The 3D reconstructed skin micronucleus assay: considerations for optimal protocol design

Implementation of the seventh amendment to the EU Cosmetics Directive has driven much research into suitable in vitro alternative assays to support satisfactory risk assessments. One such assay is the reconstructed skin micronucleus (RSMN) assay. First reported in 2006, further development occurred and a standard protocol was published in 2011. To evaluate and optimise the assay at Covance Laboratories, we tested nine chemicals [4-nitrophenol (4-NP), cyclohexanone (CH), 2-ethyl-1,3-hexanediol (2-EHD), methyl methansulfonate (MMS), mitomycin C (MMC), ethyl nitrosourea (ENU), benzo[a]pyrene (BaP), cyclophosphamide (CPA) and vinblastine (VIN)] using the EpiDerm™ 3D skin model (MatTek Corporation®, IVLSL, Bratislava, Slovakia) and compared the data using the standard 48-h treatment regimen and also an emerging 72-h treatment protocol. The EpiDerm™ tissue has reportedly some metabolic capacity but data using 48-h treatments has provided mixed results. Our investigations demonstrate that the two chemicals requiring metabolic activation (BaP and CPA) were negative following the 48-h protocol but were clearly positive following 72-h treatment. Furthermore, Replication Index (RI) data showed higher RI values in vehicle control treatments (indicating increased cell division) across the treatment set following 72-h treatments. A general greater magnitude of micronucleus (MN) induction was also observed following test chemical treatment. These data suggest that the 72-h treatment protocol is more suitable as a standard approach for the detection of clastogenic, aneugenic and metabolically activated chemicals in the RSMN assay. For further assay optimisation, we compare the statistical power of scoring cells from duplicate or triplicate cultures per treatment concentration and provide recommendations.

Global alterations to the choroid plexus blood-CSF barrier in amyotrophic lateral sclerosis

The choroid plexus (CP) is a highly vascularized structure located in the ventricles that forms the blood-CSF barrier (BCSFB) and separates the blood from the cerebrospinal fluid (CSF). In addition to its role as a physical barrier, the CP functions in CSF secretion, transport of nutrients into the central nervous system (CNS) and a gated point of entry of circulating immune cells into the CNS. Aging and neurodegeneration have been reported to affect CP morphology and function and increase protein leakage from blood to the CSF. Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease associated with both upper and lower motor neuron loss, as well as altered proteomic and metabolomic signatures in the CSF. The role of the BCSFB and the CP in ALS is unknown. Here we describe a transcriptomic and ultrastructural analysis of BCSFB and CP alterations in human postmortem tissues from ALS and non-neurologic disease controls. ALS-CP exhibited widespread disruptions in tight junctional components of the CP epithelial layer and vascular integrity. In addition, we detected loss of pericytes around ALS blood vessels, accompanied by activation of platelet aggregation markers vWF and Fibrinogen, reminiscent of vascular injury. To investigate the immune component of ALS-CP, we conducted a comprehensive analysis of cytokines and chemokine panels in CP lysates and found a significant down-regulation of M-CSF and V-CAM1 in ALS, as well as up-regulation of VEGF-A protein. This phenotype was accompanied by an infiltration of MERTK positive macrophages into the parenchyma of the ALS-CP when compared to controls. Taken together, we demonstrate widespread structural and functional disruptions of the BCSFB in human ALS increasing our understanding of the disease pathology and identifying potential new targets for ALS therapeutic development.

Analysis of historical negative control group data from the rat in vivo micronucleus assay

A database of micronuclei counts for historical negative control data from rat in vivo micronuclei tests performed in 10 different laboratories was established. Data were available from over 4000 negative control rats from 10 laboratories. The mean frequency of micronucleated cells (MN)/1000 cells ranged from 0.44 to 2.22, a 5-fold range. Overall there were no major sex or strain differences in frequency, although there were some small but statistically significant differences within laboratories. There was appreciable variability between experiments compared with variability within experiments in some laboratories. No specific factor was identified which could explain this variability although it was noted that many different vehicles were used in the experiments. It is hoped that these data will help laboratories beginning studies with the rat micronucleus assay and those involved in the assessment of micronucleus assay results.

Discussion on statistical analysis of carcinogenicity studies with an early terminated treated group

High rates of mortality on long term carcinogenicity studies can often result in challenges when it comes to the statistical analysis of tumor incidence. The current regulatory advice often results in treated groups being terminated earlier than the control group. However, this advice rarely considers the impact of this action on the statistical analyses. The nature of these analyses means that groups terminated at different times may not be directly comparable due to age differences of the animals. Here we discuss the issues related to this and investigate several approaches of how to incorporate these groups within the statistical analyses. Although no single method appears to resolve these issues consistently, inclusion of the early terminated group is still informative. Depending on the timing of the early termination, either pooling of the groups into a single terminal kill (TK) interval or reassignment of intervals based purely on time of death (ie, no separate TK interval) appear preferable. However, to draw meaningful conclusions the time of onset of a given tumor must also be considered alongside incident rates and any statistical findings.

Fewer invited talks by women in evolutionary biology symposia

Lower visibility of female scientists, compared to male scientists, is a potential reason for the under-representation of women among senior academic ranks. Visibility in the scientific community stems partly from presenting research as an invited speaker at organized meetings. We analysed the sex ratio of presenters at the European Society for Evolutionary Biology (ESEB) Congress 2011, where all abstract submissions were accepted for presentation. Women were under-represented among invited speakers at symposia (15% women) compared to all presenters (46%), regular oral presenters (41%) and plenary speakers (25%). At the ESEB congresses in 2001–2011, 9–23% of invited speakers were women. This under-representation of women is partly attributable to a larger proportion of women, than men, declining invitations: in 2011, 50% of women declined an invitation to speak compared to 26% of men. We expect invited speakers to be scientists from top ranked institutions or authors of recent papers in high-impact journals. Considering all invited speakers (including declined invitations), 23% were women. This was lower than the baseline sex ratios of early-mid career stage scientists, but was similar to senior scientists and authors that have published in high-impact journals. High-quality science by women therefore has low exposure at international meetings, which will constrain Evolutionary Biology from reaching its full potential. We wish to highlight the wider implications of turning down invitations to speak, and encourage conference organizers to implement steps to increase acceptance rates of invited talks.

The resolving power of in vitro genotoxicity assays for cigarette smoke particulate matter

In vitro genotoxicity assays are often used to compare tobacco smoke particulate matter (PM) from different cigarettes. The quantitative aspect of the comparisons requires appropriate statistical methods and replication levels, to support the interpretation in terms of power and significance. This paper recommends a uniform statistical analysis for the Ames test, mouse lymphoma mammalian cell mutation assay (MLA) and the in vitro micronucleus test (IVMNT); involving a hierarchical decision process with respect to slope, fixed effect and single dose comparisons. With these methods, replication levels of 5 (Ames test TA98), 4 (Ames test TA100), 10 (Ames test TA1537), 6 (MLA) and 4 (IVMNT) resolved a 30% difference in PM genotoxicity.

Recommendations on the statistical analysis of the Comet assay

In 2010, the Statisticians in the Pharmaceutical Industry (PSI) Toxicology Special Interest Group met to discuss the design and analysis of the Comet assay. The Comet assay is one potential component of the package of safety studies required by regulatory bodies. As these studies usually involve a three-way nested experimental design and as the distribution of the measured response is usually either lognormal or lognormal plus a point mass at zero, the analysis is not straightforward. This has led to many different types of analysis being proposed in the literature, with several different methods applied within the pharmaceutical industry itself. This article summarises the PSI Toxicology Group's discussions and recommendations around these issues.

Seismic images of crust and upper mantle beneath Tibet: evidence for Eurasian plate subduction

Seismic data from central Tibet have been combined to image the subsurface structure and understand the evolution of the collision of India and Eurasia. The 410- and 660-kilometer mantle discontinuities are sharply defined, implying a lack of a subducting slab beneath the plateau. The discontinuities appear slightly deeper beneath northern Tibet, implying that the average temperature of the mantle above the transition zone is about 300 degrees C hotter in the north than in the south. There is a prominent south-dipping converter in the uppermost mantle beneath northern Tibet that might represent the top of the Eurasian mantle lithosphere underthrusting the northern margin of the plateau.

Sociodemographic, behavioral, and clinical correlates of inconsistent condom use in HIV-serodiscordant heterosexual couples

We examined sociodemographic, behavioral, and clinical characteristics associated with inconsistent condom use in a cross-sectional analysis of 145 sexually active HIV-serodiscordant heterosexual couples who participated in the California Partners Study II. All couples were aware of their HIV-serodiscordant status. Forty-five percent of couples reported having had unprotected vaginal or anal sex in the previous 6 months. In the multivariate couple-level analyses, factors independently associated with inconsistent (i.e., <100%) condom use in the previous 6 months included lower educational level, unemployment, African-American ethnicity, and practice of anal sex by the couple. Injection drug use was associated with inconsistent condom use among couples with younger HIV-infected partners. In addition, couples with HIV-infected partners who had higher CD4 cell counts and couples in which the HIV-infected male partner ever had sex with a man were more likely to use condoms inconsistently. Consistency of condom use did not depend on the gender of the HIV-infected partner or duration of sexual relationship. The findings suggest that many HIV-serodiscordant heterosexual couples remain at high risk of HIV transmission and may benefit not only from behavioral interventions but also from structural interventions aimed at improving their social and economic conditions.

Teaching senior nurses how to teach communication skills in oncology

Many nurses acknowledge that their nursing practice is hampered by inadequate teaching about communication skills during their nursing education. Ineffective communication has negative effects on patient care and causes stress when nurses interact with each other, with medical colleagues, with patients and their relatives. Many senior nurses teach junior staff about communication and feel uncertain about their competence to do so despite recognition of its importance. This article reports data from a training initiative endorsed by the Royal College of Nursing in the United Kingdom (UK) aimed at helping senior nurses to identify their personal strengths and weaknesses when communicating, learn new teaching methods and encourage new teaching initiatives. A residential 2-day course, based on learner-centered methods was employed. One hundred and twenty nine nurses from UK cancer centers worked on personal communication problems via group discussions, video demonstrations, small group teaching exercises and role-plays with professional actors. Post-course, participants reported significantly greater confidence in handling 14 common communication problem areas in cancer (p < .0001) and in 8 different areas of teaching. Participants were very enthusiastic about the course overall and especially valued the training approach and teaching materials provided. Three months post-course 91% reported changing their own teaching practice and 85% had initiated new communication skills teaching.

The relationships between ethnicity, sex, risk group, and virus load in human immunodeficiency virus type 1 antiretroviral-naive patients

This cross-sectional study examined the relationships between ethnicity, sex, risk group, and virus load in human immunodeficiency virus type 1 (HIV-1) antiretroviral-naive patients. HIV-1 RNA levels were measured in 322 patients attending St. Thomas' Hospital between May 1997 and February 1999. By univariate analyses, only clinical status and CD4(+) cell count were related to virus load. In multivariate analysis, variables independently related to virus load were CD4(+) cell count (P=.001), being black African (P=.001), having a nonsexual risk for HIV infection (P=.03), and having AIDS (P=.05). Neither sex nor age was a significant predictor of initial virus load after adjusting for other variables. For a given CD4(+) cell count, black Africans and people who contracted HIV nonsexually presented with a virus load lower than that of patients in other groups. Because virus loads may need to be interpreted differently according to ethnicity, this may affect decisions on when to initiate antiretroviral therapy and how to interpret clinical trial results.

Subarachnoid-pleural fistula treated with noninvasive positive-pressure ventilation. Case report

The authors describe the case of a 24-year-old man who underwent an L-1 corpectomy for spinal decompression and stabilization following an injury that caused an L-1 burst fracture. Postoperatively, an accumulation of spinal fluid developed in the pleural space, which was refractory to 1 week of thoracostomy tube drainage and lumbar cerebrospinal fluid (CSF) diversion. The authors then initiated a regimen of positive-pressure ventilation in which a bi-level positive airway pressure (PAP) mask was used. After 5 days, the CSF collection in the pleural space resolved. Use of a bi-level PAP mask represents a safe, noninvasive method of reducing the negative intrathoracic pressure that promotes CSF leakage into the pleural cavity and may be a useful adjunct in the treatment of subarachnoid-pleural fistula.

Psychiatric morbidity and its recognition by doctors in patients with cancer

Psychiatric morbidity in patients with cancer is high and without appropriate treatment unremitting. We assessed the ability of 143 doctors to establish the psychological status of 2297 patients during outpatient consultations in 34 cancer centres and hospitals in the UK. Prior to seeing the doctor, consenting patients completed a short self-report questionnaire (GHQ12), designed for the psychological screening of large populations. At the end of the consultation, doctors completed visual analogue scales rating patients' distress. 837/2297 (36.4%) patients had GHQ scores suggestive of psychiatric morbidity. The doctors' sensitivity (true positive rate) was 28.87% (SD 25.29), specificity (true negative rate) 84.79% (SD 17.44). The misclassification rate was 34.7% (SD 13.79) meaning that for 797 patients the wrong assessment was probably made. These data show that much of the probable psychiatric morbidity experienced by patients with cancer goes unrecognized and therefore untreated. Doctors need communication skills training to elicit problems during consultations. Appropriate referrals to psychological services are necessary when patients requiring help are identified and ought to be an integral part of cancer care.

Information needs of patients with cancer: results from a large study in UK cancer centres

As part of a multi-centred study evaluating a communication skills training model for clinicians, we collected information preferences using an adaptation of Cassileth's Information Needs questionnaire from a heterogeneous sample of 2331 patients. Results showed that 87% (2027) wanted all possible information, both good and bad news and 98% (2203) preferred to know whether or not their illness was cancer. Cross tabulation of responses revealed no significant differences in information preferences for tumour site or treatment aims but did show an effect of age and sex. The few 58/440 (13.2%) patients who stated that in general they preferred to leave disclosure of details up to the doctor, tended to be older patients more than 70 years of age (chi square = 26.01, df = 2, P< 0.0001), although paradoxically they still wanted to know certain specific details. In comparison to men women preferred to know the specific name of the illness (chi square = 4.9, df = 1, P< 0.02) and what were all the possible treatments (chi square = 8.26, df = 1, P< 0.004). The results from this very large sample provide conclusive evidence that the vast majority of patients with cancer want a great deal of specific information concerning their illness and treatment. Failure to disclose such information on the grounds that significant numbers of patients prefer not to know is untenable.

Sexual risk behaviors among heterosexual HIV serodiscordant couples in the era of post-exposure prevention and viral suppressive therapy

OBJECTIVES

To describe awareness and use of antiretroviral treatments, viral load monitoring, and post-exposure prevention; to assess changing concerns about HIV transmission; and to examine the effect of these advances on sexual behavior in HIV-serodiscordant heterosexual couples.

METHODS

Cross-sectional analysis of a baseline sample of 104 couples (n = 208 individuals) from the California Partners Study II, an intervention trial for HIV-serodiscordant couples in California. Questions on sexual practices, viral load testing, HIV treatment, post-exposure prevention, and their effect on sexual behaviors, risk taking and transmission concerns were measured at intake.

RESULTS

Over two-thirds of couple members surveyed reported unprotected sex with their partner in the past 6 months. Among seropositive respondents, 37% were taking protease inhibitor therapy, 92% had undergone viral load testing, and of those, 40% said it had ben undetectable at their most recent test. Most respondents, regardless of serostatus, said that viral load testing and awareness of post-exposure prevention had no effect on their condom use. In addition, perceiving that their partner had an undetectable viral load was associated with having protected sex among seronegative subjects (P < 0.05). Seropositive respondent taking protease inhibitors were 2.4 times less likely to report unprotected sex compared with those not taking protease inhibitors (P = 0.05). However, up to 33% of seropositive and 40% of seronegative respondents acknowledged decreased transmission concerns in the light of the new HIV treatments. In comparison with their seropositive partners, seronegative individuals were more likely to acknowledge increased risk taking and decreased HIV transmission concerns (P < 0.05).

CONCLUSIONS

New medical advances were not associated with unprotected sex in HIV-serodiscordant couples. However, new treatment options may decrease concerns about HIV transmission, particularly among seronegative partners. Providers should discuss the effect of antiretroviral treatments on sexual transmission risk with their patients. The inclusion of seronegative partners in counseling interventions may decrease risk taking in serodiscordant couples.

Prehospital interventions in children

OBJECTIVES

Frequently performing procedures assists in skill maintenance. This study was conducted to characterize frequency and types of basic and advanced prehospital interventions performed on children.

METHODS

A retrospective study was conducted over a three-month period from emergency medical services (EMS) units working in central Michigan. Data were collected for age, sex, at-scene time, total run time, basic procedures (e.g., spinal immobilization), and advanced procedures (e.g., venous access).

RESULTS

A total of 535 EMS runs were reviewed. Runs were excluded for transport refusal (105) and site-to-site transfer (6). Of the remaining 424 children, 287 received an intervention (group 1) and 137 did not (group 2). Group 1 (9.5 +/- 5.6 years) was older (p < 0.001) than group 2 (6.0 +/- 5.8 years). There was no gender predominance between group 1 and group 2 (p = 0.06). In group 1 there were 104 patients who received multiple procedures. Basic procedures (n = 382) included spinal immobilization (149), oxygen administration (123), splinting (27), wound care (24), use of military anti-shock trousers (4), and cardiopulmonary resuscitation (1). Advanced procedures (n = 112) included venous access (65), medications of all routes (26), and cardiacoximetry monitoring (21). No child had an intraosseous line started and no child was successfully intubated. Only 82 of the 424 children (19.3%) had an advanced procedure. Group 1 at-scene times (16.1 +/- 8.1 min) were longer (p < 0.001) than those of group 2 (11.1 +/- 6.6 min). Total run times for group 1 (35.7 +/- 15.5 min) were longer (p < 0.001) than those for group 2 (26.7 +/- 11.3 min).

CONCLUSIONS

Advanced EMS procedures were performed on only 19.3% of children. Opportunities to perform critical interventions (e.g., intubation) were rarely present. Children receiving procedures were older and had longer scene and run times.

The epidemiology of pityriasis versicolor in Malawi, Africa

During a total population survey in 1988 and 1989 in Karonga district, northern Malawi, 4915/61735 (8.0%) people examined were found to have extensive pityriasis versicolor (PV). An additional 6085 people (9.9%) were diagnosed as having mild disease. The highest prevalence rates of extensive and mild PV were found among subjects aged 15-24 years. In this age group between 20% and 25% of people had extensive PV. Rates were generally higher among males than among females. PV was rarely found in prepubertal subjects.

Plasma digoxin levels in anuric patients and normal subjects taking digitoxin

Plasma digoxin suspected to be elevated in anuric patients taking digitoxin was determined by radioimmunoassay in 15 anuric patients and 15 normal persons subjected to 0.1 mg digitoxin therapy per day. All plasma digoxin values from the anuric patients and the normal subjects were far below the lower limit of the therapeutic range of plasma digoxin. There existed no difference between the digoxin values determined in anuric patients and subjects with normal renal function; in both groups there was a scatter of digoxin values about the cross reaction line between digitoxin and digoxin antibody. It is concluded from the results that digoxin retention in anuric patients taking digitoxin plays an insignificant role; thus, the pharmacological effect is mediated by digitoxin itself.

[Simplified rapid determination of plasma digoxin. Methods and clinical evaluation]

The introduction of the Gamma Coat 125I-Digoxin Radioimmunoassay has simplified the digoxin determination to an extent that it may be used even in general hospitals with an intensive care unit. The total time for a stat determination has been reduced to 70 min. The coefficient of variation of the digoxin determination at low levels (less than 0.8 ng/ml) was less than 15% for simultaneous and repeated measurements even when using one of the inexpensive nuclear counting systems. At high levels (greater than 2.5 ng/ml) the coefficient of variation showed to be less than 6%. Hemolysis, low albumine concentration and other than digoxin-bound isotopes in the blood samples did not cause methologic problems. Provided that resorption and elimination kinetics of the different digoxin preparations were taken into account, digoxin levels of more than 2 ng/ml as measured by the Gamma Coat method in patients with normal renal function plasma were usually associated with clinical signs of overdosage; therapeutic concentrations were mostly higher than 1.2 ng/ml. The incidence of digitalis toxicity with high digoxin levels was lower in uremic than in normal patients. According to preliminary observations in dialysis patients this increase in tolerance to digitalis, may be a consequence of hyperkalemia and renal acidosis. Erroneously high digoxin concentrations were found in patients up to 2 hrs after injection of high doses of spironolactone (400-1000 mg) due to cross reaction. Therapeutic concentrations of digitoxin (10-25 ng/ml) caused only subtherapeutic digoxin concentrations of 0.4-0.9 ng/ml.