TASK DEFINITION: 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.
PROBLEM: 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?

SOLUTION: 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.

PROBLEM: Context: The purpose of this study was to investigate the ability of neutrophil gelatinase-associated lipocalin (NGAL), cystatin C, and their combination in predicting the duration and severity of acute kidney injury (AKI) after cardiac surgery in adults.', 'Using data from a prospective observational study of 100 adult cardiac surgical patients, we correlated early postoperative concentrations of plasma NGAL and serum cystatin C with the duration (time during which AKI persisted according to the Acute Kidney Injury Network criteria) and severity of AKI (change in serum creatinine) and with length of stay in intensive care.', 'We found a mean AKI duration of 67.2 +/- 41.0 hours which was associated with prolonged hospitalization (p < 0.001). NGAL, cystatin C, and their combination on arrival in intensive care correlated with subsequent AKI duration (all p < 0.01) and severity (all p < 0.001). The area under the receiver operating characteristic curve for AKI prediction was 0.77 (95% confidence interval: 0.63 to 0.91) for NGAL and 0.76 (95% confidence interval: 0.61 to 0.91) for cystatin C on arrival in intensive care. Both markers also correlated with length of stay in intensive care (p = 0.037; p = 0.001). Neutrophil gelatinase-associated lipocalin and cystatin C were independent predictors of AKI duration and severity and of length of stay in intensive care (all p < 0.05). The value of cystatin C on arrival in intensive care appeared to be due to a carry-over effect from preoperative values.\Question: Do novel biomarkers early predict the severity of acute kidney injury after cardiac surgery in adults?

SOLUTION: Immediately postoperatively, NGAL and cystatin C correlated with and were independent predictors of duration and severity of AKI and duration of intensive care stay after adult cardiac surgery. The combination of both renal biomarkers did not add predictive value.

PROBLEM: Context: To investigate the impact of disorders of arousal and sleep disturbance on everyday living and participation in rehabilitation.', 'Survey of rehabilitation centres based on naturalistic observation.', 'One hundred and thirty-five adults with acquired brain injury were reported by rehabilitation staff in seven centres across the UK for presence of arousal and/or sleep disturbance, the impact on rehabilitation and daily living and treatment strategies in use.', 'Disturbance of arousal or sleep patterns was reported in 47% of the sample, with significant adverse effect on activity evident in two-thirds of such cases. Prevalence of disordered arousal was consistent over time for up to 10 years post-injury. Concurrent psychiatric illness, but not epilepsy, was associated with arousal and sleep disorder. Non-pharmacological interventions and benzodiazepine/hypnotic drugs were in use in 34% and 20% of cases respectively. In all cases of prescribed hypnotic drugs, period of use exceeded recommended UK guidelines.\Question: Is rehabilitation compromised by arousal and sleep disorders : results of a survey of rehabilitation centres?

SOLUTION:
Long-term outcome from severe brain injury can be compromised by enduring disturbance of arousal, most commonly evidenced as sleep disorder. Treatment should be based on judicious use of medication (beyond hypnotic drugs) and greater emphasis on non-pharmacological management.