Impact of Age and Polytherapy on Fingolimod Induced Bradycardia: a Preclinical Study

Fingolimod is a an oral disease modifying drug for relapsing remitting multiple sclerosis (MS) preventing egress of B and T cells from lymph nodes. Relevant first dose adverse events include bradycardia and atrioventricular conduction slowing. Cardiac side effects of fingolimod and combinational pharmacotherapy including duloxetine and tolterodine were monitored in mice of different age using implantable ECG telemetric systems. Cardiac tissue was assessed for S1P-receptor subtype (1 and 3), and for GIRK1 expression. Fingolimod led to a significant heart rate reduction within 60 min, which returned to baseline values within 24 h. In older mice bradycardia was more pronounced compared to younger mice. Atrioventricular conduction was not affected. Older mice showed a higher S1PR3 expression in a naïve state and receptor expression was reduced after fingolimod administration. Combination with duloxetine or tolterodine alleviated fingolimod induced heart rate decrease. Our data provide preclinical evidence that negative chronotropic effects of fingolimod might be age dependent, possibly due to an altered expression and internalization of cardiac S1PR3 in older animals. This data could be relevant for future clinical monitoring and patient selection in the aging MS population. Combinational therapies of fingolimod and duloxetine or tolterodine are well tolerated and safe without an increased risk for pronounced bradycardia or arrhythmia.     

Methadone injecting in Australia: a tale of two cities

Aims. The injection of methadone syrup designed for oral consumption is potentially associated with increased morbidity and mortality. Previous reports from Sydney, Australia have suggested a high prevalence of methadone injecting by clients in methadone programmes and by heroin users not in methadone treatment. This study sought to estimate the prevalence of methadone injecting by clients in community based methadone programmes in Melbourne, Australia, which operate under different take away policies. Design. The study used a cross-sectional survey of methadone clients using a self-complete questionnaire. Subjects were recruited from randomly selected methadone dispensing pharmacies across Melbourne. Participation was voluntary. Participants. One hundred and sixty-eight methadone clients were recruited to the study. The mean age was 34.2 years; 59% were male. Findings. Two of 168 methadone clients reported having injected methadone within the preceding 6-month period. Conclusions. The lower prevalence of methadone injecting in Melbourne (compared to Sydney) is thought to be due to the less liberal take-away policy, and the mandatory dilution of methadone take-aways to 200 ml of liquid. Implications for methadone take-away policies and procedures are discussed.     

Human burst-forming units-erythroid need direct interaction with stem cell factor for further development

To understand the factors that regulate the early growth and development of immature erythroid progenitor cells, the burst-forming units-erythroid (BFU-E), it is necessary to have both highly purified target cells and a medium free of serum. When highly purified human blood BFU-E were cultured in a serum-free medium adequate for the growth of later erythroid progenitors, BFU-E would not grow even with the addition of recombinant human interleukin-3 (rIL-3), known to be essential for these cells. However, the addition of recombinant human stem cell factor (rSCF), which supports germ cell and pluripotential stem cell growth, stimulated BFU-E to grow equally well in serum-free as in serum-containing medium. Limiting dilution studies showed that rSCF acts directly on the BFU-E that do not require accessory cells for growth. Furthermore, rSCF was necessary for BFU-E development during the initial 7 days of culture, until these cells reached the stage of the late progenitors, the colony-forming units-erythroid (CFU-E). These studies indicate that early erythropoiesis is dependent on the direct action of SCF that not only affects early stem cells but is continually necessary for the further development of committed erythroid progenitor cells until the CFU-E stage of maturation.     

Monitoring CD8 T cell responses to NY-ESO-1: correlation of humoral and cellular immune responses

NY-ESO-1, a member of the cancer-testis family of antigens, is expressed in a subset of a broad range of different human tumor types. Patients with advanced NY-ESO-1-expressing tumors frequently develop humoral immunity to NY-ESO-1, and three HLA A2-restricted peptides were defined previously as targets for cytotoxic CD8(+) T cells in a melanoma patient with NY-ESO-1 antibody. The objectives of the present study were (i) to develop enzyme-linked immunospot (ELISPOT) and tetramer assays to measure CD8(+) T cell responses to NY-ESO-1, (ii) to determine the frequency of CD8(+) T cell responses to NY-ESO-1 in a series of HLA-A2 patients with NY-ESO-1 expressing tumors, (iii) to determine the relation between CD8(+) T cell and humoral immune responses to NY-ESO-1, and (iv) to compare results of NY-ESO-1 ELISPOT assays performed independently in two laboratories with T cells from the same patients. NY-ESO-1 ELISPOT and tetramer assays with excellent sensitivity, specificity, and reproducibility have been developed and found to correlate with cytotoxicity assays. CD8(+) T cell responses to HLA-A2-restricted NY-ESO-1 peptides were detected in 10 of 11 patients with NY-ESO-1 antibody, but not in patients lacking antibody or in patients with NY-ESO-1-negative tumors. The results of ELISPOT assays were concordant in the two laboratories, providing the basis for standardized monitoring of T cell responses in patients receiving NY-ESO-1 vaccines.     

Patterns of drug preference and use among people who inject drugs in Melbourne,Australia

Background: Understanding of substitution patterns in drug using careers is limited. Between 2009 and mid-2013, the purity-adjusted price of methamphetamine declined sharply in Melbourne in absolute terms and relative to the purity-adjusted price of heroin. We determine whether there were associated increases among people who inject drugs (PWID) in (1) use of methamphetamine and (2) citing methamphetamine as the drug of choice. Method: Responses to “drug of choice” and “most used drug” were obtained from baseline and follow-up interviews of the 688 PWID enrolled in the Melbourne Injecting Drug User Cohort Study between April 2008 and August 2013, categorised as heroin, methamphetamine, cannabis or other. Previous month heroin and methamphetamine use was reported at baseline by 82% and 41% of participants, respectively, and 51% had completed four or more interviews in this period. A Markov model that included marginal effects for methamphetamine purity-adjusted price was used to calculate (1) transitions between drug of choice and (2) conditional probabilities for most used drug. Parameters were determined by fitting multinomial logistic models to appropriate data subsets. Results: At baseline, the majority of participants reported heroin as both their preferred drug and the drug they used most. There were no significant increases in reports of methamphetamine as drug of choice, or as the most used drug. Conclusion: In a cohort of PWID who reported a range of drug behaviours, there was little evidence of drug substitution into methamphetamine, despite substantial declines in its purity-adjusted price.