Productive infection of in vitro generated haemopoietic progenitor cells from normal human adult peripheral blood with parvovirus B19: studies by morphology, immunocytochemistry, flow-cytometry and DNA-hybridization

Parvovirus B19 exerts a highly selective cytopathic effect on erythroid progenitor cells. Studies so far on the pathogenesis of B19-infection have been performed using bone marrow samples providing large amounts of erythroid progenitor cells. Extensive study, however, has been hampered by the limited access to bone marrow samples. We have designed a liquid culture method allowing the generation of large numbers of erythroid progenitor cells, initiating cultures with CD3- and CD14-poor peripheral blood mononuclear cells. Following a 12 d preincubation in liquid cultures containing recombinant human interleukin 3 (rhIl-3) and recombinant human erythropoietin (rhEpo), cells harvested from the liquid cultures were exposed to B19-containing plasma, followed by a further cultivation in liquid culture for up to 96 h. Cells expressing the CD13 and the glycophorin A (GlyA) antigens, respectively, were monitored sequentially by flow-cytometry, demonstrating a selective inhibition of GlyA-positive cells following B19-inoculation. Typical morphological changes were observed on cytocentrifuge-spots, and typical giant-cells were identified as staining for GlyA. Productive infection by B19 was demonstrable, as B19-DNA increased by about x 100 after 72 h of culture. The liquid culture method generating erythroid target cells for effective infection by B19 virus promises to be a useful and easily accessible tool for further research on B19 infection of haemopoietic cells.     

Impact of Intraoperative Radiotherapy on Cosmetic Outcome and Complications after Oncoplastic Breast Surgery

Breast cancer is one of the most common tumors in the population worldwide. Conservative breast surgery (CBS) is one of the preferred surgical options, because both the oncologic and esthetic needs of the patient can be addressed. CBS surgical outcomes tend to be more effective with reduced chances of disease recurrence when radiotherapy (RT) treatment is considered as an adjunct treatment, either applied during surgery (IORT) and/or after (EBRT). The purpose of our study was to compare surgical outcomes between IORT and EBRT after CBS. In the past 5 years, we performed CBS in 489 patients in our clinic. Of these patients, 83 underwent adjunct treatment with IORT and 109 were treated with EBRT in accordance with our university approved clinical protocol. Surgical outcomes, early complication rates, and esthetic results were compared between these two groups of CBS patients, with a mean follow‐up time of 17 months. IORT allowed breast irradiation treatment to be performed without effecting overlying skin, thus cosmetic outcomes tended to be favorable. Esthetic postoperative results assessed with the Breast Cancer Conservation Treatment (BCCTcore) software showed that the differences between IORT and EBRT were not statistically significant (including those patients that underwent further oncoplastic techniques after EBRT). The disease recurrence rates between the two groups were not significantly different. IORT is a safe, fast, and feasible technique that provides effective and comparable CBS outcomes for patients with breast cancer.     

Conservative management of post-intubation tracheal tears—report of three cases

Iatrogenic tracheal rupture is a rare complication after intubation. We present three patients with tracheal tears. In all of these patients, a common finding was a lesion of the posterior tracheal wall with postoperative subcutaneous and emphysema as the first clinical sign of the rupture. Diagnosis and follow-up were based on clinical and endoscopic findings and chest computed tomography (CT) scans. In our cases with progressive subcutaneous and mediastinal emphysema or dyspnea, we performed a tracheotomy and bypassed the lesion with a tracheostomy tube to avoid an increase in air leakage into the mediastinum. Under broad-spectrum antibiotic therapy, no mediastinitis occurred and all patients survived without sequelae. Closure of tracheostomy was scheduled for 1-2 months after tracheal injury. Analysis of surgical and anesthesiological procedures revealed no abnormalities and the accumulation of tracheal injuries was considered as accidental. We found that in clinically stable patients with spontaneous breathing and with no mediastinitis, a conservative management of tracheal tears is a safe procedure.     

Brain lateralisation and motor learning: Selective effects of dominant and non-dominant hand practice on the early acquisition of throwing skills

Findings from neurosciences indicate that the two brain hemispheres are specialised for the processing of distinct movement features. How this knowledge can be useful in motor learning remains unclear. Two experiments were conducted to investigate the influence of initial practice with the dominant vs non-dominant hand on the acquisition of novel throwing skills. Within a transfer design two groups practised a novel motor task with the same amount of practice on each hand, but in opposite hand-order. In Experiment 1, participants acquired the position throw in basketball, which places high demands on throwing accuracy. Participants practising this task with their non-dominant hand first, before changing to the dominant hand, showed better skill acquisition than participants practising in opposite order. In Experiment 2 participants learned the overarm throw in team handball, which requires great throwing strength. Participants initially practising with their dominant hand benefited more from practice than participants beginning with their non-dominant hand. These results indicate that spatial accuracy tasks are learned better after initial practice with the non-dominant hand, whereas initial practice with the dominant hand is more efficient for maximum force production tasks. The effects are discussed in terms of brain lateralisation and bilateral practice schedules.     

Errors and near misses in digestive endoscopy units

Background

Not much is known about errors and near misses in digestive endoscopy.

Aims

To verify whether an incident report, with certain facilitating features, gives useful information about unintended events, only excluding errors in medical diagnosis.

Method

Nine endoscopy units took part in this cross sectional, prospective, multicentre study which lasted for two weeks. Members of the staff were required to report any unintended, potentially dangerous event observed during the daily work. A form was provided with a list of “reminders” and facilitators were appointed to help.The main outcome measurements were type of event, causes, corrective interventions, stage of occurrence in the workflow and qualification of the reporters.

Results

A total of 232 errors were reported (two were not related to endoscopy). The remaining 230 amount to 10.3% of 2239 procedures; 66 (29%) were considered errors with consequences, 164 (71%) “near misses”. There were 150 pre-operative errors (65%), 22 operative (10%) and 58 post-operative (25%). Corrective interventions were provided for 60 cases of errors and 119 near misses. Most of the events were reported by the nurses (106 out of 232, 46%).

Conclusions

Short-term incident reporting focusing on near misses, using forms with lists of “reminders”, and the help of a facilitator, can give useful information on errors and near misses in digestive endoscopy.     

Small business activity does not measure entrepreneurship

Entrepreneurship policy mainly aims to promote innovative Schumpeterian entrepreneurship. However, the rate of entrepreneurship is commonly proxied using quantity-based metrics, such as small business activity, the self-employment rate, or the number of startups. We argue that those metrics give rise to misleading inferences regarding high-impact Schumpeterian entrepreneurship. To unambiguously identify high-impact entrepreneurs we focus on self-made billionaires (in US dollars) who appear on Forbes Magazine’s list and who became wealthy by founding new firms. We identify 996 such billionaire entrepreneurs in 50 countries in 1996–2010, a systematic cross-country study of billionaire entrepreneurs. The rate of billionaire entrepreneurs correlates negatively with self-employment, small business ownership, and firm startup rates. Countries with higher income, higher trust, lower taxes, more venture capital investment, and lower regulatory burdens have higher billionaire entrepreneurship rates but less self-employment. Despite its limitations, the number of billionaire entrepreneurs appears to be a plausible cross-country measure of Schumpeterian entrepreneurship.Given the prominence of entrepreneurship, it may come as a surprise that there is no consensus on how it should be defined in empirical research. Sometimes entrepreneurship is used to refer to anyone operating a private business, regardless of size and activity. Driven by greater data availability, most empirical studies rely on definitions such as the self-employment rate, the number of startups, and small business activity (1). In other contexts, entrepreneurship refers to the subset of firms that are innovative and growth-driven (2, 3). This Schumpeterian definition of the entrepreneur as an innovator and as a driver of growth dominates in theoretical entrepreneurship research and in entrepreneurship policy (4, 5). Thus, when academics and business leaders were asked to define entrepreneurship, the most common choices were the creation and growth of new ventures and innovation. By contrast, the creation of a mom-and-pop business was not viewed as entrepreneurship (6).Leaving aside the semantic discussion of what exactly constitutes entrepreneurship, there is an important empirical issue of how well commonly used operationalizations capture the rate of Schumpeterian entrepreneurship. An implicit assumption appears to be that countries and industries with a large number of small firms and startups also tend to be those where most innovative high-growth firms emerge.However, an overwhelming majority of the self-employed are not entrepreneurial in the Schumpeterian sense, as they never bring a new innovation to the market and do not plan to grow their business. In the United States, the industries with the largest concentrations of self-employed men are construction, landscaping services, auto repair, restaurants, truck transportation, and farming. For women, the corresponding industries include private households (cooks and maids), child day care services, restaurants, and beauty salons. The majority of small businesses in the United States have no employees other than the owner. Nor do most small businesses eventually grow large. Most small businesses are best described as permanently small rather than nascent entrepreneurial firms.Shane (7) argues that necessity-driven and opportunity entrepreneurs should be treated separately, documenting a negative cross-country correlation between having many high- and low-expectation startups. Baumol (3) distinguishes between “innovative” and “replicative” entrepreneurs, where the former are the type of entrepreneurs studied by Schumpeter (2). Hurst and Pugsley (8) forcefully argue against using self-employment as synonymous with entrepreneurship. They estimate that only 10–20% of small businesses report any innovative activity at all and point out that when new startups were asked about growth ambitions, 75% of respondents stated that “I want a size I can manage myself or with a few key employees” (ref. 8, p. 96). Different types of business owners also differ in terms of personality traits (9).Both types of businesses are important for a well-functioning economy, but their workings are entirely different. Innovative and replicative businesses operate in different ways, but are not easily distinguishable in statistics, which means that special approaches must be designed for empirical analysis.One way through which scholars have attempted to distinguish the different classes of firms is by restricting attention to “high-impact entrepreneurs” (10, 11), which is to say those that grow rapidly. The difficulty of estimating the rate of high-impact entrepreneurship in a standardized way across countries has thus far prevented cross-country comparisons.We propose a measure of high-impact Schumpeterian entrepreneurship across countries using information from the Forbes Magazine worldwide list of billionaires during 2 decades. Our measure of high-impact entrepreneurship is based on the accumulation of wealth for founders of new business ventures. We compare this measure to quantity-based empirical proxies for entrepreneurship such as self-employment, small business ownership, and number of startups. Henceforth in the paper for the sake of brevity, “entrepreneurship” refers to billionaire entrepreneurship, the focus of this paper.For each billionaire, the source of wealth was investigated, allowing us to identify 996 self-made billionaires who became rich by founding new firms. Using these individuals to construct a per capita rate of high-impact entrepreneurship, we show that this measure is robustly and negatively correlated with self-employment rates, small business ownership rates, and the rate of startup activity.