Changes in Serum Prestin Concentration After Exposure to Cisplatin.

HYPOTHESIS: There are temporal changes in the outer-hair-cell-specific protein, prestin, in the blood after administration of low-dose cisplatin. METHODS: Two rodent models of ototoxicity were used. After control and baseline data collection, mice (n = 30) and guinea pigs (n = 10), respectively, were treated with cisplatin at 8 mg/kg. Auditory brainstem responses were recorded on Days 1, 3, 7, and 14 after treatment. Five mice were sacrificed at each time point and serum samples were obtained. A group of 10 guinea pigs were tested and serum samples were collected at each time point. Serum prestin concentrations were measured using separate enzyme-linked immunosorbent assays for each species. RESULTS: Auditory brainstem responses thresholds changed relatively little in mice, but gradually increased in guinea pigs, as a function of time after cisplatin exposure. In contrast, serum prestin concentrations rose, reaching a peak on Days 3 and 7 after cisplatin treatment in mouse and guinea pig, respectively, before declining back to or below baseline/control levels 14 days after treatment. CONCLUSION: There was a time-dependent pattern of change in serum prestin after exposure to low-dose cisplatin in a resistant (mouse) and sensitive (guinea pig) rodent models. These comparative results suggest prestin may serve as a biomarker for cisplatin ototoxicity.

PRBC-derived plasma induces non-muscle myosin type IIA-mediated neutrophil migration and morphologic change.

CONTEXT: Neutrophils are the primary effector cells in the pathogenesis of transfusion-related acute lung injury or multiple organ failure after blood transfusion. OBJECTIVE: We aimed to investigate the effect of fresh (1 day preparation) and aged (42 day preparation) PRBC-derived plasma on neutrophil morphology, migration and phagocytosis. MATERIALS AND METHODS: We evaluated the production of reactive oxygen species (ROS) and the expression of non-muscle myosin heavy chain IIA (MYH9) in neutrophils treated with PRBC-derived plasma. We used western blots and antibody arrays to evaluate changes in signal transduction pathways in plasma-treated neutrophils. RESULTS: Aged PRBC-derived plasma elicited a stronger oxidative burst in neutrophils when compared with fresh PRBC-derived plasma (p < 0.05). Antibody arrays showed increased phosphorylation of NF-ĸB proteins (p105, p50 and Ikk) in aged PRBC-derived plasma-treated neutrophils. The expression of non-muscle myosin IIA (MYH9), a cytoskeleton protein involved in immune cell migration and morphological change, was also significantly upregulated in neutrophils treated with aged PRBC-derived plasma compared to fresh plasma (p < 0.05). Pretreatment of neutrophils with blebbistatin (a specific type II myosin inhibitor), ascorbic acid (an antioxidant), or staurosporine (a protein tyrosine kinase inhibitor), effectively abrogated the morphological changes, neutrophil migration, and phagocytosis induced by aged PRBC-derived plasma. CONCLUSION: Upregulation of MYH9 in neutrophils treated with aged PRBC-derived plasma and abrogation of neutrophil migration in blebbistatin-treated neutrophils suggested a functional role of MYH9 in the directional migration of immune cells. Our data help elucidate the cellular and molecular mechanisms of transfusion-related injury.

International collaboration as a tool for diagnosis of patients with inherited thrombocytopenia in the setting of a developing country.

BACKGROUND: Inherited thrombocytopenias (ITs) are heterogeneous genetic disorders that frequently represent a diagnostic challenge. The requirement of highly specialized tests for diagnosis represents a particular problem in resource-limited settings. To overcome this difficulty, we applied a diagnostic algorithm and developed a collaboration program with a specialized international center in order to increase the diagnostic yield in a cohort of patients in Argentina. METHODS: Based on the algorithm, initial evaluation included collection of clinical data, platelet size, blood smear examination and platelet aggregation tests. Confirmatory tests were performed according to diagnostic suspicion, which included platelet glycoprotein expression, immunofluorescence for myosin-9 in granulocytes and platelet thrombospondin-1 and molecular screening of candidate genes. RESULTS: Thirty-one patients from 14 pedigrees were included; their median age was 32 (4-72) years and platelet count 72 (4-147)×10(9) L(-1). Autosomal dominant inheritance was found in nine (64%) pedigrees; 10 (71%) had large platelets and nine (29%) patients presented with syndromic forms. A definitive diagnosis was made in 10 of 14 pedigrees and comprised MYH9-related disease in four, while classic and monoallelic Bernard-Soulier syndrome, gray platelet syndrome, X-linked thrombocytopenia, thrombocytopenia 2 (ANKRD26 mutation) and familial platelet disorder with predisposition to acute myelogenous leukemia were diagnosed in one pedigree each. CONCLUSIONS: Adoption of an established diagnostic algorithm and collaboration with an expert referral center proved useful for diagnosis of IT patients in the setting of a developing country. This initiative may serve as a model to develop international networks with the goal of improving diagnosis and care of patients with these rare diseases.

[MYH9 syndrome and auto-immune haemolytic anaemia: an unrelated association?]. / Syndrome MYH9 et anémie hémolytique auto-immune : une association fortuite?

INTRODUCTION: The MYH9 syndrome is a group of rare autosomal dominant platelet disorders associating in most of the cases a macrothrombocytopenia and characteristic leukocyte inclusions. Clinical features may include renal, visual, or hearing impairment. The bleeding tendency is usually moderate. CASE REPORT: We report a 28-year-old-man, with an auto-immune haemolytic anaemia associated with a MYH9 syndrome. CONCLUSION: To our knowledge, this is the first report of such an association.

Heavy chain myosin 9-related disease (MYH9 -RD): neutrophil inclusions of myosin-9 as a pathognomonic sign of the disorder.

MYH9-related disease ( MYH9-RD) is an autosomal dominant thrombocytopenia with giant platelets variably associated with young-adult onset of progressive sensorineural hearing loss, presenile cataract, and renal damage. MYH9-RD is caused by mutations of MYH9 , the gene encoding for non-muscle heavy-chain myosin-9. Wild-type and mutant myosin-9 aggregate as cytoplasmic inclusions in patients' leukocytes, the identification of which by immunofluorescence has been proposed as a suitable tool for the diagnosis of MYH9-RD. Since the predictive value of this assay, in terms of sensitivity and specificity, is unknown, we investigated 118 consecutive unrelated patients with a clinical presentation strongly consistent with MYH9-RD. All patients prospectively underwent both the immunofluorescence assay for myosin-9 aggregate detection and molecular genetic analysis of the MYH9 gene. Myosin-9 aggregates were identified in 82 patients, 80 of which (98%) had also a MYH9 mutation. In the remaining 36 patients neither myosin-9 aggregates nor MYH9 mutations were found. Sensitivity and specificity of the immunofluorescence assay was evaluated to be 100% and 95%, respectively. Except for the presence of aggregates, we did not find any other significant difference between patients with or without aggregates, demonstrating that the myosin-9 inclusions in neutrophils are a pathognomonic sign of the disease. However, the identification of the specific MYH9 mutation is still of importance for prognostic aspects of MYH9-RD.