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Intracellular studies reveal that, during slow wave sleep (SWS), the entire cortical network can swing rhythmically between extremely different microstates, ranging from wakefulness-like network activation to functional disconnection in the space of a few hundred milliseconds. This alternation of states also involves the thalamic neurons and is reflected in the EEG by a slow (<1 Hz) oscillation. These rhythmic changes, occurring in the thalamo-cortical circuits during SWS, may have relevant, phasic effects on the transmission and processing of sensory information. However, brain reactivity to sensory stimuli, during SWS, has traditionally been studied by means of sequential averaging, a procedure that necessarily masks any short-term fluctuation of responsiveness. The aim of this study was to provide a dynamic evaluation of brain reactivity to sensory stimuli in naturally sleeping humans. To this aim, single-trial somatosensory evoked potentials (SEPs) were grouped and averaged as a function of the phase of the ongoing sleep slow (<1 Hz) oscillation. This procedure revealed a dynamic profile of responsiveness, which was conditioned by the phase of the spontaneous sleep EEG. Overall, the amplitude of the evoked potential changed sistematically, increasing and approaching wakefulness levels along the negative slope of the EEG oscillation and decaying below SWS average levels along the positive drift. These marked and fast changes of stimulus-correlated electrical activity involved both short (N20) and long latency (P60 and P100) components of SEPs. In addition, the observed short-term response variability appeared to be centrally generated and specifically related to the evolution of the spontaneous oscillatory pattern. The present findings demonstrate that thalamo-cortical processing of sensory information is not stationary in the very short period (approximately 500 ms) during natural SWS.

Candida spp. are increasingly important nosocomial pathogens in critically ill children. Data on risk factors of acquisition in children with candidaemia are limited. To determine the incidence, prognosis and risk factors for acquisition of nosocomial candidaemia in children, a prospective case-control study was performed between July 1998 and January 2000. Candidaemia was defined as the presence of at least one positive blood culture containing Candida spp. For each case, two controls were selected and matched for time and site of hospital admission. Logistic regression was used to obtain estimates of risk after simultaneous control for other variables. Candidaemia was diagnosed in 24 children (1.09/1000 admissions). The species most frequently isolated were Candida albicans (50%) and Candida parapsilosis (17%). Mean age was 58.2+/-58 months between cases and 41.8+/-52.2 months in controls (P not significant). The strongest risk factors for acquisition found in the univariate analysis were underlying disease, previous antibiotic treatment, the number of antibiotics administered, presence of a long-duration catheter and total parenteral nutrition (P<0.05). Sex, the site of hospital admission, artificial ventilatory assistance, transitory venous catheters, arterial and peripherally venous accesses, bladder catheter and transfusions were not statistically significant. The risk factors identified by multiple logistic regression analysis were: permanent catheter (OR 31.5; 3.19-310) and total parenteral nutrition (OR 10.5; 2.76-40.0). Nine (37%) children with nosocomial candidaemia and seven (15%) controls died (P=0.05). These findings should facilitate development of rational approaches to preventing infection and assist clinicians in identifying those patients in whom this life-threatening complication is likely to occur., (Copyright 2002 The Hospital Infection Society.)

In order to assess the epidemiology, clinical features and outcome of tuberculous meningitis, a retrospective review of patients was conducted between January 1989 and December 1995. Forty cases (representing 10%, of all paediatric patients with tuberculosis) were included. Mean age was 46 months (range 1-165 months). Eighteen (45%) children were classified as stage I (non-specific febrile illness without neurological signs), 16 (40%) as stage II (neurological signs without marked changes in sensorium) and 6 (15%) as stage III (major neurological signs with sensorial changes and/or coma). Twenty-seven (67%) patients had received BCG vaccination and 14 (35%) displayed an induration zone higher than 10 mm after a 2-TU PPD test. Mycobacterium tuberculosis was recovered from 24 (61%) patients. Hydrocephalus was demonstrated by cranial computed tomography in 31 (78%) children. Overall, 18 (45%) children had a full recovery. Mild, moderate and severe neurological sequelae were shown by 7 (18%), 3 (8%) and 9 (22%) of the patients, respectively. Three fatal cases (7%) were observed. The presence of seizures (RR 15.6, 2.02-119.1) and absence of extrameningeal foci (RR 4.95, 1.10-22.1) were identified as risk factors by multivariate analysis. These findings emphasize the need quickly to diagnose tuberculosis in children in order to give appropriate and early treatment.

Sixty episodes of community-acquired Staphylococcus aureus bacteremia (SaCB) were prospectively analyzed between January 1990 and December 1994. The mean age of the patients was 78 (1-180) months. Thirteen (55%) of the children had underlying disease, the most frequent one being acute lymphoblastic leukemia. In 83% of the episodes a primary site of infection was observed. Skin and osteoarticular foci were the most frequently encountered. Only two patients had endocarditis. Arterial hypotension was detected in 17% of the patients. Ninety two percent of S. aureus isolated were penicillin-resistant. Only two strains were methicillin-resistant. In 24 (40%) episodes where metastatic foci were detected, osteoarticular infections were predominant. Mortality due to SaCB was 20%. Multivariate analysis by logistic regression revealed that arterial hypotension (RR = 24.8; 4.77-128.9), leucopenia (RR = 10.3; 1.25-86.2) and non hemato-oncologic diseases (RR = 10.0; 1.09-92.2) correlated with high mortality rate (p = < 0.001).

1. Any hemangioma that involves the upper or lower lid and leads to partial closure in infancy may interfere with or prevent development of normal binocular vision in a matter of days to weeks. 2. Hemangiomas least likely to interfere with vision are lower lid lesions occupying one third of the lid margin or less, not extending beyond the eyelid region, and resolving early. 3. Hemangiomas associated with deprivation amblyopia (with or without anisometropia) are lesions occupying more than one half of the lid margin, extending beyond the eyelid region, resolving late, and obstructing the visual axis. 4. Hemangiomas associated with isolated anisometropic amblyopia are local but bulky lesions that are usually but not always restricted to the upper lid, closing the eye partly and resolving late. 5. The treatment of choice for periorbital hemangiomas is corticosteroids, either systemic or intralesional.