Melanogenic Regulatory Factors in Coated Vesicles from Melanoma Cells

Coated vesicles have been found to contain much higher tyrosinase and γ-glutamyl transpeptidase activities than pre-melanosomes. This indicates that similar to tyrosinase, γ-glutamyl transpeptidase, an enzyme responsible for pheomelanogenesis, is highly concentrated in coated vesicles after its maturation in Golgi associated endoplasmic reticulum (GERL). Furthermore, in the pre- and post-dopaquinone melanogenic pathway, coated vesicles convert dopachrome to colorless indole compounds mere quickly than in premelanosomes because of their higher dopachrome conversion factor activity. Melanosomes have been found to exhibit indole conversion factor activity, while coated vesicles show indole blocking factor activity. In moderately tyrosinase-rich premelanosomes, the levels of dopachrome conversion factor and indole blocking factor are lower than in coated vesicles or melanosomes. High levels of indole blocking factor in coated vesicles may indicate why melanin polymer formation does not occur there in vivo despite their high tyrosinase activity

Higher incidence of pegfilgrastim-induced bone pain in younger patients receiving myelosuppressive chemotherapy: a real-world experience

Abstract Background Pegfilgrastim is widely used for the prevention of febrile neutropenia (FN) in patients receiving myelosuppressive chemotherapy for various types of cancer. However, pegfilgrastim-induced bone pain (PIBP) is a relevant adverse event occurring during cancer treatment. Thus, we aimed to determine the risk factors for PIBP in real-world clinical practice. Main body We retrospectively collected the clinical records of patients who received pegfilgrastim to support myelosuppressive chemotherapy with at least a 10% risk of FN between 2015 and 2018 at our center. Patients received pegfilgrastim 3.6 mg between days 2 and 7 after chemotherapy administration (day 1) for primary or secondary prophylaxis against FN. All adverse events were recorded according to the Common Terminology Criteria for Adverse Events. Patients who experienced intermittent bone pain in the back, femur, or other anatomic sites after the pegfilgrastim administration were considered to have PIBP. To evaluate the relationship between PIBP incidence and patient characteristics, we performed univariate and multivariate logistic regression analyses to calculate the odds ratios (ORs) of possible risk factors for PIBP. We analyzed the data of 305 patients (median age: 63 years), who underwent 1220 chemotherapy cycles with pegfilgrastim per cycle. Univariate analysis revealed that female sex (vs. male sex), younger age (< 55 years vs. ≥ 55 years), and solid cancers (vs. hematologic cancers) had significantly higher ORs (p < 0.05). However, only younger age (< 55 years) was an independent risk factor for PIBP on multivariate analysis (OR 3.62, 95% confidence interval 1.51–8.69, p = 0.004). Conclusions Younger age (< 55 years) was significantly associated with a higher risk of PIBP among patients receiving chemotherapy with a ≥ 10% risk of FN. Therefore, oncologists should meticulously formulate management plan for PIBP in younger patients after administering pegfilgrastim