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SummaryAim To understand the experiences of students and problem-based learning (PBL) facilitators during an evidence-based curriculum change to a PBL programme within an undergraduate medical course in South West England. Methods Four novel PBL cases were designed and implemented, based on educational theory and evidence. Eight focus groups were undertaken with Year-1 and -2 students (n = 18) and PBL facilitators (n = 14) to explore the experiences of participants. Thematic analysis and conceptual abstraction led to insights into the intended and unintended consequences of the change. Results Participant responses to the change process were influenced by the perceived relevance and value of the change (e.g. benefit to student learning), which was shaped by individual beliefs and preferences (e.g. presumed purpose of PBL, relative value placed on different curriculum topics, and desire for uniform educational experience), and the wider education context (e.g. expectations of assessment). It appears that the three distinct elements must align for the changes to be received positively. We updated our PBL curriculum in response to new evidence Discussion This study describes how we updated our PBL curriculum in response to new evidence, and demonstrates the importance of communicating the pedagogic rationale behind changes, and meticulous planning, preparation and alignment, even in distant parts of the curriculum. Engaging with existing views and attitudes is an essential requirement for successful curriculum change.

SUMMARYInfections by Campylobacter spp. are a major cause of gastrointestinal disease in the United Kingdom. Most cases are associated with the consumption of chicken that has become contaminated during production. We investigated the epidemiology of Campylobacter spp. in chickens in a 3-year longitudinal study of flocks reared on 30 farms in the United Kingdom. We used Generalized Linear Mixed Effect Models (GLMM) to investigate putative risk factors associated with incidence and prevalence of flock infection arising from farm and flock management and local environmental conditions during rearing. We used survival analysis to investigate infection events and associated risk factors over the course of the study using two marginal models – the independent increment approach, which assumed that individual infection events were independent; and a conditional approach, which assumed that events were conditional on those preceding. Models of flock prevalence were highly overdispersed suggesting that infection within flocks was aggregated. The key predictors of flock infection identified from the GLMM analyses were mean temperature and mean rainfall in the month of slaughter and also the presence of natural ventilation. Mean temperature in the month of slaughter was also a significant predictor of flock infection, although the analyses suggested that the risk in flocks increased in a unimodal way in relation to temperature, peaking at 12°C. The extent of pad burn was also identified as a predictor in these analyses. We conclude that predicting prevalence within flocks with linear modelling approaches is likely to be difficult, but that it may be possible to predict when flocks are at risk of Campylobacter infection. This is a key first step in managing disease and reducing the risks posed to the human food chain.

In this paper we present results on transverse mass spectra and Hanbury-Brown and Twiss correlation functions of negatively charged hadrons, which are expected to be mostly negative pions, measured in Pb-Pb collisions at 40 A GeV/c beam momentum. Based on these data, the collision dynamics and the space-time extent of the system at the thermal freeze-out are studied over a centrality range corresponding to the most central 53% of the Pb--Pb inelastic cross section. Comparisons with freeze-out conditions of strange particles and HBT results from other experiments are discussed., 29 pages, 18 figures

Results are presented on hyperon and antihyperon production in Pb-Pb, pPb and pBe collisions at 158 GeV/c per nucleon. Lambda, Xi and Omega yields have been measured at central rapidity and medium transverse momentum as functions of the centrality of the collision. Comparing the yields in Pb-Pb to those in pBe interactions, strangeness enhancement is observed. The enhancement increases with the centrality and with the strangeness content of the hyperons, reaching a factor of about 20 for the Omega in the central Pb-Pb collisions., submitted to J. Phys. G.: Nucl. Part. Phys

We present central-to-peripheral nuclear modification factors, R CP , for the p T distributions of K S 0 , Λ, Λ ¯ , and negatively charged particles, measured at central rapidity in Pb–Pb collisions at top SPS energy. The data cover the 55% most central fraction of the inelastic cross section. The K S 0 and Λ R CP ( p T ) are similar in shape to those measured at s NN = 200 GeV at RHIC, though they are larger in absolute value. We have compared our K S 0 R CP data to a theoretical calculation. The prediction overestimates the data at p T ≈ 3 – 4 GeV / c , unless sizeable parton energy loss is included in the calculation.

A measurement of strange baryon and antibaryon production in Pb-Pb collisions has been carried out by the NA57 experiment at the CERN SPS, with 40 and 158 A GeV/c beam momentum. Results on $\Lambda$, $\Xi$ and $\Omega$ hyperon yields at mid-rapidity in the most central 53% of Pb-Pb collisions at 40 A GeV/c are presented and compared with those obtained at higher energy, in the same collision centrality range. The $\Lambda$ and $\Xi^-$ yields per unit rapidity stay roughly constant while those of $\Omega^-$, $\bar\Lambda$, $\bar\Xi^+$ and $\bar\Omega^+$ increase when going to the higher SPS energy. Hyperon yields at the SPS are compared with those from the STAR experiment in $\sqrt{s_{NN}}$ = 130 GeV Au-Au collisions at RHIC., Comment: 9 pages, 4 figures, 3 tables, accepted for publication in Physics Letters B

This paper presents an experimental investigation of the effects of reverse bending and straightening process on the mechanical properties of a typical carbon steel bar used for civil engineering applications. Twenty four specimens each were used for the metallogarphy, microhardness and tensile tests. The investigation revealed that the reverse bending and straightening process has no significant effect on the bars’ through-thickness microstructure and hardness. However, the reverse bending and straightening process reduces the yield load, ultimate load, and displacement at fracture of the bars by 4.27%, 2.58%, and 18.62% respectively. These results highlight the need to take into consideration the effects of the previous loading history of the bars/wires, particularly the reduction in the displacement at fracture and consequently, the ductility of the bars/wires in the design and fitness for purpose assessment of components made from them, since the bars/wires could experience high strain during installation and in service due to overloads.

The new results on hyperon production in Pb-Pb collisions at 158 A GeV/c and 40 A GeV/c are presented. Publisher Summary This chapter discusses the yields of hyperon in Pb–Pb collisions from the NA57 experiment. The aim of NA57 was to study the dependence of the strangeness enhancement on the interaction volume and the collision energy per incoming nucleon. The centrality range of the NA57 experiment extended down to a limit of about 50 wounded nucleons. The experiment collected data using 158 and 40 A GeV/c beams at the CERN SPS. There was indication of an increase of the enhancements with the centrality of the collisions. The data were corrected for acceptance and efficiency losses by calculating weight for each particle with a GEANT-based Monte-Carlo simulation.

[EN] Geographical and seasonal variation in the incidence and prevalence of Campylobacter jejuni and C. coli in housed broiler flocks reared in Great Britain in 2004 to 2006 was investigated in this study. Ceca (30) from 797 flocks, not subject to prior partial depopulation and reared on 211 farms, were examined individually for the presence of Campylobacter spp. The best-fitting climatic factors explained approximately 46% of the prevalence of Campylobacter-colonized flocks at slaughter and consisted of a combination of temperature at slaughter, number of sunshine hours in placement month, and millimeters of rainfall in placement month. Positive flocks were more likely to be slaughtered between June and November than during the rest of the year and to be reared in northern Great Britain than in central or southern Great Britain. C. jejuni was identified in approximately 90% of flocks, and C. coli was present in 10% of flocks. The most common clonal complexes identified in 226 isolates typed by multilocus sequence typing (MLST) were ST-45, ST-21, ST-574, ST-443, and ST-828. Flocks slaughtered at the same time were more likely to have similar complexes, and ST-45 had a seasonal pattern, with the highest prevalence in June, and was also more likely to be present in flocks reared in northern Great Britain. © 2011, American Society for Microbiology., This work was supported by the UK Food Standards Agency (project code B15001) and by the Health Protection Agency.

We describe two methods for the optimization of gas transmission networks. The first method reduces the number of variables in the optimization problem by eliminating the pipe-flow variables. The second method solves an optimization problem with the full set of variables to achieve better behaviour. These two methods are compared by a series of tests based on the British Gas NTS (National Transmission System). The results of these tests are reported. By formulating the network problem as an optimization problem we have been able to replace heuristics by well proven methods. The reliability of the algorithm using the reduced set of unknowns varied depending on the size of problem and the type of objective function being minimized. The algorithm using the full set of unknowns had no such difficulties, even though it needs to be used with some care. The algorithm is robust in the sense that when the objective function has the necessary continuities, there is a feasible point and the penalty terms ensure positive curvature, then a solution is found reliably. The algorithm based on the reduced set of unknowns is considerably faster than that using the full set, when it succeeds. The factor between the times taken ranges from 1.2 to 5 (average 3) for the smallest network. For the second case comparison is harder since the reduced set algorithm was given a head start in five cases. For the other five the factor is between 2.3 and 8.3. For the largest problem there is just one case in which the comparison is on equal terms, and here the factor is 18. It is clear that the reliability of the full set algorithm is bought at a considerable cost which rises as the problem gets bigger. The main conclusion is that the Sequential Augmented Lagrange Method yields a reliable algorithm for minimizing objective functions of practical interest based on gas networks such as the British Gas National Transmission System. It is not satisfactory to carry over to the case with machines techniques like those of the nodal and loop methods which work well on networks with no machines.

Rates of homogeneous nucleation of ice in micrometre-sized water droplets are reported. Measurements were made using a new system in which droplets were supported on a hydrophobic substrate and their phase was monitored using optical microscopy as they were cooled at a controlled rate. Our nucleation rates are in agreement, given the quoted uncertainties, with the most recent literature data. However, the level of uncertainty in the rate of homogeneous freezing remains unacceptable given the importance of homogeneous nucleation to cloud formation in the Earth's atmosphere. We go on to use the most recent thermodynamic data for cubic ice (the metastable phase thought to nucleate from supercooled water) to estimate the interfacial energy of the cubic ice-supercooled water interface. We estimate a value of 20.8 +/- 1.2 mJ m(-2) in the temperature range 234.9-236.7 K.

This study investigated the relationship between flock health and Campylobacter infection of housed commercial broilers in Great Britain. Thirty ceca were collected at slaughter from batches of broilers from 789 flocks, at either full or partial depopulation, between December 2003 and March 2006 and examined individually for Campylobacter by direct plating onto selective media. Management and health data were collected from each flock and included information on mortality or culling during rearing, the number of birds rejected for infectious or noninfectious causes at slaughter, the proportion of birds with digital dermatitis (also termed hock burn), and other general characteristics of the flock. Campylobacter spp. were isolated from 280 (35%) flocks. The relationship between bird health and welfare and Campylobacter status of flocks was assessed using random-effects logistic regression models, adjusting for region, month, year, and rearing regime. Campylobacter -positive batches of ceca were associated with higher levels of rejection due to infection (odds ratio [OR], 1.5; 95% confidence interval [CI 95% ], 0.98 to 2.30) and digital dermatitis (OR, 2.08; CI 95% , 1.20 to 3.61). Furthermore, higher levels of these conditions were also associated with the highest-level category of within-flock Campylobacter prevalence (70 to 100%). These results could indicate that improving health and welfare may also reduce Campylobacter in broilers.

The study aimed to identify sources of campylobacter in 10 housed broiler flocks from three United Kingdom poultry companies. Samples from (i) the breeder flocks, which supplied the broilers, (ii) cleaned and disinfected houses prior to chick placement, (iii) the chickens, and (iv) the environments inside and outside the broiler houses during rearing were examined. Samples were collected at frequent intervals and examined for Campylobacter spp. Characterization of the isolates using multilocus sequence typing (MLST), serotyping, phage typing, and flaA restriction fragment length polymorphism typing was performed. Seven flocks became colonized during the growing period. Campylobacter spp. were detected in the environment surrounding the broiler house, prior to as well as during flock colonization, for six of these flocks. On two occasions, isolates detected in a puddle just prior to the birds being placed were indistinguishable from those colonizing the birds. Once flocks were colonized, indistinguishable strains of campylobacter were found in the feed and water and in the air of the broiler house. Campylobacter spp. were also detected in the air up to 30 m downstream of the broiler house, which raises the issue of the role of airborne transmission in the spread of campylobacter. At any time during rearing, broiler flocks were colonized by only one or two types determined by MLST but these changed, with some strains superseding others. In conclusion, the study provided strong evidence for the environment as a source of campylobacters colonizing housed broiler flocks. It also demonstrated colonization by successive campylobacter types determined by MLST during the life of a flock.

The transverse mass spectra of K0s, Lambda, Xi and Omega particles produced in Pb-Pb collisions at 40 A GeV/c have been studied for a sample of events corresponding to the most central 53% of the inelastic Pb-Pb cross-section. We analyze the distributions in the framework of a parameterized model inspired by hydrodynamics. The dependence of the freeze-out parameters on particle species and event centrality is discussed and comparisons with results at higher energy are shown., Comment: submitted to Journal Of Physics G: Nuclear And Particle Physics

The NA57 experiment has measured the production of strange and multi-strange hadrons in heavy-ion collisions at the CERN SPS. After briefly introducing the NA57 apparatus and analysis procedures, we present recent results on strangeness enhancement in Pb-Pb relative to $\textrm{p}$-Be collisions, on the study of the $m_{T}$ distributions of strange particles, and on central-to-peripheral nuclear modification factors in Pb-Pb collisions at top SPS energy. The NA57 experiment has measured the production of strange and multi-strange hadrons in heavy-ion collisions at the CERN SPS. After briefly introducing the NA57 apparatus and analysis procedures, we present recent results on strangeness enhancement in Pb-Pb relative to p-Be collisions, on the study of the m_T distributions of strange particles, and on central-to-peripheral nuclear modification factors in Pb-Pb collisions at top SPS energy. The NA57 experiment has measured the production of strange and multi-strange hadrons in heavy-ion collisions at the CERN SPS. After briefly introducing the NA57 apparatus and analysis procedures, we present recent results on strangeness enhancement in Pb+Pb relative to p+Be collisions, on the study of the m T distributions of strange particles, and on central-to-peripheral nuclear modification factors in Pb+Pb collisions at top SPS energy.

The multiplicity of charged particles in the central rapidity region has been measured by the NA57 experiment in Pb--Pb collisions at the CERN SPS at two beam momenta: 158 A GeV/{\it c} and 40 A GeV/{\it c}. The value of $dN_{ch}/d\eta$ at the maximum has been determined and its behaviour as a function of centrality has been studied in the centrality range covered by NA57 (about 50% of the inelastic cross section). The multiplicity increases approximately logarithmically with the centre of mass energy., Comment: 19 pages, 8 figures

The NA57 experiment has measured strange baryon and antibaryon production in Pb-Pb collisions at 40 A GeV/c and 160 A GeV/c beam momenta. This presentation covers strangeness enhancement and transverse spectra from the 160 A GeV/c data, and energy dependence of the particle yields. Enhancement factors increase with increasing strangeness content of the particle, when production yields from Pb-Pb collisions are compared with those observed in p-Be and p-Pb interactions. The transverse mass spectra have been analysed both with exponential fits and using a transverse flow model.

The NA57 experiment has been designed to study the onset of enhanced production of strange baryons and anti-baryons in Pb-Pb collisions with respect to p-Be collisions. Results from 40 and 160 A GeV/c Pb-Pb data will be shown. The main focus is on the checks of the NA57 analysis chain.

The recent development of simple, rapid genotyping techniques for Campylobacter species has enabled investigation of the determinative epidemiology of these organisms in a variety of situations. In this study we have used the technique of fla typing (PCR-restriction fragment length polymorphism analysis of the flaA and flaB genes) to identify the sources of strains contaminating the carcasses of five campylobacter-positive and two campylobacter-negative broiler flocks during abattoir processing. The results confirmed that, in the United Kingdom, individual broiler flocks are colonized by a limited number of subtypes of Campylobacter jejuni or C. coli . In some but not all cases, the same subtypes, isolated from the ceca, contaminated the end product as observed in carcass washes. However, the culture methodology, i.e, use of direct plating or enrichment, affected this subtype distribution. Moreover, the number of isolates analyzed per sample was limited. fla typing also indicated that some campylobacter subtypes survive poultry processing better than others. The extent of resistance to the environmental stresses during processing varied between strains. The more robust subtypes appeared to contaminate the abattoir environment, surviving through carcass chilling, and even carrying over onto subsequent flocks. From these studies it is confirmed that some campylobacter-negative flocks reach the abattoir but the carcasses from such flocks are rapidly contaminated by various campylobacter subtypes during processing. However, only some of these contaminating subtypes appeared to survive processing. The sources of this contamination are not clear, but in both negative flocks, campylobacters of the same subtypes as those recovered from the carcasses were isolated from the crates used to transport the birds. In one case, this crate contamination was shown to be present before the birds were loaded.

PoS(hep2001)248; New data on strange baryon yields in Pb–Pb interactions at 158 GeV/c per nucleon are presented as a function of the collision centrality. The possible onset of a deconfined phase when the collision involves from 50 to 100 wounded nucleons is discussed.

The potential of Norway rats (Rattus norvegicus) to spread the parasite Cryptosporidium parvum was investigated by examining parasite prevalence in relation to the structure and movements of three permanent rat populations living on farmland in Warwickshire (UK) from October 1994 to March 1997. One population lived among a group of farm buildings housing cattle, while the other two had no contact with livestock, one living around a pond and its outflowing stream and the other on a rubbish tip. Overall, parasite occurrence was 24% (n = 438), but it varied according to body weight (age) with 40% of juveniles (or =100 g) infected decreasing to 12% for adults400 g, suggesting that actively breeding populations are potentially more likely to spread the parasite than non-breeding populations. There was no difference in prevalence between the three populations. The parasite was detected in more males (29%) than females (19%). Seasonally, on the livestock farm, prevalence was significantly lower in autumn (10%), but varied little (31-36%) from winter to summer. In contrast, on the arable farm, prevalence peaked in summer (50%) with a trough in winter (6%). Infection in rats appeared to last67 days. Rats living on the livestock farm had home ranges largely confined to the cattle sheds, thereby maintaining a potential source of infection for livestock if rodent control was not part of a decontamination program. Equally, rats living around the pond on the arable farm provided a source of oocysts to contaminate the pond water, as well as being able to carry the parasite to nearby farm buildings or even to neighboring farms.

Phenobarbital treatment has been observed to be negatively associated with bladder cancer risk in a few studies. It has been suggested that phenobarbital may induce drug-metabolizing enzymes that detoxify the bladder carcinogens found in cigarette smoke. We examined the relationship of barbiturate use to bladder cancer risk and the potential modifying effect of cigarette smoking in a large cohort of Kaiser Permanente Medical Care Program members with computerized pharmacy prescriptions and smoking information. Newly diagnosed bladder cancers were identified among individuals in the study cohort by linkage with data from cancer registries. The overall standardized incidence ratio associated with barbiturate use was 0.71 [95% confidence interval (CI), 0.51-0.99]. Among current smokers, former smokers, and never smokers, the standardized incidence ratios were 0.56 (95% CI, 0.23-1.16), 0.68 (95% CI, 0.27-1.40), and 1.04 (95% CI, 0.48-1.98), respectively. Although our estimates were imprecise, the finding of an inverse association between barbiturate treatment and bladder cancer risk only among current and former cigarette smokers is consistent with the hypothesis that treatment with these medications induces drug-metabolizing enzymes that deactivate bladder carcinogens found in cigarette smoke.

In skeletal research, one of the techniques available to measure bone mineralization produces compositional data, which consist of vectors of ordered proportions of bone sample in prespecified density intervals. We investigated the value of two multivariate data transformations, the cumulative log ratio and the continuation log ratio, in the analysis of an experimental study of the dose-response effect of a drug treatment on bone mineralization. Based on a comparison of alternative approaches to the analysis of compositional bone mineralization data in the application and in a simulation study, we recommend the use of the average of the cumulative log ratios over all the density intervals to detect change in the density distribution. We also recommend the use of one of the continuation log ratios when a specific density interval of interest can be specified a priori.

Although there are few monoclonal antibody (MoAb) products on the market, the biotechnology industry has made considerable progress over the last decade. The industry has developed new technology to address the primary hurdles facing the development of MoAbs--including the immune response to murine-derived antibodies as well as lack of tumor specificity. As the techniques for development become more refined, more products will be approved by the Food and Drug Administration. Integrating these products into the existing healthcare system will be a challenge, given their high acquisition costs. Recent pharmacoeconomic examples outlined in this paper confirm that MoAb products will need to be supported with proven clinical and economic profiles. As long as a global clinical and economic perspective is taken and patient care benefits can be demonstrated, the place of MoAbs in the future of healthcare will be assured.

While much progress in curtailing exposure to environmental tobacco smoke has occurred in Ontario, many jurisdictions still do not have any restrictions on smoking. To assess support in Ontario for restrictions, and recent changes in knowledge, attitudes, and behavior, we compared the findings of a population-based telephone survey conducted in 1991 (n = 1421) to those of a similar survey conducted in 1983 (n = 1383). Increases were found in the population's reported knowledge of specific health effects. Marked changes occurred in attitudes to restrictions on smoking. In 1991, the population consistently favoured more restrictions on smoking and their enactment by all levels of government. A role for local health departments in enforcement was clearly recognized. Most smokers indicated that they would comply with more restrictions. We also found that the self-reported prevalence of smoking had decreased 8 percentage points between 1983 and 1991. Population-based evidence of strong and increasing support for restrictions, accompanied by predictions of a high level of compliance, especially by smokers themselves, should facilitate legislation aimed at further curtailing smoking.

To describe recent changes in knowledge, attitudes and behaviour with regard to restrictions on smoking, we compared the findings of population-based surveys conducted in Metropolitan Toronto in 1983 and 1988. In both surveys identical questions and similar data collection procedures were used. There were no changes in knowledge scores regarding the health effects of active smoking or environmental tobacco smoke (ETS), nor in smoking behaviour. In contrast, there were marked changes in attitudes. The population favoured more restrictions on smoking, including prohibition in specific locations, and there was greater support for restrictions on sales and advertising, for differential insurance rates favouring nonsmokers, and for higher taxes on cigarettes. Fewer 1988 respondents reported smoking among their associates and more reported being bothered by others' smoking. The implications for public health education and policy development are discussed.

Nuala Campbell and colleagues look at how to plan your career in the post-Modernising Medical Careers world

The effects of antibiotics on bovine luteinizing hormone (bLH)-stimulated output of androstenedione were examined in intact small white follicles (SWF, n = six hens), aliquots of 100,000 Fl and F2 theca cells (n = six hens), and aliquots of 10,000 Fl and F2 granulosa cells (n = eight hens). Cells and SWF were isolated from ovaries of Leghorn hens killed 20 h prior to ovulation and were incubated for 3 h in 1 mL of Medium 199 (Sigma Chemical Co., St. Louis, MO) at 37 C. Cells and follicles were incubated with 10 ng bLH and Penicillin-streptomycin (Pen-Strep; 20, 100, and 200 μ.g), gentamicin sulfate (gentamicin; 10, 50, and 100 μg), and fungizone (.5, 2.5, and 5.0 μg). Two control treatments consisted of tissues incubated alone (no bLH, no antibiotic) and tissues incubated with 10 ng bLH (no antibiotic). Androstenedione output by SWF and Fl and F2 theca cells and progesterone output by Fl and F2 granulosa cells were determined by radioimmunoassay of incubation media. The steroid contents of the incubation media were significantly increased in SWF and theca and granulosa cells with the addition of bLH. Neither Pen-Strep nor gentamicin significantly affected steroid output. Progesterone output by Fl and F2 granulosa cells was significantly reduced by the inclusion of fungizone. The inhibition of steroid output with the use of fungizone should be considered when using this antibiotic in studies of steroidogenesis in preparations of ovarian cells.

The effects of antibiotics on bovine luteinizing hormone (bLH)-stimulated output of androstenedione were examined in intact small white follicles (SWF, n = six hens), aliquots of 100,000 F1 and F2 theca cells (n = six hens), and aliquots of 10,000 F1 and F2 granulosa cells (n = eight hens). Cells and SWF were isolated from ovaries of Leghorn hens killed 20 h prior to ovulation and were incubated for 3 h in 1 mL of Medium 199 (Sigma Chemical Co., St. Louis, MO) at 37 C. Cells and follicles were incubated with 10 ng bLH and Penicillin-streptomycin (Pen-Strep; 20, 100, and 200 micrograms), gentamicin sulfate (gentamicin; 10, 50, and 100 micrograms), and fungizone (.5, 2.5, and 5.0 micrograms). Two control treatments consisted of tissues incubated alone (no bLH, no antibiotic) and tissues incubated with 10 ng bLH (no antibiotic). Androstenedione output by SWF and F1 and F2 theca cells and progesterone output by F1 and F2 granulosa cells were determined by radioimmunoassay of incubation media. The steroid contents of the incubation media were significantly increased in SWF and theca and granulosa cells with the addition of bLH. Neither Pen-Strep nor gentamicin significantly affected steroid output. Progesterone output by F1 and F2 granulosa cells was significantly reduced by the inclusion of fungizone. The inhibition of steroid output with the use of fungizone should be considered when using this antibiotic in studies of steroidogenesis in preparations of ovarian cells.