Mapping DNase I hypersensitive sites is an accurate method of identifying the location of gene regulatory elements, including promoters, enhancers, silencers and locus control regions. Although Southern blots are the traditional method of identifying DNase I hypersensitive sites, the conventional manual method is not readily scalable to studying large chromosomal regions, much less the entire genome. Here we describe DNase-chip, an approach that can rapidly identify DNase I hypersensitive sites for any region of interest, or potentially for the entire genome, by using tiled microarrays. We used DNase-chip to identify DNase I hypersensitive sites accurately from a representative 1% of the human genome in both primary and immortalized cell types. We found that although most DNase I hypersensitive sites were present in both cell types studied, some of them were cell-type specific. This method can be applied globally or in a targeted fashion to any tissue from any species with a sequenced genome.

No abstract

Multiple endocrine neoplasia type I (MEN1) is a familial cancer syndrome characterized primarily by tumors of multiple endocrine glands. The gene for MEN1 encodes a ubiquitously expressed tumor suppressor protein called menin. Menin was recently shown to interact with several components of a trithorax family histone methyltransferase complex including ASH2, Rbbp5, WDR5, and the leukemia proto-oncoprotein MLL. To elucidate menin's role as a tumor suppressor and gain insights into the endocrine-specific tumor phenotype in MEN1, we mapped the genomic binding sites of menin, MLL1, and Rbbp5, to approximately 20,000 promoters in HeLa S3, HepG2, and pancreatic islet cells using the strategy of chromatin-immunoprecipitation coupled with microarray analysis. We found that menin, MLL1, and Rbbp5 localize to the promoters of thousands of human genes but do not always bind together. These data suggest that menin functions as a general regulator of transcription. We also found that factor occupancy generally correlates with high gene expression but that the loss of menin does not result in significant changes in most transcript levels. One exception is the developmentally programmed transcription factor, HLXB9, which is overexpressed in islets in the absence of menin. Our findings expand the realm of menin-targeted genes several hundred-fold beyond that previously described and provide potential insights to the endocrine tumor bias observed in MEN1 patients.

Multiple endocrine neoplasia type I (MEN1) is a familial cancer syndrome characterized primarily by tumors of multiple endocrine glands. The gene for MEN1 encodes a ubiquitously expressed tumor suppressor protein called menin. Menin was recently shown to interact with several components of a trithorax family histone methyltransferase complex including ASH2, Rbbp5, WDR5, and the leukemia proto-oncoprotein MLL. To elucidate menin's role as a tumor suppressor and gain insights into the endocrine-specific tumor phenotype in MEN1, we mapped the genomic binding sites of menin, MLL1, and Rbbp5, to approximately 20,000 promoters in HeLa S3, HepG2, and pancreatic islet cells using the strategy of chromatin-immunoprecipitation coupled with microarray analysis. We found that menin, MLL1, and Rbbp5 localize to the promoters of thousands of human genes but do not always bind together. These data suggest that menin functions as a general regulator of transcription. We also found that factor occupancy generally correlates with high gene expression but that the loss of menin does not result in significant changes in most transcript levels. One exception is the developmentally programmed transcription factor, HLXB9, which is overexpressed in islets in the absence of menin. Our findings expand the realm of menin-targeted genes several hundred-fold beyond that previously described and provide potential insights to the endocrine tumor bias observed in MEN1 patients.

Open fractures are complex injuries associated with high morbidity and mortality. Despite advances made in fracture care and infection prevention, open fractures remain a therapeutic challenge with varying levels of evidence to support some of the most commonly used practices. Additionally, a significant number of studies on this topic have focused on open tibial fractures. A systematic approach to evaluation and management should begin as soon as immediate life-threatening conditions have been stabilized. The Gustilo classification is arguably the most widely used method for characterizing open fractures. A first-generation cephalosporin should be administered as soon as possible. The optimal duration of antibiotics has not been well defined, but they should be continued for 24 hours. There is inconclusive evidence to support either extending the duration or broadening the antibiotic prophylaxis for type Gustilo type III wounds. Urgent surgical irrigation and debridement remains the mainstay of infection eradication, although questions persist regarding the optimal irrigation solution, volume, and delivery pressure. Wound sampling has a poor predictive value in determining subsequent infections. Early wound closure is recommended to minimize the risk of infection and cannot be substituted by negative-pressure wound therapy. Antibiotic-impregnated devices can be important adjuncts to systemic antibiotics in highly contaminated or comminuted injuries. Multiple fixation techniques are available, each having advantages and disadvantages. It is extremely important to maintain a high index of suspicion for compartment syndrome, especially in the setting of high-energy trauma.

No abstract

Optimal perioperative pain control for total joint arthroplasty remains a challenge. Whereas traditional regimens have relied heavily on opioids, newer multimodal pathways are increasingly gaining popularity as safer and more effective alternatives. The main premise of multimodal analgesia is decreased consumption of opioids, and hence lesser opioid-related adverse events. Other reported advantages include lower pain scores, faster functional recovery, higher patient satisfaction, and shorter length of hospital stay. Unfortunately, despite the advent of numerous analgesic techniques, the multimodal approach has remained widely variable, making direct comparison between studies difficult to interpret. This article provides an extensive review of traditional and modern perioperative interventions in pain management for total joint arthroplasty, including intravenous patient-controlled analgesia, epidural infusion, oral opioids, nonsteroidal anti-inflammatory drugs, acetaminophen, peripheral nerve blocks, periarticular infiltration, steroids, anticonvulsants, and long-acting local anesthetics. Emphasis is placed on pathophysiology, clinical evidence, and timing. A standardized multimodal analgesia protocol is also proposed based on best available evidence. In addition to pharmacologic interventions, patient education and interdisciplinary collaboration among the care teams play an important role in the success of any treatment pathway. With a growing demand for total joint arthroplasty in an era of bundled payments and accountable care, there has never been a greater need for a standardized multimodal analgesia pathway.

Pelvic ring injuries are associated with significant morbidity and mortality. Understanding the anatomy of the pelvic ring is essential for accurate diagnosis and treatment. A systematic approach taking into account the mechanism of injury, physical examination, and radiographic assessment is important to quickly identify unstable pelvic disruptions and associated injuries. Because the pelvis is a ring structure, isolated pubic rami fractures on plain radiographs are unusual and should warrant careful evaluation for posterior pelvic disruption with computed tomography. Hemorrhagic shock can occur in about 10% of pelvic ring injuries. Immediate recognition and treatment of this life-threatening condition is critical in emergency management. In addition to fluid resuscitation and blood transfusion, circumferential wrapping, angiographic embolization, laparotomy with pelvic packing, and external fixation can be important life-saving adjuncts in the setting of hemodynamic instability.