Regulation of hematopoietic stem cells during mouse development

The hematopoietic system is comprised of many different cell types that fulfill important physiological functions throughout embryonic and adult stages of mouse development. As the mature blood cells have a limited life-span, the pool of blood cells needs constant replenishing. At the basis of the hematopoietic system reside the hematopoietic stem cells (HSCs). HSCs are characterized by the ability to self-renew and to produce all the different mature hematopoietic cell types. These HSCs differentiate to the common lymphoid and myeloid progenitors (CLP and CMP) which in tum give rise to more lineage restricted precursor cells that then differentiate into mature hematopoietic cells (Figure 1 p.8). Mature hematopoietic cells can be subdivided into the lymphoid compartment, comprising T and B lymphocytes which form the adaptive immune (defense) system, and the myeloid compartment which is comprised of the oxygen transporting erythrocytes (red blood cells), blood clot-mediating platelets, immune response-mediating neutrophils, eosinophils and basophils and the macrophages, of which the main function is to remove dead and foreign cells. Although the mature blood cells fulfill the physiological functions of the hematopoietic system, the hematopoietic stem cells are essential within the adult hematopoietic hierarchy since these cells are responsible for the life long production of the different mature hematopoietic cells

Reducing Inappropriate Proton Pump Inhibitors Use for Stress Ulcer Prophylaxis in Hospitalized Patients:Systematic Review of De-Implementation Studies

Background: A large proportion of proton pump inhibitor (PPI) prescriptions, including those for stress ulcer prophylaxis (SUP), are inappropriate. Our study purpose was to systematically review the effectiveness of de-implementation strategies aimed at reducing inappropriate PPI use for SUP in hospitalized, non-intensive care unit (non-ICU) patients. Methods: We searched MEDLINE and Embase databases (from inception to January 2020). Two authors independently screened references, performed data extraction, and critical appraisal. Randomized trials and comparative observational studies were eligible for inclusion. Criteria developed by the Cochrane Effective Practice and Organisation of Care (EPOC) group were used for critical appraisal. Besides the primary outcome (inappropriate PPI prescription or use), secondary outcomes included (adverse) pharmaceutical effects and healthcare use. Results: We included ten studies in this review. Most de-implementation strategies contained an educational component (meetings and/or materials), combined with either clinical guideline implementation (n = 5), audit feedback (n = 3), organizational culture (n = 4), or reminders (n = 1). One study evaluating the de-implementation strategy effectiveness showed a significant reduction (RR 0.14; 95% CI 0.03–0.55) of new inappropriate PPI prescriptions. Out of five studies evaluating the effectiveness of de-implementing inappropriate PPI use, four found a significant reduction (RR 0.21; 95% CI 0.18–0.26 to RR 0.76; 95% CI 0.68–0.86). No significant differences in the occurrence of pharmaceutical effects (n = 1) and in length of stay (n = 3) were observed. Adverse pharmaceutical effects were reported in two studies and five studies reported on PPI or total drug costs. No pooled effect estimates were calculated because of large statistical heterogeneity between studies. Discussion: All identified studies reported mainly educational interventions in combination with one or multiple other intervention strategies and all interventions were targeted at providers. Most studies found a small to moderate reduction of (inappropriate) PPI prescriptions or use

Altered Intracellular Localization and Mobility of SBDS Protein upon Mutation in Shwachman-Diamond Syndrome

Shwachman-Diamond Syndrome (SDS) is a rare inherited disease caused by mutations in the SBDS gene. Hematopoietic defects, exocrine pancreas dysfunction and short stature are the most prominent clinical features. To gain understanding of the molecular properties of the ubiquitously expressed SBDS protein, we examined its intracellular localization and mobility by live cell imaging techniques. We observed that SBDS full-length protein was localized in both the nucleus and cytoplasm, whereas patient-related truncated SBDS protein isoforms localize predominantly to the nucleus. Also the nucleo-cytoplasmic trafficking of these patient-related SBDS proteins was disturbed. Further studies with a series of SBDS mutant proteins revealed that three distinct motifs determine the intracellular mobility of SBDS protein. A sumoylation motif in the C-terminal domain, that is lacking in patient SBDS proteins, was found to play a pivotal role in intracellular motility. Our structure-function analyses provide new insight into localization and motility of the SBDS protein, and show that patient-related mutant proteins are altered in their molecular properties, which may contribute to the clinical features observed in SDS patients

SBDS Expression and Localization at the Mitotic Spindle in Human Myeloid Progenitors

BACKGROUND: Shwachman-Diamond Syndrome (SDS) is a hereditary disease caused by mutations in the SBDS gene. SDS is clinically characterized by pancreatic insufficiency, skeletal abnormalities and bone marrow dysfunction. The hematologic abnormalities include neutropenia, neutrophil chemotaxis defects, and an increased risk of developing Acute Myeloid Leukemia (AML). Although several studies have suggested that SBDS as a protein plays a role in ribosome processing/maturation, its impact on human neutrophil development and function remains to be clarified. METHODOLOGY/PRINCIPAL FINDINGS: We observed that SBDS RNA and protein are expressed in the human myeloid leukemia PLB-985 cell line and in human hematopoietic progenitor cells by quantitative RT-PCR and Western blot analysis. SBDS expression is downregulated during neutrophil differentiation. Additionally, we observed that the differentiation and proliferation capacity of SDS-patient bone marrow hematopoietic progenitor cells in a liquid differentiation system was reduced as compared to control cultures. Immunofluorescence analysis showed that SBDS co-localizes with the mitotic spindle and in vitro binding studies reveal a direct interaction of SBDS with microtubules. In interphase cells a perinuclear enrichment of SBDS protein which co-localized with the microtubule organizing center (MTOC) was observed. Also, we observed that transiently expressed SDS patient-derived SBDS-K62 or SBDS-C84 mutant proteins could co-localize with the MTOC and mitotic spindle. CONCLUSIONS/SIGNIFICANCE: SBDS co-localizes with the mitotic spindle, suggesting a role for SBDS in the cell division process, which corresponds to the decreased proliferation capacity of SDS-patient bone marrow CD34(+) hematopoietic progenitor cells in our culture system and also to the neutropenia in SDS patients. A role in chromosome missegregation has not been clarified, since similar spatial and time-dependent localization is observed when patient-derived SBDS mutant proteins are studied. Thus, the increased risk of myeloid malignancy in SDS remains unexplained

Antibiotic prophylaxis for prevention of postoperative wound infection in adults undergoing open elective inguinal or femoral hernia repair

Background: Inguinal or femoral hernia is a tissue protrusion in the groin region and has a cumulative incidence of 27% in adult men and of 3% in adult women. As most hernias become symptomatic over time, groin hernia repair is one of the most frequently performed surgical procedures worldwide. This type of surgery is considered 'clean' surgery with wound infection rates expected to be lower than 5%. For clean surgical procedures, antibiotic prophylaxis is not generally recommended. However after the introduction of mesh-based hernia repair and the publication of studies that have high wound infection rates the debate as to whether antibiotic prophylaxis is required to prevent postoperative wound infections started again. Objectives: To determine the effectiveness of antibiotic prophylaxis in reducing postoperative (superficial and deep) wound infections in elective open inguinal and femoral hernia repair. Search methods: We searched several electronic databases: Cochrane Registry of Studies Online, MEDLINE Ovid, Embase Ovid, Scopus and Science Citation Index (search performed on 12 November 2019). We also searched two trial registers and the reference list of included studies. Selection criteria: We included randomised controlled trials comparing any type of antibiotic prophylaxis versus placebo or no treatment for preventing postoperative wound infections in adults undergoing inguinal or femoral open hernia repair surgery (tissue repair and mesh repair). Data collection and analysis: Two review authors independently selected studies, extracted data and assessed risk of bias. We separately analysed results for two different surgical methods (herniorrhaphy and hernioplasty). Several studies revealed infection rates that were higher than the expected 5% for clean surgery and we therefore divided studies into two subgroups: high infection risk environments (≥ 5% infection rate); and low infection risk environments (< 5% infection rate). We performed meta-analyses with random-effects models. We analysed three outcomes: superficial surgical site infections (SSSI); deep surgical site infections (DSSI); and all postoperative wound infections (SSSI + DSSI). Main results: In this review update we identified and included 10 new studies. In total, we included 27 studies with 8308 participants in this review. It is uncertain whether antibiotic prophylaxis as compared to placebo (or no treatment) prevents all types of postoperative wound infections after herniorrhaphy surgery (risk ratio (RR) 0.86, 95% confidence interval (CI) 0.56 to 1.33; 5 studies, 1865 participants; very low quality evidence). Subgroup analysis did not change these results. We could not perform meta-analyses for SSSI or DSSI as these outcomes were not reported separately. Twenty-two studies related to hernioplasty surgery (total of 6443 participants) and we analysed three outcomes: SSSI; DSSI; SSSI + DSSI. Within the low infection risk environment subgroup, antibiotic prophylaxis as compared to placebo probably makes little or no difference for the outcomes 'prevention of all wound infections' (RR 0.71, 95% CI 0.44 to 1.14; moderate-quality evidence) and 'prevention of SSSI' (RR 0.71, 95% CI 0.44 to 1.17, moderate-quality evidence). Within the high infection risk environment subgroup it is uncertain whether antibiotic prophylaxis reduces all types of wound infections (RR 0.58, 95% CI 0.43 to 0.77, very low quality evidence) or SSSI (RR 0.56, 95% CI 0.41 to 0.77, very low quality evidence). When combining participants from both subgroups, antibiotic prophylaxis as compared to placebo probably reduces the risk of all types of wound infections (RR 0.61, 95% CI 0.48 to 0.78) and SSSI (RR 0.60, 95% CI 0.46 to 0.78; moderate-quality evidence). Antibiotic prophylaxis as compared to placebo probably makes little or no difference in reducing the risk of postoperative DSSI (RR 0.65, 95% CI 0.26 to 1.65; moderate-quality evidence), both in a low infection risk environment (RR 0.67, 95% CI 0.11 to 4.13; moderate-quality evidence) and in the high infection risk environment (RR 0.64, 95% CI 0.22 to 1.89; low-quality evidence). Authors' conclusions: Evidence of very low quality shows that it is uncertain whether antibiotic prophylaxis reduces the risk of postoperative wound infections after herniorrhaphy surgery. Evidence of moderate quality shows that antibiotic prophylaxis probably makes little or no difference in preventing wound infections (i.e. all wound infections, SSSI or DSSI) after hernioplasty surgery in a low infection risk environment. Evidence of low quality shows that antibiotic prophylaxis in a high-risk environment may reduce the risk of all wound infections and SSSI, while evidence of very low quality shows that it is uncertain whether antibiotic prophylaxis reduces DSSI after hernioplasty surgery