Alternative BRAF mutations in BRAF V600E‐negative hairy cell leukaemias

The BRAF V600E mutation in exon 15 is considered the disease‐defining mutation in hairy cell leukaemia (HCL), but single HCL cases lacking this mutation have been described. In 24 HCL, as well as in 194 various mature B‐ and T‐cell neoplasms, we extended the search for BRAF mutations to exon 11. Two V600E‐negative HCL contained novel, potentially functionally relevant mutations in exon 11 (F468C and D449E), while one other HCL was BRAF wild‐type in exons 2–17. All non‐HCL lymphomas lacked BRAF mutations. We therefore suggest screening of BRAF V600E‐negative HCL for alternative exon 11 mutations in the diagnostic setting.     

Der Einfluss Von Strukturänderungen Auf Peroxydative Und Reduzierende Fermentreaktionen Bei Menschlichen Leukocyten

Zusammenfassung Das Freiwerden der Peroxydasereaktion menschlicher Leukocyten ist an eine Strukturschädigung gebunden, die der Hämolyse der Erythrocyten ähnlich ist. Die Strukturänderung schafft Vorbedingungen für ein Unwirksamwerden der Ascorbinsäure der Leukocyten. Das Triphenyltetrazoliumchlorid-reduzierende Fermentsystem stört die Peroxydasereaktion nicht.     

Epithelkörperchen-Untersuchungen mit besonderer Berücksichtigung der Tetania infantum

Ohne Zusammenfassung     

Cysteine proteinases produced by cultured rabbit V2 carcinoma cells and rabbit skin fibroblasts

Rabbit V2 carcinoma cells and normal rabbit skin fibroblasts produced cysteine proteinases with properties similar to those of purified rabbit liver cathepsin B. Both cell types secreted into the culture medium enzymes with an apparent Mr of 43,000, which reacted with synthetic substrates commonly used for cathepsin B. After limited proteolysis with pepsin or treatment at pH 3, the Mr = 43,000 species could be converted into forms with Mr = 34,000 and an increased specific activity. In the intracellular pool of both V2 carcinoma cells and fibroblasts, a cysteine proteinase with the same Mr of cathepsin B (27,000) was found. Despite the similarity in molecular size, substrate specificity and sensitivity to inhibitors, the tumor and fibroblast enzymes were not identical in their stability at pH greater than or equal to 7 and were produced by the 2 cell types in considerably different amounts. In terms of enzyme units and normalized to an equal cell number, the ratios of fibroblast enzyme/tumor enzyme were as follows: secreted 130-150; intracellular, 150-180. The pH stability of the cysteine proteinases was determined quantitatively by measuring the half-life of enzyme activity. At pH 8.0 and 25 degrees C the secreted tumor cysteine proteinase had a half-life of at least 5 hr, whereas the secreted fibroblast enzyme and liver cathepsin B had half-lives of 8.8 min and 4.4 min, respectively.     

Heart transplantation in the early phase of the COVID-19 pandemic: A single-center case series

The infectious disease coronavirus disease 2019 (COVID-19) was declared a pandemic by the World Health Organization in March 2020. The impact of COVID-19 on solid organ transplantations, including heart transplantation, is currently unclear. Many transplant programs have been forced to swiftly re-evaluate and adapt their practices, leading to a marked decrease in transplants performed. This trend has been due to various factors, including increased donor COVID-19 screening scrutiny and recipient waiting list management in anticipation of COVID-19 critical care surge capacity planning. In the face of these unknown variables, determining when and how to proceed with transplantation in our population of patients with end-stage cardiomyopathies is challenging. Here, we describe our center's experience with orthotopic heart transplantation (OHT) in one of the country's pandemic epicenters, where we performed eight OHTs in the first 2 months after community spread began in late February 2020.     

SEROLOGICALLY DEMONSTRABLE ALLOANTIGENS OF MOUSE EPIDERMAL CELLS

Single cells were prepared from mouse tail epidermis by a method which gives high viability counts and so permits their use in cytotoxicity tests. According to tests with standard alloantisera, the antigen phenotype of mouse epidermal cells is H-2⁺θ⁺Sk⁺H-Y⁺TL^-Ly-A^-Ly-B,C^-PC^-. The skin differentiation alloantigen Sk, which is responsible for homograft reactions directed selectively against skin, is expressed also on brain, but not on other cell types; it is present on the transplanted neuroblastoma C1300. Cytotoxicity tests with epidermal cells of H-2 congenic mouse stocks confirm that the Sk locus is not closely linked to H-2. The lymphoid cell differentiation antigen θ also is present on both epidermal cells and brain. Mice frequently retain θ-incompatible or Sk-incompatible skin grafts although they have formed substantial titers of θ or Sk antibody in response to grafting. Male (H-Y) antigen is demonstrable on epidermal cells by cytotoxicity tests with H-Y antibody, as it is also on one other type of cell, spermatozoa.     

Eccrine poroma. A clinico-pathologic and immunohistologic study with special reference to tumor cell differentiation]

In this study 15 eccrine poromas were analysed clinically, histologically and immunohistologically. They were all solitary lesions, showing a predilection for the head and neck. In none of the tumours was diagnosis possible on the basis of clinical examination. Histomorphologically, eccrine poromas were characterized by aggregations of neoplastic cells continuous with the epidermis. The neoplasms consisted of two cell types, poroid and cuticular. Poroid cells predominated, while cuticular cells were only found in small foci, sometimes showing tubular differentiation. Immunohistologically, most of the tumour cells showed a cytokeratin pattern (CK1, 5, 10, 11+, CK1-19+) favouring differentiation toward the abluminal cell of the dermal eccrine duct rather than toward the abluminal cell of the intraepidermal segment of the eccrine duct. Only a small proportion of cells revealed the immunohistological features of the abluminal cell of the intraepidermal duct (CK1+, CK1, 5, 10, 11+, CK1-19+). In addition, cuticular cells showed differentiation toward the luminal cell of the eccrine duct (CK19+, CK1, 5, 10, 11+, CK1-19+). Simple-type cytokeratins such as CK7 and CK18 were not expressed. In conclusion, our findings favour the hypothesis that ascribes the origin of eccrine poroma to a pluripotential stem cell of the transitional zone between the dermal and the intraepidermal segments of the eccrine duct.