Explaining survival differences between two consecutive studies with allogeneic stem cell transplantation in patients with chronic myeloid leukemia

Purpose

In the two consecutive German studies III and IIIA on chronic myeloid leukemia, between 1995 and 2004, 781 patients were randomized to receive either allogeneic hematopoietic stem cell transplantation with a related donor or continued drug treatment. Despite comparable transplantation protocols and most centers participating in both studies, the post-transplant survival probabilities for patients transplanted in first chronic phase were significantly higher in study IIIA (144 patients) than in study III (113 patients). Prior to the decision on a combined analysis of both studies, reasons for this discrepancy had to be investigated.

Methods

The Cox proportional hazard cure model was used to identify prognostic factors for post-transplant survival.

Results

Donor–recipient matching for human leukocyte antigen, patient age, time between diagnosis and transplantation, and calendar time showed a significant influence on survival and/or the incidence of cure. Added as a further factor, affiliation to study IIIA had no significant impact any longer.

Conclusions

Discrepancies in influential prognostic factors explained the different post-transplant survival probabilities between the studies. The significance of calendar time suggests a lack of consistency of transplantation practice over time. Accordingly, the prerequisite for a common assessment of overall survival in the two randomized transplantation arms was not met. Moreover, our analyses provide an independent validation of established prognostic factors and their cutoffs. The statistical approach in investigating and modeling potential prognostic factors for survival sets an example for the examination of studies with unexpected outcome differences in concurrent treatment arms.     

Role of lon, an ATP-dependent protease homolog, in resistance of Pseudomonas aeruginosa to ciprofloxacin

With few novel antimicrobials in the pharmaceutical pipeline, resistance to the current selection of antibiotics represents a significant therapeutic challenge. Microbial persistence in subinhibitory antibiotic environments has been proposed to contribute to the development of resistance. Pseudomonas aeruginosa cultures pretreated with subinhibitory concentrations of ciprofloxacin were found to exhibit an adaptive resistance phenotype when cultures were subsequently exposed to suprainhibitory ciprofloxacin concentrations. Microarray experiments revealed candidate genes involved in such adaptive resistance. Screening of 10,000 Tn5-luxCDABE mutants identified several mutants with increased or decreased ciprofloxacin susceptibilities, including mutants in PA1803, a close homolog of the ATP-dependent lon protease, which were found to exhibit > or = 4-fold-increased susceptibilities to ciprofloxacin and other fluoroquinolones, but not to gentamicin or imipenem, as well as a characteristic elongated morphology. Complementation of the lon mutant restored wild-type antibiotic susceptibility and cell morphology. Expression of the lon mutant, as monitored through a luciferase reporter fusion, was found to increase over time in the presence of subinhibitory ciprofloxacin concentrations. The data are consistent with the hypothesis that the induction of Lon by ciprofloxacin is involved in adaptive resistance.     

Interleukin-31: The “itchy” cytokine in inflammation and therapy

The cytokine interleukin-31 has been implicated in the pathophysiology of multiple atopic disorders such as atopic dermatitis (AD), allergic rhinitis, and airway hyper-reactivity. In AD, IL-31 has been identified as one of the main “drivers” of its cardinal symptom, pruritus. Here, we summarize the mechanisms by which IL-31 modulates inflammatory and allergic diseases. T_H2 cells play a central role in AD and release high levels of T_H2-associated cytokines including IL-31, thereby mediating inflammatory responses, initiating immunoregulatory circuits, stimulating itch, and neuronal outgrowth through activation of the heterodimeric receptor IL-31 receptor A (IL31RA)/Oncostatin M receptor (OSMRβ). IL31RA expression is found on human and murine dorsal root ganglia neurons, epithelial cells including keratinocytes and various innate immune cells. IL-31 is a critical cytokine involved in neuroimmune communication, which opens new avenues for cytokine modulation in neuroinflammatory diseases including AD/pruritus, as validated by recent clinical trials using an anti-IL-31 antibody. Accordingly, inhibition of IL-31-downstream signaling may be a beneficial approach for various inflammatory diseases including prurigo. However, as to whether downstream JAK inhibitors directly block IL-31-mediated-signaling needs to be clarified. Targeting the IL-31/IL31RA/OSMRβ axis appears to be a promising approach for inflammatory, neuroinflammatory, and pruritic disorders in the future.     

Reproductive function and risk for PCOS in women treated for bipolar disorder

INTRODUCTION: This study examined the reproductive function and prevalence of polycystic ovary syndrome (PCOS) in women with bipolar disorder taking antimanic medications. METHOD: Women aged 18-45 treated for bipolar disorder and not taking steroid contraceptives were recruited to complete questionnaires about their menstrual cycle and to provide blood samples for measurement of a range of reproductive endocrine and metabolic hormone levels. Eighty women participated in completing the questionnaires and 72 of them provided blood samples. RESULTS: Fifty-two of the 80 women (65%) reported current menstrual abnormalities, 40 of which (50%) reported one or more menstrual abnormalities that preceded the diagnosis of bipolar disorder. Fifteen women (38%) reported developing menstrual abnormalities since treatment for bipolar disorder, 14 of which developed abnormalities since treatment with valproate (p = 0.04). Of the 15 patients reporting menstrual abnormalities since starting medication, 12 (80%) reported changes in menstrual flow (heavy or prolonged bleeding) and five (33%) reported changes in cycle frequency. No significant differences were observed between women receiving or not receiving valproate in mean levels of free or total serum testosterone levels. This was true for the total sample and for the sub-group without preexisting menstrual problems. However, within the valproate group, duration of use was significantly correlated with free testosterone levels (r = 0.33, p = 0.02). Three of the 50 women (6%) taking VPA, and 0% of the 22 taking other antimanic medications, met criteria for PCOS (p = 0.20). Other reproductive and metabolic values outside the normal range across treatment groups included elevated 17 alpha-OH progesterone levels, luteinizing hormone: follicle-stimulating hormone ratios, homeostatic model assessment (HOMA) values, and low estrogen and dehydroepiandrosterone sulfate (DHEAS) levels. Preexisting menstrual abnormalities predicted higher levels of 17 alpha-OH progesterone, free testosterone, and estrone as well as development of new menstrual abnormalities. Body mass index (BMI) was significantly positively correlated with free testosterone levels and insulin resistance (HOMA) across all subjects, regardless of medication used. CONCLUSIONS: Rates of menstrual disturbances are high in women with bipolar disorder and, in many cases, precede the diagnosis and treatment for the disorder. Treatment with valproate additionally contributes significantly to the development of menstrual abnormalities and an increase in testosterone levels over time. A number of bipolar women, regardless of type of medication treatment received, have reproductive and metabolic hormonal abnormalities, yet the etiology of such abnormalities requires further study. Women with preexisting menstrual abnormalities may represent a group at risk for development of reproductive dysfunction while being treated for bipolar disorder.     

Oscillatory MEG gamma band activity dissociates perceptual and conceptual aspects of visual object processing: a combined repetition/conceptual priming study

We used a combined repetition/conceptual priming task to investigate attenuations of induced gamma-band activity (iGBA) due to prior experience. We hypothesized that distinguishable iGBA suppression effects can be related to the processing of (a) perceptual aspects, and (b) conceptual aspects of cortical object representations. Participants were asked to perform a semantic classification task with pictures of real world objects and their semantically corresponding words, using a design that isolated distinct levels of the neural suppression effect. By means of volumetric source analysis we located stimulus domain-specific iGBA repetition suppression effects (60-90 Hz) in temporal, parietal, and occipital areas of the human cortex. In contrast, domain-unspecific iGBA repetition suppression, corresponding to conceptual priming, was restricted to left temporal brain regions. We propose that the selective involvement of left temporal areas points to the activation of conceptual representations, whereas more posterior temporal, parietal, and occipital areas probably reflect perceptual aspects of higher-order visual object processing.