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The WN x precursor WN(NMe2)3 was prepared from WN(O tBu)3 and Zr(NMe2)4 by using an amide/alkoxide exchange reaction. Structural analysis of WN(NMe2)3 revealed an overall pseudo-tetrahedral geometry with a distortion towards trigonal pyramidal. Aerosol-assisted chemical vapor deposition (AACVD) from WN(NMe2)3 resulted in deposition of WN x nanospheres onto Si(100) and Si(111) substrates at low temperatures (75-125 °C). The nanospheres were imaged by SEM and characterized by using energy dispersive spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS). These preliminary results demonstrate the viability of WN(NMe2)3 as a single-source precursor for the deposition of WN x at low temperature. [ABSTRACT FROM AUTHOR]

Histiocytic diseases arise from MAPK mutations in myeloid progenitors. Depending on whether the progenitor follows a dendritic cell or macrophage/monocyte lineage the final histology results in Langerhans cell histiocytosis, Rosai-Dorfman disease or Erdheim-Chester disease. Commentary on: Friedman et al. Mixed histiocytic neoplasms: A multicentre series revealing diverse somatic mutations and responses to targeted therapy. Br J Haematol 2024;205:127-137., (© 2024 British Society for Haematology and John Wiley & Sons Ltd.)

Objective: Postoperative pain for tonsillectomy with or without adenoidectomy or uvulopalatopharyngoplasty (UPPP) can be severe. Ketorolac is a nonsteroidal anti-inflammatory drug that can be administered for analgesia in these patients. In the literature, ketorolac has been associated with an increased risk of hemorrhage after tonsillectomy with or without adenoidectomy. Many other surgical fields have successfully utilized this medicine for postoperative pain control without increased incidence of hemorrhage. The goal of this study was to analyze the effectiveness of ketorolac after tonsillectomy with or without adenoidectomy or UPPP in adults on postoperative hemorrhage rates., Methods: Adult patients older than 18 years of age who underwent tonsillectomy with or without adenoidectomy and UPPP between 2013 and 2018 were assessed to determine hemorrhage rates. Hemorrhage rates were assessed based on patients presenting to the emergency department with complaint of hemorrhage., Results: There was no significant difference between groups in the postoperative hemorrhage rates (P = .331) or the method of hemorrhage control., Conclusion: Ketorolac did not increase postoperative hemorrhage rates in patients posttonsillectomy with or without adenoidectomy or UPPP., Level of Evidence: 4 Laryngoscope, 130:876-879, 2020., (© 2019 The American Laryngological, Rhinological and Otological Society, Inc.)

The etiology of Langerhans cell histiocytosis (LCH) is unknown. Viral causes, including human herpesvirus type 6 (HHV6), have been suggested but remain unproved. The recently discovered human herpesvirus type 8 (HHV8), the cause of Kaposi's sarcoma, infects dendritic cells in the bone marrow associated with multiple myeloma. Evidence for an association of HHV8 infection with LCH in children was studied by two approaches: indirectly by HHV8-specific serologic assays and directly by detection of HHV8 sequences using polymerase chain reaction in affected bone marrow samples. Using three different assays specific for HHV8 antibodies, 3 of 10 (30%) children with LCH had detectable HHV8 antibodies, which was not different from the prevalence of 5 of 30 (17%) in healthy controls of similar age (P = 0.65). Of bone marrow samples from three additional children with LCH, all had amplifiable DNA but were negative for HHV8 sequences. These studies of a small number of patients do not demonstrate an increased prevalence of HHV8 infection in children with LCH, and they do not suggest a causal role for HHV8 in the etiology of LCH., (Copyright 2000 Wiley-Liss, Inc.)

The association of human herpesvirus-8 (HHV-8) with a small non-cleaved cell lymphoma is described in a child with the acquired immunodeficiency syndrome (AIDS) who developed a malignant pleural effusion and radiologic evidence of multiple solid tumors. HHV-8 DNA and Epstein-Barr virus DNA were identified in pleural fluid cells by polymerase chain reaction (PCR) amplification. The serum antibody titer against lytic HHV-8 proteins was 1:640; antibodies to latent HHV-8 proteins were not detected. Cytogenetic analysis of malignant cells revealed three abnormal karyotypes sharing the common finding of a t(8;14) translocation. Rearrangement of c-myc was demonstrated by PCR analysis. Oligoclonal JH immunoglobulin bands were found. Insufficient pleural fluid cells were available to permit localization of HHV-8 to malignant cells by in situ hybridization. This malignancy contrasts with HHV-8-associated lymphomas reported in adult patients with AIDS with respect to cell morphology, c-myc translocation, and oligoclonal immunoglobulin gene rearrangement. HHV-8 is associated with a wider spectrum of malignancies than recognized previously.

Human herpesvirus type 6 DNA derived from human breath was discovered to contaminate PCR reactions during routine reaction preparation. Parallel PCR experiments were conducted in which expiratory secretions were blocked by a surgical mask, while others were performed without any attempt to circumvent respiratory contamination. The experimenter was previously determined to harbor HHV-6 DNA in the saliva. All reactions in which expiration was obstructed were negative for HHV-6 DNA via PCR. Reactions in which there was no attempt to obstruct respiratory secretions were positive for HHV-6 DNA. These data suggest that PCR assays investigating the presence of HHV-6 may be highly susceptible to contamination from the experimenter leading to false positive results.

Langerhans cell histiocytosis (LCH) is an enigmatic histiocytic proliferative disorder of unknown etiology that affects children primarily. We have investigated the possibility that viruses are etiological or that they have a "triggering effect" in LCH. Sensitive in situ hybridization and polymerase chain reaction (PCR) techniques were used in 56 cases of LCH. We sought and failed to find evidence of genomes for adenovirus, cytomegalovirus, Epstein-Barr virus, herpes simplex virus, human herpesvirus type 6, human immunodeficiency virus, human T-cell leukemia virus types I and II, and parvovirus. Although some probes hybridized to tissues from several cases, PCR failed to confirm the presence of viral genome in any. We conclude that there is no evidence that these viruses are associated with LCH.

Children with neutropenia of more than 3 months duration often have evidence of immune-mediated destruction of mature neutrophils and variable abnormalities of myeloid precursors in their bone marrow. These patients often have anti-neutrophil antibodies which persist for several months. To further investigate the aetiology of neutropenia in such patients, bone marrow cells were evaluated for the presence of common viruses. Fifteen of 19 patients tested had evidence for parvovirus infection by PCR amplification of bone marrow DNA with parvovirus specific primers. Of these 15, six also had serologic evidence of parvovirus infection. Anti-neutrophil antibodies were identified in nine of 12 patients with parvovirus infection. Bone marrow culture studies done on six patients revealed varying degrees of myeloid and erythroid inhibition by patient plasma. These studies indicate that parvovirus may be a common cause of immune-mediated neutropenia in children.

Severe aplastic anemia has been reported in children following Epstein-Barr virus (EBV) infection. The pathophysiology of disease is not known, but an immunologic mechanism is suspected because of the rapid response to steroids. A patient with severe aplastic anemia following EBV infection experienced bone marrow recovery after treatment with high-dose prednisone. After reviewing the literature it is concluded that steroid therapy is indicated in this select group of patients.