Measurement of transepidermal water loss in Tanzanian cot-nursed neonates and its relation to postnatal weight loss

In healthy cot-nursed Tanzanian neonates ( n = 92, gestation 26–42 weeks) measurements of transepidermal water loss (TEWL) and weight change were performed during the first 24 h after birth at an average ambient humidity of 70% and an environmental temperature of 32°C. Urine production on day 1 (ml/kg per 24h) was documented for a subgroup of 13 preterm and 8 term infants. In a limited group of preterm infants ( n = 5) TEWL measurements, weight and 24 h urine volume measurements were repeated daily for 7 days. Maximum weight loss was determined in 7 preterm (gestational age 30–36 weeks) and 6 term infants. TEWL was estimated by measuring the evaporation rate at three sites of the body using the water vapour pressure gradient method. On day 1, TEWL was highest in the most preterm infants, whereas TEWL and urine production were higher in large for gestational age infants as compared to appropriate for gestational age (AGA) infants of the same gestational age (31–36 weeks). For the whole group, weight loss on day 1 was correlated with TEWL ( r = 0.49, p <0.05). At follow-up TEWL in preterm infants remained almost constant during the first 4 days and decreased after the fourth day, at which time weight gain commenced. Preterm AGA infants (gestational age 24–37 weeks) showed a mean postnatal weight loss of 4.4% of the birth weight, while in term infants this loss was only 2.6%. A reduced postnatal weight loss as compared to Caucasian infants may be explained by a lower water loss during the first days after birth, through both skin evaporation and urine excretion.     

'Inappropriate' attenders at accident and emergency departments II: health service responses

BACKGROUND: Health services have responded to perceived 'inappropriate' attenders at accident and emergency (A&E) departments in three ways. Firstly, they have responded by attempting to decrease the numbers of patients attending A&E departments. There is little evidence supporting the efficacy of such policies. Secondly, they have responded by referring inappropriate attenders to another site. Research indicates that whilst such referral may be feasible, resultant decreases in departmental workloads have yet to be demonstrated. Patient outcome has also to be determined. Thirdly, by performing triage of attenders they provide care appropriate to their needs. Sessional GPs working in A&E departments manage non-emergency A&E attenders safely and use fewer resources than do usual A&E staff. Long-term effects on health-seeking behaviour and patient perception of the distinction between primary care services have yet to be determined. CONCLUSIONS: Rather than vainly attempting to make the patients appropriate to the service, future initiatives should concentrate on making the A&E service more appropriate to the patient.      

Postdialysis fatigue: lack of effect of a biocompatible membrane

Tumor necrosis factor-alpha (TNF-alpha) has been shown to have somnogenic properties. Plasma levels of this cytokine have been found to increase significantly during dialysis with a bioincompatible (cuprophane) membrane in patients with postdialysis fatigue (PDF). We conducted a crossover study with random assignment to ascertain whether a biocompatible membrane might attenuate the increase of TNF-alpha and severity of PDF. Sixteen patients on maintenance hemodialysis underwent dialysis with either cuprophane (n = 8) or polymethylmethacrylate (PMMA; n = 8) membranes for 1 week and then switched to the opposite membrane during the second week. Predialysis and postdialysis measurements of plasma TNF-alpha levels were performed during the first and last dialysis treatments of each week. A fatigue score was determined from the sum of duration of fatigue and sleep within 6 hours of the completion of dialysis. TNF-alpha levels increased by an average of 18.3% during dialysis with cuprophane membranes but only 2.4% with PMMA membranes (P = 0.04). Despite this, fatigue scores remained unaltered (approximately 4 of 6). Hence, the biocompatible membrane, PMMA, failed to alleviate PDF. This suggests that dialytic stimulation of TNF-alpha plays no substantial role in the pathogenesis of PDF.     

Cortical variability and asymmetry in normal aging and Alzheimer's disease

The onset of Alzheimer's disease (AD) is accompanied by a complex and distributed pattern of neuroanatomic change, difficult to distinguish clinically from dynamic alterations in normal aging. Extreme variations in the sulcal patterns of the human cortex have made it difficult to identify diffuse and focal variations in cortical structure in neurodegenerative disease. We report the first comprehensive 3D statistical analysis of deep sulcal structure in vivo, in both normal aging and dementia. High-resolution 3D T1-weighted fast SPGR (spoiled GRASS) MRI volumes were acquired from 10 patients diagnosed with AD (NINCDS-ARDRA criteria; age: 71.9 +/- 10.7 years) and 10 normal subjects matched for age (72.9 +/- 5.6 years), gender, educational level and handedness. Scans were digitally transformed into Talairach stereotaxic space. To determine specific patterns of cortical variation in dementia patients, 3D average and probabilistic maps of primary deep sulci were developed for both normal and AD groups. Major sulci (including supracallosal, cingulate, marginal, parieto-occipital, anterior and posterior calcarine sulci, and Sylvian fissures) were modeled as complex systems of 3D surfaces using a multi-resolution parametric mesh approach. Variations and asymmetries in their extents, curvature, area and surface complexity were evaluated. Three- dimensional maps of anatomic variability, structural asymmetry and local atrophy indicated severe regionally selective fiber loss in AD. A midsagittal area loss of 24.5% at the corpus callosum's posterior midbody (P < 0.025) matched increases in structural variability in corresponding temporo-parietal projection areas. Confidence limits on 3D cortical variation, visualized in 3D, exhibited severe increases in AD from 2 to 4 mm at the callosum to a peak SD of 19.6 mm at the posterior left Sylvian fissure. Normal Sylvian fissure asymmetries (right higher than left; P < 0.0005), mapped for the first time in three dimensions, were accentuated in AD (P < 0.0002), and were greater in AD than in controls (P < 0.05). Severe AD-related increases in 3D variability and asymmetry may reflect disease-related disruption of the commissural system connecting bilateral temporal and parietal cortical zones, regions known to be at risk of early metabolic dysfunction, perfusion deficits and selective neuronal loss in AD.