The transcription factor scleraxis differentially regulates gene expression in tenocytes isolated at different developmental stages.

The transcription factor scleraxis (SCX) is expressed throughout tendon development and plays a key role in directing tendon wound healing. However, little is known regarding its role in fetal or young postnatal tendons, stages in development that are known for their enhanced regenerative capabilities. Here we used RNA-sequencing to compare the transcriptome of adult and fetal tenocytes following SCX knockdown. SCX knockdown had a larger effect on gene expression in fetal tenocytes, affecting 477 genes in comparison to the 183 genes affected in adult tenocytes, indicating that scleraxis-dependent processes may differ in these two developmental stages. Gene ontology, network and pathway analysis revealed an overrepresentation of extracellular matrix (ECM) remodelling processes within both comparisons. These included several matrix metalloproteinases, proteoglycans and collagens, some of which were also investigated in SCX knockdown tenocytes from young postnatal foals. Using chromatin immunoprecipitation, we also identified novel genes that SCX differentially interacts with in adult and fetal tenocytes. These results indicate a role for SCX in modulating ECM synthesis and breakdown and provide a useful dataset for further study into SCX gene regulation.

Genome-wide transcriptome analysis reveals equine embryonic stem cell-derived tenocytes resemble fetal, not adult tenocytes.

BACKGROUND: Tendon injuries occur frequently in human and equine athletes. Treatment options are limited, and the prognosis is often poor with functionally deficient scar tissue resulting. Fetal tendon injuries in contrast are capable of healing without forming scar tissue. Embryonic stem cells (ESCs) may provide a potential cellular therapeutic to improve adult tendon regeneration; however, whether they can mimic the properties of fetal tenocytes is unknown. To this end, understanding the unique expression profile of normal adult and fetal tenocytes is crucial to allow validation of ESC-derived tenocytes as a cellular therapeutic. METHODS: Equine adult, fetal and ESC-derived tenocytes were cultured in a three-dimensional environment, with histological, morphological and transcriptomic differences compared. Additionally, the effects on gene expression of culturing adult and fetal tenocytes in either conventional two-dimensional monolayer culture or three-dimensional culture were compared using RNA sequencing. RESULTS: No qualitative differences in three-dimensional tendon constructs generated from adult, fetal and ESCs were found using histological and morphological analysis. However, genome-wide transcriptomic analysis using RNA sequencing revealed that ESC-derived tenocytes' transcriptomic profile more closely resembled fetal tenocytes as opposed to adult tenocytes. Furthermore, this study adds to the growing evidence that monolayer cultured cells' gene expression profiles converge, with adult and fetal tenocytes having only 10 significantly different genes when cultured in this manner. In contrast, when adult and fetal tenocytes were cultured in 3D, large distinctions in gene expression between these two developmental stages were found, with 542 genes being differentially expressed. CONCLUSION: The information provided in this study makes a significant contribution to the investigation into the differences between adult reparative and fetal regenerative cells and supports the concept of using ESC-derived tenocytes as a cellular therapy. Comparing two- and three-dimensional culture also indicates three-dimensional culture as being a more physiologically relevant culture system for determining transcriptomic difference between the same cell types from different developmental stages.

Outcomes of laparoscopic donor nephrectomy in obese patients.

The applicability of laparoscopic donor nephrectomy (LDN) has not been assessed in the obese donor. We hypothesized that obesity is not a technical contraindication to LDN. From May 1998 to February 1999, 40 patients underwent LDN at the Georgetown Transplant Institute with the transperitoneal technique. Prophylaxis against deep venous thrombosis consisted of venous compression stockings, low-molecular weight heparin in obese patients, and early ambulation. The following variables were examined: donor sex, age, weight, height, related versus nonrelated donation, body mass index (BMI; wt/ht2), operating room time, estimated blood loss, length of stay, time out of work, and complications. BMI>31 indicates morbid obesity, BMI>27 indicates >20% over ideal body weight, and normal BMI is 25. The patients were divided into nonobese (BMI< or =31) and obese groups (BMI>31). The two groups do not differ in outcome after LDN. Our data indicate that obesity is not associated with increased morbidity or mortality after LDN.

The impact of physician order entry on nursing roles.

This study examines the impact of physician order entry (POE) on nurses perceptions of work, quality of care, and nurse/physician communication. Four hospitals that have implemented a computerized order-entry system with POE were compared with four similar hospitals using the same computerized system with clerk order entry only. Three factors were extracted from the 29 item survey using principal component extraction with varimax rotation that accounted for 16.5%, 12.4% and 8.7% of the variance respectively. Three scales were constructed from these factors measuring perceptions of impact of the information system on the quality of care, job, control, and nurse/physician communication. Nurses working in the POE environment rated their computer system as having greater impact on the quality of care and lower ratings of perceived control than those working in non-POE environments. No differences were found between nurses working in POE environments and those working in POE in terms of their ratings of frequency of contact and ease of access to physicians.