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.

[Q]: Context: Somatic cells in vitro have a finite life expectancy before entering a state of senescence, but it is unclear whether this state occurs in vivo in kidney development, growth, and aging. We previously showed that human kidney cortex displays telomere shortening with age. In this study, we compared the structural and functional changes in rat kidney with age to phenomena associated with cellular senescence in vitro.', 'We assessed the changes in Fischer 344 rat kidneys from age 1 to 9 months to define growth and development and from age 9 to 24 months to define aging.', 'Rat kidney telomeres were approximately 35 to 40 kb long and did not shorten significantly. Expression of mRNA for p16INK4a, a characteristic senescence gene in vitro, was undetectable in most young rats but rose 27 fold during growth and a further 72-fold during aging. p16INK4a protein was localized to the nucleus and increased with age. p16INK4a mRNA also increased in other tissues. Lipofuscin and senescence-associated beta-galactosidase increased in epithelium with growth and aging and their occurrence was significantly associated with each other. Lipofuscin was particularly found in atrophic nephrons.\Question: Does cell senescence in rat kidneys in vivo increase with growth and age despite lack of telomere shortening?
[A]: We conclude that cell senescence occurs in both growth and aging in rat kidney and may contribute to the age-related pathology. These changes are not due to telomere shortening, but may reflect cumulative environmental stress.


[Q]: Context: We measured the effect of two weight adjusted i.v. doses (0.2 mg per 70 kg and 0.4 mg per 70 kg) of the potent opioid buprenorphine on analgesia and respiratory depression in healthy volunteers. The aim of the study was to compare buprenorphine's behaviour with respect to the occurrence of ceiling (or apparent maximum) in these typical micro-opioid protein-(MOP) receptor effects.", 'Ten subjects (5 males) received 0.2 mg per 70 kg, 10 others (5 males) 0.4 mg per 70 kg i.v. buprenorphine. Steady-state inspired minute ventilation at a fixed end-tidal Pco(2) of 7 kPa was measured before drug infusion and at regular intervals after drug infusion. Experimental pain was induced using transcutaneous electrical stimulation and a gradually increasing current. Pain tolerance was measured at regular intervals before and after drug infusion. The studies lasted 8 h.', 'After infusion of the drug ventilation showed a rapid decline and reached peak depression between 150 and 180 min after drug administration. This effect was dose-independent with respect to timing and magnitude. At peak respiratory depression minute ventilation was 13.1 (sd 1.8) litre min(-1) in the 0.2 mg group vs 12.0 (sd 1.3) litre min(-1) in the 0.4 mg group (n.s.). At buprenorphine 0.2 mg a small short-lived analgesic effect was observed with a maximum increase in pain tolerance current of 6.7 (sd 2.8) mA occurring at 75 min after drug administration. Peak analgesic effect was 29% above baseline current. In contrast, buprenorphine 0.4 mg caused a large and long-lived analgesic effect with a maximum increase in pain tolerance current of 23.8 (sd 7.4) mA occurring at 130 min after drug administration. Peak analgesic effect was 160% above baseline current (0.4 vs 0.2 mg, P<0.01).\Question: Does buprenorphine induce ceiling in respiratory depression but not in analgesia?
[A]: While buprenorphine's analgesic effect increased significantly, respiratory depression was similar in magnitude and timing for the two doses tested. We conclude that over the dose range tested buprenorphine displays ceiling in respiratory effect but none in analgesic effect.


[Q]: Context: The early recovery period after periacetabular osteotomy (PAO) can be limited by pain and activity restrictions. Modifications of the Bernese PAO, including sparing the rectus tendon and discontinuing routine arthrotomy, may accelerate early postoperative recovery compared with the standard approach.', 'Does a modified approach for PAO (1) lead to improved pain control immediately after surgery; (2) lead to improved ambulation during the hospital stay; (3) lead to shorter stays, less blood loss, and shorter surgical times; and (4) compromise acetabular correction?', "We retrospectively reviewed all 75 patients who underwent PAO for developmental dysplasia of the hip between August 2009 and May 2013. The control group included 44 consecutive patients who underwent a standard Bernese PAO with rectus takedown (RT). The study group consisted of 31 consecutive patients who underwent PAO using a modified rectus-sparing (RS) approach without routine arthrotomy. The groups were similar in age, body mass index, and American Society of Anesthesiologists score, but the RT group was comprised of a greater percentage of men than the RS group. Outcome variables were collected from patient charts and included inpatient pain, inpatient ambulation as well as length of stay, estimated blood loss, surgical time, and postoperative radiographic measurements. Cohen's f(2) was used to calculate the effect size in the regression analysis and effects were considered small for values<0.15, moderate for 0.15 to 0.34, and large for values>0.35.", 'Patients who underwent PAO with a RS approach had less overall pain (RT median 4 versus RS median 2); however, the difference may not have been perceptible to the typical patient (p=0.001, f2=0.059). Patients treated with the RS approach ambulated similar distances during the hospital stay with a median 11 feet (interquartile range [IQR], 0-72.5) for the RT group and a median 30 feet (IQR, 0-100) for the RS group (p=0.215, f2=0.095). Patients in the RT group had a median length of stay of 4 days (IQR, 4-5) compared with a median 3 days (IQR, 3-4) in the RS group (p<0.001). The median estimated blood loss was greater (p=0.010) in the RT group (median, 500 mL; IQR, 350-700) versus the RS group (median, 300; IQR, 250-500). The median surgical time was longer (p<0.001) in patients undergoing PAO with the RT approach (median, 159.5 minutes; IQR, 145.5-177) compared with the RS approach (median, 103 minutes; IQR, 75-114). Acetabular reorientation based on postoperative radiographs was not compromised by the modified approach.\Question: Does preservation of the rectus femoris origin during periacetabular osteotomy compromise acetabular reorientation?
[A]:
The approach modification was straightforward to implement in all patients and did not compromise acetabular fragment mobilization or final positioning. Two of the three key variables that the approach might have influenced-pain and length of stay-were below the minimum clinically important difference and different by only a fraction of a day, respectively. The difference in ambulation was of only modest clinical importance. More definitive evidence for clinical superiority in terms of pain, ambulation, and return of muscle function will likely require more sophisticated instruments such as gait analysis, muscle strength testing, and longer-term outcome studies with sensitive instruments.