Stem cell factor and basic fibroblast growth factor are synergistic in augmenting committed myeloid progenitor cell growth

Stem cell factor (SCF) and basic fibroblast growth factor (bFGF) are hematopoietic cytokines produced by bone marrow stromal cells. It is known that, although SCF and bFGF have limited clonogenic activity on their own, they can augment colony-stimulating factor (CSF)-mediated progenitor cell growth. Because these factors are both sequestered by stromal cells, we examined their interaction on progenitor cell growth in conjunction with granulocyte-macrophage-CSF (GM-CSF). In this study, we show that clonogenic growth derived from low-density bone marrow cells stimulated by GM-CSF is significantly augmented (P < .001) in the presence of maximal (100 ng/mL) concentrations of SCF in combination with 100 ng/mL of bFGF. When CD34+ cells are used, the synergistic effect of bFGF and SCF for GM-CSF-mediated progenitor cell growth is further increased, resulting in as much as a sevenfold increase in detectable colony-forming units granulocyte-macrophage (P < .001). These data suggest that the synergistic activity of bFGF and SCF is mediated directly on hematopoietic precursors. These observations suggest that bFGF and SCF, concentrated locally on stromal cell surfaces, might interact in concert with other hematopoietic cytokines to regulate stem cell proliferation and differentiation in hematopoietic niches in the bone marrow.     

Killing of primary CD4+ T cells by non-syncytium-inducing macrophage-tropic human immunodeficiency virus type 1.

Understanding the mechanism by which human immunodeficiency virus type 1 (HIV-1) kills CD4+ T lymphocytes is important to the development of therapeutic and prophylactic strategies. Recent studies have indicated that, in some cases, progression to AIDS is associated with the appearance of syncytium-inducing, T cell line-tropic HIV-1 variants. Nevertheless, approximately 50% of subjects with AIDS harbor only non-syncytium-inducing, macrophage-tropic (NSI-M) variants of HIV-1. In most asymptomatic patients, NSI-M HIV-1 isolates are the predominant virus type found. We report here that cytopathicity of NSI-M HIV-1 for primary CD4+ T lymphocytes can be directly detected in vitro. The extent of CD4+ T-cell killing was not completely correlated with the rate of viral replication, suggesting that other characteristics of HIV-1 contribute to its cytopathicity. Our findings suggest that: (i) direct killing by NSI-M HIV-1 may contribute to CD4+ T-lymphocyte depletion in vivo, and (ii) the determinants of HIV-1 cytopathicity for CD4+ T lymphocytes and cell tropism or syncytia-forming ability are not necessarily tightly linked.     

Le sarcome stromal périductal : une nouvelle observation d’une tumeur rare

Periductal stromal sarcoma is an extremely rare malignant fibroepithelial breast tumor, long confused with phyllodes tumors. This confusion is justified by its biphasic histology comprising two components: ductal or epithelial benign, surrounded by a sarcomatous periductal stroma made of spindle cells. Currently, it is a distinct pathological entity. Wide surgery with free margins is enough and is the only treatment currently validated, the value of adjuvant therapy based on radiation and/or chemotherapy remains to be demonstrated. The prognosis is marked by local recurrence sometimes as phyllodes tumors or specific soft tissue sarcoma more aggressive, which requires close monitoring based on clinical examination.     

Unruptured aneurysm with intramural thrombus is an unusual cause of spinal cord infarction: a case report

Infarction of the spinal cord is a rather rare occurrence. Paraparesis or quadriparesis with vibration and proprioceptive senses sparing are symptoms of anterior cord syndrome. Ischemic anterior cord syndrome can result from an obstruction of the anterior spinal artery or the Adamkiewicz Artery. Spinal infarction due to abdominal aortic aneurysm with intramural thrombosis is an extremely rare condition, because of its rarity, it presents a diagnostic difficulty to clinicians, which may result in an inaccurate or delayed diagnosis. We present a case of spontaneous spinal cord infarction due to a previously asymptomatic aortic aneurysm with intraluminal thrombus, with a review of the literature.     

Social media opposition to the 2022/2023 UK nurse strikes

Previous research has established that the success of strikes, and social movements more broadly, depends on their ability to garner support from the public. However, there is scant published research investigating the response of the public to strike action by healthcare workers. In this study, we address this gap through a study of public responses to UK nursing strikes in 2022–2023, using a data set drawn from Twitter of more than 2300 publicly available tweets. We focus on negative tweets, investigating which societal discourses social media users draw on to oppose strike action by nurses. Using a combination of corpus-based approaches and discourse analysis, we identified five categories of opposition: (i) discourse discrediting nurses; (ii) discourse discrediting strikes by nurses; (iii) discourse on the National Health System; (iv) discourse about the fairness of strikers' demands and (v) discourse about potential harmful impact. Our findings show how social media users operationalise wider societal discourses about the nursing profession (e.g., associations with care, gender, vocation and sacrifice) as well as recent crises such as the Covid-19 pandemic to justify their opposition. The results also provide valuable insights into misconceptions about nursing, strike action and patient harm, which can inform strategies for public communication.     

Preferred nucleotide sequence at the integration target site of human T-cell leukemia virus type I from patients with adult T-cell leukemia

Human T-cell leukemia virus type I (HTLV-I) is etiologically associated with adult T-cell leukemia/lymphoma (ATL). We cloned and sequenced host DNA adjacent to the long terminal repeats of HTLV-I from uncultured leukemic cells of 4 ATL patients. The region flanking the provirus was generally A/T-rich (60–64% A/T), and a nucleotide composition bias was noticed when sequences within 25 bp on both sides of the integration target site were analyzed. In the 6-bp direct repeat, both end positions are preferentially occupied by G/C, whereas the middle positions are preferentially occupied by A/T. Furthermore, AA or TT dinucleotides are frequently present on each side adjacent to the center of the direct repeat. Our finding suggests preferential integration target sites of HTLV-I in the host genome. Further study is warranted to determine whether each of the target sequence preference is a general property of HTLV-I integration or may be associated with the leukemogenesis of ATL. © 1996 Wiley-Liss, Inc.