Percutaneous Gastrojejunostomy Tube Insertion in Patients with Surgical Gastrojejunal Anastomoses: Analysis of Success Rates and Durability.

Patients with a gastrojejunal anastomosis pose challenging anatomy for percutaneous gastrojejunostomy (GJ)-tube placement. A retrospective review of 24 patients (mean age 67.8 years, 13 males) with GJ anastomoses who underwent attempted GJ tube placement revealed infeasible placement in 6 patients (25%) due to an inadequate window for puncture. When a gastric puncture was achieved, GJ tube insertion was technically successful in 83% (15/18) of attempts, resulting in an overall technical success rate of 63% (15/24). The most common tube-related complication was the migration of the jejunal limb into the stomach, which occurred in 40% (6/15) of successful cases. No major procedure related complications were encountered.

Sulfate and thiosulfate inhibit oxalate transport via a dPrestin (Slc26a6)-dependent mechanism in an insect model of calcium oxalate nephrolithiasis.

Nephrolithiasis is one of the most common urinary tract disorders, with the majority of kidney stones composed of calcium oxalate (CaOx). Given its prevalence (US occurrence 10%), it is still poorly understood, lacking progress in identifying new therapies because of its complex etiology. Drosophila melanogaster (fruitfly) is a recently developed model of CaOx nephrolithiasis. Effects of sulfate and thiosulfate on crystal formation were investigated using the Drosophila model, as well as electrophysiological effects on both Drosophila (Slc26a5/6; dPrestin) and mouse (mSlc26a6) oxalate transporters utilizing the Xenopus laevis oocyte heterologous expression system. Results indicate that both transport thiosulfate with a much higher affinity than sulfate Additionally, both compounds were effective at decreasing CaOx crystallization when added to the diet. However, these results were not observed when compounds were applied to Malpighian tubules ex vivo. Neither compound affected CaOx crystallization in dPrestin knockdown animals, indicating a role for principal cell-specific dPrestin in luminal oxalate transport. Furthermore, thiosulfate has a higher affinity for dPrestin and mSlc26a6 compared with oxalate These data indicate that thiosulfate's ability to act as a competitive inhibitor of oxalate via dPrestin, can explain the decrease in CaOx crystallization seen in the presence of thiosulfate, but not sulfate. Overall, our findings predict that thiosulfate or oxalate-mimics may be effective as therapeutic competitive inhibitors of CaOx crystallization.

Isolation and Culture of Murine Primary Chondrocytes: Costal and Growth Plate Cartilage.

Primary chondrocyte isolation and culture is a useful tool to characterize how cellular perturbations impact chondrocyte behavior and mineralization in vitro. This protocol conveys methods for isolating and culturing primary chondrocytes from costal and growth plate cartilage. Following gross dissection of the neonatal murine anterior rib cage or long bone growth plate cartilage, chondrocytes are isolated via enzymatic digestion and plated at high density. Genetic perturbation of plated primary murine chondrocytes using viral infection of Cre recombinase to excise floxed alleles and/or overexpress genes of interest are also described.

Sharp Recanalization of Chronic Central Venous Occlusions of the Thorax Using a Steerable Coaxial Needle Technique from a Supraclavicular Approach.

PURPOSE: To evaluate the technical success and safety of a steerable coaxial sharp recanalization technique that utilizes routine needles in patients with refractory thoracic central venous occlusions. MATERIALS AND METHODS: This retrospective study was performed on 36-attempted sharp recanalizations in 35 patients (mean age 50 years, 23 male) performed via a supraclavicular approach. In all cases, an 18-gauge trocar needle was custom curved to provide directional control during fluoroscopic triangulation. A 22-gauge Chiba needle was then advanced coaxially across the occlusion. A tractogram was performed to assess for traversal of unintended structures. Procedures were completed by catheter placement, angioplasty, or stenting follow successful recanalizations. RESULTS: Sharp recanalization using this steerable coaxial needle technique demonstrated a technical success rate of 94% (34/36). The mean occlusion length was 30 mm (range 3-53 mm). In 11 patients, success was achieved using this technique after failure of other advanced techniques. In five procedures, stent interstices were traversed. Sharp recanalization was the direct cause of one major complication consisting of pleural transgression causing mild hemothorax treated successfully with a stent graft. CONCLUSION: The proposed technique is effective and safe for patients who have failed traditional blunt recanalization techniques. LEVEL OF EVIDENCE: Level 4, Case Series.

Percutaneous gastrojejunostomy tubes: Identification of predictors of retrograde jejunal limb migration into the stomach.

PURPOSE: To identify whether technically modifiable factors during gastrojejunostomy (GJ) tube insertion are predictive of retrograde jejunal limb migration into the stomach. MATERIALS AND METHODS: Retrospective review of our procedural database over a 5-year period revealed 988 successful primary GJ tube insertions. Medical records and imaging were reviewed for cases of retrograde jejunal limb migration. Primary analysis was performed on 74 patients with retrograde tip migration within 3 months after placement (37 males, mean age = 57). Comparison was performed on 67 control patients (34 males, mean age = 51) who had radiologically confirmed GJ tube stability for at least 6 months. Procedural fluoroscopic images were analyzed for multiple GJ tube configuration parameters. The stomach was designated into antrum, body, and fundus. Predictors of retrograde tip migration were analyzed with univariate and multivariate logistic regression analysis. RESULTS: A total of 110 patients (11.1%) had retrograde jejunal limb migration, with 74 (7.5%) occurring within 3 months of placement. On multivariate analysis, the factors associated with a significantly lower risk of tip malposition included gastric puncture site in the antrum (OR: 0.27, 95% CI: 0.13-0.56, p < 0.001) and GJ tract angle less than 30 degrees away from the pylorus (OR: 0.35, 95% CI: 0.16-0.76, p = 0.008). No patient in either cohort had a major complication within 30 days of procedure. CONCLUSION: To minimize the risk of retrograde tip migration, GJ tubes should be inserted into the gastric antrum with an entry tract oriented as directly towards the pylorus as possible.

Ferumoxytol-enhanced MR Venography of the Central Veins of the Thorax for the Evaluation of Stenosis and Occlusion in Patients with Renal Impairment.

PURPOSE: To assess the diagnostic performance of ferumoxytol-enhanced MR venography for the detection of thoracic central vein stenosis or occlusion with conventional venography as the reference standard. MATERIALS AND METHODS: In this retrospective study, consecutive patients from May 2012 to December 2018 underwent dedicated ferumoxytol-enhanced MR venography of the thoracic central veins and conventional venography within 6 months for detecting central venous stenosis. The central veins were divided into seven segments for evaluation. MR venography images were evaluated by three radiologists for presence of stenosis or occlusion. Interobserver agreement was assessed using Fleiss κ. RESULTS: A total of 35 patients were included (mean age, 49 years; age range, 12-75 years; 18 females). Of the 122 total venous segments with corresponding conventional venography, 73 were stenotic or occluded. The sensitivity and specificity for detection of stenosis or occlusion was 99% and 98%, respectively. The sensitivity and specificity for detecting occlusion alone was 96% and 98%, respectively. MR venography readers demonstrated moderate agreement in their ability to grade stenosis or occlusion (κ = 0.59). There were no adverse events related to contrast agent administration. CONCLUSION: Ferumoxytol-enhanced MR venography demonstrated excellent sensitivity and specificity for detection of thoracic central vein stenosis or occlusion.© RSNA, 2020See also the commentary by Finn in this issue.