Multiple Niche Compartments Orchestrate Stepwise Germline Stem Cell Progeny Differentiation.

The niche controls stem cell self-renewal and progenitor differentiation for maintaining adult tissue homeostasis in various organisms. However, it remains unclear whether the niche is compartmentalized to control stem cell self-renewal and stepwise progeny differentiation. In the Drosophila ovary, inner germarial sheath (IGS) cells form a niche for controlling germline stem cell (GSC) progeny differentiation. In this study, we have identified four IGS subpopulations, which form linearly arranged niche compartments for controlling GSC maintenance and multi-step progeny differentiation. Single-cell analysis of the adult ovary has identified four IGS subpopulations (IGS1-IGS4), the identities and cellular locations of which have been further confirmed by fluorescent in situ hybridization. IGS1 and IGS2 physically interact with GSCs and mitotic cysts to control GSC maintenance and cyst formation, respectively, whereas IGS3 and IGS4 physically interact with 16-cell cysts to regulate meiosis, oocyte development, and cyst morphological change. Finally, one follicle cell progenitor population has also been transcriptionally defined for facilitating future studies on follicle stem cell regulation. Therefore, this study has structurally revealed that the niche is organized into multiple compartments for orchestrating stepwise adult stem cell development and has also provided useful resources and tools for further functional characterization of the niche in the future.

Prospectively Isolated Tetraspanin+ Neoblasts Are Adult Pluripotent Stem Cells Underlying Planaria Regeneration.

Proliferating cells known as neoblasts include pluripotent stem cells (PSCs) that sustain tissue homeostasis and regeneration of lost body parts in planarians. However, the lack of markers to prospectively identify and isolate these adult PSCs has significantly hampered their characterization. We used single-cell RNA sequencing (scRNA-seq) and single-cell transplantation to address this long-standing issue. Large-scale scRNA-seq of sorted neoblasts unveiled a novel subtype of neoblast (Nb2) characterized by high levels of PIWI-1 mRNA and protein and marked by a conserved cell-surface protein-coding gene, tetraspanin 1 (tspan-1). tspan-1-positive cells survived sub-lethal irradiation, underwent clonal expansion to repopulate whole animals, and when purified with an anti-TSPAN-1 antibody, rescued the viability of lethally irradiated animals after single-cell transplantation. The first prospective isolation of an adult PSC bridges a conceptual dichotomy between functionally and molecularly defined neoblasts, shedding light on mechanisms governing in vivo pluripotency and a source of regeneration in animals. VIDEO ABSTRACT.

Retinoid-Sensitive Epigenetic Regulation of the Hoxb Cluster Maintains Normal Hematopoiesis and Inhibits Leukemogenesis.

Hox genes modulate the properties of hematopoietic stem cells (HSCs) and reacquired Hox expression in progenitors contributes to leukemogenesis. Here, our transcriptome and DNA methylome analyses revealed that Hoxb cluster and retinoid signaling genes are predominantly enriched in LT-HSCs, and this coordinate regulation of Hoxb expression is mediated by a retinoid-dependent cis-regulatory element, distal element RARE (DERARE). Deletion of the DERARE reduced Hoxb expression, resulting in changes to many downstream signaling pathways (e.g., non-canonical Wnt signaling) and loss of HSC self-renewal and reconstitution capacity. DNA methyltransferases mediate DNA methylation on the DERARE, leading to reduced Hoxb cluster expression. Acute myeloid leukemia patients with DNMT3A mutations exhibit DERARE hypomethylation, elevated HOXB expression, and adverse outcomes. CRISPR-Cas9-mediated specific DNA methylation at DERARE attenuated HOXB expression and alleviated leukemogenesis. Collectively, these findings demonstrate pivotal roles for retinoid signaling and the DERARE in maintaining HSCs and preventing leukemogenesis by coordinate regulation of Hoxb genes.

The effects of chronic marijuana use on circadian entrainment.

Animal literature suggests a connection between marijuana use and altered circadian rhythms. However, the effect has not yet been demonstrated in humans. The present study examined the effect of chronic marijuana use on human circadian function. Participants consisted of current users who reported smoking marijuana daily for at least a year and non-marijuana user controls. Participants took a neurocognitive assessment, wore actigraphs and maintained sleep diaries for three weeks. While no significant cognitive changes were found between groups, data revealed that chronic marijuana use may act as an additional zeitgeber and lead to increased entrainment in human users.

Motivational interviewing techniques - facilitating behaviour change in the general practice setting.

BACKGROUND: One of the biggest challenges that primary care practitioners face is helping people change longstanding behaviours that pose significant health risks. OBJECTIVE: To explore current understanding regarding how and why people change, and the potential role of motivational interviewing in facilitating behaviour change in the general practice setting. DISCUSSION: Research into health related behaviour change highlights the importance of motivation, ambivalence and resistance. Motivational interviewing is a counselling method that involves enhancing a patient's motivation to change by means of four guiding principles, represented by the acronym RULE: Resist the righting reflex; Understand the patient's own motivations; Listen with empathy; and Empower the patient. Recent meta-analyses show that motivational interviewing is effective for decreasing alcohol and drug use in adults and adolescents and evidence is accumulating in others areas of health including smoking cessation, reducing sexual risk behaviours, improving adherence to treatment and medication and diabetes management.

Growth and development in a child with resistance to thyroid hormone and ectopic thyroid gland.

Resistance to thyroid hormone is an uncommon problem, which has rarely been associated with thyroid dysgenesis. We report a case with both thyroid gland ectopy and resistance to thyroid hormone and, thus, a reduced capacity to produce and respond to thyroid hormone. The patient presented at 2 years of age with developmental delay, dysmorphic features, and elevation in both thyroxine and thyrotropin. We document her response to therapy with thyroxine, with particular regard to her growth and development. Persistent elevation of thyrotropin is commonly recognized during treatment of congenital hypothyroidism. Resistance to thyroid hormone may be an important additional diagnosis to consider in cases where thyrotropin remains persistently elevated.

Adverse events in bevacizumab and chemotherapy: patient management.

Bevacizumab (Avastin) is an anti-angiogenic agent recently approved for the treatment of metastatic breast cancer in combination with paclitaxel. It is important that nurses are familiar with the side-effects associated with this agent--several of which differ from those seen with traditional chemotherapy agents--and how these can be optimally identified, monitored and managed. Side-effects associated with bevacizumab include hypertension, proteinuria, thromboembolic events, bleeding, cardiac toxicity, wound-healing complications and gastrointestinal perforations. Many of these are easily manageable, often without the need to discontinue bevacizumab therapy. This article, the second in a series, provides nurses with management recommendations for these toxicities in order to deliver optimal patient care and improve patients quality of life.

Managing adverse events in the use of bevacizumab and chemotherapy.

The anti-angiogenic agent bevacizumab (Avastin) has received regulatory approval for the treatment of metastatic breast cancer (MBC) in combination with the taxane chemotherapy agent paclitaxel. A range of side-effects associated with this agent have been identified across different tumour types; these are known to differ from those frequently reported with chemotherapy agents. This article is part one of a two-part literature review that was conducted to provide insight into the range, frequency and severity of adverse events that arise specifically in breast cancer when bevacizumab is combined with cytotoxic chemotherapy. PubMed and the websites of oncology conferences were searched to identify studies of bevacizumab plus chemotherapy in patients with MBC. Seventeen studies met the search criteria, including 3,836 bevacizumab-treated patients. Side-effects associated with bevacizumab included hypertension, proteinuria, thromboembolic events, bleeding and cardiac toxicity. Part two of the series will appear in the next issue of BJN.

Implementation of the newborn screening programme for sickle cell disease in England: results for 2003-2005.

OBJECTIVES: This paper reports early screening results from the newborn sickle cell disease screening programme recently implemented in England. SETTING: England. Screening is offered at 5-8 days of age as part of the existing bloodspot test and offered to all babies irrespective of ethnicity. METHODS: The laboratory methods recommended are high performance liquid chromatography (HPLC) and iso-electric focusing (IEF). Two methods of analysis must be applied to all screen positive results. The conditions screened for are:- Sickle cell anaemia (Hb SS), Hb SC disease, Hb S/beta-thalassaemia, Hb S/D(Punjab), Hb S/O(Arab), Hb S/HPFH. Carriers identified for the common haemoglobin variants are reported to parents and follow-up counselling is offered. A bespoke laboratory quality assurance programme has been established which has defined standards of satisfactory performance. RESULTS: Provisional figures from the first seven months of screening (up to March 2004) 108,255 infants were screened gave a screen positive rate of 1:900 for these high prevalence areas and a carrier rate of 2.7%. Figures for 2004-2005 show about 250 significant screen positive results for sickle cell disorders and about 6,500 carriers were identified. The birth prevalence for screen positive results from 2004-05 is 1:1500. We estimate that when there is countrywide data, the national birth prevalence will be about 1:2000-1:2,500. CONCLUSION: The results from the national newborn sickle cell screening programme in England-show that the sickle cell disorders are as common as cystic fibrosis (CF) in England, although the distribution of cases is concentrated in London and other urban areas. The findings and approach to implementation adopted in England may be of interest to other Western European countries with increasing rates of sickle cell disease who are considering such programmes and also to other developed countries.

Tumor necrosis factor alpha as a new target for renal cell carcinoma: two sequential phase II trials of infliximab at standard and high dose.

PURPOSE: Tumor necrosis factor alpha (TNF-alpha) may play a role in renal cell carcinoma (RCC). We performed two sequential phase II studies of infliximab, an anti-TNF-alpha monoclonal antibody, in patients with immunotherapy-resistant or refractory RCC. PATIENTS AND METHODS: Patients progressing after cytokine therapy were treated with intravenous infliximab as follows: study 1 (19 patients), 5 mg/kg at weeks 0, 2, and 6, and then every 8 weeks; study 2 (18 patients), 10 mg/kg at weeks 0, 2, and 6, and then every 4 weeks. Treatment continued until disease progression (PD). Response was assessed according to Response Evaluation Criteria in Solid Tumors. Plasma levels of TNF-alpha, CCL2, and interleukin-6 (IL-6) were measured before and during treatment. RESULTS: TNF-alpha and its receptors were detected in malignant cells in RCC biopsies. In study 1, three patients (16%) achieved partial response (PR) and three patients (16%) achieved stable disease (SD). Median duration of response (PR + SD) was 7.7 months (range, 5.0 to 40.5+ months). In study 2, 11 patients (61%) achieved SD. Median duration of response was 6.2 months (range, 3.5 to 24+ months). One patient developed grade 3 hypersensitivity and another died as a result of pulmonary infection/sepsis. Enzyme-linked immunosorbent assay analysis of plasma revealed that higher levels of TNF-alpha at baseline and higher levels of CCL2 during treatment were associated with PD. There were also correlations between higher levels of TNF-alpha, IL-6, and CCL2 and poor survival (< 12 months). CONCLUSION: This is the first direct clinical evidence suggesting that TNF-alpha may be a therapeutic target in RCC. Plasma levels of TNF-alpha, IL-6, and CCL2 may have predictive and prognostic significance.