A novel niche for skin derived precursors in non-follicular skin

BackgroundSkin derived precursors (SKP) comprise a subset of specialized dermal cells that can be distinguished from fibroblast by their capacity for spheroidal growth. Recent investigations have shown that hair follicles constitute a niche for this cell type, but their localization and their definite function in non-follicular skin remains largely unknown.ObjectiveTo identify the dermal niche of non-follicular SKPs and to analyze whether functional aspects correlate with this localization.MethodsSKPs were isolated from separate anatomical regions of human abdominal skin. Fluorescence activated cell sorting then was used to obtain a pure population of non-follicular SKPs. Functional characterization of these cells was performed applying differentiation and proliferation assays. Information on specific in vivo functions was derived from histological evaluation of quantity and localization patterns.ResultsSphere forming capacity and differentiation assays show that SKPs reside in the papillary part of the dermis. Further delineation revealed that the dermal capillaries represent a niche for these cells which subsequently could be isolated by FACS utilizing a perivascular marker. Whereas functional properties described for follicular SKPs could also be detected in the perivascular SKP population, histological analyses additionally point to a cross-talk with epidermal stem cells and a reduction during chronological aging.ConclusionOur data show that SKPs isolated from non-follicular skin originate from a perivascular niche. Compared to their follicular counterparts, no functional differences could be observed upon cultivation, but ex vivo analyses also point to unique functions and a contribution to the phenotype of aged skin.     

Assignment test method using hypervariable markers for blue marlin (Makaira nigricans) stock identification

Blue marlin (Makaira nigricans) stock status varies among ocean basins, and the Atlantic-wide stock is overfished. United States regulations prohibit commercial landing, importation and sale of Atlantic blue marlin, but not of Pacific or Indian Ocean conspecifics. We genotyped 344 blue marlin of known origin and 16 samples used as unknowns at 13 microsatellite loci and the mitochondrial control region. Assignment tests were conducted using GENECLASS2 to investigate the efficacy of available genotypic data to identify individual origin. We successfully discriminated Atlantic and Pacific blue marlin using genetic characters, providing more power to assign marketed blue marlin products to ocean of origin.     

The effect of nightshift on emergency registrars' clinical skills

Objective: The effect of nightshift on ED staff performance is of clinical and risk‐management significance. Previous studies have demonstrated deterioration in psychomotor skills but the present study specifically assessed the impact of nightshift on clinical performance. Methods: The ED registrars in a tertiary hospital were enrolled in a prospective observational study and served as their own controls. During nightshift, subjects were presented simulated scenarios and tested with eight clinical questions developed to Fellowship examination standard. Matched scenarios and questions for the same subjects during dayshift served as controls. Two investigators, blinded to subject identity and the setting in which questions were attempted, independently collated answers. Results: Of 22 eligible subjects, all were recruited; four were excluded owing to incomplete data. A correlation of 0.99 was observed between the independent scoring investigators. Of a possible score of 17, the median result for nightshift was 9.5 (interquartile range: 8–11); corresponding value for dayshift was 12 (interquartile range: 10–13); P= 0.047. Conclusion: Nightshift effect on clinical performance is anecdotally well known. The present study quantifies such effects, specifically for the ED setting, and paves the way for focused research. The implications for clinical governance strategies are significant, as the fraternity embraces the mandate to maintain quality emergency care 24 h per day.     

Roles for Event Representations in Sensorimotor Experience,Memory Formation,and Language Processing

The unifying theme for the papers in this volume is that event‐predictive representations play an important role in cognitive processes, and they are a particularly fruitful object of study for cognitive scientists. In this paper, we present our own model of event representations that draws together several disparate strands of research into event representations, relating to event perception, event encodings in working memory and their role in prediction, and events as they are reported in language. Our main claim is that the notion of deictic routines originally developed by Ballard et al. (1997) is of great use in explaining how these different types of event representation interface with one another.     

EEG and the passive P300 in dementia of the Alzheimer type.

Quantitatively analyzed resting electroencephalographic (EEG) activity and P300 event-related potentials elicited with a passive tone sequence paradigm were examined in 30 patients with dementia of the Alzheimer type (DAT) and 15 age matched controls. Background electrical rhythms of DAT patients evidenced slowing as shown by increased absolute and relative amplitudes in slow frequency bands and decreased amplitudes in fast frequency bands (relative to controls). Electrical slowing was more evident in patients with higher clinical ratings of global intellectual deterioration. Passive P300 amplitude and latency did not differentiate patients and controls and were not related to severity of dementia.     

Advanced heart failure: prognosis, uncertainty, and decision making

Heart failure is a serious clinical management challenge for both patients and primary care physicians. The authors studied the perceptions and practices of internal medicine residents and faculty at an academic medical center in the Southeast to guide design of strategies to improve heart failure care. Data were collected via a self-administered survey. Eighty-nine faculty and resident physicians in general internal medicine and geriatrics participated (74% response rate). Items measured perceived skills and barriers, adherence to guidelines, and physician understanding of patient prognosis. Case studies explored practice approaches. Clinical knowledge and related scales were generally good and comparable between physician groups. Palliative care and prognostic skills were self-rated with wide variance. Physicians rated patient noncompliance and low lifestyle change motivation as major barriers. Given the complexities of caring for elderly persons with heart failure and comorbid conditions, there are significant opportunities for improving physician skills in decision making, patient-centered counseling, and palliative care.     

Can transcatheter PDA closure be performed in neonates ≤1000 grams? The Memphis experience

Objective: Advancements in transcatheter technology have now made it possible to safely close patent ductus arteriosus (PDA) in extremely low birth weight (ELBW) infants. The objective of this article is to describe our technique for transcatheter PDA closure (TCPC) in ELBW infants.
Design: The techniques employed are very specific to this population and are drasti‐ cally different when compared to the procedure performed in patients weighing >5 kg.
Setting: A multidisciplinary team approach should be taken to evaluate and manage ELBW infants in order to achieve success. It is important that specific techniques with venous‐only approach outlined in this article be followed to achieve optimal results with low risk of complications.
Patients: To date, in Memphis, 55 ELBW infants have had successful TCPC at a weight of ≤1000 g with minimal procedure‐related complications.
Interventions: It is important that specific techniques with venous‐only approach outlined in this article be followed to achieve optimal results with low risk of complications.
Outcome measures: This procedure entails a steep learning curve and should be lim‐ ited to specialized centers with expertise in these thanscatheter procedures.
Results: There has been 100% procedural success of performing TCPC in children ≤1000 g. There have been only two procedure‐related complications which hap‐ pened to the first two patients, ≤1000 g, that we performed TCPC on.
Conclusions: It is feasible and probably safe to perform TCPC in children ≤1000 g. The techniques described in this article represent our institutional experience and have helped us improve clinical outcomes in ELBW infants.     

Expression of decorin and collagens I and III in different layers of human skin in vivo: a laser capture microdissection study

Extracellular matrix (ECM) organization is a complex process that requires the coordinated efforts of many molecules. For the regulation of collagen fiber diameter, the proteoglycan decorin appears to be of major relevance. To investigate the role of decorin in the process of (photo-)aging in more detail, full-thickness punch biopsies were isolated from human buttock skin. Single exposure with two minimal erythemal doses of solar simulated irradiation caused down-regulation of decorin mRNA in young (n = 5) and old subjects (n = 5) after 24 h. Interestingly, decorin mRNA was elevated with age. To test the hypothesis that a decreased collagen-to-decorin-ratio impairs collagen structure we also investigated collagens I and III gene expression. Both were down-regulated with increasing age and after single UV-irradiation. As determined by laser capture microdissection-quantitative real time-Polymerase chain reaction (n = 11), decorin is mostly present in the reticular dermis while being absent from the papillary dermis. Minor expression was also observed in the epidermis. However, in contrast to full-thickness skin biopsies age-dependent changes in collagens I, III, and decorin expression could not be observed with this methodology indicating technical limitations. Together with our finding that collagens I and III mRNA are similarly expressed in the reticular and papillary dermis and are down-regulated by UV, our studies support the idea of a major role of decorin in ECM organization. Altered expression of decorin mRNA in the different dermal strata and a decrease in the collagen-to-decorin ratio inflicted by both age and ultraviolet irradiation possibly affect collagen bundle diameter and subsequently the mechanical properties of human skin.