Radial organization of developing preterm human cerebral cortex revealed by non-invasive water diffusion anisotropy MRI

Cerebral cortical development involves a complex cascade of events which are difficult to visualize in intact, living subjects. In this study, we apply diffusion tensor imaging (DTI) to the evaluation of cortical development in human infants ranging from 26 to 41 weeks gestational age (GA). Apparent diffusion of water in cortex is maximally anisotropic at 26 weeks GA and anisotropy values approach zero by 36 weeks GA. During this period, the major eigenvector of the diffusion tensor in cerebral cortex is oriented radially across the cortical plate, in accord with a predominately radial deployment of its neuronal constituents. Values for the rotationally averaged water diffusion coefficient increase between 26 and 32 weeks GA, then decrease thereafter. These changes in DTI parameters are specific to cerebral cortex and reflect changes in underlying cortical architecture and formation of neuronal connections. Because of its correlation with tissue microstructure and non-invasive nature, DTI offers unique insight into cortical development in preterm human newborns and, potentially, detection of derangements of its basic cytoarchiteture.     

The thoracic suspension orthosis--a seating option for patients with pressure ulcers

BACKGROUND/OBJECTIVE: For patients with pressure ulcers, wound healing and prevention are important steps in reducing disability. Ulcers that fail to heal adequately may interfere with normal sitting. By relieving pressure, the thoracic suspension orthosis (TSO) may allow some patients with recurrent pressure ulcers to return to sitting and sit for longer periods. METHODS: In this retrospective case series, 6 patients with chronic pressure ulcers were managed with TSO. Each patient had at least one of the following: (1) severe, non-healing pressure ulcers unresponsive to standard therapy, (2) recurrent ulcers requiring multiple surgeries, (3) chronic pain associated with sitting, or (4) bilateral lower extremity amputation resulting in instability or ischial pain in the seated position. RESULTS: Each participant had a favorable functional outcome. Patients were able to resume modified sitting. Others were able to sit for longer periods. Some have used the TSO for long-term management. CONCLUSIONS: A TSO is an additional seating option for patients with chronic pressure ulcer, chronic pain associated with sitting, or bilateral lower extremity amputation. It is recommended after less restrictive, conservative measures have failed. In some patients, it has been used in lieu of extreme surgical measures.     

Traumatic aneurysm of the internal carotid artery in an infant: a surprise diagnosis

Isolated aneurysm of the extracranial section of the internal carotid artery has been reported in children but never, to our knowledge, in an infant. It can represent a major anaesthetic challenge with compromise of both airway and cerebral perfusion and the associated risks of rupture. We report on an 11-month-old infant, who had undergone an examination under anaesthesia of her nose and throat for epistaxis and gastrointestinal endoscopy due to apparent gastrointestinal bleeding shortly before presenting to us with signs of rapidly progressive upper airway obstruction. Emergency examination under anaesthesia revealed a large pulsatile mass in the posterior nasopharynx which, on subsequent radiological investigation, was revealed to be a large pseudoaneurysm of the right internal carotid artery, obstructing distal flow. An apparently minor episode of trauma had occurred around the time of the first nosebleed; she had allegedly fallen onto her face with a spoon in her mouth.     

Assessment of the human epidermis model SkinEthic RHE for in vitro skin corrosion testing of chemicals according to new OECD TG 431.

Based on two successfully completed ECVAM validation studies for in vitro skin corrosion testing of chemicals, the National Co-ordinators of OECD Test Guideline Programme endorsed in 2002 two new test guidelines: TG 430 'Transcutaneous Electrical Resistance assay' and TG 431 'Human Skin Model Test'. To allow all suitable in vitro human reconstructed (dermal or epidermal) models to be used for skin corrosion testing, the OECD TG 431 defines general and functional conditions that the model must meet before it will be routinely used for skin corrosion testing. In addition, the guideline requires correct prediction of 12 reference chemicals and assessment of intra- and inter-laboratory variability. To show that the OECD TG 431 concept works, in 2003 ZEBET tested several chemicals from the ECVAM validation trials on the SkinEthic reconstituted human epidermal (RHE) model. Based on knowledge that reconstructed human skin models perform similarly in toxicological studies, it was decided to adopt the validated EpiDerm skin corrosion test protocol and prediction model to the SkinEthic model. After minor technical changes, classifications were obtained in concordance with those reported for the validated human skin models EPISKIN and EpiDerm. To allow adequate determination of inter-laboratory reproducibility, a blind trial was conducted in three laboratories -- ZEBET (D), Safepharm (UK) and BASF (D), in which the 12 endorsed reference chemicals were tested. Results obtained with the SkinEthic epidermal model were reproducible, both within and between laboratories, and over time. Concordance between the in vitro predictions of skin corrosivity potential obtained with the SkinEthic model and the predictions obtained with the accepted tests of OECD TG 430 and TG 431 was very good. The new test was able to distinguish between corrosive and non-corrosive reference chemicals with an accuracy of 93%.     

Identification of optimal combinations for empirical dual antimicrobial therapy of Pseudomonas aeruginosa infection: potential role of a Combination Antibiogram.

To better determine the optimal combinations for empirical dual antimicrobial therapy of Pseudomonas aeruginosa infection, we evaluated the utility of a novel combination antibiogram. Although the combination antibiogram allowed modest fine-tuning of choices for dual antibiotic therapy, selections based on the 2 antibiograms did not differ substantively. Drug combinations with the broadest coverage were consistently composed of an aminoglycoside and a beta-lactam.     

Comparison of unit-specific and hospital-wide antibiograms: potential implications for selection of empirical antimicrobial therapy.

OBJECTIVE: To identify differences between unit-specific and hospital-wide antibiograms and to determine the potential impact of these differences on selection of empirical antimicrobial therapy. SETTING: A 625-bed tertiary care medical center. METHODS: Antimicrobial susceptibility results were collected for all inpatient clinical bacterial isolates recovered over a 3-year period; isolates were categorized by the hospital location of the patient at the time of sampling and by the anatomic site from which the isolate was recovered. Antibiograms from each unit were compiled for the most commonly isolated organisms and were compared to the hospital-wide antibiogram. RESULTS: A total of 9,970 bacterial isolates were evaluated in this study, including 2,646 enterococcal isolates, 2,806 S. aureus isolates, 2,795 E. coli isolates, and 1,723 Pseudomonas aeruginosa isolates. The percentages of bacterial isolates resistant to antimicrobials were significantly higher in the medical ICU and surgical ICU than the hospital-wide antibiogram would have predicted, whereas the percentages of isolates susceptible to antimicrobials were significantly higher in the non-ICU units, compared with the hospital overall. However, on general medicine units, the prevalence of susceptibility to levofloxacin was significantly lower than that for the hospital overall. CONCLUSIONS: Unit-specific antibiograms are important for making informed decisions about empirical antimicrobial therapy, because the hospital-wide antibiogram may mask important differences in susceptibility rates across different units. These differences may have important implications for selecting the optimal empirical antimicrobial therapy.     

Genetic abnormalities responsible for dilated cardiomyopathy

Dilated cardiomyopathy (DCM), a disorder in which left ventricular dilation and dysfunction leads to congestive heart failure, is inherited in over 30% of cases. The underlying genetic mechanisms are slowly being unraveled, with multiple genes recently identified as causing DCM in some patients. The genes identified to date appear to encode proteins that either support the cytoskeleton or interact with the cytoskeleton. When mutated, these proteins destabilize the cardiomyocyte membrane or cytoskeleton via mechanical instability or force transduction causing poor cardiac systolic function and compensatory dilation. Once the entire group of genes causing DCM (genetic heterogeneity) are identified, improvements in diagnosis and treatment are expected.     

Pulmonary Hemangiomas of Infancy and Childhood: Report of Two Cases and Review of the Literature

Pulmonary hemangiomas are exceptionally rare in childhood and more so in infancy. They may involve the airways or the parenchyma, and may be localized or multifocal. We present two cases of pulmonary capillary hemangiomas. The first case is a localized form of capillary hemangioma that was resected from an 8-week-old infant with signs of respiratory distress. A computed tomography scan showed a cystic mass initially thought to be an intrapulmonary bronchogenic cyst. A segmental resection was performed and examination revealed a localized capillary hemangioma without cystic or cavernous features. The second case is an example of a multifocal capillary hemangioma from a 9-year-old child who presented clinically with clubbing of fingers and toes and radiologically had multiple discrete nodules localized to the right lung. The clinical and pathological features of the cases are discussed together with a review of the literature. The distinction from other vascular neoplasms of childhood is briefly described. Although rare, pulmonary hemangiomas should be entertained in the diagnosis of both solid and cystic intrapulmonary lesions of childhood and infancy. Received September 6, 2001; accepted November 13, 2001.