instruction:
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.
question:
Context: The effect of inhalational anesthetics on sensory-evoked unit activity in the cerebral cortex has been controversial. Desflurane has desirable properties for in vivo neurophysiologic studies, but its effect on cortical neuronal activity and neuronal responsiveness is not known. The authors studied the effect of desflurane on resting and visual evoked unit activity in rat visual cortex in vivo.', 'Desflurane was administered to adult albino rats at steady-state concentrations at 2%, 4%, 6%, and 8%. Flashes from a light emitting diode were delivered to the left eye at 5-s intervals. Extracellular unit activity within the right visual cortex was recorded using a 49-electrode array. Individual units were identified using principal components analysis.', 'At 2% desflurane, 578 active units were found. Of these, 75% increased their firing rate in response to flash. Most responses contained early (0-100 ms) and late (150-1000 ms) components. With increasing desflurane concentration, the number of units active at baseline decreased (-13%), the number of early-responding units increased (+31%), and number of late-responding units decreased (-15%). Simultaneously, baseline firing rate decreased (-77%), the early response was unchanged, and the late response decreased (-60%).\Question: Does desflurane selectively suppress long-latency cortical neuronal response to flash in the rat?
answer:
The results indicate that visual cortex neurons remain responsive to flash stimulation under desflurane anesthesia, but the long-latency component of their response is attenuated in a concentration-dependent manner. Suppression of the long-latency response may be related to a loss of corticocortical feedback and loss of consciousness.


question:
Context: Total shoulder arthroplasty (TSA) results in superior clinical outcomes to hemiarthroplasty (HA); however, TSA is a more technical and invasive procedure. This study retrospectively compares perioperative complications after HA and TSA using the National Surgical Quality Improvement Program (NSQIP) database.', 'The NSQIP user file was queried for HA and TSA cases from the years 2005 through 2010. Major complications were defined as life-threatening or debilitating. All complications occurred within 30 days of the initial procedure. We performed multivariate analysis to compare complication rates between the two procedures, controlling for patient comorbidities.', 'The database returned 1,718 patients (HA in 30.4% [n = 523] and TSA in 69.6% [n = 1,195]). The major complication rates in the HA group (5.2%, n = 29) and TSA group (5.1%, n = 61) were similar (P = .706). Rates of blood transfusions for postoperative bleeding in patients undergoing HA (2.3%, n = 12) and TSA (2.9%, n = 35) were indistinguishable (P = .458). Venous thromboembolism was a rare complication, occurring in 0.4% of patients in each group (2 HA patients and 5 TSA patients, P > .999). On multivariate analysis, the operative procedure was not associated with major complications (P = .349); however, emergency case, pulmonary comorbidity, anemia with a hematocrit level lower than 36%, and wound class of III or IV increased the risk of a major complication (P < .05 for all).\Question: Are perioperative complications after hemiarthroplasty and total shoulder arthroplasty equivalent?
answer:
Multivariate analysis of patients undergoing TSA or HA in the NSQIP database suggests that patient factors-not the procedure being performed-are significant predictors of major complications. Controlling for patient comorbidities, we found no increased risk of perioperative major complications in patients undergoing TSA compared with HA.


question:
Context: Dopamine receptors in the kidney, especially those belonging to the D1-like receptor family, are important in the regulation of renal function and blood pressure. Because of increasing evidence that G protein-coupled receptors (GPCRs) are associated with caveolae and lipid rafts, we tested the hypothesis that the D1 dopamine receptor (D1R) and signaling molecules are regulated by caveolin in caveolae or lipid rafts.', 'Six experimental approaches were used: (1) construction of tagged human D1Rs (hD1Rs) and transfectants; (2) cell culture [human embryonic kidney (HEK)-293 and immortalized rat renal proximal tubule cells] and biotinylation; (3) cell fractionation by sucrose gradient centrifugation; (4) immunoprecipitation and immunoblotting; (5) immunofluorescence and confocal microscopy; and (6) adenylyl cyclase assays.', 'hD1Rs, heterologously expressed in HEK-293 cells, formed protein species with molecular mass ranging from 50 to 250 kD, and were localized in lipid rafts and nonraft plasma membranes. The hD1Rs cofractionated with caveolin-2, G protein subunits, and several signaling molecules. Both exogenously expressed hD1Rs and endogenously expressed rat D1Rs colocalized and coimmunoprecipitated with caveolin-2. A D1R agonist (fenoldopam) increased the amount of caveolin-2beta associated with hD1Rs and activated adenylyl cyclase to a greater extent in lipid rafts than in nonraft plasma membranes. Reduction in the expression of caveolin-2 with antisense oligonucleotides attenuated the stimulatory effect of fenoldopam on cyclic adenosine monophosphate (cAMP) accumulation.\Question: Does d1 dopamine receptor signaling involve caveolin-2 in HEK-293 cells?
answer:

The majority of hD1Rs are distributed in lipid rafts. Heterologously and endogenously expressed D1Rs in renal cells are associated with and regulated by caveolin-2.