In this task, you are given a passage which has a question and the context. You have to generate an answer to the question based on the information present in the context.

Context: Benign esophageal strictures are frequently encountered pathologies occurring due to various reasons. Repeated dilatations may be needed, particularly in resistant strictures. This study aimed to evaluate patients who underwent repeated dilatations in our clinic due to resistant esophageal strictures.', 'Sixteen patients who underwent multiple dilatations in our clinic with the diagnosis of resistant benign esophageal stricture between 2007 and 2014 were studied for age, sex, etiology, symptoms, complications, number of dilatations, and intervals between dilatations. Under general anesthesia, all patients underwent dilatation with Savary-Gilliard bougie dilators with the help of rigid esophagoscopy.', 'In 10 of the patients, stenosis was cervical, and in others it was in the thoracic esophagus. The mean dilatation performance was 4.4 (range: 3-12). In 9 patients, dilatations were performed when the patients presented with the complaint of dysphagia. Following the initial dilatation performed for dysphagia, 7 patients underwent endoscopy and dilatation 3-5 times with 1-week intervals without waiting for the development of dysphagia symptoms. These patients developed no complications, and no stenting was needed. In 5 patients, restenosis developed despite multiple dilatations, and esophageal stent placement was performed.\Question: Is recurrent dilatation in resistant benign esophageal strictures : timing significant?
Dilatations performed at frequent intervals without waiting for the symptoms of dysphagia can contribute to safer and more effective results in resistant benign esophageal strictures.

Context: The aim of this study was to evaluate the characteristics of low-energy femoral insufficiency fractures in elderly patients.', 'The study retrospectively evaluated the clinical course of 4 patients with low-energy femoral shaft and subtrochanteric fractures admitted to our department between 2009 and 2011. Three patients had prior long-term alendronate therapy and one had prior glucocorticoid therapy.', 'There were 5 femoral shaft fractures, 2 incomplete shaft fractures, 2 subtrochanteric and 1 intertrochanteric fractures. All femoral shaft fractures had characteristic fracture patterns with thickened lateral cortices at the proximal fragment. Six femurs had excessive medial femoral bowing, which complicated intramedullary nailing. Additional fractures were seen on both femurs of one patient who had been primarily treated with short implants. A bifocal femoral fracture was seen in one femur. Union was achieved in all patients. Two patients were able to walk independently, one with a cane and one with double crutches.\Question: Does femoral insufficiency fractures in the elderly - excessive medial femoral bowing complicate intramedullary nailing?
We suggest the addition of another radiographic pattern of 'excessive medial femoral bowing' in low-energy femoral shaft fractures in elderly patients. This bowing complicates intramedullary nailing. Moreover, these insufficiency fractures should be fixed with long cephalomedullary nails.

Context: Oxidative stress occurs in chronic renal failure patients undergoing hemodialysis (HD). The objective of our study was to measure oxidation products of cholesterols, so-called oxysterols, in the serum of HD patients in comparison to healthy control persons.', 'In 42 HD patients, plasma oxysterols were measured before and after HD. The values were compared with those in 40 healthy controls. The following cholesterol derivatives were analyzed: dienes, 7beta-OH, beta-epoxy, alpha-epoxy, 20alpha-OH, alpha-triol, and 7-keto cholesterol.', 'In HD patients, serum levels of oxysterols are increased in comparison to controls. The highest values were measured for beta-epoxy cholesterol and for 20alpha-OH cholesterol. During HD oxysterol concentrations increased, obviously by water removal and concentration of nondialyzable compounds.\Question: Are oxysterols increased in plasma of end-stage renal disease patients?
Due to oxidative stress which is known as a typical sign of chronic renal failure the plasma concentrations of oxysterols are also significantly increased in comparison to healthy controls. This underlines the data on accelerated lipid peroxidation in end-stage renal disease (ESRD) patients. Accumulated oxysterols which are accused of exerting atherosclerosis-stimulating effects, which can contribute to the increased cardiovascular risk of ESRD patients, could either induce atherosclerosis via signaling or chronic effects. Direct chemical reactions stimulating plaque formation can be excluded because of the low levels of oxysterols. The share of oxysterols within the total cholesterol ranges from 4 to 15 per thousand.