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The Journal of Invasive Cardiology Feb 2022During an optical coherence tomography (OCT)-guided percutaneous coronary intervention (PCI) of a calcified left anterior descending artery (LAD), the distal tip of the...
During an optical coherence tomography (OCT)-guided percutaneous coronary intervention (PCI) of a calcified left anterior descending artery (LAD), the distal tip of the OCT catheter got stuck, and forceful tugging on the catheter by the operator led to LAD stent deformation proximally across the overlap between the proximal and middle stents. The purpose of these images is to make the readers aware of the very real and serious risk of a stuck OCT catheter, especially while imaging distal coronary arteries and overlapping stents. Increasing the length of the over-the-wire segment and hydrophilic coating of the OCT catheter may also be explored with manufacturers to prevent this complication.
Topics: Catheters; Coronary Angiography; Coronary Artery Disease; Coronary Vessels; Humans; Percutaneous Coronary Intervention; Stents; Tomography, Optical Coherence; Treatment Outcome; Ultrasonography, Interventional
PubMed: 35100558
DOI: No ID Found -
Cureus Mar 2020Introduction The aim of our study was to describe the injury pattern and outcomes of active-duty subjects that underwent humeral external fixation and to determine if...
Introduction The aim of our study was to describe the injury pattern and outcomes of active-duty subjects that underwent humeral external fixation and to determine if the placement of external fixator pins outside of the radial nerve safe zones is correlated with injury to the radial nerve. Materials and methods We examined all US Service members treated with humeral external fixation at our facility from June 2005 through June 2015. The mechanism of injury, injury pattern, location of external fixation application, pre- and postoperative radial nerve function, presence or absence of radial nerve transection from injury or external fixation, anatomic location of pins in relation to the radial nerve safe zone, and final radial nerve outcomes were recorded. We defined the proximal safe zone as 5 cm distal to the acromion to 14.8 cm proximal to the lateral epicondyle, and we defined the distal safe zone as the proximal 70% of the transepicondylar width of the humerus when projected proximally from the lateral epicondyle. Results For our study, 123 patients were identified over our date range, and 16 subjects were included with documentation regarding nerve function/injury characteristics, appropriate radiographs, and active duty status. Around 80% of injuries resulted from a blast mechanism, and 80% of injury patterns included either an intraarticular or open fracture. The radial nerve safe zone was violated in 15 of the 16 subjects (94%). The one subject with a safe construct did not sustain a nerve injury. Complete preoperative documentation on nerve function was only available for half of the subjects. Two of five subjects known to have intact function prior to external fixation had a postoperative neurologic deficit (40%). Of eight subjects with unknown radial nerve function prior to external fixation, seven subjects had full nerve function at the final follow up, and one subject had partial sensory function only. Of the three subjects with impaired preoperative radial nerve function, two made a full recovery, and the third recovered sensory function only. Around 50% of all subjects required medical retirement. Conclusion External fixation of upper extremity injuries in combat is rarely absolutely indicated, often results in the placement of pins outside of the radial nerve safe zone, and is associated with up to a 40% incidence of radial nerve injury.
PubMed: 32351815
DOI: 10.7759/cureus.7435 -
Cellular and Molecular Life Sciences :... Jul 2021Cyclin-dependent kinase 9 (CDK9), the kinase component of positive transcription elongation factor b (P-TEFb), is essential for transcription of most protein-coding... (Review)
Review
Cyclin-dependent kinase 9 (CDK9), the kinase component of positive transcription elongation factor b (P-TEFb), is essential for transcription of most protein-coding genes by RNA polymerase II (RNAPII). By releasing promoter-proximally paused RNAPII into gene bodies, CDK9 controls the entry of RNAPII into productive elongation and is, therefore, critical for efficient synthesis of full-length messenger (m)RNAs. In recent years, new players involved in P-TEFb-dependent processes have been identified and an important function of CDK9 in coordinating elongation with transcription initiation and termination has been unveiled. As the regulatory functions of CDK9 in gene expression continue to expand, a number of human pathologies, including cancers, have been associated with aberrant CDK9 activity, underscoring the need to properly regulate CDK9. Here, I provide an overview of CDK9 function and regulation, with an emphasis on CDK9 dysregulation in human diseases.
Topics: Animals; Cyclin-Dependent Kinase 9; Cyclin-Dependent Kinases; Humans; Phosphorylation; RNA Polymerase II; Transcription, Genetic
PubMed: 34146121
DOI: 10.1007/s00018-021-03878-8 -
Clinics in Colon and Rectal Surgery Jan 2023Many surgeons tend to overuse proximal fecal diversion in the setting of colonic surgery. The decision to proximally divert an anastomosis should be made with careful... (Review)
Review
Many surgeons tend to overuse proximal fecal diversion in the setting of colonic surgery. The decision to proximally divert an anastomosis should be made with careful consideration of the risks and benefits of proximal diversion. Proximal diversion does not decrease the rate of anastomotic leak, but it does decrease the severity of leaks. Anastomotic height for low pelvic anastomoses, hemodynamic instability, steroid use, male sex, obesity, malnutrition, smoking, and alcohol abuse increase the rate of anastomotic leak. Biologics, most immunosuppressive agents, unprepped colons, and radiation for rectal cancer do not contribute to increased rates of anastomotic leak. Proximal fecal diversion creates additional potential morbidity, higher rates of readmission, and need for a subsequent hospitalization and operation for reversal. Additionally, diverted patients have higher rates of anastomotic stricture and delayed recognition of chronic leaks. These downsides to diversion must be weighed with a patient's perceived ability to handle the physiologic stress and consequences of a severe leak if reoperation is required. When trying to determine which patients can handle a leak, the modified frailty index can help to objectively determine a patient's risk for increased rate of morbidity and failure to rescue in the event of a leak. While proximal diversion is still warranted in many cases, we find that certain clinical scenarios often lead to overuse of proximal diversion. The old surgical adage "If you are considering diverting, you should probably do it" should be tempered by an understanding of the risk and benefits of diversion.
PubMed: 36619277
DOI: 10.1055/s-0042-1757559 -
Updates in Surgery Feb 2023Classification of adenocarcinomas (AC) arising around or within the gastroesophageal junction (GEJ) is hampered by major morphologic and phenotypic overlaps. We reviewed... (Review)
Review
Classification of adenocarcinomas (AC) arising around or within the gastroesophageal junction (GEJ) is hampered by major morphologic and phenotypic overlaps. We reviewed the surgical pathology of esophagectomy specimens of 115 primary resected AC of the esophagus as defined by the 5th edition of the WHO classification regarding the anatomical site of the tumor, with corresponding categorization according to the Siewert AEG Classification and the preceding 4th edition of the WHO (discriminating esophageal adenocarcinomas/EAC and adenocarcinomas of the gastroesophageal junction/AdGEJ), and further histology findings. In addition, immunohistochemistry (IHC) for CDX2, CK7, CK20, MUC2, MUC5AC and MUC6 was performed. Sixty-eight cases were Siewert AEG type I and 47 cases Siewert AEG type II. Out of the AEG I tumors, 26 were classified as AdGEJ. Regardless of the classification system, more proximally located tumors showed less aggressive behavior with lower rates of lymph node metastases, lymphatic, venous and perineural invasion, better histological differentiation (p < 0.05 each) and were more frequently associated with pre-neoplastic Barrett's mucosa (p < 0.001). Histologically, the tumors displayed intestinal morphology in the majority of cases. IHC showed non-conclusive patterns with a frequent CK7+/CK20+ immunophenotype in all tumors, but also a gastric MUC5AC+ and MUC6+ phenotype in some proximal tumors. In conclusion, histology of the tumors and IHC failed to distinguish reliably between more proximal and more distal tumors. The presence of Barrett's mucosa rather than location alone, however, may help to further differentiating adenocarcinomas arising in this region and may be indicative for a particular biologic type.
Topics: Humans; Barrett Esophagus; Pathology, Surgical; Stomach Neoplasms; Esophageal Neoplasms; Esophagogastric Junction; Adenocarcinoma
PubMed: 36001283
DOI: 10.1007/s13304-022-01360-z -
JBJS Essential Surgical Techniques Mar 2017Management of pediatric femoral fractures is dependent on patient age and injury pattern. For length-stable femoral shaft fractures in school-age children (5 to 11 years...
Management of pediatric femoral fractures is dependent on patient age and injury pattern. For length-stable femoral shaft fractures in school-age children (5 to 11 years of age), flexible intramedullary nailing (IMN) is a popular treatment method. However, for fracture patterns that are length-unstable or involve the proximal or distal third of the femur, flexible IMN has a higher rate of postoperative complications. Use of a submuscular bridge plate has been shown to be an effective alternative to IMN for these injuries. Because this long plate is inserted with a minimally invasive technique and indirect reduction, it acts as an internal type of "external fixator," thereby avoiding soft-tissue stripping at the fracture site and decreasing strain across the fracture site.Step 1: Position the patient supine on a radiolucent table with a bump under the ipsilateral hip.Step 2: Lay a 4.5-mm narrow stainless-steel plate over the injured thigh and use fluoroscopy to determine the appropriate length for this plate. Contour the plate as needed.Step 3: Make a lateral, longitudinal incision of 2 to 3 cm at the proximal or distal part of the femur through the iliotibial band. Elevate the vastus lateralis extraperiosteally from the femur using a Cobb elevator. Pass the plate through this plane proximally or distally while maintaining contact between the plate and the femur.Step 4: Adjust the plate position using fluoroscopy. Obtain fracture reduction using closed techniques and secure the plate temporarily with Kirschner wires through the most proximal and distal holes.Step 5: Place the first screw near the end of the plate under direct visualization. Place the second screw using a percutaneous technique and insert it immediately proximal or distal to the fracture site where the femur is farthest from the plate. The drilling and length measurement of this screw are fluoroscopically aided and will bring the plate down into contact with the femoral cortex.Step 6: Place the remaining screws in a similar fashion; 3 screws proximal and distal to the fracture site provide adequate stability. Locking screws or lag screws are typically not necessary in this construct. Obtain final radiographs to ensure appropriate reduction length, alignment, and rotation.Postoperatively, patients begin hip and knee range-of-motion exercises without immobilization. Touch-down weight-bearing with crutches is used until callus formation is seen on radiographs, usually in 6 to 8 weeks. The plate can be removed 6 months after the index surgery.
PubMed: 30233936
DOI: 10.2106/JBJS.ST.15.00059 -
Scientific Reports Sep 2018Nephrocalcinosis often begins on a calcium phosphate deposit, at the tip of the medullo-papillary complex (MPC) known as Randall's plaque (RP). Contextualizing...
Nephrocalcinosis often begins on a calcium phosphate deposit, at the tip of the medullo-papillary complex (MPC) known as Randall's plaque (RP). Contextualizing proximally observed biominerals within the MPC has led us to postulate a mechanobiological switch that can trigger interstitial biomineralization at the MPC tip, remote from the intratubular biominerals. Micro X-ray computed tomography scans of human MPCs correlated with transmission and scanning electron micrographs, and X-ray energy dispersive spectrometry demonstrated novel findings about anatomically-specific biominerals. An abundance of proximal intratubular biominerals were associated with emergence of distal interstitial RP. The fundamental architecture of the MPC and mineral densities at the proximal and distal locations of the MPC differed markedly. A predominance of plate-like minerals or radially oriented plate-like crystallites within spheroidal minerals in the proximal intratubular locations, and core-shell type crystallites within spheroidal minerals in distal interstitial locations were observed. Based on the MPC anatomic location of structure-specific biominerals, a biological switch within the mineral-free zone occurring between the proximal and distal locations is postulated. The "on" and "off" switch is dependent on changes in the pressure differential resulting from changes in tubule diameters; the "Venturi effect" changes the "circumferential strain" and culminates in interstitial crystal deposits in the distal tubule wall in response to proximal tubular obstruction. These distal interstitial mineralizations can emerge into the collecting system of the kidney linking nephrocalcinosis with nephrolithiasis.
Topics: Biomineralization; Calcium Phosphates; Humans; Kidney Medulla; Minerals; Nephrocalcinosis; X-Ray Microtomography
PubMed: 30242165
DOI: 10.1038/s41598-018-30717-x -
RSC Chemical Biology Jun 2021Proximal multi-site phosphorylation is a critical post-translational modification in protein biology. The additive effects of multiple phosphosite clusters in close... (Review)
Review
Proximal multi-site phosphorylation is a critical post-translational modification in protein biology. The additive effects of multiple phosphosite clusters in close spatial proximity triggers integrative and cooperative effects on protein conformation and activity. Proximal phosphorylation has been shown to modulate signal transduction pathways and gene expression, and as a result, is implicated in a broad range of disease states through altered protein function and/or localization including enzyme overactivation or protein aggregation. The role of proximal multi-phosphorylation events is becoming increasingly recognized as mechanistically important, although breakthroughs are limited due to a lack of detection technologies. To date, there is a limited selection of facile and robust sensing tools for proximal phosphorylation. Nonetheless, there have been considerable efforts in developing optical chemosensors for the detection of proximal phosphorylation motifs on peptides and proteins in recent years. This review provides a comprehensive overview of optical chemosensors for proximal phosphorylation, with the majority of work being reported in the past two decades. Optical sensors, in the form of fluorescent and luminescent chemosensors, hybrid biosensors, and inorganic nanoparticles, are described. Emphasis is placed on the rationale behind sensor scaffolds, relevant protein motifs, and applications in protein biology.
PubMed: 34458812
DOI: 10.1039/d1cb00055a -
Journal of Wrist Surgery Oct 2023The scaphotrapeziotrapezoidal (STT) joint transfers forces to the proximal carpal row from the thumb and fingers. Clinically, STT joint osteoarthritis is frequently...
The scaphotrapeziotrapezoidal (STT) joint transfers forces to the proximal carpal row from the thumb and fingers. Clinically, STT joint osteoarthritis is frequently observed on plain radiographs though its role in the mechanics of the wrist joint remains unclear. Our purpose was to use a model of normal wrist types, to predict STT motion upon load. Five normal computed tomography scans of a wrist type 1 and five wrist type 2 were used to model the wrist. A 200-N force was split and applied to the trapezoid and capitate to replicate forces during a knuckle pushup. The bony movement was predicted by the model as bony movement using finite element analysis. We found differences in force transfer through the STT joint between the two wrist types when loading the index and middle fingers. Type 1 wrists moved quantitatively more anterior-posterior, type 2 wrists moved more medially-laterally and more proximally-distally. The trapezium in type 1 wrists moved more in the coronal plane than in type 2 wrists. The trapezoid moved more from distal to proximal in a type 2 wrist, = 0.03. This study found differences in motion upon loading through the STT joint between type 1 and 2 wrists. Type 2 wrists moved more radially toward the proximal scaphoid and scapholunate ligament. This study may provide a mechanical basis for degenerative configurations. By linking observed patterns of degeneration to their mechanical causes we can aid in prevention of arthritis.
PubMed: 37841353
DOI: 10.1055/s-0043-1761287