bluuebunny/crossref_metadata_2025 huggingface dataset:
Mechanics and hierarchical structure transformation mechanism of wool fibers
Authors: Liu Hongling , Zhao Liang , Zhang Guosheng , Pan Feng , Yu Weidong
Published: August 2020

Various natural protein materials have hierarchical microscale and nanoscale structures that protect animals from suffering cold weather or external threats. Herein, we contribute an effective strategy for exploring the hierarchical structure transformation mechanism by stretching a single fiber and bundle fibers. Taking advantage of controllable stretching, the disulfide bonds and peptide chains were taken apart or reconstructed by the new crosslinking bonds inside the wool fiber. If the temperature, solution concentration and stretching velocity were appropriate, the strain was more than 230% and the microstructure transformation of a single fiber underwent α→ β transition, disulfide bond breakage and macromolecule slippage occurred during the tensile process. The transformation mechanism was modeled and experimentally tested in wool bundle fibers after setting, suggesting that the stretching led to the transformation from α helix to β-pleated sheet, the breakage of disulfide bonds and the slippage of microfibrils. The availability of wool fibers provides many opportunities for bio-friendly cellular substrates and biosensor devices.
Regional housing price dependency in the UK: A dynamic network approach
Authors: Zhang Dayong , Ji Qiang , Zhao Wan-Li , Horsewood Nicholas J
Published: August 2020

The cross-regional dependency in the UK housing market is analysed using regional house price indices. In this article, a network approach based on partial correlations is proposed, along with rolling-window analysis to consider potential time-varying dependency. The results show that house prices in the outer South East region have the strongest influence on regional housing market interactions in the UK. This influence is stronger when the markets are highly interconnected, whereas the house prices in London have the strongest influence when the UK regional housing markets are relatively less connected.
“For the services of shipwrights, coopers, and grumettas”: Freetown’s ship repair cluster in nineteenth-century Sierra Leone
Authors: Everill Bronwen
Published: August 2020

This article looks at the development of Sierra Leone’s ship repair cluster, particularly focusing on the period 1780 to 1860. It argues that several factors contributed to the colony’s ability to develop a ship repair cluster. The first was the local environment, which provided both a safe harbor for ships and boats, and local materials that could be used on European and American ships. Secondly, the port’s increasing commercial role and its unique position as the site of the Courts of Mixed Commission for the adjudication of condemned slaving ships after the abolition of the slave trade gave ship’s carpenters access to a wide and varied range of both customers and supplies. Finally, these material effects were enhanced by the cluster’s effect on knowledge spillover and on-the-spot tacit knowledge creation as disruptions in the supply chain, competition with slave traders, and other local circumstances fostered innovation in Freetown’s repair cluster.
Perceived benefits of nature-based experiences as mediators of connectedness with nature: the case of Mystic Mountain
Authors: Ward-Smith Chesney , Naidoo Tony , Olvitt Lausanne , Akhurst Jacqui
Published: August 2020

Perceived nature disconnection lies at the heart of the world’s socio-ecological crisis. Finding ways to reconnect with nature is fundamental towards reducing the adverse psychological–social–ecological consequences of this disconnection. Understanding the psychological and social benefits of nature-based experiences is important towards actualising reconnection. This article discusses such benefits for child and adult participants from the Eastern Cape, South Africa. This work stems from Ecopsychology research with an outdoor education centre, Mystic Mountain. The experiences of two groups of children ( n = 25, aged 10–14 years) and adult instructors ( n = 12, aged 18–50 years) were explored using interpretive case-study methodology. Through semi-structured interviews and focus groups, participant observation, and reflexive journaling, data were collected and analysed thematically. This article centralises participants’ perceived psychological and social benefits of nature-based experiences as mediators of deeper self and nature connectedness. Integrating these benefits into nature-based pedagogy-design processes could contribute towards more effective enhancements of nature connectedness, and in turn, foster Earth’s larger flourishment.
Exploring the reciprocal correspondence among workplace relationships, career goal instrumentality, career satisfaction, and organisational commitment
Authors: Coetzee Melinde , Bester Marais S
Published: August 2020

Individuals’ satisfaction with their career development remains an important research theme. Little is known about the extent to which individuals’ cognitive evaluations of organisational context conditions are simultaneously influenced by their affective responses to, and mindsets about such conditions. The study explored the reciprocal correspondence among workers’ (1) cognitive evaluations of organisational career development support conditions (i.e., functions of workplace relationships and organisational career goal instrumentality) and (2) their affective responses (i.e., career satisfaction) and mindsets (i.e., affective, continuance, and normative commitment) that are embedded in experiencing such conditions. Drawing from the recent living systems theory of vocational behaviour and development, these constructs represent simultaneously occurring evaluative thought processes, mindsets, and affective responses that pertain to experiencing context conditions as either supporting or thwarting individuals’ career development. A sample of ( N = 606) professional people (mean age = 37 years; SD = 11.08) employed in cross-boundary service industry settings across the globe participated in the study. The multivariate statistical procedure canonical correlation analysis was performed. Three core synthetic common psychological themes emerged from studying the corresponding associations among the two variable sets. Overall, the feelings of career satisfaction and mindsets of affective/normative commitment were positively intertwined with context-condition evaluations of the organisation being instrumental to career goal achievement and coworkers providing active support in career advancement and personal growth. The study findings contribute new insights to contemporary career development theory.
Factors affecting color stability of maxillofacial prosthetic silicone elastomer: A systematic review and meta-analysis
Authors: Rashid Farah , Barman Aparna , Farook Taseef Hasan , Jamayet Nafij Bin , Yhaya Mohd Firdaus Bin , Alam Mohammad Khursheed
Published: August 2020

Purpose:

This systematic review and meta-analysis explored the factors involved in the color stability and degradation of Maxillo-Facial Prosthetic Silicone Elastomer (MFPSE). Further exploration was done to analyze past literature discussing the potential benefits to color stability when nano-particles were combined with pigmented MFPSE.

Method:

The search for the articles was done according to PRISMA guidelines. Articles were searched from “Scopus” and “Web of Sciences” from the year 1970 to 2019. Searches were carried out by two reviewers until November 2019. Articles for systematic review were selected based on predefined eligibility criteria. Information regarding weathering conditions, pigments and filler-particle inclusion were extracted as appropriate. Further screening was done for meta-analyze case-control studies of red, blue and yellow pigments according to predefined scoring criteria. Meta-analysis was conducted on case-control studies that incorporated 5%,10% and 15% TiO2 in MFPSE with the said pigments and was carried out using Cochrane Review Manager 5.3.

Results:

30 studies were selected for systematic review and 6 studies were eligible for meta-analysis. The most prominent influencers of color stability were nano-fillers and the type of color used in the mixing. Furthermore, experimental conditions, weathering, color of investment plaster and the method of color detection all affected the degree of degradation. There was an overall significant difference found when TiO2 was incorporated with the pigmented silicone. There is significant difference when 10% ( P = 0.0004) TiO2 is incorporated with the red pigment, 5% ( P = 0.03) TiO2 with the yellow and 10% ( P < 0.0001) and 15% ( P = 0.02) TiO2 with the blue pigment.

Conclusion:

Type of pigment and nano-filler incorporated into the silicone play a role in influencing color stability. Incorporation of 10% TiO2 with red pigment,5% with yellow pigment and 10% or 15% TiO2 with blue pigment provided some protection to the silicone elastomer from color degradation.
Structure-property correlation of an impact- modified random polypropylene copolymer
Authors: Pereira JRD , Bernardes GP , Silva JAP , Bönmann VC , Calcagno CIW , Santana RMC
Published: August 2020

The combination of rheological and interfacial properties is utilized in this work to explain the thermal and mechanical properties of a random polypropylene copolymer (RPP) toughened with an ethylene-propylene copolymer (EPR). RPP/EPR blends are directly prepared by injection molding. The EPR exhibits higher viscosity in comparison with the RPP over the evaluated shear rate, while the RPP/EPR blends show similar viscosities at high shear rates. The interfacial properties indicate a strong interaction between the RPP and EPR domains. Differential scanning calorimetry analyses indicate that the EPR does not act as a nucleating agent for the RPP, with the RPP crystallinity only decreasing at high EPR contents, suggesting that the EPR can modify the RPP crystallite size. Scanning electron micrographs of the blends demonstrate a ductile fracture surface, indicating that EPR can increase the RPP tenacity. The RPP impact strength is improved by up to 102% in the RPP/EPR 90/10 wt.% blend, while the RPP deformation at break is increased from 183% to 246% after the incorporation of 10% EPR. The tensile strengths of the RPP and RPP/EPR blends are very similar, indicating that the RPP achieves a good balance between stiffness and toughness after being blended with the EPR.
Toward a Culturally Specific Spirituality for Black Sexual Minority Men
Authors: Lassiter Jonathan Mathias , Brewer Russell , Wilton Leo
Published: August 2020

Spirituality is a culturally relevant phenomenon that has been found to significantly affect Black sexual minority (SM) men’s health in the United States. However, many studies that have investigated spirituality among Black SM men have often used conceptualizations of spirituality that were not defined by this group. This research investigation used qualitative methods to determine how Black SM men defined spirituality for themselves. Ten Black SM men from across the United States were individually interviewed via Zoom videoconferencing. Grounded theory analyses revealed four themes that described Black SM men’s culturally specific spirituality: (a) spiritual definition, (b) specificity of Black SM men’s spirituality, (c) physical manifestations of spirituality, and (d) images of the sacred. The implications of these findings for future research and clinical work with Black SM men, within a Black psychological framework, are discussed.
Experimental study on the influence of coal powders on the performance of water-based polymer drilling fluid
Authors: Zhang Lei , Wu Xiaoming , Lyu Shuaifeng , Shen Penglei , Liu Lulu , Mou Yongzhong , Sun Yujie
Published: August 2020

Coal powders, as cuttings, invade the drilling fluid along a coal seam during coalbed methane development, thereby changing the properties of the drilling fluid. Therefore, this work aims to investigate the influence of coal powders on drilling fluid performance. The powders of lignite, anthracite, and contrasting shale were added to a water-based polymer drilling fluid. Then, the rheology, filtration, lubricity, and adhesiveness were measured, and the natural degradation, as well as the wettability were further evaluated. The results show that some parameters of the drilling fluid, including viscosity, lubrication coefficient, adhesion coefficient, contact angle, and surface tension, increase after adding coal powders, while other parameters, such as filtration loss and natural degradation, decrease. Compared with lignite and shale, anthracite powders, with the lowest mineral content, exhibit the smallest change in the rheological property, lubricity, adhesion, and natural degradation of the drilling fluid. Moreover, the content and size of the coal powders generally have opposing effects on the drilling fluid. When the coal powder content reaches 3 wt.%, the surface tension and contact angle of the drilling fluid show more evident changes than other parameters. Based on the analysis of the stress intensity factor, the drilling fluid with coal powders exceeding 100 mesh can reduce the capillary force in microfractures, and in combination with other factors (such as reduced filtration loss and sealing and supporting of the microfractures), improves wellbore stability. Therefore, coal powders with suitable particle sizes and concentration levels are expected to become a new drilling fluid material to protect coal field reservoirs.
Decision Making in Patients with Natural Myringostapediopexy: A Study of the Contralateral Ear
Authors: Schmidt Viviane Bom , da Costa Sady Selaimen , Schmidt Rosito Letícia Petersen , Sperling Neil , Dias Rodrigo Gonçalves
Published: August 2020

Naturally occurring myringostapediopexy frequently results in minimal hearing loss and is asymptomatic. Management decisions in such ears, however, often hinge on an appraisal of evolution toward cholesteatoma. The study of the contralateral ear has been used by our research team to infer the progression of chronic otitis media. This cross-sectional, comparative study describes the clinical findings of the contralateral ear in a series of patients with myringostapediopexy. This study included a historical and current sample of 46 patients divided into a pediatric (< 18 years) and an adult group. Patient distribution according to sex was similar (52.2% male), and 56.5% were adults. Mean conductive hearing loss ranged from 14.1 to 21.2 dB in ears with myringostapediopexy and from 16.0 to 26.6 dB in the contralateral ears according to the frequency assessed. The contralateral ear was normal in only 19.6% of the cases of myringostapediopexy. Central tympanic membrane perforation was found in 6.5% of the cases; perforation-retraction, in 17.4%; moderate or severe retraction, in 28.3%; and cholesteatoma, in 28.3%. The prevalence of cholesteatoma in the contralateral ear in the pediatric and adult groups was not significantly different (p = 0.5; χ2 test). The presence of significant abnormalities, particularly cholesteatoma, in the contralateral ears suggests a probable unfavorable progression in cases of myringostapediopexy and may influence management decisions.
Management Options for Patients With Nasopharyngeal Carcinoma Undergoing Cochlear Implantation
Authors: Lee Chee-Yee , Lin Wei-Chieh , Lin Chung-Ching , Hsu Chuan-Jen , Wu Hung-Pin
Published: August 2020

Objectives:

Cochlear implantation (CI) has been successfully used to restore hearing in patients with severe to profound hearing loss. In addition to hearing loss, irradiated patients with nasopharyngeal carcinoma (NPC) also often have chronic otitis media and Eustachian tube (ET) dysfunction. These features may result in difficulties in CI. We conducted this study to review the management options for irradiated patients with NPC undergoing CI. Furthermore, we investigated the results of CI in irradiated patients with NPC with chronic otitis media and obstructive ET dysfunction, accordingly to different treatment strategies.

Methods:

We retrospectively reviewed the data of patients with NPC who underwent CI in our hospital between 2006 and 2020. All subjects were found to be eligible according to the following inclusion criteria: had NPC, received irradiation, underwent cochlear implant surgery, and had chronic otitis media with obstructive ET dysfunction.

Results:

A total of 9 patients with obstructive ET dysfunction and chronic otitis media underwent cochlear implant surgery. Seven patients with an inflamed ETs underwent a 2-stage operation. Two patients with obliterated ETs, we performed a single-stage CI surgery. Only 1 patient had otitis media effusion after the surgery.

Conclusion:

With the proper management of chronic otitis media and ET dysfunction, cochlear implant is an effective treatment for irradiated patients with NPC when conventional hearing aids failed.
Moving Evidence: Patients’ Groups, Biomedical Research, and Affects
Authors: Lindén Lisa
Published: August 2020

Research in science and technology studies has analyzed how patients’ groups engage in practices that connect biomedicine and patient experience in order to become involved in the shaping of biomedical research. However, there has been limited attention to the affective dimensions of such practices. Based on ethnographic fieldwork with a gynecological cancer patients’ group in Sweden, this article focuses on practices that aim to influence researchers and research institutions to prioritize biomedical gynecological cancer research. It analyzes how “affects” are woven through these practices and pays attention to the entanglements of affects, biomedical research, and lay experience they involve. The article explores the relation between the gynecological cancer patients’ group and biomedical research as a set of material-semiotic practices of “moving evidence.” These practices of moving evidence (1) enact gynecological cancer as under-researched; (2) collect and produce new “evidence”; (3) “mobilize” the evidence at public events, in interactions with biomedical researchers, and in different online settings; and (4) entangle affects with biomedical and experiential evidence to enact (a lack of) gynecological cancer biomedical research as a matter of concern.
Domestication outside of the domestic: shaping technology and child in an educational moral economy
Authors: Martínez Carolina , Olsson Tobias
Published: August 2020

This article explores the usability of domestication theory in an educational setting integrating a wide variety of information and communication technologies (ICTs). More specifically, the article analyses domestication of digital media in the Swedish leisure-time centre (LTC), an institution in which children receive education and care before and after compulsory school. The study draws on qualitative in-depth interviews with 21 teachers as well as observations of LTCs. The article reveals what it means to have limited agency as an educator when ICTs are appropriated, and further illustrates the contradictory fact that mobile phones are objectified as stationary technologies. It also shows how both devices and content are incorporated in ways that are perceived suitable to the LTCs’ educational moral economy. An especially interesting finding is the extent to which domestication theory sheds light on power relations when applied outside of the domestic sphere.
From “Crying Expands the Lungs” to “You’re Going to Spoil That Baby”: How the Cry-It-Out Method Became Authoritative Knowledge
Authors: Rosier Jennifer G. , Cassels Tracy
Published: August 2020

The cry-it-out (CIO) method is a sleep training method that encourage parents to let their infants cry at night by themselves for increments of time in order to get them to eventually sleep through the night, on their own. The purpose of this analysis is to explore how the CIO method was constructed as authoritative knowledge to become a normative practice among modern parents. Drawing on various forms of media relevant to laying the groundwork for the promotion of the CIO method over the last 200 years, we examine how parents’ methods for getting babies to sleep have changed. We then argue that the CIO method ascended as authoritative knowledge mostly via the use of fear-based messages, enabling parents to feel validated when they decide to ignore their infants’ nighttime cries so that they can achieve better household sleep.
Life Stories of Voluntarily Childless Older People: A Retrospective View on Their Reasons and Experiences
Authors: Stegen Hannelore , Switsers Lise , De Donder Liesbeth
Published: August 2020

This article investigates the reasons for and experiences of voluntary childlessness throughout the life course. Thirteen voluntarily childless people aged 60 years and older (Belgium) were interviewed using the McAdams approach (2005). Four profiles were derived from the reasons given for voluntary childlessness: the “liberated careerist,” the “social critic,” the “acquiescent partner,” and “voluntarily childless because of life course circumstances.” Results further indicate that older people experience feelings of acceptance, loss (missing familiarity with current trends, being helped, and children’s company), and relief concerning their voluntary childlessness. Moreover, they rarely seem to regret their choice. The discussion indicates the existence of voluntary childlessness among older people, a phenomenon sometimes questioned in the existing scientific literature. As part of a diverse target group, each of these older adults has their personal reasons and experiences regarding childlessness.
Frequency of fruit juice consumption and association with nutrient intakes among Canadians
Authors: Murphy Mary M , Barraj Leila M , Brisbois Tristin D , Duncan Alison M
Published: August 2020

Background:

In Canada, studies on consumption of 100% fruit juice and nutrient intakes are limited.

Aim:

This study aimed to evaluate nutrient intakes and adequacy of intake by frequency of fruit juice consumption.

Methods:

Individuals ≥1 year ( n = 34,351) participating in the Canadian Community Health Survey, 2004 with a 24-hour dietary recall and reported usual frequency of fruit juice consumption (assumed to be 100% juice) were categorized by frequency of consumption as <0.5, ≥0.5 to <1.5, or ≥1.5 times/day.

Results:

More frequent consumption of fruit juice (≥0.5 times/day) was associated with higher intakes of total fruits and vegetables, whole fruits, energy, total sugars, vitamin C and potassium. More frequent consumption of fruit juice was associated with improved intake adequacy of vitamin C for adults.

Conclusions:

Fruit juice consumption contributes to increased intakes of vitamin C and potassium as well as energy and total sugars, thus presenting a trade-off for consumers to balance.
Instructions for Participants in the Multicentre Evaluation Study of in Vitro Cytotoxicity (MEIC)
Authors: Bondesson Inger , Ekwall Björn , Stenberg Kjell , Romert Lennart , Walum Erik
Published: August 2020

A programme for a multicentre evaluation study of in vitro cytotoxicity (MEIC) has been proposed. The programme represents an attempt to evaluate the correlation between in vitro cytotoxicity and both lethal and sublethal toxic effects in man. Instructions for laboratories wishing to participate are given.
Comments on the Use of Diverse Cell Systems in Toxicity Testing
Authors: Ekwall Björn , Ekwall Karl
Published: August 2020

To initiate a discussion of the relative merits of various cell systems in acute toxicity testing we have considered the suitability of seven systems in testing three types of toxicity i.e. systemic toxicity in general, systemic toxicity to specific target organs, and local toxicity Available data indicate that systemic toxicity can be predicted by simple systems with non-differentiated cell lines, as well as by primary cultures of hepatocytes. The combined use of both cell systems is probably the method of choice. Specific, cellular, target organ toxicity is often tested in primary cultures of various specific cells. Such use of these cells seems to be irrational, and ought to be replaced by a parallel use of specific and non-specific cell cultures. An analysis of the differential cytotoxicity to both cell types would then point out specific target organ toxicity. It is uncertain whether non-specific cell lines or primary cultures of target-specific cells should be used in tests of local toxicity. Future parallel use of both cell types to produce data on differential cytotoxicity would settle the question.
Differential Effects of Allyl Alcohol on Hepatocytes and Fibroblasts Demonstrated in Roller Chamber Co-Cultures
Authors: Ericsson Ann-Charlotte , Walum Erik
Published: August 2020

A roller incubation procedure was used to co-cultivate primary cultures of chick hepatocytes with a human fibroblast-like cell line (HFB). When HFB cells alone were incubated, in the presence of allyl alcohol, an increased rate of protein synthesis was observed. In the hepatocyte-fibroblast co-cultures, allyl alcohol caused a dose-dependent decrease in the rate of protein synthesis in the cells of both types. This effect was much more pronounced in the hepatocytes. It was concluded that in the co-cultures allyl alcohol was oxidised to acrolein, which exerted its toxic action primarily on the hepatic cells.
Use of Isolated Periportal and Perivenous Rat Hepatocytes for Studying the Acinar Heterogeneity of Xenobiotic Metabolism: Cytotoxicity of Allyl Alcohol
Authors: Penttilä Kai E.
Published: August 2020

The periportal hepatotoxicity of allyl alcohol (AlOH) was investigated by studying its metabolism and cytotoxicity in suspensions of periportal (pp) and perivenous (pv) rat hepatocytes isolated by digitonin-collagenase perfusion. No marked difference in alcohol dehydrogenase activity between the cell types was observed. The cells also oxidised AlOH at about equal rates. AlOH depleted cellular glutathione by about 95% within 10 minutes in both cell types, but was partially restored during subsequent incubation. The pp cells suffering from AlOH toxicity in vivo tended to resist AlOH in vitro better than pv hepatocytes, as judged from the measurement of cellular ATP and K+ ion content, and LDH leakage. It is suggested that the oxidation of AlOH may be restricted to the pp region in intact liver simply because of the high rate of uptake and oxidation of AlOH by the liver tissue.
A Sensitive Method for Assay of Mixed-Function Oxygenase (p-450 complex) in Cell Culture
Authors: Clausen Jørgen , Nielsen Søren Achim
Published: August 2020

The mixed-function oxygenase system involved in the metabolism of drugs and xenobiotics has been extensively studied in various animal species and in various organs (1). It is now apparent that in humans the p-450 complex is one representative of a related family, expressed by 13 c-DNA genes showing approximately 36% similarity between the different subfamilies (2). In order to compare the in vivo and in vitro metabolic effects of drugs and xenobiotics, the induction capabilities of the mixed-function oxygenase must be known. The most sensitive non-isotopic assay system for determination of mixed-function oxygenase activity is the method of Nebert & Gelboin (3,4), which is based on the metabolic transformation of benzo-(a)-pyrene to its fluorescent hydroxyl derivatives (5). However, the levels of the mixed-function oxygenase enzymes in different cellular systems show great variations, with the highest activities in liver cells. Therefore, in order to use human lymphocytes and other cellular systems with low mixed-function oxygenase activities, the assay method for determining oxygenase activity must have the highest possible sensitivity. The present communication is devoted to a study aimed at increasing the sensitivity of Nebert & Gelboin's methods for assay of mixed-function oxygenase subfamilies using benzo-(a)-pyrene as a substrate.
Triethyllead Stimulates Oligodendroglial Development in Primary Cultures of Newborn Rat Brain
Authors: Grundt Inger K. , Roussel Guy , Neskovic Nenad M.
Published: August 2020

In order to elucidate the effects of triethyllead (Et3Pb) on the development of oligodendroglial cells (OG) in primary cultures of newborn rat brain, the expression of the OG marker enzyme UDP-galactose:ceramide galactosyltransferase (CGalT) was studied. The results show that CGalT activity increased about three times compared to the control level of enzyme activity, when 5-day-old cultures were exposed for 16 days to 2.5 x 10-9M Et3Pb in the culture medium. Using anti-CGalT antibodies in immunohistochemical studies, it appeared that the increase in CGalT activity in Et3Pb-treated cultures was accompanied by an increase in the number of oligodendroglial cells.
Microcomputer Simulations of Laboratory Experiments in Physiology
Authors: Dewhurst David G. , Brown Guy J. , Meehan Anthony S.
Published: August 2020

Three interactive computer-assisted learning programs based on simulations of simple experiments in physiology (frog sciatic nerve, frog sciatic nerve-gastrocnemius muscle and frog heart) are described. The programs use experimental data to generate realistic, high-resolution graphic simulations of results and present these either on a simulated oscilloscope or on a continuously scrolling display to simulate a chart recorder. Students can thus conduct an experiment and take measurements directly from the monitor, as they would in the real situation. The programs fulfil most of the main objectives of practical physiology teaching and offer an alternative to animal experiments. They are most suitable either for students of biology and health-related subjects, where physiology is an essential component but dissection and tissue handling skills are of minor importance, or in institutions (for example schools, and colleges of further education) where animal experiments are not permitted or the expensive equipment or technical expertise required are lacking. The feasibility of using computer simulation programs to replace animal experiments in teaching is discussed in relation to the teaching objectives of practical physiology classes.
Evaluation of the In Vitro Uridine Uptake Inhibition Assay in Comparison with the In Vivo Eye Irritation Test as Prescribed by the EEC
Authors: Jacobs Guido A. , Dierickx Paul J. , Martens Mark A.
Published: August 2020

In vivo eye irritation tests were carried out on 17 substances (mainly solvents) according to the experimental protocols laid down in the European Community legislation on dangerous substances and the OECD Guidelines. Erythema, chemosis, corneal opacity and iritis were observed and evaluated according to the interpretation rules laid down in EEC legislation.

The uridine uptake inhibition assay was carried out on Human Hep G2 cells according to the method of Shopsis & Sathe (1), modified by Dierickx & Martens (2). Inhibition of uridine uptake was expressed as the UI50 (Hep G2 cells, mM).

Comparison of the results of our two studies revealed only a poor relationship between the UI50 values and the mean scores obtained for corneal opacity (Spearman rank correlation; r=0.57, p<0.02). Consideration of just the monoalcohols, together with the ketones and the formamides, gave a good linear correlation between the UI50 (Hep G2 cells) and the <> (r=0.93). If a UI50 value of 50mM is accepted as a limit for classification of irritancy for the eye, no false positives or false negatives are obtained.

The UI50 can only be used within strictly defined chemical classes, as a first screening method for detecting possible irritants.
The Detection of Reactive Metabolites Generated by the Microsomal Mixed Function Oxidase System
Authors: Fry Jeffrey R. , Garle Michael J. , Hammond Alison H.
Published: August 2020

It is recognised that the cytotoxicity of a number of xenobiotics is mediated through the production of reactive metabolites (1). Given this, and the current emphasis on the development of in vitro tests for assessment of xenobiotic cytotoxicity (2), it is of considerable interest to develop systems for the detection in vitro of cytotoxic reactive metabolites. Indeed, it would seem appropriate to employ a limited battery of tests for detection of xenobiotic-mediated cytotoxicity, some of which would be dedicated to assessment of the role of metabolism in such toxicity. The aim of this review is to identify and discuss the approaches currently being employed to this end, and to suggest some possible future trends.
Human Granulocyte LTB4 Production and Respiratory Burst Impaired by Styrene
Authors: Valentino Matteo , Governa Mario , Marchiseppe Isabella , Visona' Isabella
Published: August 2020

Human granulocytes (PMN) incubated in vitro with styrene at a concentration of 3.3 x 10-4 M have shown an impairment of leucotriene B4 (LTB4) production and of respiratory burst after stimulation with N-formyl-methyonil-leucyl-phenylalanine peptide (nFMLP), which has a specific membrane receptor. The level of impairment in LTB4 production was lower in cells pretreated for 15 minutes with styrene than in cells treated with styrene and nFMLP simultaneously. Styrene did not cause irreversible damage, because 15 minutes after styrene treatment PMN partially recovered their function. The determination of styrene and styrene oxide, the presumed active metabolite, in the supernatant of cell culture, showed that styrene rapidly enters the cell and only 15 minutes or more after styrene addition was styrene oxide found. On this basis, the action of styrene does not seem to be mediated by metabolites.
Kinetic Studies of Cultured Human Keratinocytes: A Comparison between 5-Bromodeoxyuridine and Tritiated Thymidine Incorporation
Authors: Benassi Luisa , Zambruno Giovanna , Massimi Paola , Fantini Fabrizio , Gianetti Alberto
Published: August 2020

5-Bromodeoxyuridine (5-BrdU), a pyrimidine analogue of thymidine, is incorporated into the DNA which is actively synthesised during the S-phase of the cell cycle. In the present study, the labelling indices of cultured human keratinocytes, marked by monoclonal antibodies to 5-BrdU and by tritiated thymidine (3H-TdR), were compared.

The proportion of cells found to be labelled by the two methods was similar. The immunological method has advantages over 3H-TdR autoradiography, because it does not require radioactive material, and is both faster and less expensive.
An In Vitro Toxicity Assay for Human Endothelial Cells
Authors: Sbarbati Rosella , Schinetti Maria Luisa , Scarlattini Maria
Published: August 2020

Cultured human endothelial cells can replace living animals in studying the toxic role of noxious agents in the pathogenesis of vascular diseases and in the elucidation of the mechanism of action of protective drugs.

Preliminary data are presented which examine the effects that oxidative stress produces on human endothelial cells in vitro.

Human umbilical vein endothelial cells were subjected to an anoxia-re-oxygenation treatment and tested for the production of Super Oxide Dismutase (SOD)-inhibitable superoxide radicals. The results show that under our experimental conditions endothelial cells produce oxygen-free radicals and that the generation reaches a maximum after an anoxic challenge of 20 minutes.

We conclude that the in vitro system presented in this paper could be a suitable tool for further studies on the effects of oxidative stress on the vascular endothelium, which mimics the in vivo conditions of re-perfusion after heart ischemia.
In Vitro Modulation of Glutathione Levels by Buthionine-S,R-Sulphoximine in a Human Cell Line: Effect on Cytotoxicity
Authors: Rossini Liliana , Cova Dario
Published: August 2020

The effects of glutathione (GSH) depletion by buthionine-S,R-sulphoximine (BSO) on MCF-7, a human cell line which exhibits high levels of GSH, were investigated. Pre-incubation with 5μM BSO for 48 hours significantly decreases GSH content in these cells and the depletion lasts as long as BSO is present in the culture medium. The cytotoxic activity of two antineoplastic agents, doxorubicin (DXR) and cisplatin (CDDP), whose interaction with GSH metabolism is known, was tested to evaluate whether GSH depletion would enhance the effectiveness of these compounds on MCF-7 cells. The results showed no significant improvement of the cytotoxic effect of either compound, suggesting the presence of concurrent mechanisms (e.g. interactions with enzymatic activities or intracellular macromolecular components), which may explain the positive results obtained with GSH depletion in other cell lines and in animal tumour models in vivo.
An Approach to Pain in Research Animals
Authors: Adams David B.
Published: August 2020

Pain can either signal the threat of tissue-damage (nociception) or can result from tissue damage itself. The physiology and “pathology” of pain, in the second instance, suggest that it can be diagnosed (not “measured”, “assessed”, etc.) on the basis of its association, but not equality, with tissue damage and by its coincidence with changes in behaviour. Pain will be present as part of a syndrome and cannot occur without cause or association. Pain may occur in experiments:

a) coincidentally and unrelated to any experimental procedure,

b) accidentally, when a procedure goes amiss, and

c) as part of the experimental design.

Where pain is intrinsic to the aims of an experiment (for example in the testing of analgesics), “escape routes” and “limits” must be formulated for the benefit of experimental subjects. In addition, the empirical value of the experiment must be assessed.

There is insufficient information on the use and efficacy of analgesic drugs in animals. These drugs, however, are neither the only nor the most effective means of alleviating physical pain in animals. Other forms of treatment are considered. All depend on sound diagnosis and prognosis. Decisive action against the cause of pain is necessary.
Monoclonal Antibodies: In Vivo and In Vitro Production on a Laboratory Scale, with Consideration of the Legal Aspects of Animal Protection
Authors: Kuhlmann Ingrid , Kurth Waltraud , Ruhdel Irmela
Published: August 2020

Antibodies in the serum of immunised animals are polyclonal. That is, they react with all determinants of an antigen. Monoclonal antibodies, however, are produced by cells which are all derived from a single antibody-producing cell; hence they are highly specific and react with only one antigenic determinant.

Monoclonal antibodies are valuable tools in medical and biological research and can be used for identifying, characterising and purifying medically and biologically important substances. Due to their high specificity, monoclonal antibodies are increasingly used in the diagnosis of infectious disease and neoplasia. Large amounts of antibodies are needed for use in these areas and this necessitates mass production (in the g–kg range); so many authors have described production systems and possibilities for optimising mass production. In contrast, at universities and other research institutions, the production of monoclonal antibodies on a laboratory scale (in the mg range) is still carried out, mostly in the ascites mouse. Certain research areas, require only {minimum amounts μg range) of monoclonal antibodies, so maximising production of antibodies is unnecessary, and as a rule, the yield of a stationary cell culture will suffice.

This article summarises the in vivo and in vitro methods described up to now, as well as our own experiences and results. Taking the German animal protection law (22.8.86) as a basis, the legal aspects of animal protection in the production of monoclonal antibodies are discussed. In addition, the legal regulations in Switzerland and the Netherlands are considered.
In Vitro Cytotoxicity of 26 Coded Chemicals to HEp-2 Cells: A Validation Study
Authors: Mazziotti Isabella , Stammati Anna-Laura , Zucco Flavia
Published: August 2020

Twenty-six chemicals supplied coded by FRAME, were tested on HEp-2 cells. Three endpoints were used to measure the cytotoxicity of these compounds: total protein content, LDH release and total acid phosphatase content.

The sensitivity of these parameters is discussed. The results are compared with those obtained by other groups participating in the validation scheme organised by FRAME.
In Vitro Toxicology: A Challenge for the 21st Century
Authors: Roberfroid Marcel B. , Goethals Fabienne
Published: August 2020

Foreword — Animal experimentation is an emotional topic, which arouses passionate feelings both in animal protection groups and in the scientific community. For many years, antivivisectionists have fought for the abolition of all animal experimentation, whereas other groups campaign for suppression/reduction of the level of pain animals suffer because of experimentation. Despite all these efforts, the number of animals used in scientific research does not seem to have decreased significantly during the last few years. At best, this number remains constant or shows minor reductions in some countries, whereas in others it is still increasing. In addition to this situation, which certainly does not satisfy the antivivisectionists, the validity of the use of animal models in biomedical research is increasingly being questioned. On the other hand, a number of developments and projects exist which attest to the growing interest of scientists in in vitro models which use few, or even no, animals. Such a change in attitude is particularly evident in practice and research in toxicology, which uses a large number of animals. Taking into account the special status of toxicology among the biomedical sciences, since its practice is required and defined by laws and directives, a semantic problem exists over which adjective should be applied to describe such new methods. For some, it must be alternative — for consistancy to underline the possibility of replacing classical in vivo tests with new in vitro tests, the validity of which is demonstrated by reference to these in vivo tests. For others, it has to be complementary — to characterise the new protocols and the new experimental models which are of interest, because they contribute to the improvement of toxicology by strengthening its scientific nature. For a third group, it must be adjunct — to emphasise the relatively minor role of non-animal tests in relation to the conventional animal tests. It is the second concept that is favoured in this article. The experimental models to which it applies will, according to the Three Rs of Russell & Burch (1), lead either to the replacement of animal models, or to a reduction in the number of animals used or to refinement of test procedures in order to minimise the suffering and stress caused to animals.
Animal Pain Scales in Public Policy
Authors: Orlans F. Barbara
Published: August 2020

Pain scales classify the severity of pain inflicted on laboratory animals from little or none up to severe. A pain scale as part of public policy serves beneficial purposes that promote animal welfare. It can be used to educate people about the two alternatives of refinement and replacement, and the need to reduce animal pain. Furthermore, a pain scale has practical applications: 1) in review procedures for animal welfare concerns; 2) in developing policies on the use of animals in education; and 3) as a basis for collecting national data on animal experimentation, so that meaningful data can be collected on trends in reduction and control in animal pain.

So far, only a few countries (including Sweden, the Netherlands, Canada and New Zealand) have adopted pain scales as part of their public policy. Most countries, including the United States, have not yet done so. The history of the development and adoption of pain scales by various countries is described and the case is presented for wider adoption of a pain scale in countries not currently using one.
Alternatives to and Reduction of Animal Use in Biomedical Research, Education and Testing
Authors: Frazier John M. , Goldberg Alan M.
Published: August 2020

Biomedical endeavours can be divided into three major categories: research, education, and testing. Within the context of each of these categories, activities involving whole animals have made major contributions and will continue to do so in the future. However, with technological developments in the areas of biotechnology and computers, new methods are already reducing the use of whole animals in certain areas. This article discusses the general issues of alternatives and then focuses on the development of new approaches to toxicity testing.
Applications of the Neutral Red Cytotoxicity Assay to In Vitro Toxicology
Authors: Babich Harvey , Borenfreund Ellen
Published: August 2020

A concerted effort is currently in progress to develop alternatives to the use of live animals for the acute toxicity testing of xenobiotics. To this end, the neutral red in vitro cytotoxicity assay was developed which, although initially based on the use of mammalian cells in culture, has also been adapted for ecotoxicity studies using fish cells in culture. The neutral red assay is based on the binding of neutral red, a weakly cationic supravital dye, to the lysosomal matrix of viable cells after their incubation with toxic agents. Spectrophotometric quantitation of the extracted dye with a scanning microtitre well reader at 540nm was found to be linear with the number of surviving, viable cells. The assay has been used to determine the relative acute cytotoxicities of a broad spectrum of chemical test agents, to establish structure-toxicity relationships for series of related chemicals, to study metabolism-mediated cytotoxicity, to evaluate interactions between combinations of test agents, to evaluate differential and selective toxicities of cancer chemotherapeutics and other pharmaceuticals, and to study temperature-toxicity interactions.
In Vitro Testing of Neurotoxicity
Authors: Walum Erik , Hansson Elisabeth , Harvey Alan L.
Published: August 2020

Many of the toxic compounds that are at large in the environment represent a risk to our neuronal functions. Chemicals may have a direct or indirect effect on the nervous system and they may interfere with general biochemical properties or specific neuronal structures and processes. In this review, a brief presentation of the major neurotoxicological targets is given, together with a discussion of some aspects of the use of different in vitro models for screening purposes and mechanistic studies. It is believed that in vitro methods offer special opportunities for the development of new neurotoxicological assays, and that this development will mainly involve cultured model systems. Therefore, a presentation of nerve and glia tissue culture methods is given, followed by an overview of how information on the action of mercury and mercurials, excitotoxins and acrylamide has been obtained through the use of cultured cell models. It is concluded that the developmental potential in cell neurotoxicology lies within the areas of separation and identification of cells representative for different structures in the nervous system, co-cultivation of different cell types, in vivo/in vitro (ex vivo) procedures, chemically defined media, metabolic competent cultures of human cells and improved physiological conditions for cultivation and exposure.