As we age, our bones undergo a process of loss, often accompanied by muscle weakness and reduced physical activity. This is exacerbated by decreased responsiveness to mechanical stimulation in aged ...skeleton, leading to the hypothesis that decreased mechanical stimulation plays an important role in age‐related bone loss. Piezo1, a mechanosensitive ion channel, is critical for bone homeostasis and mechanotransduction. Here, we observed a decrease in Piezo1 expression with age in both murine and human cortical bone. Furthermore, loss of Piezo1 in osteoblasts and osteocytes resulted in an increase in age‐associated cortical bone loss compared to control mice. The loss of cortical bone was due to an expansion of the endosteal perimeter resulting from increased endocortical resorption. In addition, expression of Tnfrsf11b, encoding anti‐osteoclastogenic protein OPG, decreases with Piezo1 in vitro and in vivo in bone cells, suggesting that Piezo1 suppresses osteoclast formation by promoting Tnfrsf11b expression. Our results highlight the importance of Piezo1‐mediated mechanical signaling in protecting against age‐associated cortical bone loss by inhibiting bone resorption in mice.
Age‐related bone loss is associated with decreased expression of Piezo1, a mechanosensitive ion channel, and osteoprotegerin (OPG), an osteoclastogenesis inhibitory factor. Loss of Piezo1 signaling in osteoblasts and osteocytes exacerbates cortical bone loss in old mice by enhancing osteoclast formation in endocortical bone surface. Our results indicate the importance of Piezo1‐mediated signaling in protecting against age‐associated cortical bone loss.
This article develops an option-theoretic perspective for organizational strategic management. Grounded in the basic intuition that people seek to "keep options open" in situations that involve an ...unforeseeable future, and supported by theory in financial economics, this view is a recent development in strategy. The theory integrates resource allocation, sense making, organizational learning, and strategic positioning in a unified framework, and it provides a new explanation for some counterintuitive empirical findings.
Injectable skin fillers Narins, Rhoda S; Bowman, Paul H
Clinics in plastic surgery,
04/2005, Letnik:
32, Številka:
2
Journal Article
Recenzirano
The list of injectable skin fillers available for soft tissue augmentation is constantly growing, giving aesthetic surgeons more options in the treatment of scars, lines, and wrinkles. Each type of ...filler is distinct with regard to intended use, placement technique, duration in tissue, ease of use, and cost. Physicians who are well acquainted with the strengths and weaknesses of each class of filler will be best equipped to use this rapidly expanding class of agents in serving their patients. The authors review the most commonly used injectable skin fillers and discuss their differences in terms of composition, source (eg, human, animal), intended use, placement technique, tissue duration (nonpermanent, semipermanent, or permanent), side effects, and specific advantages and disadvantages.
In this book, John Bowman provides an introduction to the Dewey Decimal Classification suitable either for beginners or for librarians who are out of practice using Dewey. He outlines the content and ...structure of the scheme and then, through worked examples using real titles, shows readers how to use it. Most chapters include practice exercises, to which answers are given at the end of the book. A particular feature of the book is the chapter dealing with problems of specific parts of the scheme. Later chapters offer advice on how to cope with compound subjects, and a brief introduction to the Web version of Dewey. Written in an engaging and direct style, this text is a companion volume both to the author's own bestselling Essential Cataloguing and to Vanda Broughton's Essential Classification. It is ideal for library students, and for public, school and solo librarians and classifiers who are just beginning to use Dewey and need some simple examples.
This study examined a statewide trend in Maryland toward regionalization of pancreaticoduodenectomy over a 12-year period and its effect on statewide in-hospital mortality rates for this procedure.
...Previous studies have demonstrated that the best outcomes are achieved in centers performing large numbers of pancreaticoduodenectomies, which suggests that regionalization could lower the overall in-hospital mortality rate for this procedure.
Maryland state hospital discharge data were used to select records of patients undergoing a pancreaticoduodenectomy between 1984 and 1995. Hospitals were classified into high-volume and low-volume provider groups. Trends in surgical volume and mortality rates were examined by provider group and for the entire state. Regression analyses were used to examine whether hospital share of pancreaticoduodenectomies was a significant predictor of the in-hospital mortality rate, adjusting for study year and patient characteristics. The portion of the decline in the statewide in-hospital mortality rate for this procedure attributable to the high-volume provider's increasing share was determined.
A total of 795 pancreaticoduodenectomies were performed in Maryland at 43 hospitals from 1984 to 1995 (Maryland residents only). During this period, one institution increased its yearly share of pancreaticoduodenectomies from 20.7% to 58.5%, and the statewide in-hospital mortality rate for the procedure decreased from 17.2% to 4.9%. After adjustment for patient characteristics and study year, hospital share remained a significant predictor of mortality. An estimated 61% of the decline in the statewide in-hospital mortality rate for the procedure was attributable to the increase in share of discharges at the high-volume provider.
A trend toward regionalization of pancreaticoduodenectomy over a 12-year period in Maryland was associated with a significant decrease in the statewide in-hospital mortality rate for this procedure, demonstrating the effectiveness of regionalization for high-risk surgery.
To determine whether individual surgeon experience is associated with improved short-term clinical and economic outcomes for patients with benign and malignant thyroid disease who underwent thyroid ...procedures in Maryland between 1991 and 1996.
There is a prevailing belief that surgeon experience affects patient outcomes in endocrine surgery, but there is a paucity of objective evidence outside of clinical series published by experienced surgeons that supports this view.
A cross-sectional analysis of all patients who underwent thyroidectomy in Maryland between 1991 and 1996 was conducted using a computerized statewide hospital discharge data base. Surgeons were categorized by volume of thyroidectomies over the 6-year study period: A (1 to 9 cases), B (10 to 29 cases), C (30 to 100 cases), and D (>100 cases). Multivariate regression was used to assess the relation between surgeon caseload and in-hospital complications, length of stay, and total hospital charges, adjusting for case mix and hospital volume.
The highest-volume surgeons (group D) performed the greatest proportion of total thyroidectomies among the 5860 discharges, and they were more likely to operate on patients with cancer. After adjusting for case mix and hospital volume, highest-volume surgeons had the shortest length of stay (1.4 days vs. 1.7 days for groups B and C and 1.9 days for group A) and the lowest complication rate (5.1 % vs. 6.1% for groups B and C and 8.6% for group A). Length of stay and complications were more determined by surgeon experience than hospital volume, which had no consistent association with outcomes.
Individual surgeon experience is significantly associated with complication rates and length of stay for thyroidectomy.
Mystified by main entry? Confused by corporate bodies? Can't tell a description from an access point? Then this is the book for you. Cataloguing is important, despite what some people may tell you. ...Because it is hardly taught nowadays, there is all the more likelihood that you will find yourself having to catalogue without having been taught anything about it. This book covers descriptive cataloguing, and is designed as a simple companion to the Anglo-American Cataloguing Rules (revised 2002 edition). Dealing primarily with printed books, but including many references to other formats, the author leads you step by step through the cataloguing process, covering: description; access points; multipart works; headings for persons; headings for corporate bodies; authority control and uniform titles.
Summary
Background Keratinocytes undergo a defined programme of proliferation and differentiation during normal stratification of the epidermis. Anomalies in the signalling pathways controlling this ...process probably contribute to the pathogenesis of hyperproliferative dermatological diseases, including psoriasis and basal cell carcinoma (BCC). We have previously proposed that protein kinase D (PKD) is a proproliferative signalling enzyme in keratinocytes and have speculated that abnormalities in its levels or regulation may contribute to hyperproliferative disorders of the skin.
Objectives To determine if hyperproliferative human skin disorders are characterized by abnormal protein expression or distribution of PKD, normal human epidermis was compared with BCC and uninvolved and involved psoriatic epidermis.
Methods To examine protein expression, immunohistochemical analysis of human samples and Western blotting of neoplastic mouse keratinocytes was performed. Western analysis of neoplastic mouse cells using a phosphospecific PKD antibody allowed estimation of PKD activation status.
Results Normal human epidermis demonstrated predominant PKD protein expression in the stratum basalis, the proliferative epidermal compartment, with decreased relative expression throughout the suprabasal strata. Uninvolved psoriatic skin showed a similar pattern, but in contrast, psoriatic lesions demonstrated a diffuse distribution of PKD staining throughout all strata. The majority of BCCs examined showed significant PKD protein levels and, in those biopsies in which the levels could be compared, elevated PKD levels relative to normal epidermis. PKD levels and activation status were also increased in a neoplastic mouse keratinocyte cell line.
Conclusions PKD was elevated or misdistributed in the hyperproliferative human skin disorders, BCC and psoriasis, as well as neoplastic mouse keratinocytes. We speculate that PKD exerts proproliferative and/or antidifferentiative effects in the epidermis, and that anomalous distribution and/or activation of PKD may be involved in precipitating or sustaining the disease process in BCC and psoriasis.
There is considerable current interest in neural modeling of the attentional blink phenomenon. Two prominent models of this task are the Simultaneous Type Serial Token (ST(2)) model and the Locus ...Coeruleus-Norepinephrine (LC-NE) model. The former of these generates a broad spectrum of behavioral data, while the latter provides a neurophysiologically detailed account. This paper explores the relationship between these two approaches. Specifically, we consider the spectrum of empirical phenomena that the two models generate, particularly emphasizing the need to generate a reciprocal relationship between bottom-up trace strength and the blink bottleneck. Then we discuss the implications of using ST(2) token mechanisms in the LC-NE setting.
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