A proposal for calculating the no-observed-adverse-effect level (NOAEL) for organic compounds responsible for liver toxicity based on their physicochemical properties

Objectives: Both environmental and occupational exposure limits are based on the no-observed-adverse-effect level (NOAEL), lowest-observed-adverse-effect level (LOAEL) or benchmark dose (BMD) deriving from epidemiological and experimental studies. The aim of this study is to investigate to what extent the NOAEL values for organic compounds responsible for liver toxicity calculated based on their physicochemical properties could be used for calculating occupational exposure limits. Material and Methods: The distribution coefficients from air to the liver (log Kliver) were calculated according to the Abraham solvation equation. NOAEL and LOAEL values for early effects in the liver were obtained from the literature data. The descriptors for Abraham's equation were found for 59 compounds, which were divided into 2 groups: "non-reactive" (alcohols, ketones, esters, ethers, aromatic and aliphatic hydrocarbons, amides) and "possibly reactive" (aldehydes, allyl compounds, amines, benzyl halides, halogenated hydrocarbons, acrylates). Results: The correlation coefficients between log-log K and log NOAEL for non-reactive and reactive compounds amounted to r = -0.8123 and r = -0.8045, respectively, and were statistically significant. It appears that the Abraham equation could be used to predict the NOAEL values for compounds lacking information concerning their liver toxicity. Conclusions: In view of the tendency to limit animal testing procedures, the method proposed in this paper can improve the practice of setting exposure guidelines for the unstudied compounds

The BLIMP1-EZH2 nexus in a non-Hodgkin lymphoma.

To access publisher's full text version of this article click on the hyperlink belowWaldenström's macroglobulinemia (WM) is a non-Hodgkin lymphoma, resulting in antibody-secreting lymphoplasmacytic cells in the bone marrow and pathologies resulting from high levels of monoclonal immunoglobulin M (IgM) in the blood. Despite the key role for BLIMP1 in plasma cell maturation and antibody secretion, its potential effect on WM cell biology has not yet been explored. Here we provide evidence of a crucial role for BLIMP1 in the survival of cells from WM cell line models and further demonstrate that BLIMP1 is necessary for the expression of the histone methyltransferase EZH2 in both WM and multiple myeloma cell lines. The effect of BLIMP1 on EZH2 levels is post-translational, at least partially through the regulation of proteasomal targeting of EZH2. Chromatin immunoprecipitation analysis and transcriptome profiling suggest that the two factors co-operate in regulating genes involved in cancer cell immune evasion. Co-cultures of natural killer cells and cells from a WM cell line further suggest that both factors participate in immune evasion by promoting escape from natural killer cell-mediated cytotoxicity. Together, the interplay of BLIMP1 and EZH2 plays a vital role in promoting the survival of WM cell lines, suggesting a role for the two factors in Waldenström's macroglobulinaemia

European myeloma network recommendations on diagnosis and management of patients with rare plasma cell dyscrasias

The introduction of novel agents in the management of multiple myeloma and related plasma cell dyscrasias has changed our treatment approaches and subsequently the outcome of patients. Due to current advances, the European Myeloma Network updated the diagnostic and therapeutic recommendations for patients with Waldenström’s macroglobulinemia (WM), AL-amyloidosis, monoclonal immunoglobulin deposition disease (MIDD), POEMS syndrome, and primary plasma cell leukemia. For patients with WM, the combination of rituximab with chemotherapy remains the treatment cornerstone, while the Bruton-tyrosine kinase inhibitor ibrutinib has been introduced and approved for relapsed/refractory disease. The management of light chain amyloidosis depends on the presence and severity of heart disfunction. If present, intensification with an autologous stem cell transplantation (ASCT) is not recommended. Further aggregation of misfolded light chains could be prevented by doxycycline or monoclonal antibodies targeting amyloid deposits. Initial treatment generally consists of melphalan/dexamethasone or bortezomib-based regimens. For relapsing patients, one can consider proteasome inhibitors, immunomodulatory agents, melphalan or daratumumab. Because intact or light-chain immunoglobulins are also the culprits for MIDD, the small monoclonal plasma cells' clones should be treated and generally respond well to bortezomib-based treatment. POEMS syndrome is a well-defined clinical entity that can present as solitary bone lesions or disseminated disease. Radiation therapy is used for patients with localized disease and result in long-lasting response. Systemic treatment should be proposed to patients with disseminated disease, but regimens that can worsen a pre-existing polyneuropathy should be avoided. PPCL is located at the other end of the spectrum of plasma cell disorders and is associated with an aggressive disease course and poor prognosis. It requires an imminent, multi-phase and novel agents-based therapy, including induction, ASCT, consolidation and maintenance, with short treatment-free intervals. Patients not eligible for transplant procedures require personalized, intensive therapeutic approach. Allogeneic stem cell transplantation can be used in selected patients