A randomized clinical trial of a group cognitive-behavioral therapy to reduce alcohol use among human immunodeficiency virus-infected outpatients in western Kenya.

BACKGROUND AND AIMS: Culturally relevant and feasible interventions are needed to address limited professional resources in sub-Saharan Africa for behaviorally treating the dual epidemics of HIV and alcohol use disorder. This study tested the efficacy of a cognitive-behavioral therapy (CBT) intervention to reduce alcohol use among HIV-infected outpatients in Eldoret, Kenya. DESIGN: Randomized clinical trial. SETTING: A large HIV outpatient clinic in Eldoret, Kenya, affiliated with the Academic Model Providing Access to Healthcare collaboration. PARTICIPANTS: A total of 614 HIV-infected outpatients [312 CBT; 302 healthy life-styles (HL); 48.5% male; mean age: 38.9 years; mean education 7.7 years] who reported a minimum of hazardous or binge drinking. INTERVENTION AND COMPARATOR: A culturally adapted six-session gender-stratified group CBT intervention compared with HL education, each delivered by paraprofessionals over six weekly 90-minute sessions with a 9-month follow-up. MEASUREMENTS: Primary outcome measures were percentage of drinking days (PDD) and mean drinks per drinking day (DDD) computed from retrospective daily number of drinks data obtained by use of the time-line follow-back from baseline to 9 months post-intervention. Exploratory analyses examined unprotected sex and number of partners. FINDINGS: Median attendance was six sessions across condition. Retention at 9 months post-intervention was high and similar by condition: CBT 86% and HL 83%. PDD and DDD marginal means were significantly lower in CBT than HL at all three study phases. Maintenance period, PDD - CBT = 3.64 (0.696), HL = 5.72 (0.71), mean difference 2.08, 95% confidence interval (CI) = 0.13 - 4.04; DDD - CBT = 0.66 (0.96), HL = 0.98 (0.098), mean difference = 0.31, 95% CI = 0.05 - 0.58. Risky sex decreased over time in both conditions, with a temporary effect for CBT at the 1-month follow-up. CONCLUSIONS: A cognitive-behavioral therapy intervention was more efficacious than healthy lifestyles education in reducing alcohol use among HIV-infected Kenyan outpatient drinkers.

Transformer mineral oil ingestion induces systemic sub-acute toxicity in Wistar rats.

We investigated the potential toxicities associated with the sub-acute ingestion of transformer mineral oil (TMO) at a heated low dose (HLD-50 mg/kg), heated high dose (HHD-500 mg/kg) and unheated high dose (UHD-500 mg/kg) in Wistar rats. There were increases in red blood cells and haemoglobin levels in HHD females and UHD males respectively versus control. The serum total proteins, albumin, and creatinine of the HHD females showed a significant increase versus control. The HHD males and UHD groups showed significant increase in liver malondialdehyde versus control. The livers of HHD groups had bile duct proliferation while those of HLD females and UHD groups showed focal areas of periportal chronic inflammation. HHD groups had kidneys with mild chronic inflammation and the HHD and UHD groups showed small intestines with chronic inflammation. In conclusion, sub-acute oral administration of TMO induced various degrees of dermal, haematological, hepatic, renal and small-intestinal toxicities in rats.

Associations with Unprotected Sexual Behavior Among HIV-Infected Drinkers in Western Kenya.

Approximately 71% of HIV-infected individuals live in sub-Saharan Africa. Alcohol use increases unprotected sex, which can lead to HIV transmission. Little research examines risky sex among HIV-infected individuals in East Africa who are not sex workers. The study purpose was to examine associations with unprotected sex in a high-risk sample of 507 HIV-infected sexually active drinkers in western Kenya. They were enrolled in a trial to reduce alcohol use. Past-month baseline alcohol use and sexual behavior were assessed using the Timeline Followback. A zero-inflated negative binomial model examined associations with occurrence and frequency of unprotected sex. Results showed heavy drinking days were significantly associated with unprotected sex occurrence across gender, and with unprotected sex frequency among women. Among women, transactional sex, alcohol-related sexual expectations, condom use self-efficacy, drinking-and-protected-sex days and age were associated with unprotected sex occurrence while alcohol-related sexual expectations, depressive symptoms and condom use self-efficacy were associated with unprotected sex frequency. Among men, alcohol-related sexual expectations, condom use self-efficacy, and age were associated with unprotected sex occurrence, while drinking-and-protected-sex days were associated with unprotected sex occurrence and frequency. Findings suggest robust relationships between heavy drinking and unprotected sex. Further research is needed elucidating the temporal relationships between drinking and unprotected sex in this population.

Task-shifting alcohol interventions for HIV+ persons in Kenya: a cost-benefit analysis.

BACKGROUND: Among HIV+ patients, alcohol use is a highly prevalent risk factor for both HIV transmission and poor adherence to HIV treatment. The large-scale implementation of effective interventions for treating alcohol problems remains a challenge in low-income countries with generalized HIV epidemics. It is essential to consider an intervention's cost-effectiveness in dollars-per-health-outcome, and the long-term economic impact -or "return on investment" in monetary terms. METHODS: We conducted a cost-benefit analysis, measuring economic return on investment, of a task-shifted cognitive-behavioral therapy (CBT) intervention delivered by paraprofessionals to reduce alcohol use in a modeled cohort of 13,440 outpatients in Kenya. In our base-case, we estimated the costs and economic benefits from a societal perspective across a six-year time horizon, with a 3% annual discount rate. Costs included all costs associated with training and administering task-shifted CBT therapy. Benefits included the economic impact of lowered HIV incidence as well as the improvements in household and labor-force productivity. We conducted univariate and multivariate probabilistic sensitivity analyses to test the robustness of our results. RESULTS: Under the base case, total costs for CBT rollout was $554,000, the value of benefits were $628,000, and the benefit-to-cost ratio was 1.13. Sensitivity analyses showed that under most assumptions, the benefit-to-cost ratio remained above unity indicating that the intervention was cost-saving (i.e., had positive return on investment). The duration of the treatment effect most effected the results in sensitivity analyses. CONCLUSIONS: CBT can be effectively and economically task-shifted to paraprofessionals in Kenya. The intervention can generate not only reductions in morbidity and mortality, but also economic savings for the health system in the medium and long term. The findings have implications for other countries with generalized HIV epidemics, high prevalence of alcohol consumption, and shortages of mental health professionals. TRIAL REGISTRATION: This paper uses data derived from "Cognitive Behavioral Treatment to Reduce Alcohol Use Among HIV-Infected Kenyans (KHBS)" with ClinicalTrials.gov registration NCT00792519 on 11/17/2008; and preliminary data from "A Stage 2 Cognitive-behavioral Trial: Reduce Alcohol First in Kenya Intervention" ( NCT01503255 , registered on 12/16/2011).

Rates and Covariates of Recent Sexual and Physical Violence Against HIV-Infected Outpatient Drinkers in Western Kenya.

Victimization from physical and sexual violence presents global health challenges. Partner violence is higher in Kenya than Africa. Violence against drinkers and HIV-infected individuals is typically elevated, so dual vulnerabilities may further augment risk. Understanding violence risks can improve interventions. Participants were 614 HIV-infected outpatient drinkers in western Kenya enrolled in a randomized trial to reduce alcohol use. At baseline, past 90-day partner physical and sexual violence were examined descriptively and in gender-stratified regression models. We hypothesized higher reported violence against women than men, and positive violence association with HIV stigma and alcohol use across gender. Women reported significantly more current sexual (26.3 vs. 5.7%) and physical (38.9 vs. 24.8%) victimization than men. Rates were generally higher than Kenyan lifetime national averages. In both regression models, HIV stigma and alcohol-related sexual expectations were significantly associated with violence while alcohol use was not. For women, higher violence risk was also conferred by childhood violence, past-year transactional sex, and younger age. HIV-infected Kenyan drinkers, particularly women, endorse high current violence due to multiple risk factors. Findings have implications for HIV interventions. Longitudinal research is needed to understand development of risk.

Super-resolution for scanning light stimulation systems.

Super-resolution (SR) is a technique used in digital image processing to overcome the resolution limitation of imaging systems. In this process, a single high resolution image is reconstructed from multiple low resolution images. SR is commonly used for CCD and CMOS (Complementary Metal-Oxide-Semiconductor) sensor images, as well as for medical applications, e.g., magnetic resonance imaging. Here, we demonstrate that super-resolution can be applied with scanning light stimulation (LS) systems, which are common to obtain space-resolved electro-optical parameters of a sample. For our purposes, the Projection Onto Convex Sets (POCS) was chosen and modified to suit the needs of LS systems. To demonstrate the SR adaption, an Optical Beam Induced Current (OBIC) LS system was used. The POCS algorithm was optimized by means of OBIC short circuit current measurements on a multicrystalline solar cell, resulting in a mean square error reduction of up to 61% and improved image quality.

Relationship between HIV stage and psychomotor speed neurocognitive score at a Kenyan sub-county hospital.

BACKGROUND: Human immunodeficiency virus (HIV) and acquired immunodeficiency syndrome (AIDS) is associated with cognitive impairment which affects psychomotor speed. Psychomotor slowing is a predictor of dementia and death in people living with HIV and AIDS. The purpose of this study was to assess the relationship between HIV disease stage and psychomotor speed neurocognitive score which will add to the body of knowledge required to manage patients with HIV and AIDS. OBJECTIVE: To determine the relationship between psychomotor speed neurocognitive score and the HIV disease stage in adults at initiation of care. SETTING: This study was conducted at Kangundo Sub-county hospital comprehensive care centre. METHODS: This was a cross-sectional study. All HIV seropositive patients aged 18 to 50 years recently initiated into care were studied. A pretested questionnaire was used to collect data. The World Health Organization (WHO) stage was used during data collection to classify study participants into asymptomatic and symptomatic groups. The grooved pegboard test was used to obtain psychomotor speed neurocognitive scores. Descriptive statistics were used to summarise data. Mann-Whitney U test, Spearman's rho and multiple linear regression were employed in the analysis; p-value of 0.05 was considered significant. RESULTS: The WHO stage did not have a significant effect on the psychomotor speed neurocognitive score (p ≥ 0.05). The CD4 count had a significant effect on psychomotor speed neurocognitive score (p = 0.001). CONCLUSIONS: There was a significant correlation between CD4 counts and psychomotor speed neurocognitive score. Efforts should be made to ensure that the CD4 counts of people living with HIV and AIDS do not continue to fall after initiation into care in order to preserve psychomotor function.

Associations Between the Phosphatidylethanol Alcohol Biomarker and Self-Reported Alcohol Use in a Sample of HIV-Infected Outpatient Drinkers in Western Kenya.

BACKGROUND: To counteract the syndemics of HIV and alcohol in Sub-Saharan Africa, international collaborations have developed interventions to reduce alcohol consumption. Reliable and accurate methods are needed to estimate alcohol use outcomes. A direct alcohol biomarker called phosphatidylethanol (PEth) has been shown to validate heavy, daily drinking, but the literature indicates mixed results for moderate and nondaily drinkers, including among HIV-infected populations. This study examined the associations of the PEth biomarker with self-report alcohol use at 2 time points in 127 HIV-infected outpatient drinkers in western Kenya. METHODS: Participants were consecutively enrolled in a randomized clinical trial to test the efficacy of a behavioral intervention to reduce alcohol use in Eldoret, Kenya. They endorsed current alcohol use, and a minimum score of 3 on the Alcohol Use Disorders Identification Test-Consumption or consuming ≥6 drinks per occasion at least monthly in the past year. Study interviews and blood draws were conducted at baseline and at 3 months post treatment from July 2012 through September 2013. Alcohol use was assessed using the Timeline Followback questionnaire. Blood samples were analyzed for the presence of the PEth biomarker and were compared to self-reported alcohol use. We also conducted semistructured interviews with 14 study completers in February through March 2014. RESULTS: Baseline data indicated an average of moderate-heavy alcohol use: 50% drinking days and a median of 4.5 drinks per drinking day. At baseline, 46% of women (31 of 67) and 8% of men (5 of 60) tested negative for PEth (p < 0.001). At the 3-month follow-up, 93% of women (25 of 27) and 97% of men (30 of 31) who reported drinking tested positive, while 70% of women (28 of 40) and 35% of men (10 of 29) who denied drinking tested negative for PEth. Interviews were consistent with self-reported alcohol use among 13 individuals with negative baseline results. CONCLUSIONS: These results add to the growing literature showing lack of agreement between self-report and PEth results among unhealthy and nondaily drinkers, particularly women. More research is needed to determine at what level of consumption over what period of time PEth becomes a reliable and accurate indicator of alcohol use.

Effects of crude kerosene on testosterone levels, aggression and toxicity in rat.

The use of crude kerosene as a dietary supplement in boarding schools has been a common practice in east Africa and other countries for many years, with the belief of it reducing the sex drive (libido) at the pubertal stage. There is however no scientific basis for this belief. The present study aimed at using a rat animal model to investigate the effects of crude kerosene on serum testosterone levels, aggression and its possible toxic effects. Fifteen male albino rats of approximately similar age and average weights were put into three groups of five animals each; the control group (placebo), low kerosene dose (10 µl/day) group and high kerosene dose (300 µl/day) group. ELISA was used to determine the serum testosterone levels. During treatment, changes in aggression were observed and noted. Liver toxicity was determined using enzyme assays, total protein and albumin while renal toxicity was monitored using serum creatinine levels. A full hemogram was conducted to determine hematological effects. Various tissue biopsies were obtained and examined using histopathological techniques for evidence of toxicity. Contrary to the common belief, our findings showed an overall increase of serum testosterone levels of up to 66% in the low dose and 75% in the high dose groups, with an increasing trend by the end of the study. The high dose group showed significantly increased levels of white blood cells (WBC) (p = 0.036), red blood cells (RBC) (p = 0.025), hematocrit (HCT) (p = 0.03), red cell distribution width (p = 0.028) and platelets (p = 0.017). The histological results of the stomach indicated chronic gastritis.

Note: Automated optical focusing on encapsulated devices for scanning light stimulation systems.

Recently, a scanning light stimulation system with an automated, adaptive focus correction during the measurement was introduced. Here, its application on encapsulated devices is discussed. This includes the changes an encapsulating optical medium introduces to the focusing process as well as to the subsequent light stimulation measurement. Further, the focusing method is modified to compensate for the influence of refraction and to maintain a minimum beam diameter on the sample surface.

A systems pharmacology perspective on the clinical development of Fatty Acid amide hydrolase inhibitors for pain.

The level of the endocannabinoid anandamide is controlled by fatty acid amide hydrolase (FAAH). In 2011, PF-04457845, an irreversible inhibitor of FAAH, was progressed to phase II clinical trials for osteoarthritic pain. This article discusses a prospective, integrated systems pharmacology model evaluation of FAAH as a target for pain in humans, using physiologically based pharmacokinetic and systems biology approaches. The model integrated physiological compartments; endocannabinoid production, degradation, and disposition data; PF-04457845 pharmacokinetics and pharmacodynamics, and cannabinoid receptor CB1-binding kinetics. The modeling identified clear gaps in our understanding and highlighted key risks going forward, in particular relating to whether methods are in place to demonstrate target engagement and pharmacological effect. The value of this modeling exercise will be discussed in detail and in the context of the clinical phase II data, together with recommendations to enable optimal future evaluation of FAAH inhibitors.CPT: Pharmacometrics Systems Pharmacology (2014) 3, e91; doi:10.1038/psp.2013.72; published online 15 January 2014.

Containing a Lassa fever epidemic in a resource-limited setting: outbreak description and lessons learned from Abakaliki, Nigeria (January-March 2012).

OBJECTIVES: Despite the epidemic nature of Lassa fever (LF), details of outbreaks and response strategies have not been well documented in resource-poor settings. We describe the course of a LF outbreak in Ebonyi State, Nigeria, during January to March 2012. METHODS: We analyzed clinical, epidemiological, and laboratory data from surveillance records and hospital statistics during the outbreak. Fisher's exact tests were used to compare proportions and t-tests to compare differences in means. RESULTS: The outbreak response consisted of effective coordination, laboratory testing, active surveillance, community mobilization, contact and suspected case evaluation, and case management. Twenty LF cases (10 confirmed and 10 suspected) were recorded during the outbreak. Nosocomial transmission to six health workers occurred through the index case. Only 1/110 contacts had an asymptomatic infection. Overall, there was high case fatality rate among all cases (6/20; 30%). Patients who received ribavirin were less likely to die than those who did not (p=0.003). The mean delay to presentation for patients who died was 11 ± 3.5 days, while for those who survived was 6 ± 2.6 days (p<0.001). CONCLUSIONS: The response strategies contained the epidemic. Challenges to control efforts included poor local laboratory capacity, inadequate/poor quality of protective materials, fear among health workers, and inadequate emergency preparedness.

Model-based drug development: a rational approach to efficiently accelerate drug development.

The pharmaceutical industry continues to face significant challenges. Very few compounds that enter development reach the marketplace, and the investment required for each success can surpass $1.8 billion. Despite attempts to improve efficiency and increase productivity, total investment continues to rise whereas the output of new medicines declines. With costs increasing exponentially through each development phase, it is failure in phase II and phase III that is most wasteful. In today's development paradigm, late-stage failure is principally a result of insufficient efficacy. This is manifested as either a failure to differentiate sufficiently from placebo (shown for both novel and precedented mechanisms) or a failure to demonstrate sufficient differentiation from existing compounds. Set in this context, this article will discuss the role model-based drug development (MBDD) approaches can and do play in accelerating and optimizing compound development strategies through a series of illustrative examples.

A new adaptive light beam focusing principle for scanning light stimulation systems.

In this article a novel principle to achieve optimal focusing conditions or rather the smallest possible beam diameter for scanning light stimulation systems is presented. It is based on the following methodology: First, a reference point on a camera sensor is introduced where optimal focusing conditions are adjusted and the distance between the light focusing optic and the reference point is determined using a laser displacement sensor. In a second step, this displacement sensor is used to map the topography of the sample under investigation. Finally, the actual measurement is conducted, using optimal focusing conditions in each measurement point at the sample surface, that are determined by the height difference between camera sensor and the sample topography. This principle is independent of the measurement values, the optical or electrical properties of the sample, the used light source, or the selected wavelength. Furthermore, the samples can be tilted, rough, bent, or of different surface materials. In the following the principle is implemented using an optical beam induced current system, but basically it can be applied to any other scanning light stimulation system. Measurements to demonstrate its operation are shown, using a polycrystalline silicon solar cell.

Ethical issues in a stage 1 cognitive-behavioral therapy feasibility study and trial to reduce alcohol use among HIV-infected outpatients in western Kenya.

Epidemics of both HIV/AIDS and alcohol abuse in sub-Saharan Africa have spurred the conduct of local behavioral therapy trials for these problems, but the ethical issues involved in these trials have not been fully examined. In this paper, we discuss ethical issues that emerged during the conduct of a behavioral intervention adaptation and trial using cognitive-behavioral therapy to reduce alcohol use among HIV-infected outpatients in Eldoret, Kenya. The study was performed within our multinational collaboration, the USAID-Academic Model Providing Access to Healthcare Partnership. We discuss relevant ethical considerations and how we addressed them.

Reducing systems biology to practice in pharmaceutical company research; selected case studies.

Reviews of the productivity of the pharmaceutical industry have concluded that the current business model is unsustainable. Various remedies for this have been proposed, however, arguably these do not directly address the fundamental issue; namely, that it is the knowledge required to enable good decisions in the process of delivering a drug that is largely absent; in turn, this leads to a disconnect between our intuition of what the right drug target is and the reality of pharmacological intervention in a system such as a human disease state. As this system is highly complex, modelling will be required to elucidate emergent properties together with the data necessary to construct such models. Currently, however, both the models and data available are limited. The ultimate solution to the problem of pharmaceutical productivity may be the virtual human, however, it is likely to be many years, if at all, before this goal is realised. The current challenge is, therefore, whether systems modelling can contribute to improving productivity in the pharmaceutical industry in the interim and help to guide the optimal route to the virtual human. In this context, this chapter discusses the emergence of systems pharmacology in drug discovery from the interface of pharmacokinetic-pharmacodynamic modelling and systems biology. Examples of applications to the identification of optimal drug targets in given pathways, selecting drug modalities and defining biomarkers are discussed, together with future directions.

Treatment outcomes of a stage 1 cognitive-behavioral trial to reduce alcohol use among human immunodeficiency virus-infected out-patients in western Kenya.

AIMS: Dual epidemics of human immunodeficiency virus (HIV) and alcohol use disorders, and a dearth of professional resources for behavioral treatment in sub-Saharan Africa, suggest the need for development of culturally relevant and feasible interventions. The purpose of this study was to test the preliminary efficacy of a culturally adapted six-session gender-stratified group cognitive-behavioral therapy (CBT) intervention delivered by paraprofessionals to reduce alcohol use among HIV-infected out-patients in Eldoret, Kenya. DESIGN: Randomized clinical trial comparing CBT against a usual care assessment-only control. SETTING: A large HIV out-patient clinic in Eldoret, Kenya, part of the Academic Model for Providing Access to Healthcare collaboration. PARTICIPANTS: Seventy-five HIV-infected out-patients who were antiretroviral (ARV)-initiated or ARV-eligible and who reported hazardous or binge drinking. MEASUREMENTS: Percentage of drinking days (PDD) and mean drinks per drinking days (DDD) measured continuously using the Time line Follow back method. FINDINGS: There were 299 ineligible and 102 eligible out-patients with 12 refusals. Effect sizes of the change in alcohol use since baseline between the two conditions at the 30-day follow-up were large [d=0.95, P=0.0002, mean difference=24.93, 95% confidence interval (CI): 12.43, 37.43 PDD; d=0.76, P=0.002, mean difference=2.88, 95% CI: 1.05, 4.70 DDD]. Randomized participants attended 93% of the six CBT sessions offered. Reported alcohol abstinence at the 90-day follow-up was 69% (CBT) and 38% (usual care). Paraprofessional counselors achieved independent ratings of adherence and competence equivalent to college-educated therapists in the United States. Treatment effect sizes were comparable to alcohol intervention studies conducted in the United States. CONCLUSIONS: Cognitive-behavioral therapy can be adapted successfully to group paraprofessional delivery in Kenya and may be effective in reducing alcohol use among HIV-infected Kenyan out-patients.

Systematic cultural adaptation of cognitive-behavioral therapy to reduce alcohol use among HIV-infected outpatients in western Kenya.

Two-thirds of those with HIV worldwide live in sub-Saharan Africa. Alcohol use is associated with the HIV epidemic through risky sex and suboptimal ARV adherence. In western Kenya, hazardous drinking was reported by HIV (53%) and general medicine (68%) outpatients. Cognitive behavioral treatment (CBT) has demonstrated strong efficacy to reduce alcohol use. This article reports on a systematic cultural adaptation and pilot feasibility study of group paraprofessional-delivered CBT to reduce alcohol use among HIV-infected outpatients in Eldoret, Kenya. Following adaptation and counselor training, five pilot groups were run (n = 27). Overall attendance was 77%. Percent days abstinent from alcohol (PDA) before session 1 was 52-100% (women) and 21-36% (men), and by session 6 was 96-100% (women) and 89-100% (men). PDA effect sizes (Cohen's d) between first and last CBT session were 2.32 (women) and 2.64 (men). Participants reported treatment satisfaction. Results indicate feasibility, acceptability and preliminary efficacy for CBT in Kenya.

PDGF up-regulates CSF-1 gene transcription in ameloblast-like cells.

Macrophage colony-stimulating factor (CSF-1) is a key regulatory cytokine for amelogenesis, and ameloblasts synthesize CSF-1. We hypothesized that PDGF stimulates DNA synthesis and regulates CSF-1 in these cells. We determined the effect of PDGF on CSF-1 expression using MEOE-3M ameloblasts as a model. By RT-PCR, MEOE-3M expressed PDGFRs and PDGF A- and B-chain mRNAs. PDGF-BB increased DNA synthesis and up-regulated CSF-1 mRNA and protein in MEOE-3M. Cells transfected with CSF-1 promoter deletion constructs were analyzed. A PDGF-responsive region between -1.7 and -0.795 kb, containing a consensus Pea3 binding motif, was identified. Electrophoretic mobility shift assay (EMSA) showed that PDGF-BB stimulated protein binding to this motif that was inhibited in the presence of anti-Pea3 antibody. Analysis of these data provides the first evidence that PDGF-BB is a mitogen for MEOE-3M and increases CSF-1 protein levels, predominantly by transcription. Elucidation of the cellular pathways that control CSF-1 expression may provide novel strategies for the regulation of enamel matrix formation.

Synergistic control of oscillations in the NF-kappaB signalling pathway.

In previous work, we studied the behaviour of a model of part of the NF-kappaB signalling pathway. The model displayed oscillations that varied both in number, amplitude and frequency when its parameters were varied. Sensitivity analysis showed that just nine of the 64 reaction parameters were mainly responsible for the control of the oscillations when these parameters were varied individually. However, the control of the properties of any complex system is distributed, and, as many of these reactions are highly non-linear, we expect that their interactions will be too. Pairwise modulation of these nine parameters gives a search space some 50 times smaller (81 against 4096) than that required for the pairwise modulation of all 64 reactions, and this permitted their study (which would otherwise have been effectively intractable). Strikingly synergistic effects were observed, in which the effect of one of the parameters was strongly (and even qualitatively) dependent on the values of another parameter. Regions of parameter space could be found in which the amplitude, but not the frequency (timing), of oscillations varied, and vice versa. Such modelling will permit the design and performance of experiments aimed at disentangling the role of the dynamics of oscillations, rather than simply their amplitude, in determining cell fate. Overall, the analyses reveal a level of complexity in these dynamic models that is not apparent from study of their individual parameters alone and point to the value of manipulating multiple elements of complex networks to achieve desired physiological effects.