An automated home-cage-based 5-choice serial reaction time task for rapid assessment of attention and impulsivity in rats.

RATIONALE: The 5-choice serial reaction time task (5-CSRTT) is a widely used operant task for measuring attention and motor impulsivity in rodents. Training animals in this task requires an extensive period of daily operant sessions. Recently, a self-paced, automated version of this task has been developed for mice, which substantially reduces training time. Whether a similar approach is effective for rats is currently unknown. OBJECTIVE: Here, we tested whether attention and impulsivity can be assessed in rats with a self-paced version of the 5-CSRTT. METHODS: Operant boxes were connected to home-cages with tunnels. Two groups of rats self-paced their training by means of an automated script. The first group of animals was allowed unlimited access (UA) to start trials in the task; for the second group, trial availability was restricted to the first 2.5 h of the dark cycle (TR). Task parameter manipulations, such as variable inter-trial intervals and stimulus durations as well as pharmacological challenges with scopolamine, were tested to validate the task. RESULTS: Self-paced training took less than 1 week. Animals in the UA group showed higher levels of omissions compared with the TR group. In both protocols, variable inter-trial intervals increased impulsivity, and variable stimulus durations decreased attentional performance. Scopolamine affected cognitive performance in the TR group only. CONCLUSIONS: Home-cage-based training of the 5-CSRTT in rats, especially the TR protocol, presents a valid and fast alternative for measuring attention and impulsivity.

Polyethylene glycol protects primary hepatocytes during supercooling preservation.

Cold storage (at 4°C) offers a compromise between the benefits and disadvantages of cooling. It allows storage of organs or cells for later use that would otherwise quickly succumb to warm ischemia, but comprises cold ischemia that, when not controlled properly, can result in severe damage as well by both similar and unique mechanisms. We hypothesized that polyethylene glycol (PEG) 35 kDa would ameliorate these injury pathways and improve cold primary hepatocyte preservation. We show that reduction of the storage temperature to below zero by means of supercooling, or subzero non-freezing, together with PEG supplementation increases the viable storage time of primary rat hepatocytes in University of Wisconsin (UW) solution from 1 day to 4 days. We find that the addition of 5% PEG 35 kDa to the storage medium prevents cold-induced lipid peroxidation and maintains hepatocyte viability and functionality during storage. These results suggest that PEG supplementation in combination with supercooling may enable a more optimized cell and organ preservation.

Subnormothermic machine perfusion for ex vivo preservation and recovery of the human liver for transplantation.

To reduce widespread shortages, attempts are made to use more marginal livers for transplantation. Many of these grafts are discarded for fear of inferior survival rates or biliary complications. Recent advances in organ preservation have shown that ex vivo subnormothermic machine perfusion has the potential to improve preservation and recover marginal livers pretransplantation. To determine the feasibility in human livers, we assessed the effect of 3 h of oxygenated subnormothermic machine perfusion (21°C) on seven livers discarded for transplantation. Biochemical and microscopic assessment revealed minimal injury sustained during perfusion. Improved oxygen uptake (1.30 [1.11-1.94] to 6.74 [4.15-8.16] mL O2 /min kg liver), lactate levels (4.04 [3.70-5.99] to 2.29 [1.20-3.43] mmol/L) and adenosine triphosphate content (45.0 [70.6-87.5] pmol/mg preperfusion to 167.5 [151.5-237.2] pmol/mg after perfusion) were observed. Liver function, reflected by urea, albumin and bile production, was seen during perfusion. Bile production increased and the composition of bile (bile salts/phospholipid ratio, pH and bicarbonate concentration) became more favorable. In conclusion, ex vivo subnormothermic machine perfusion effectively maintains liver function with minimal injury and sustains or improves various hepatobiliary parameters postischemia.

Intracranial compartment volumes in normal pressure hydrocephalus: volumetric assessment versus outcome.

BACKGROUND AND PURPOSE: Although enlargement of the cerebral ventricles plays a central role in the diagnosis of normal pressure hydrocephalus (NPH), there are no reports on the use of volumetric assessment to distinguish between patients who respond to ventriculoperitoneal shunt surgery and those who do not. The purpose of this study is to explore the association between preoperative intracranial compartment volumes and postoperative improvement. METHODS: Twenty-six patients (17 men; mean age, 75 years [range, 54-87 years]) with a clinical or radiologic suspicion of NPH were included in the study. Gait, cognition, and bladder function were evaluated by clinical rating. MR imaging of the brain was acquired at 0.5 T and 1.5 T. Total intracranial volume, ventricular volume, brain volume, and pericerebral CSF volume were determined by volumetric assessment. Four imaging variables were determined: ventricular volume ratio, brain volume ratio, pericerebral CSF volume ratio, and the ratio of ventricular volume to pericerebral CSF volume. All patients underwent ventriculoperitoneal shunt surgery. RESULTS: Clinical follow-up was assessed 1 year after shunt surgery. No difference in the mean ventricular volume ratio, the mean brain volume ratio, the mean pericerebral CSF volume ratio, and the mean ratio between ventricular and pericerebral CSF volume was found between subjects who improved on gait or cognition or bladder function and those who did not. CONCLUSION: Volumetric assessment has no predictive value in differentiating between NPH patients who respond to ventriculoperitoneal shunt surgery and those who do not.

The ghost joint: transient osteoporosis of the hip.

Seven adult patients identified as having idiopathic transient osteoporosis of the hip (TOH) are reported. TOH is an uncommon entity, most often seen in women during the third trimester of pregnancy and in middle-aged men. It is characterized by groin pain, limited hip range of motion, nonspecific laboratory findings, localized radiographic evidence of osteopenia, and spontaneous recovery usually within two to nine months. Diagnosis remains dependent on clinical recognition and x-ray confirmation. Radioisotope scanning aids in the diagnosis; both bone and synovial biopsies are often less productive. Treatment consists of joint protection with limited weight bearing, range of motion exercise, progressive ambulation, and analgesics. An awareness of TOH facilities appropriate diagnosis and treatment and curtails unnecessary diagnostic procedures.