Given a passage with a context and an answer, construct a question on the basis of the information present in the passage. Construct the question in such a way that (i) it is unambiguous, (ii) it is answerable from the passage, (iii) its answer is unique (iv) it answer uses text phrases from the passage. Avoid creating questions that (i) can't be answered correctly without actually understanding the passage and (ii) uses the same words or phrases given in the passage.

Context: Spinal anesthesia can be challenging in patients undergoing total joint arthroplasty because of poorly palpable surface landmarks and age-related changes in the lumbar spine. We hypothesized that pre-procedural ultrasound imaging would be effective in identifying the lumbar intervertebral spaces and would provide an accurate measure of the depth to the intrathecal space.', "Fifty patients undergoing elective total joint arthroplasty were recruited in this prospective descriptive study. Using a curved-array 2-5 MHz transducer, the lumbar spine was imaged in two views, i.e., longitudinal parasagittal (LP) and transverse midline (TM). The intervertebral levels were identified by counting upwards from the sacrum. The locations of the interlaminar spaces were identified by visualizing the ligamentum flavum-dura mater complex and the posterior aspect of the vertebral body. The needle insertion point for a midline approach was determined from the ultrasound examination and was marked on the skin of the patient's back.", 'The mean patient age was 67 +/- 10 yr, and 46% of the patients had a body mass index >30 kg . m(-2). Surface landmarks were difficult or impossible to palpate in 38% of the patients. The scan quality on the LP and TM views was adequate or better in 100 and 98% of the patients, respectively. Dural puncture was achieved with one needle insertion attempt and within two needle insertion attempts in 84% and 98% of the patients, respectively. The ultrasound-measured depth to the intrathecal space correlated well with the actual needle insertion depth (concordance correlation coefficient = 0.82, accuracy 0.95, precision 0.86), with a tendency to overestimate the depth by just 2.1 +/- 5.4 mm.
Answer: Ultrasound imaging of the lumbar spine provides clinically useful information that can facilitate spinal anesthesia in the older orthopedic patient population.
Does an ultrasound-assisted approach facilitate spinal anesthesia for total joint arthroplasty?

Context: Side effects of mitotane (o,p'-DDD) have suggested estrogenic effects.", "The objective of the study was to explore o,p'-DDD potential estrogenic effect on SHBG and corticosteroid-binding globulin (CBG).", 'Human hepatoma cell lines (HepG2), lacking estrogen receptor (ER)-alpha, and Hep89, stably transfected by ERalpha, were used.', 'The study was conducted at an academic research laboratory and medical center.', 'The study included 10 male patients with recurrent adrenal carcinoma, receiving mitotane (4-6.5 g daily) for more than 6 months.', 'The main outcome measures were SHBG/CBG mRNA levels measured by real-time PCR, culture medium SHBG/CBG concentrations measured by specific immunoassays, and transient transfection experiments with human SHBG proximal promoter reporter constructs.', "Increased serum SHBG and CBG concentrations, which exceeded normal male limits, were observed in most mitotane-treated patients. In the HepG2 cell line, 17beta-estradiol (E2) or o,p'-DDD treatment had no effect on mRNA or SHBG/CBG concentrations. In contrast, in the Hep89 cell line, E2 increased concentrations of SHBG (r = 0.44, P < 0.0001) and CBG (r = 0.585, P < 0.0001) secreted into culture media in a dose-dependent manner. o,p'-DDD significantly increased SHBG (150% vs. control, P < 0.05) and CBG (184% vs. control, P < 0.05) production by Hep89 cells, at a concentration of 2 x 10(-5) m. Transient transfection experiments in Hep89 cells showed that E2 or o,p'-DDD treatment did not increase the transcriptional activity of the minimal proximal promoter of human SHBG gene.
Answer: Mitotane increased SHBG/CBG gene expression and liver production by mechanisms requiring the presence of ERalpha.
Does mitotane have an estrogenic effect on sex hormone-binding globulin and corticosteroid-binding globulin in humans?

Context: Measurement of pulse-wave velocity (PWV) is a non-invasive technique for assessing arterial stiffness. Although insulin resistance is associated with intimal-medial thickness of the carotid artery evaluated by B-mode ultrasonography, it is not known whether it is related to PWV. The aim of this study was to determine the relationship between homeostasis model assessment insulin sensitivity index (HOMA-%S) and PWV in non-diabetic subjects. We also examined the effects of oral glucose tolerance test (OGTT) 2-h glucose and plasma high-sensitivity C-reactive protein (CRP) on PWV, as these two parameters are associated with atherosclerosis.', 'A 75-g oral glucose tolerance test was performed in 1934 Japanese subjects who were undergoing health examinations. Of these subjects, we recruited 1541 non-diabetic subjects without chronic or acute inflammation, malignant diseases, autoimmune disorders, elevated serum creatinine levels, and abnormal hepatic function tests. Subjects who had an abnormal ankle/brachial blood pressure index of less than 0.9 were also excluded. Brachial-ankle PWV and plasma high-sensitivity CRP were measured on 1541 subjects who satisfied the admission criteria.', 'PWV was 12.55+/-1.61 (mean+/-sd) m/s and plasma CRP concentration was 0.4 mg/l (median, range, 0.1-5.8 mg/l) in the study subjects. By multivariate regression analysis, HOMA-%S was found to be an independent negative risk factor for PWV, while systolic blood pressure, age and triglycerides were positively associated with PWV. OGTT 2-h glucose was weakly and independently related to PWV in male subjects. Plasma CRP was not independently associated with PWV.
Answer: Insulin resistance is independently associated with PWV in non-diabetic subjects.
Does insulin sensitivity independently influence brachial-ankle pulse-wave velocity in non-diabetic subjects?