Exploring the effects of experimental parameters and data modeling approaches on in vitro transcriptomic point-of-departure estimates

Multiple new approach methods (NAMs) are being developed to rapidly screen large numbers of chemicals to aid in hazard evaluation and risk assessments. High-throughput transcriptomics (HTTr) in human cell lines has been proposed as a first-tier screening approach for determining the types of bioactivity a chemical can cause (activation of specific targets vs. generalized cell stress) and for calculating transcriptional points of departure (tPODs) based on changes in gene expression. In the present study, we examine a range of computational methods to calculate tPODs from HTTr data, using six data sets in which MCF7 cells cultured in two different media formulations were treated with a panel of 44 chemicals for 3 different exposure durations (6, 12, 24 hr). The tPOD calculation methods use data at the level of individual genes and gene set signatures, and compare data processed using the ToxCast Pipeline 2 (tcplfit2), BMDExpress and PLIER (Pathway Level Information ExtractoR). Methods were evaluated by comparing to in vitro PODs from a validated set of high-throughput screening (HTS) assays for a set of estrogenic compounds. Key findings include: (1) for a given chemical and set of experimental conditions, tPODs calculated by different methods can vary by several orders of magnitude; (2) tPODs are at least as sensitive to computational methods as to experimental conditions; (3) in comparison to an external reference set of PODs, some methods give generally higher values, principally PLIER and BMDExpress; and (4) the tPODs from HTTr in this one cell type are mostly higher than the overall PODs from a broad battery of targeted in vitro ToxCast assays, reflecting the need to test chemicals in multiple cell types and readout technologies for in vitro hazard screening.

Enhancing diabetes care for the most vulnerable in the 21st century: Interim findings of the National Advisory Panel on Care Home Diabetes (NAPCHD)

Older adults with diabetes may carry a substantial health burden in Western ageing societies, occupy more than one in four beds in care homes, and are a highly vulnerable group who often require complex nursing and medical care. The global pandemic (COVID-19) had its epicentre in care homes and revealed many shortfalls in diabetes care resulting in hospital admissions and considerable mortality and comorbid illness. The purpose of this work was to develop a national Strategic Document of Diabetes Care for Care Homes which would bring about worthwhile, sustainable and effective quality diabetes care improvements, and address the shortfalls in care provided. A large diverse and multidisciplinary group of stakeholders (NAPCHD) defined 11 areas of interest where recommendations were needed and using a subgroup allocation approach were set tasks to produce a set of primary recommendations. Each subgroup was given 5 starter questions to begin their work and a format to provide responses. During the initial phase, 16 key findings were identified. Overall, after a period of 18 months, 49 primary recommendations were made, and 7 major conclusions were drawn from these. A model of community and integrated diabetes care for care home residents with diabetes was proposed, and a series of 5 'quick-wins' were created to begin implementation of some of the recommendations that would not require significant funding. The work of the NAPCHD is ongoing but we hope that this current resource will help leaders to make these required changes happen.

Ready for regulatory use: NAMs and NGRA for chemical safety assurance

New approach methodologies (NAMs) that do not use experimental animals are, in certain settings, entirely appropriate for assuring the safety of chemical ingredients, although regulatory adoption has been slow. In this opinion article we discuss how scientific advances that utilize NAMs to certify systemic safety are available now and merit broader acceptance within the framework of next generation risk assessments (NGRA).

Mapping the dynamics of Nrf2 antioxidant and NFκB inflammatory responses by soft electrophilic chemicals in human liver cells defines the transition from adaptive to adverse responses

A comprehensive understanding of the dynamic activation and crosstalk between different cellular stress response pathways that drive cell adversity is crucial in chemical safety assessment. Various chemicals have electrophilic properties that drive cell injury responses in particular oxidative stress signaling and inflammatory signaling. Here we used bacterial artificial chromosome-based GFP cellular stress reporters with live cell confocal imaging, to systematically monitor the differential modulation of the dynamics of stress pathway activation by six different soft electrophiles: sulforaphane, andrographolide, diethyl maleate, CDDO-Me, ethacrynic acid and tert-butyl hydroquinone. The various soft electrophiles showed differential potency and dynamics of Nrf2 activation and nuclear translocation. These differences in Nrf2 dynamics correlated with distinct activation pattern of Nrf2 downstream targets SRNX1 and HMOX1. All soft electrophiles caused a strong dose dependent suppression of a cytokine-induced NFĸB response represented by suppression of NFĸB nuclear oscillation and inhibition of the downstream target gene activation A20 and ICAM1, which followed the potency of Nrf2 modulation but occurred at higher concentration close to saturation of Nrf2 activation. RNAi-based depletion of RelA resulted in a prolonged presence of Nrf2 in the nucleus after soft electrophile treatment; depletion of Nrf2 caused the induction of NFĸB signaling and activation of its downstream targets A20 and ICAM1. A systematic transcriptome analysis confirmed these effects by soft electrophiles on Nrf2 and NFκB signaling crosstalk in human induced-pluripotent stem cell-derived hepatocyte-like cells. Altogether our data indicate that modulation of Nrf2 by soft electrophiles may have consequences for efficient inflammatory signaling.

Latent Variables Capture Pathway-Level Points of Departure in High-Throughput Toxicogenomic Data

Estimation of points of departure (PoDs) from high-throughput transcriptomic data (HTTr) represents a key step in the development of next-generation risk assessment (NGRA). Current approaches mainly rely on single key gene targets, which are constrained by the information currently available in the knowledge base and make interpretation challenging as scientists need to interpret PoDs for thousands of genes or hundreds of pathways. In this work, we aimed to address these issues by developing a computational workflow to investigate the pathway concentration–response relationships in a way that is not fully constrained by known biology and also facilitates interpretation. We employed the Pathway-Level Information ExtractoR (PLIER) to identify latent variables (LVs) describing biological activity and then investigated in vitro LVs’ concentration–response relationships using the ToxCast pipeline. We applied this methodology to a published transcriptomic concentration–response data set for 44 chemicals in MCF-7 cells and showed that our workflow can capture known biological activity and discriminate between estrogenic and antiestrogenic compounds as well as activity not aligning with the existing knowledge base, which may be relevant in a risk assessment scenario. Moreover, we were able to identify the known estrogen activity in compounds that are not well-established ER agonists/antagonists supporting the use of the workflow in read-across. Next, we transferred its application to chemical compounds tested in HepG2, HepaRG, and MCF-7 cells and showed that PoD estimates are in strong agreement with those estimated using a recently developed Bayesian approach (cor = 0.89) and in weak agreement with those estimated using a well-established approach such as BMDExpress2 (cor = 0.57). These results demonstrate the effectiveness of using PLIER in a concentration–response scenario to investigate pathway activity in a way that is not fully constrained by the knowledge base and to ease the biological interpretation and support the development of an NGRA framework with the ability to improve current risk assessment strategies for chemicals using new approach methodologies.

Next generation risk assessment (NGRA): Bridging in vitro points-of-departure to human safety assessment using physiologically-based kinetic (PBK) modelling - A case study of doxorubicin with dose metrics considerations

Using the chemical doxorubicin (DOX), the objective of the present study was to evaluate the impact of dose metrics selection in the new approach method of integrating physiologically-based kinetic (PBK) modelling and relevant human cell-based assays to inform a priori the point of departure for human health risk. We reviewed the literature on the clinical consequences of DOX treatment to identify dosing scenarios with no or mild cardiotoxicity observed. Key concentrations of DOX that induced cardiomyocyte toxicity in vitro were derived from studies of our own and others. A human population-based PBK model of DOX was developed and verified against pharmacokinetic data. The model was then used to predict plasma and extracellular and intracellular heart concentrations of DOX under selected clinical settings and compared with in vitro outcomes, based on several dose metrics: C_max (maximum concentration) or AUC (area under concentration-time curve) in free or total form of DOX. We found when using in vitro assays to predict cardiotoxicity for DOX, AUC is a better indicator. Our study illustrates that when appropriate dose metrics are used, it is possible to combine PBK modelling with in vitro-derived toxicity information to define margins of safety and predict low-risk human exposure levels.

A Retrospective Study of Administrative Data to Identify Factors Associated with Future Disability Status among Older Colorectal Cancer Survivors

Disability is associated with loss of independence and early mortality. Currently, only 1–2% of cancer survivors who reported physical limitations received rehabilitation services. It is critical to identify factors associated with the development of disability to guide clinical practice given treatment changes. We aimed to 1) identify demographic and cancer-related characteristics associated with future disability status among older colorectal cancer survivors, and 2) compared the future disability status among cancer and matched non-cancer cohorts. Methods: We conducted a retrospective cohort study using the Texas Cancer Registry-national Medicare linked database. The cancer cohort included Medicare beneficiaries with a primary colorectal cancer diagnosis between 2005 and 2013 (n = 13,229). The non-cancer cohort was identified from a 5% sample of Medicare beneficiaries (n = 11,416). Diagnosis dates from the cancer cohort were used as the index date for the non-cancer cohort. Cohorts were matched 1:1 based on index date, age, and gender. Cox regression models were used to estimate hazard ratios (HRs) and 95% confidence intervals. Disability status was defined according to Davidoff and colleagues using inpatient, outpatient and durable medical equipment claims files, and assessed monthly, beginning 1 month after cancer diagnosis (or index date), continuing until disability, death, end of Medicare continuous enrollment, or end of study. Results: Factors that were significantly associated with disability status in the cancer cohort were age (HR = 3.50 for >80 years old), female gender (HR = 1.50), race/ethnicity (HR = 1.34 for Hispanic and 1.21 for Black), stage (HR = 2.26 for distant stage), comorbidity (HR = 2.18 for >1), and radiation (HR = 1.21). When compared to the non-cancer cohort, having a cancer diagnosis (HR = 1.07) and comorbidity (HR = 2.09 for >1) were associated with developing disability. Conclusions: Colorectal diagnosis is an independent risk for disability status. Beyond well-known risk factors “age and mortality” subsets of survivors (Hispanic and Black survivors and those with comorbidity) are found to be at higher risk for developing disability. This warrants further investigation and may indicate targeted intervention to prevent future disability.

Bridging the Data Gap From in vitro Toxicity Testing to Chemical Safety Assessment Through Computational Modeling

Chemical toxicity testing is moving steadily toward a human cell and organoid-based in vitro approach for reasons including scientific relevancy, efficiency, cost, and ethical rightfulness. Inferring human health risk from chemical exposure based on in vitro testing data is a challenging task, facing various data gaps along the way. This review identifies these gaps and makes a case for the in silico approach of computational dose-response and extrapolation modeling to address many of the challenges. Mathematical models that can mechanistically describe chemical toxicokinetics (TK) and toxicodynamics (TD), for both in vitro and in vivo conditions, are the founding pieces in this regard. Identifying toxicity pathways and in vitro point of departure (PoD) associated with adverse health outcomes requires an understanding of the molecular key events in the interacting transcriptome, proteome, and metabolome. Such an understanding will in turn help determine the sets of sensitive biomarkers to be measured in vitro and the scope of toxicity pathways to be modeled in silico. In vitro data reporting both pathway perturbation and chemical biokinetics in the culture medium serve to calibrate the toxicity pathway and virtual tissue models, which can then help predict PoDs in response to chemical dosimetry experienced by cells in vivo. Two types of in vitro to in vivo extrapolation (IVIVE) are needed. (1) For toxic effects involving systemic regulations, such as endocrine disruption, organism-level adverse outcome pathway (AOP) models are needed to extrapolate in vitro toxicity pathway perturbation to in vivo PoD. (2) Physiologically-based toxicokinetic (PBTK) modeling is needed to extrapolate in vitro PoD dose metrics into external doses for expected exposure scenarios. Linked PBTK and TD models can explore the parameter space to recapitulate human population variability in response to chemical insults. While challenges remain for applying these modeling tools to support in vitro toxicity testing, they open the door toward population-stratified and personalized risk assessment.

Doxorubicin-induced mitophagy and mitochondrial damage is associated with dysregulation of the PINK1/parkin pathway

The usefulness of doxorubicin (DOX), a potent anticancer agent, is limited by its cardiotoxicity. Mitochondria play a central role in DOX-induced cardiotoxicity though the precise mechanisms are still obscure. Increasing evidence indicates that excessive activation of mitophagy and mitochondrial dysfunction are key causal events leading to DOX-induced cardiac injury. The PINK1/parkin pathway has emerged as a critical pathway in regulation of mitophagy as well as mitochondrial function. The present study was aimed to investigate the role of PINK1/parkin pathway in DOX-induced mitochondrial damage and cardiotoxicity. Our results showed that DOX concentration-dependently induced cytotoxicity and mitochondrial toxic effects including mitochondrial superoxide accumulation, decreased mitochondrial membrane potential and mitochondrial DNA copy number, as well as mitochondrial ultrastructural alterations. DOX induced mitophagy as evidenced by increases of the markers of autophagosomes, LC3, Beclin 1, reduction of p62, and co-localization of LC3 in mitochondria. DOX activated PINK1/parkin pathway and promoted translocation of PINK1/parkin to mitochondria. Meanwhile, DOX inhibited the expression of PGC-1α and its downstream targets nuclear respiratory factor 1 (NRF1) and mitochondrial transcription factor A (TFAM), and reduced the expression of mitochondrial proteins. Inhibition of mitophagy by mdivi-1 was found to attenuate activation of the PINK1/parkin pathway by DOX and preserve mitochondrial biogenesis, consequently mitigating DOX-induced mitochondrial superoxide overproduction and mitochondrial dysfunction. Moreover, scavenging mitochondrial superoxide by Mito-tempo was also found to effectively attenuate activation of the PINK1/parkin pathway and rescue the cells from DOX-induced adverse effects. Taken together, these findings suggest that DOX-induced mitophagy and mitochondrial damage in cardiomyocytes are mediated, at least in part, by dysregulation of the PINK1/parkin pathway.

Optical Modulation of the Diffraction Efficiency in an Indoline Azobenzene/Amorphous Polycarbonate Film

We have made a diffraction grating in an indoline azobenzene/amorphous polycarbonate film by two-beam interference at 532 nm that periodically photodegrades the indoline azobenzene dye. Subsequent illumination of the film with 532-nm light into the trans-isomer band leads to trans-cis isomerization in the indoline azobenzene dye and results in a decrease in the trans-isomer band absorption coefficient. This causes the diffraction efficiency to decrease when probed at 655 nm. The diffraction efficiency returns to its original value when the 532-nm light is blocked by thermal relaxation from the indoline azobenzene cis-isomer to the trans-isomer. Thus, we have been able to optically modulate the diffraction efficiency in a thin film diffraction grating.

Concomitant expression of far upstream element (FUSE) binding protein (FBP) interacting repressor (FIR) and its splice variants induce migration and invasion of non-small cell lung cancer (NSCLC) cells

Transcription factors integrate a variety of oncogenic input information, facilitate tumour growth and cell dissemination, and therefore represent promising therapeutic target structures. Because over-expression of DNA-interacting far upstream element binding protein (FBP) supports non-small cell lung cancer (NSCLC) migration, we asked whether its repressor, FBP-interacting repressor (FIR) is functionally inactivated and how FIR might affect NSCLC cell biology. Different FIR splice variants were highly expressed in the majority of NSCLCs, with the highest levels in tumours carrying genomic gains of chromosome 8q24.3, which contained the FIR gene locus. Nuclear FIR expression was significantly enriched at the invasion front of primary NSCLCs, but this did not correlate with tumour cell proliferation. FIR accumulation was associated with worse patient survival and tumour recurrence; in addition, FIR over-expression significantly correlated with lymph node metastasis in squamous cell carcinomas (SCCs). In vitro, we applied newly developed methods and modelling approaches for the quantitative and time-resolved description of the pro-migratory and pro-invasive capacities of SCC cells. siRNA-mediated silencing of all FIR variants significantly reduced the speed and directional movement of tumour cells in all phases of migration. Furthermore, sprouting efficiency and single cell invasiveness were diminished following FIR inhibition. Interestingly, the silencing of FIR isoforms lacking exon 2 (FIR(Δexon2)) alone was sufficient to reduce lateral migration and invasion. In summary, by using scale-spanning data derived from primary human tissues, quantitative cellular analyses and mathematical modelling, we have demonstrated that concomitant over-expression of FIR and its splice variants drives NSCLC migration and dissemination.

Large-scale discovery of novel genetic causes of developmental disorders

Despite three decades of successful, predominantly phenotype-driven discovery of the genetic causes of monogenic disorders, up to half of children with severe developmental disorders of probable genetic origin remain without a genetic diagnosis. Particularly challenging are those disorders rare enough to have eluded recognition as a discrete clinical entity, those with highly variable clinical manifestations, and those that are difficult to distinguish from other, very similar, disorders. Here we demonstrate the power of using an unbiased genotype-driven approach to identify subsets of patients with similar disorders. By studying 1,133 children with severe, undiagnosed developmental disorders, and their parents, using a combination of exome sequencing and array-based detection of chromosomal rearrangements, we discovered 12 novel genes associated with developmental disorders. These newly implicated genes increase by 10% (from 28% to 31%) the proportion of children that could be diagnosed. Clustering of missense mutations in six of these newly implicated genes suggests that normal development is being perturbed by an activating or dominant-negative mechanism. Our findings demonstrate the value of adopting a comprehensive strategy, both genome-wide and nationwide, to elucidate the underlying causes of rare genetic disorders.

Online questionnaire development: using film to engage participants and then gather attitudes towards the sharing of genomic data

How can a researcher engage a participant in a survey, when the subject matter may be perceived as 'challenging' or even be totally unfamiliar to the participant? The Genomethics study addressed this via the creation and delivery of a novel online questionnaire containing 10 integrated films. The films documented various ethical dilemmas raised by genomic technologies and the survey ascertained attitudes towards these. Participants were recruited into the research using social media, traditional media and email invitation. The film-survey strategy was successful: 11,336 initial hits on the survey website led to 6944 completed surveys. Participants included from those who knew nothing of the subject matter through to experts in the field of genomics (61% compliance rate), 72% of participants answered every single question. This paper summarises the survey design process and validation methods applied. The recruitment strategy and results from the survey are presented elsewhere.

Early results of a new implant: 3.0 mm headless compression screw for scaphoid fracture fixation

There has been a considerable evolution of screws used for internal fixation of scaphoid fractures. We discuss here, early results of a recently introduced implant Synthes 3.0 mm headless compression screw used for scaphoid fracture fixation. Twenty eight patients with scaphoid fractures (five acute and 23 nonunions) were treated with internal fixation by this non-variable pitch screw over a period of 18 months. All nonunions had pedicle vascularized bone grafting. All five patients with acute scaphoid fracture fixation had radiological healing at a mean of 8 weeks. Fifteen of 23 scaphoid fracture nonunions showed definite signs and a further seven showed probable signs of radiological healing at a mean of 8 months. One nonunion has failed to unite after surgery.

Failures of the RM finger prosthesis joint replacement system

In our unit a high failure rate of the RM finger prosthesis joint replacement system was noted, prompting a review of cases. A series of patients underwent implantation under the care of one surgeon and the results were monitored. Twenty-one devices were implanted of which 16 were inserted for rheumatoid disease. Patients were reviewed regularly and the implant performance was assessed critically along with survival of the implant to revision, infection or death of the patient. The mean follow-up was 32 months. Unacceptable failure rates at early and medium term stages were identified, with 15 of the implants revised by 2 years. Loosening was the commonest mode of failure. The authors do not recommend the use of this implant, especially in cases of rheumatoid arthritis.

Key considerations around the risks and consequences of hypoglycaemia in people with type 2 diabetes

Hypoglycaemia and its consequences represent a significant risk for many people who have type 2 diabetes, and hypoglycaemia is currently under-recognised and commonly avoidable. Current clinical guidelines recommend the targeting of tight glycaemic control and this strategy may also be associated with an increased risk of hypoglycaemia. Hypoglycaemia impacts on morbidity, mortality and quality of life of people with type 2 diabetes, and improved recognition of the symptoms of hypoglycaemia will allow effective treatment and reduce the risk of progression to more severe episodes. A common cause of hypoglycaemia in people with type 2 diabetes is glucose-lowering medication, in particular, those which raise insulin independently of ambient glucose concentration such as sulphonylureas and exogenous insulin. The recently published National Institute for Health and Clinical Excellence guideline recommends the use of Dipeptidyl peptidase-4 inhibitors or thiazolidinediones (glitazones) as alternative second-line therapy instead of a sulphonylurea in those patients who are at significant risk of hypoglycaemia and its consequences.

Akt-induced endocrine therapy resistance is reversed by inhibition of mTOR signaling

BACKGROUND

Resistance to endocrine therapy is a major impediment in breast cancer therapeutics. The Phosphatidylinositol-3-OH kinase (PI3K)/Protein kinase B (Akt/PKB) kinase signaling pathway has been implicated in altering breast cancer response to multiple therapies. How Akt modulates response is an area of significant clinical relevance.

METHODS

We have used an in vitro model to discern the effects of robust Akt activity on breast cancer cellular response to endocrine therapies.

RESULTS

High levels of Akt activity confer resistance to the aromatase inhibitor Letrozole (Let) and the selective estrogen receptor (ER) down-regulator Fulvestrant (ICI). Akt-induced resistance is not due to failure of these endocrine agents to inhibit estrogen receptor alpha activity. Instead, resistance is characterized by altered cell cycle and apoptotic response. Cotreatment with low concentrations of the mTOR inhibitor RAD-001 and either Let or ICI restores response of the resistant cells to levels observed in the responsive cells treated with either Let or ICI as a single agent.

CONCLUSIONS

Our preliminary findings in experiments with RAD-001 indicate that cotreatment with mTOR inhibitors and either Let or ICI reverses the Akt-mediated resistance and restores responsiveness to antiestrogens. Concurrent ER and mTOR inhibition is therefore an effective strategy to overcome growth factor-induced resistance and bears significant implications for optimal clinical development of these agents in breast cancer treatment.

Achieving 2003 European lipid goals with rosuvastatin and comparator statins in 6743 patients in real-life clinical practice: DISCOVERY meta-analysis

BACKGROUND

There is an increasing body of evidence to support the benefits of reducing low-density lipoprotein cholesterol (LDL-C) levels and this has been reflected in a lowering of LDL-C goals recommended by international guidelines. Therefore, there is a growing need for effective lipid-modifying therapies to optimise the achievement of these more stringent LDL-C goals.

OBJECTIVE

A meta-analysis of data pooled from five studies participating in the DISCOVERY (DIrect Statin COmparison of LDL-C Values: an Evaluation of Rosuvastatin therapY) Programme was performed to compare the effect of rosuvastatin treatment with other statins in real-life clinical practice.

RESULTS

These studies included 6743 patients with hypercholesterolaemia from different ethnicities, countries and cultural environments. The meta-analysis showed that significantly more patients receiving rosuvastatin 10 mg achieved the 2003 European LDL-C goals compared with those who received atorvastatin 10 mg or simvastatin 20 mg (p < 0.001 for both comparisons). A significantly greater proportion of patients receiving rosuvastatin 10 mg also achieved the 2003 European total cholesterol goal compared with those on atorvastatin 10 mg (p < 0.001).

CONCLUSIONS

The meta-analysis showed that rosuvastatin was more effective than comparator statins at lowering LDL-C levels and enabling patients to achieve lipid goals at recommended start doses. In addition, all statins studied were well tolerated and confirmed that rosuvastatin had a similar safety profile to other statins.

Prevalence and surgical significance of a high-origin anterior tibial artery

PURPOSE

To assess the prevalence of proximal high-origin anterior tibial artery and its surgical significance.

METHODS

100 knees were prospectively studied using colour Doppler ultrasonography. No patient had a history of lower-limb arterial pathology or previous knee surgery. All ultrasound images were assessed by a single experienced vascular technician to eliminate inter-observer variability.

RESULTS

The mean age of the patients was 56 years (range, 21-96 years). Prevalence of the high-origin anterior tibial arterial pattern was 6%, greater than that reported by previous angiographic or cadaveric studies. In all patients with high-origin anterior tibial artery, the artery was in direct contact with the posterior cortex of the tibia.

CONCLUSION

This highlights the danger of using sharp instruments in knee procedures that involve extension of osteotomy to the posterior tibial cortex, particularly high-tibial osteotomy and total knee replacement. Knowledge of the anatomical variations in the branching of the popliteal artery is important because damage to its branches can be limb- or life-threatening.

An anatomical database of carpal bone measurements for intercarpal arthrodesis

During limited intercarpal fusion it is sometimes difficult to determine correct screw length and staple size. This is because of overlap, and the shape and orientation of the carpal bones on radiography. One hundred complete sets of dry cadaver carpal bones were measured to provide an anatomical database of carpal bone measurements. This should help prevent inadvertent overpenetration of fixation devices during surgery.

Continuous versus non-nightly use of zolpidem in chronic insomnia: results of a large-scale, double-blind, randomized, outpatient study

New treatment strategies are encouraged in insomnia and, in particular, discontinuous treatment. The aim of this double-blind study was to compare, in a large primary care population of chronic insomniacs (> 4 weeks duration) the efficacy and safety of zolpidem 10 mg 5 nights/week and placebo 2 nights/week, to that of nightly zolpidem. Seven hundred and eighty-nine drug-free insomniacs, with a Total Sleep Time (TST) of 3-6 h/night were enrolled in seven European countries. After a placebo run-in period, treatment lasted 14 days. The primary criterion was the Clinical Global Impression improvement score (CGI-II) which showed that 65.2% of patients in the continuous and 58.6% in the discontinuous groups were rated 'much' or 'very much' improved. Even though the non-inferiority test did not show the equivalence of both regimens, the difference of 7% in responder rates does not appear to be clinically relevant. Other sleep parameters such as TST, number of nocturnal awakenings and Quality of Life scales showed marked, not significantly different, improvements in both groups. Both regimens were well tolerated and no adverse event which could be related to non-treatment nights was reported in the discontinuous group. Non-nightly zolpidem appears to be a feasible and safe additional option for the management of chronic insomnia.

Comparison of once- and twice-daily clarithromycin in the treatment of adults with severe acute lower respiratory tract infections

BACKGROUND

Although the modified-release (MR) formulation of clarithromycin has demonstrated bioequivalence to the immediate-release (IR) formulation and thus can be prescribed for lower respiratory tract infections (LRTIs), a MEDLINE search from 1995 through 1998 and information on file with the manufacturer indicate that no data are available on the effectiveness of this new formulation in the treatment of severe LRTIs such as community-acquired pneumonia.

OBJECTIVE

This study was designed to compare clinical success rates (percentage of patients with clinical cure or improvement) with once- and twice-daily regimens of clarithromycin in the treatment of patients with severe, acute LRTIs requiring oral antibiotic therapy.

METHODS

In this multicenter, investigator-blinded, randomized, parallel-group study, adult patients with clinical evidence suggesting severe, acute LRTI were recruited from 22 general practices in the United Kingdom. Patients were randomly allocated to receive either clarithromycin 500 mg BID (IR tablets) or clarithromycin 1 g OD (two 500-mg MR tablets) for 7 to 14 days. The outcome measures were resolution of or improvement in clinical signs and symptoms (including resolution of cough), unscheduled visits for the same symptom, days to resumption of normal activities, and improvements in quality of life (assessed using the EQ-5D version of the EuroQoL questionnaire). Clinical, microbiologic, and serologic assessments were performed before, during, and after treatment. Efficacy and safety data were analyzed on an intent-to-treat basis.

RESULTS

One hundred sixty men (n = 83) and women (n = 77) between the ages of 19 and 88 years took part in the study, 78 receiving clarithromycin 500 mg BID and 82 receiving clarithromycin 1 g OD. At 4 weeks after the start of treatment, the high clinical success rates were comparable between groups: 84.6% with clarithromycin 500 mg BID and 90.2% with clarithromycin 1 g OD. No significant differences in outcome measures were noted between the 2 regimens. Both treatments were well tolerated, with taste disturbance being the most commonly reported adverse event (10.6% vs 6.1% with clarithromycin 500 mg BID and 1 g OD, respectively).

CONCLUSIONS

The 2 clarithromycin regimens were equally efficacious and well tolerated in the treatment of severe, acute LRTIs. However, caution should be exercised in applying these results to the general population, because the study excluded certain categories of patients who would normally be treated. In addition, the small sample size may have obscured clinically significant differences between the 2 regimens.

Modulation by cellular cholesterol of gene transcription via the cyclic AMP response element

The effect of rapid changes in cellular cholesterol content on adenosine 3',5'-cyclic monophosphate (cAMP) response element-mediated gene transcription was investigated. The study was carried out in Chinese hamster ovary (CHO-K1) cells permanently expressing the human beta(2)-adrenoceptor. Gene transcription was quantified using a reporter gene (secreted placental alkaline phosphatase) under the transcriptional control of cAMP response element (CRE) sequences. Cellular cholesterol was reduced by 42% or elevated by 47% by incubating cells for 1 hr with methyl-beta-cyclodextrin alone or methyl-beta-cyclodextrin complexed with cholesterol, respectively. There was a significant negative correlation between the free cholesterol content of the cells and CRE-mediated gene expression in response to 10(-6) M isoprenaline (slope = -4.57 +/- 0.73, P < 0.001), indicating that beta(2)-adrenoceptor-mediated activation of the CRE is inhibited by cholesterol. Cyclic AMP accumulation in response to isoprenaline (10(-12) to 10(-5) M) was also inhibited in cholesterol-enriched cells and enhanced in cholesterol-depleted cells compared to controls (P < 0.05, two-way ANOVA). Cholesterol also inhibited serum-mediated enhancement of CRE-driven gene expression, and we present data suggesting that the pathway activated by serum and inhibited by cholesterol could be independent of adrenoceptor activation and protein kinase A. We conclude that in CHO-K1 cells cholesterol inhibits at least two processes that can stimulate CRE-mediated gene expression. One is isoprenaline activation of cAMP synthesis, the other is activated by serum. These findings demonstrate that activation of gene transcription by extracellular stimuli could be influenced by cellular cholesterol content.

Zolmitriptan versus sumatriptan for the acute oral treatment of migraine: a randomized, double-blind, international study

This randomized, double-blind, parallel-group study compared the efficacy and tolerability of zolmitriptan (2.5 or 5 mg) and sumatriptan (50 mg) in the acute oral treatment of up to six moderate-to-severe migraine attacks. The intention to treat (ITT) population comprised of 1522 patients: 500 treated with zolmitriptan 2.5 mg (2671 attacks), 514 with zolmitriptan 5 mg (2744 attacks) and 508 with sumatriptan 50 mg (2693 attacks). Overall, the 2-h headache response rates in these groups were 62.9, 65.7 and 66.6%, respectively. There were no statistically significant differences between sumatriptan 50 mg and zolmitriptan 2.5 mg (P = 0.12) or 5 mg (P = 0.80). Approximately 40% of patients in each group reported a 2-h headache response in > or = 80% of attacks. There were no statistically significant differences between the groups in the rates of headache response at 1 h (zolmitriptan 2.5 mg 36.9%, zolmitriptan 5 mg 39.5% and sumatriptan 50 mg 38.0%) or 4 h (70.3, 72.9 and 72.2%, respectively) or in the rates of meaningful migraine relief at 1, 2 or 4 h or sustained (24-h) pain relief. All treatments were well tolerated. In conclusion, zolmitriptan (2.5 or 5 mg) proved similarly efficacious compared with sumatriptan (50 mg), both in terms of response rates and consistency across attacks.

Foot problems in patients with systemic sclerosis

OBJECTIVES

To assess the nature of the foot problems experienced in patients with systemic sclerosis (SSc) and patient awareness of such problems.

METHODS

Fifty unselected patients (42 females, eight males) with SSc were assessed by means of examination by a senior podiatrist, completion of a questionnaire detailing past and present foot problems, determination of random plasma glucose, plain X-rays of the feet, and measurement of the ankle/brachial index and of digital pulses by Doppler ultrasound.

RESULTS

Eighty-six per cent of patients reported colour changes in their feet in response to temperature changes, 82% reported pain usually related to cold, 26% had suffered foot ulceration and 8% had a history of foot surgery. Podiatry assessment confirmed the presence of significant abnormalities, including ulcerations in 10%, pre-ulcerative lesions in 34%, toenail changes in 62%, callus formation in 80% and calcinosis in 18%. Forty per cent of the patients had problems with the fitting of shoes, and 19% had been provided with footwear from the hospital. Plain films of the feet demonstrated the presence of erosions in 6%, soft-tissue calcification in 17%, osteopenia in 26% and degenerative changes in 60% of cases. Ten per cent of the patients had an abnormal ankle brachial index (less than 1.0). Only 21% of the 47 patients in whom digital pulses were examined had normal pulses in all toes, and in 26% all toe pulses were absent.

CONCLUSION

Although problems with the hands are well recognized in SSc, foot problems also occur in the majority of patients, and can be a cause of major disability. Care of the feet is therefore an important part of the management of SSC.

Prenatal diagnosis for inherited deafness--what is the potential demand?

Genetic testing for inherited deafness is now available within some genetics centres. This study used a structured questionnaire to assess the potential uptake of prenatal diagnosis (PND) for inherited deafness, and document the opinions of deaf and hearing individuals toward PND and termination of pregnancy (TOP) for hearing status. Participants were self-selected from the whole of the UK, of whom 644 were deaf, 143 were hard of hearing or deafened, and 527 were hearing individuals who had either a deaf parent or child. The results showed that 21% of deaf, 39% of hard of hearing and deafened, and 49% of hearing participants said they would consider PND for deafness. Six percent of deaf, 11% of hard of hearing and deafened, and 16% of hearing participants said they would consider a TOP if the fetus was found to be deaf. Two percent of deaf participants said they would prefer to have deaf children and would consider a TOP if the fetus was found to be hearing.

In-hospital delay in the diagnosis of breast cancer

BACKGROUND

There is evidence that delay in the diagnosis of breast cancer may prejudice survival. The aim of this study was to determine the incidence, time trends and causes of delay in a dedicated breast clinic.

METHODS

The interval between first breast clinic visit and a definitive diagnosis was recorded in all patients with invasive breast cancer between 1988 and 1997. In all patients with a delay of 3 months or more, the case notes were reviewed for evidence of a triple assessment (clinical examination, imaging and needle biopsy). The principal cause of delay was identified.

RESULTS

Of 1004 patients with invasive breast cancer, there was a delay in diagnosis of 3 months or more in 42 patients between 1988 and 1997, an incidence of 4.2 per cent. The median delay was 6 months and the median age at diagnosis was 53 (range 27-89) years. Triple assessment was undertaken in 30 patients; ten did not have a needle biopsy performed and three patients had no mammography. The principal cause of delay was: false-negative or inadequate fine-needle aspiration cytology (FNAC) in 19 patients, failure of follow-up in eight, clinical signs did not impress in five, FNAC not carried out in four, false-negative mammogram in three, failure of needle localization in two and one patient did not accept clinical advice. The annual incidence of delay in diagnosis did not change significantly over the 10-year interval.

CONCLUSION

Triple assessment is not sufficiently sensitive to detect every breast cancer and a small incidence of diagnostic delay is therefore inevitable with current techniques.

Congenital non-syndromal sensorineural hearing impairment due to connexin 26 gene mutations--molecular and audiological findings

We screened DNA from 72 sibships and 138 sporadically affected individuals with congenital non-syndromal sensorineural hearing impairment (NSSNHI) for mutations in the 26 (CX26) gene. A total of 20 (27.8%) of the sibships and 11 (7.9%) of the sporadically affected individuals were homozygous or compound heterozygotes for CX26 mutations. A total of 11 (17.2%) of 64 individuals with severe and 30 (30%) of 100 with profound NSSNHI compared to eight (8.7%) of 92 persons with moderate and none (0%) of 19 individuals with mild hearing impairment were homozygous or compound heterozygotes for CX26 mutations (chi2 test, 3 df, P = 0.000). CX26 mutation status bad no effect on the symmetry of the hearing impairment or configuration of the audiogram. In addition, serial audiograms showed no evidence of progression of the hearing impairment or differences in the severity of the hearing impairment in affected siblings in persons whether or not due to CX26 mutations. Sporadically affected individuals with congenital NSSNHI should be routinely tested for mutations in CX26, especially if the hearing impairment is severe or profound in severity, since identification of a mutation in CX26 allows use of Mendelian recurrence risks.

Attitudes of deaf adults toward genetic testing for hereditary deafness

Recent advances within molecular genetics to identify the genes for deafness mean that it is now possible for genetic-counseling services to offer genetic testing for deafness to certain families. The purpose of this study is to document the attitudes of deaf adults toward genetic testing for deafness. A structured, self-completion questionnaire was given to delegates at an international conference on the "Deaf Nation," held at the University of Central Lancashire in 1997. The conference was aimed at well-educated people, with an emphasis on Deaf culture issues. Eighty-seven deaf delegates from the United Kingdom returned completed questionnaires. The questionnaire had been designed to quantitatively assess attitudes toward genetics, interest in prenatal diagnosis (PND) for deafness, and preference for having deaf or hearing children. The results from this study provide evidence of a predominantly negative attitude toward genetics and its impact on deaf people, in a population for whom genetic-counseling services are relevant. Fifty-five percent of the sample thought that genetic testing would do more harm than good, 46% thought that its potential use devalued deaf people, and 49% were concerned about new discoveries in genetics. When asked about testing in pregnancy, 16% of participants said that they would consider having PND, and, of these, 29% said that they would prefer to have deaf children. Geneticists need to appreciate that some deaf persons may prefer to have deaf children and may consider the use of genetic technology to achieve this. Any genetic-counseling service set up for families with deafness can only be effective and appropriate if clinicians and counselors take into consideration the beliefs and values of the deaf community at large.

Differential roles of extracellular signal-regulated kinase-1/2 and p38(MAPK) in interleukin-1beta- and tumor necrosis factor-alpha-induced low density lipoprotein receptor expression in HepG2 cells

The inflammatory cytokines interleukin-1beta (IL-1beta) and tumor necrosis factor-alpha (TNF), elevated in inflammatory, malignant, and infectious diseases, induce low density lipoprotein (LDL) receptor transcription in HepG2 cells, and such an induction can account for hypocholesterolemia associated with these states. However, the signaling mechanisms of cytokine-mediated LDL receptor induction are largely unexplored. In the present studies, we examined the potential involvement of different mitogen-activated protein kinase (MAPK) pathways. Northern analysis demonstrated that IL-1beta or TNF significantly increased LDL receptor transcript in HepG2 cells, whereas expression of another tightly regulated sterol-responsive squalene synthase gene was unaffected. IL-1beta treatment resulted in transient activation of three MAPK cascades, namely p46/54(JNK), p38(MAPK), and ERK-1/2, with maximal activation of 20-, 25-, and 3-fold, respectively, occurring 15-30 min after cytokine addition. PD98059, a specific inhibitor of MAPK kinase activity, inhibited IL-1beta-induced LDL receptor expression. In contrast, SB202190, a specific inhibitor of p38(MAPK), enhanced IL-1beta-induced LDL receptor expression, with a concomitant increase in ERK-1/2 activity. Similarly, TNF induced LDL receptor expression also required ERK-1/2 activation. Finally, sterols repressed IL-1beta induced receptor expression, without affecting ERK-1/2 activation. These results show that IL-1beta- or TNF-induced LDL receptor expression requires ERK-1/2 activation, that the p38(MAPK) pathway negatively regulates LDL receptor expression, and that sterols inhibit induction at a point downstream of ERK-1/2 in HepG2 cells.