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: Nagashima-type palmoplantar keratosis (NPPK) is a distinct autosomal recessive genodermatosis characterized by diffuse transgressive palmoplantar keratoderma (PPK). Very recently, putative loss-of-function mutations in SERPINB7, which encodes a member of the serine protease inhibitor superfamily and is abundantly expressed in the epidermis, have been identified as a cause of NPPK.', 'To confirm further the role of SERPINB7 mutations in the pathogenesis of NPPK.', 'We analysed 10 Japanese families with NPPK using Sanger and/or whole-exome sequencing.', 'We identified one novel and three recurrent null mutations in SERPINB7. In all the families, the NPPK trait was inherited in an autosomal recessive manner; in one of the families, there was pseudodominant inheritance, which had not been described in NPPK.
Answer: These data clearly provide further evidence that NPPK is caused by loss-of-function mutations in SERPINB7.
Does highly prevalent SERPINB7 founder mutation cause pseudodominant inheritance pattern in Nagashima-type palmoplantar keratosis?

Context: Cerebral ischemia upregulates aquaporin-4 expression, increases blood-brain barrier (BBB) permeability, and induces brain edema. Mesenchymal stem cells (MSCs) can repress inflammatory cytokines and show great potential for ischemic stroke therapy. However, the effect of MSCs regarding the protection of ischemia-induced BBB break down is unknown.', 'We test whether MSCs therapy protects BBB integrity and explore the molecular mechanisms of aquaporin-4 on BBB integrity.', 'Two hundred and twenty-eight adult CD1 male mice underwent 90 minutes transient middle cerebral artery occlusion and received 2 × 10(5) MSCs intracranial transplantation. The neurological severity score was improved and both ischemia-induced brain edema and BBB leakage were reduced in MSC-treated mice. MSCs therapy reduced astrocyte apoptosis and inhibited ischemia-induced aquaporin-4 upregulation. In addition, small-interfering RNA knockdown of aquaporin-4 after cerebral ischemia effectively reduced aquaporin-4 expression, brain edema, BBB leakage, and astrocyte apoptosis. Conditional medium from lipopolysaccharide (LPS)-activated microglia enhanced aquaporin-4 expression, p38 and JNK phosphorylation, and apoptosis of cultured astrocytes. MSC treatment reduced the expression of inflammatory cytokines in LPS-activated microglia, and subsequently reduced aquaporin-4 expression and apoptosis of astrocytes. Knockdown of aquaporin-4 in cultured astrocytes also reduced apoptosis. Treatment with p38 and JNK inhibitors showed that p38, but not the JNK signaling pathway, was responsible for the aquaporin-4 upregulation.
Answer: MSCs protected BBB integrity by reducing the apoptosis of astrocytes after ischemic attack, which was due to the attenuation of inflammatory response and downregulation of aquaporin-4 expression via p38 signaling pathway.

Do mesenchymal stem cells maintain blood-brain barrier integrity by inhibiting aquaporin-4 upregulation after cerebral ischemia?