bioreactor. This could facilitate the introduction into the pharmaceutical industry of in vitro drug testing with primary human liver cells.
Reduction, Refinement and Replacement: Putting the Immune System to Work
Authors: Kimber Ian
Published: April 2019

Many chemicals are known to be, or have been implicated as, contact allergens, and allergic contact dermatitis is an important occupational and environmental health issue. It is the responsibility of toxicologists to identify those chemicals that have the potential to induce skin sensitisation, and to assess the conditions under which there will exist a risk to human health. This article describes progress that has been made in the development of new approaches to the toxicological evaluation of skin sensitisation, and the benefits to animal welfare that such developments have already produced, and are likely to produce in the future. In this context, the local lymph node assay is described with regard to hazard identification and risk assessment, and possible strategies for the development of in vitro approaches to safety assessment are discussed.
ECVAM's Role in the Implementation of the Three Rs Concept in the Field of Biologicals
Authors: Hendriksen Coenraad , Cussler Klaus , Halder Marlies
Published: April 2019

Biologicals can be defined as products that are derived from living organisms or are produced by them. They include vaccines, hormones, monoclonal and polyclonal antibodies, blood products and rDNA products. The production of conventionally produced biologicals requires an extensive batch-related quality control, to ensure that these products are both safe and potent. As several of the control tests rely on animal models, it is inevitable that large numbers of animals are used. Many initiatives have been undertaken in the last few decades to reduce, refine and replace the use of animals in this area. ECVAM has been involved in many activities to support the development, validation and implementation of these Three Rs methods. The role that ECVAM has played in a number of validation studies is summarised. It is concluded that ECVAM should continue to support the activities that have been shown to be successful, preferably in collaboration with the regulatory authorities.
Barriers, Nephrotoxicology and Chronic Testing In Vitro
Authors: Prieto Pilar
Published: April 2019

In many organs of the human body, there are effective physiological barriers which contribute to regulation of the uptake, transport and secretion of endogenous and exogenous materials. ECVAM is involved in the development of several in vitro models for detecting damage to various barriers, including, the renal epithelium, the intestinal barrier, and the blood–brain barrier, after acute and chronic exposure to chemicals and products of various kinds. Long-term toxicity testing is an important issue in toxicology. At present, there are no generally accepted in vitro models available for replacing chronic testing in animals. Under chronic exposure conditions, the cellular response is greater than that which can be predicted in the standard cytotoxicity models. Therefore, the approach to predicting chronic toxicity will need to involve more-complex in vitro models. Several currently available in vitro long-term toxicity systems are under evaluation.
Development of a Testing Strategy for Detecting Embryotoxic Hazards of Chemicals In Vitro by using Embryonic Stem Cell Models
Authors: Bremer Susanne , Pellizzer Cristian , Adler Sarah , Paparella Martin , de Lange Jan
Published: April 2019

The importance of developing in vitro tests for embryotoxicity is discussed, and ECVAM's work with its collaborators is summarised. Studies are in progress to find new endpoints for use in the scientifically validated embryonic stem (ES) cell test, so that the potential for chemical effects on endodermal, mesodermal and/or ectodermal differentiation can be identified. This involves, inter alia, the use of genetically modified ES cells.