Medium term outcome for infant repair in tetralogy of Fallot: indicators for timing of surgery

Objective: To assess the impact of early corrective surgery on the short and medium term outcome in tetralogy of Fallot (TOF). Materials and methods: All patients under 12 months of age undergoing correction of isolated TOF between February 1997 and July 2003 were reviewed retrospectively. Outcome data for mortality, post-operative care management, major morbidity and clinical follow-up were analysed. Results: Fifty-two operations were performed. The mean age at surgery was 5 months (range 1–12) of whom 16 (30.8%) were less than 3 months old, including 2 neonates, 22 (42.3%) were 3–6 months old and 14 (26.9%) were 7–12 months old. There was 1 (1.9%) early death caused by a cerebro-vascular accident and 1 (1.9%) late death secondary to acute infective endocarditis. There were no differences in post-operative morbidities attributable to age. Patients under 3 months old required greater duration of post-operative ventilation, ITU stay and in-hospital stay. At a mean follow-up of 4.0 years (range 1.5–8.0), 33 (63.5%) patients had well-tolerated pulmonary regurgitation (PR) and 3 (5.8%) patients required re-operation for right ventricular outflow tract obstruction (RVOTO). All patients had right bundle-branch-block but with QRS < 150 ms. Conclusion: Early definitive repair of TOF can be performed safely on patients under 6 months old. Age at surgery does not appear to affect the medium term haemodynamic outcome. However, early surgery does escalate the need for ICU care. This data suggests repair in asymptomatic patients be delayed until 3–6 months of age.     

Reelin-immunoreactivity in the hippocampal formation of 9-month-old wildtype mouse: effects of APP/PS1 genotype and ovariectomy

Reelin, an extracellular matrix protein has an important role in the migration, correct positioning and maturation of neurons during development. Though it is generally down-regulated in the postnatal period, expression of this large glycoprotein continues in the adult brain in some cell populations. In the present study, we examined the distribution of reelin-immunoreactivity (-ir) in the hippocampal formation of 9-month-old wildtype mice (WT). Then, reelin-ir in normal mice was compared to that of transgenic mice (APP/PS1) carrying mutated human APP and PS1 genes, which are linked to the familial form of Alzheimer's disease (AD). The APP/PS1 mice were additionally burdened with a second risk factor for AD, namely depletion of circulating gonadal hormones by ovariectomy (APP/PS1 + OVX). The analyses revealed that in adult WT reelin-ir is expressed by Cajal-Retzius cells and a subgroup of interneurons throughout the hippocampal formation. In addition, layer II projection neurons in the lateral entorhinal subfields are reelin-ir. Interestingly, ovariectomy decreases the number of reelin-ir cells in the hilus in WT mice, whereas AD-related genotype alone induces only a non-significant reduction. Unexpectedly, additional stress, e.g., depletion of gonadal hormones, does not aggravate the slight reduction in the reelin cell number in the APP/PS1 mice. We propose that the changes in normal reelin-ir are linked to disturbances in repair mechanisms in which APP/PS1 and gonadal hormones are involved and which are perturbed in neurodegenerative conditions, namely AD.     

The effect of aging on the subcellular distribution of estrogen receptor-alpha in the cholinergic neurons of transgenic and wild-type mice

The degeneration of the basal forebrain cholinergic system plays an important role in cognitive deterioration in aging and Alzheimer's disease. Brain cholinergic neurons and their projections are affected by changes in the circulating levels of estrogens, which exert their effects mainly through the estrogen receptors. In this study, we investigated the effect of aging, estrogen status and transgenic genotype on the number of cholinergic neurons and the estrogen receptor alpha (ERalpha) content in the medial septum-vertical limb of the diagonal band of Broca. We used 6- and 12-month-old female double transgenic mice carrying mutated human amyloid precursor protein (APPswe) and presenilin-1 (PS1-A246E), and their nontransgenic littermate controls, which had been sham-operated or ovariectomized at the age of 3 months. Brain sections were double immunostained for choline acetyltransferase (ChAT) and ERalpha and used for stereological cell counting. We found that the number of ChAT-immunoreactive (ir) neurons containing nuclear ERalpha-ir was significantly lower in 12- than in 6-month-old mice. However, the age of the mice, the transgenic genotype or ovariectomy had no effect on the total number of ChAT-ir neurons, or on the number and percentage of all ChAT-ir neurons that contained ERalpha. These results indicate that aging is associated with translocation of ERalphas from the nucleus to the cytoplasm. We propose that this phenomenon is linked to those age-related processes known to be involved in inhibiting ERalpha binding to nuclei.     

Preoperative stratification of pancreas-related morbidity after the Whipple procedure

Morbidity and mortality after pancreatoduodenectomy are greatly related to dehiscence of pancreatojejunostomy. We have analyzed risk factors of significance for and prediction of pancreas-related morbidity. We have retrospectively analyzed 122 patients. The relationship of fibrosis of pancreas, exocrine function, and diameter of pancreatic duct to pancreas-related morbidity was evaluated. Computer-aided morphometric analysis and the pancreatic elastase-1 stool test were used. Univariate analysis showed that the diameter of the main pancreatic duct and postoperative amylasemia were different in patients with and without pancreatic complications (P = 0.001 and P = 0.002, respectively). Pancreatic exocrine function was reduced and fibrosis was higher in patients without pancreatic complications (P = 0.003 and P = 0.026, respectively). Logistic regression analysis revealed exocrine pancreatic function as an independent risk factor. Pancreas-related morbidity is influenced by pancreatic fibrosis, diameter of pancreatic duct, and exocrine function. Preoperative evaluation of exocrine function allows detection of patients with minimal risk for pancreas-related morbidity.     

Global feature-based attention for motion and color

We used a divided attention psychophysical task to test the hypothesis that visual attention to a stimulus feature(1) facilitates the processing of other stimuli sharing the same feature. Performance on a dual-task was significantly better when human observers divided attention across two spatially separate stimuli sharing a common feature (same direction of motion or same color) compared to opposing features. This attentional effect was dependent upon the presence of competing stimuli. These results are consistent with a spatially global feature-based mechanism of attention that increases the response of cortical neurons tuned to an attended feature throughout the visual field.     

Imaging periodic currents using alternating balanced steady-state free precession.

Existing functional brain MR imaging methods detect neuronal activity only indirectly via a surrogate signal such as deoxyhemoglobin concentration in the vascular bed of cerebral parenchyma. It has been recently proposed that neuronal currents may be measurable directly using MRI (ncMRI). However, limited success has been reported in neuronal current detection studies that used standard gradient or spin echo pulse sequences. The balanced steady-state free precession (bSSFP) pulse sequence is unique in that it can afford the highest known SNR efficiency and is exquisitely sensitive to perturbations in free precession phase. It is reported herein that when a spin phase-perturbing periodic current is locked to an RF pulse train, phase perturbations are accumulated across multiple RF excitations and the spin magnetization reaches an alternating balanced steady state (ABSS) that effectively amplifies the phase perturbations due to the current. The alternation of the ABSS signal therefore is highly sensitive to weak periodic currents. Current phantom experiments employing ABSS imaging resulted in detection of magnetic field variations as small as 0.15nT in scans lasting for 36 sec, which is more sensitive than using gradient-recalled echo imaging.     

Primary malignant peripheral nerve sheath tumour of the heart

A malignant peripheral nerve sheath tumour (MPNST) is a rare variety of soft-tissue sarcoma of ectomesenchymal origin. The World Health Organisation created the term MPNST to replace previous terminology such as malignant schwannoma, malignant neurilemmoma, neurogenic sarcoma, and myxofibrosarcoma for tumours of neurogenic origin with similar biological behavior.[1–3] The vast majority of these tumours develop in extremities. They also tend to be located in unusual sites of the body, such as the pelvic retroperitoneum, infratemporal fossa, intrapericardium, and mediastinum.[1,3,4] This case study presents a patient with an extremely rare primary cardiac MPNST..     

Incidence and precipitating factors of delirium after coronary artery bypass grafting

OBJECTIVE: To analyze large contemporary patient population, undergoing on-pump coronary artery bypass grafting at our institution, and identify the prevalence and precipitating factors of delirium development. DESIGN: Baseline demographics, operative data and postoperative outcomes of 1367 consecutive patients were recorded prospectively and analysed using multivariate logistic regression analysis, to determine independent predictors of postoperative delirium development. RESULTS: Delirium was detected in 42 (3.07%) patients. Eight factors: age more than 65 years, peripheral vascular disease, Euroscore>/=5, preoperative IABP support, postoperative blood product usage and postoperative low cardiac output syndrome were independently predicting delirium development after coronary artery bypass procedures. Postoperative delirium was associated with significantly higher mortality rate (16.6% vs. 3.9%, p=0.013), prolonged mechanical ventilation time (9.2+/-3.1 vs. 5.05+/-7.6, p=0.04) and increased length of intensive care unit stay (6.8+/-4.9 vs. 2.0+/-2.7 days, p=0.001). CONCLUSIONS: Delirium is a dangerous complication, prolonging intensive care unit stay and postoperative mortality. Factors associated with delirium development are advanced age, peripheral vascular disease, diminished cardiac function and blood product usage.     

On multiple alternating steady states induced by periodic spin phase perturbation waveforms

Direct measurement of neural currents by means of MRI can potentially open a high temporal resolution (10–100 ms) window applicable for monitoring dynamics of neuronal activity without loss of the high spatial resolution afforded by MRI. Previously, we have shown that the alternating balanced steady state imaging affords high sensitivity to weak periodic currents owing to its amplification of periodic spin phase perturbations. This technique, however, requires precise synchronization of such perturbations to the radiofrequency pulses. Herein, we extend alternating balanced steady state imaging to multiple balanced alternating steady states for estimation of neural current waveforms. Simulations and phantom experiments show that the off‐resonance profile of the multiple alternating steady state signal carries information about the frequency content of driving waveforms. In addition, the method is less sensitive than alternating balanced steady state to precise waveform timing relative to radiofrequency pulses. Thus, multiple alternating steady state technique is potentially applicable to MR imaging of the waveforms of periodic neuronal activity. Magn Reson Med, 2012. © 2011 Wiley Periodicals, Inc.