Inhibition impairments in Alzheimer's disease, mild cognitive impairment and healthy aging: Effect of congruency proportion in a Stroop task

The goal of this study was to assess inhibition and goal maintenance in persons with Alzheimer's disease, mild cognitive impairment, healthy older adults and younger adults. This was done by using a task that compared the Stroop effect in pure blocks, that comprised only incongruent trials, with the Stroop effect in mixed blocks, in which 25% of trials were incongruent and 75% were congruent (Kane & Engle, 2003). Those conditions were administered to 20 healthy younger and 20 older control participants, and to 20 participants meeting criteria for MCI and 11 for AD. Results show reduced resistance to interference as a consequence of healthy aging and only partially impaired goal-maintenance capacities. Interference and goal maintenance are also impaired when comparing MCI and AD to healthy older adults, with AD suffering from a more severe impairment than MCI. In addition, there is a partial preservation of goal-maintenance capacities in MCI because reducing response speed allows them to maintain a level of error rate similar to that of healthy older adults. In contrast, AD persons suffer from a complete breakdown of goal-maintenance capacities, as is suggested by deficits on both response time and error rates.     

Manipulation of the adhesive behaviour of skeletal muscle cells on soft and stiff polyelectrolyte multilayers

Polyelectrolyte multilayer coatings have emerged as substrates to control a variety of cell behaviour, including adhesion, proliferation and differentiation. In particular, it is possible to modulate film stiffness by physical or chemical cross-linking. In this study, we evaluate the adhesive behaviour of skeletal muscle cells (C2C12 myoblasts) during the initial steps of spreading on layer-by-layer films of controlled stiffness made of poly(l-lysine) and hyaluronan as model biomaterial surfaces for muscle tissue engineering. We show that integrin clustering, integrin actin cytoskeleton connection and focal adhesion formation for cell spreading can be decoupled by controlling film stiffness. This made it possible to switch the cells morphologically between round and spreading shapes depending on the stiffness of the microenvironment. Although hyaluronan is one of the main components of cross-linked multilayer films, the HA receptor CD44 did not appear to mediate early adhesion as suggested by the use of blocking antibodies. In contrast, integrins were found to play a pivotal role in early adhesion: their activation significantly enhanced C2C12 myoblast spreading on soft films, where they were otherwise round. Integrin clustering was also induced by the softer films and enhanced on the stiffest films. Conversely, the use of soluble inhibitors or blocking antibodies directed against integrins induced a round phenotype on stiff films, where cells were well spread out in control conditions. We show that specific integrins were involved in the adhesion process as blocking β₃, but not β₁, integrins inhibited cell adhesion. These soft, stiff films can thus be used to tune the adhesion of C2C12 myoblasts, an early key event in myogenesis, via integrin clustering and subsequent signalling. They may be further used to decorticate the signalling pathways associated with β₃ integrins.     

Late cholangitis after successful surgical repair of biliary atresia

Bacterial cholangitis is a frequent complication of successful surgical repair of biliary atresia, occurring in 93% of patients before the age of 1 year, but thought to be rare after 2 years of age. Among 76 children free of jaundice more than 5 years after operation, four presented with late cholangitis (7 to 13.5 years old), consisting of fever, jaundice, and abdominal pain with biochemical features of an inflammatory process and cholestasis. Liver biopsy specimens consistently demonstrated histological features of cholangitis, growth of microorganism, or both. Cholangitis subsided spontaneously in one patient or in response to intravenous administration of antibiotics. Cholangiography consistently demonstrated biliary abnormalities but no definite obstruction to the bilioenteric anastomosis. All the children had good hepatic function 3 weeks to 4 years after the episode of cholangitis. These results suggest that cholangitis may occur several years after surgery but does not seem to alter prognosis.     

Radiological treatment of common bile duct lithiasis in infancy

the authors report a series of 10 infants aged from 20 days to 11 months, presenting with CBD lithiasis, explored and cured by radiological procedure. US showed BD dilatation in 9 cases, sludge in the GB in 5 and in the CBD in 2. Histological findings of cholangitis were present in 4 infants. PTC was performed by GB puncture in 6 and BD puncture in 4. There was evidence of a filling defect in CBD but no anatomical anomaly. Blackish concretions were removed through a side-holes catheter or pushed in the duodenum by washing with saline. An external drainage was left a few days to allow control cholangiogram. Three infants underwent subsequent surgery but no residual lithiasis was found. No recurrence has occurred with a follow-up ranging from 10 months to 7 years. Mechanisms of this entity are discussed. Presented at the ESPR meeting in Montreux 1988. Selected for publication by an International Group of the ESPR     

Variability of clinical presentation of hepatic artery thrombosis in pediatric liver transplantation: Role of imaging modalities

Among a series of 90 pediatric liver transplantations, 9 cases of hepatic artery thrombosis (HAT) in 8 patients are reported. All cases were diagnosed in the first two weeks and confirmed angiographically and surgically. Clinical presentation was often unreliable with only 2 cases showing the typical pattern of massive hepatic necrosis. Five cases presented with biliary complications and in 2 cases, HAT was discovered fortuitously on duplex sonography. The role of imaging modalities is emphasized. Duplex sonography is the best non-invasive screening method and we recommend a routine daily examination in the first 2 weeks. CT is the most useful method to assess the extension of liver infarction. PTC remains necessary to evaluate biliary complications and to plant the best therapeutic approach in this devastating event. Two patients died, 2 had to be retransplanted (one patient twice) and are doing well, 2 are on a waiting list for re-transplantation and one underwent an emergency surgical arterial desobstruction and is completely asymptomatic.Presented at the ESPR meeting in Dublin 1989. Selected for publication by an International Group of the ESPR     

Use of cadaveric fascia lata for closure of bladder exstrophy with diplomyelia

We describe a technique for the repair of bladder exstrophy using cadaveric fascia lata. The graft is folded in a four-layer configuration, passed through the obturator foramina, and then wrapped and anchored in front of the pubis. The resultant ring-shaped graft is useful when complex deformities preclude proper apposition of the pelvis anteriorly.     

Exposure of mice to a predator odor increases acoustic startle but does not disrupt the rewarding properties of VTA intracranial self-stimulation

The present investigation assessed the propensity of an acute psychogenic stressor exposure to induce behavioral change in paradigms assessing fear/anxiety (acoustic startle) and motivation/anhedonia (intracranial self-stimulation) in CD-1 mice. In the acoustic startle paradigm, a 10-min exposure of 2-4 month old mice (young adult mice) to fox odor (2,5-dihydro-2,4,5-trimethylthiazoline; TMT) was associated with decreased acoustic startle relative to mice exposed to the control odor, butyric acid (BA), immediately and relative to both saline and BA exposure 24 h following odor exposure in the home cage. In contrast, a 2-min exposure of young adult mice to TMT was associated with an increase in startle relative to saline and BA during the immediate post-odor test session only. In young adult mice a 2-min and a 10-min exposure to BA resulted in a startle profile of mice reminiscent of saline-treated mice. In comparison to young adult mice, a 2-min exposure of mature adult mice (5-7 months old) to TMT enhanced startle for up to 48 h relative to both saline and BA, while a 10-min exposure of mature adult mice to TMT enhanced startle for 168 h post-odor exposure relative to saline-exposed mice only. However, the greatest increase in startle amplitude (i.e. 48 h) was acquired following the 2-min exposure of mature mice to TMT. Among mature adult mice, a 10-min exposure to BA in the home cage eventuated in enhanced startle relative to saline-exposed animals 168 h following odor exposure. In comparison, exposure of mice to 10 min of TMT depressed responding for VTA brain stimulation at the initial 80 Hz frequency, but was ineffective in elevating reward thresholds relative to mice merely exposed to saline. Mice assessed in the ICSS paradigm were approximately 2-4 months old at the time of surgery and 5-7 months old at the completion of testing. These data suggest that acute odor exposure may induce a fear gradient dependent upon the perceived stressor severity and that the resultant anxiety-like effects are dependent on the duration of odor exposure, age of the animals and the temporal interval between odor presentation and behavioral testing. Moreover, the anxiogenic properties of psychogenic stressors can be separated from their anhedonic effects. The implications of these data for clinical psychopathology are discussed.     

The hemodynamic effects of pediatric caudal anesthesia assessed by esophageal Doppler

Pediatric caudal anesthesia is an effective method with an infrequent complication rate. However, little is known about its cardiovascular consequences. Transesophageal Doppler, a noninvasive method, provides the opportunity for a reappraisal of the hemodynamic effects of this technique. After parental informed consent, we studied 10 children aged 2 mo to 5 yr who were scheduled for lower abdominal surgery. General anesthesia was induced using sevoflurane and was followed by the insertion of a transesophageal Doppler probe. Caudal anesthesia was performed using 1 mL/kg of 0.25% bupivacaine with 1/200,000 epinephrine. Hemodynamic variables were collected before and after caudal anesthesia. No complications arose during insertion of the probe. The mean time between the two sets of measurements was 15 min. Heart rate, systolic, diastolic, and mean arterial blood pressures were not modified by caudal anesthesia. Descending aortic blood flow increased significantly from 1.14 to 1.92 L/min. (P = 0.0002). Aortic ejection volume increased from 8.5 to 14.5 mL (P = 0.0002). Aortic vascular resistances decreased from 6279 to 3901 dynes. s(-1) x m(-5) (P = 0.005). Caudal anesthesia did not affect heart rate and mean arterial blood pressure but induced a significant increase in descending aortic blood flow. IMPLICATIONS: Although pediatric caudal anesthesia does not alter heart rate nor arterial blood pressure, significant changes occur in regional blood flow distribution. Descending aortic blood flow increases significantly after caudal anesthesia, whereas lower body vascular resistances decrease.