Full 1H NMR assignment of a 24-nucleotide RNA hairpin: application of the 1H 3D-NOE/2QC experiment

A mixed general linear model analysis of the development of sleep-wake states was conducted on 37 high-risk preterm infants and replicated with a second cohort of 34 infants. Most dependent variables showed significant development over the preterm period: active sleep decreased, and active waking, quiet waking, and the organization of active sleep and quiet sleep increased over the preterm period in both cohorts. The amount of quiet sleep also increased over age, but this change was significant only for Cohort 1. Seven infant characteristics used as covariates had only minor effects. There were no significant differences in the developmental trajectories (slopes) of the two cohorts. The amounts of four variables differed between cohorts: Cohort 2 infants had less sleep-wake transition, more active sleep, less active sleep without REM, and more regular quiet sleep. These findings suggest that developmental patterns of sleep wake states are stable enough in the preterm period that deviant individual patterns might be used to identify infants with neurological problems.     

Extreme power dispersion profiles for Nakagami-m fading channels with maximal-ratio diversity

Using nonlinear optimization theory, we derive extreme power dispersion profiles (PDPs) for wireless channels with maximal-ratio diversity. Specifically, we obtain the best and worst PDPs that respectively minimize and maximize the symbol error probability in Nakagami-m fading channels having not necessarily identical means.     

Left atrial appendage flow velocity and spontaneous echo contrast in patients with rheumatic mitral stenosis: a multiplane transesophageal echocardiographic study

BACKGROUND: Left atrial spontaneous echo contrast (LASEC), a putative marker of thrombo-embolic risk, is commonly located in the left atrial appendage (LAA). The aims of this work were to evaluate, using multiplane transesophageal echography, the echocardiographic determinants, specifically LAA outflow Doppler velocity, in the presence of SEC in patients with rheumatic MS. METHODS: Transthoracic and transesophageal echocardiographic tests were performed on 61 patients. The patients were divided into 3 groups based on the presence and type of valvular disease. Patients in group I (n = 28) presented with rheumatic mitral stenosis (MS). Patients in group II (n = 18) presented with valvular heart disease other than MS, and patients in group III (n = 15) had no history of valvular heart disease. The left atrium and appendage were examined for the presence of spontaneous echocontrast and thrombus, using multiplane echo scopy with transducer rotation. Minimal and maximal appendage areas were measured, on a computer-assisted bablet, by tracing a line from the top of the limbus of the left upper pulmonary vein to the appendage endocardial border. The LAA ejection fraction was calculated according to the formula: (maximal area-minimal area)/maximal area. Mitral valvular condition was evaluated with transthoracic and transesophageal echocardiography. Left atrial appendage blood flow velocity profiles were obtained with pulsed-wave Doppler at the orifice of the LAA. RESULTS: LASEC was present in 18 of 28 patients with mitral stenosis (64.3%). Patients with LASEC showed a greater incidence of atrial fibrillation (14/18 vs 12/43, p < 0.005), larger LAD (53.67 +/- 8.74 vs 40.54 +/- 14.85, p < 0.005), smaller LAAEF (38.7 +/- 1.53 vs 69.5 +/- 24.0, p < 0.05), smaller LAAMEV (20.28 +/- 10.07 vs 2.95 +/- 25.11, p < 0.005) and smaller LAAMFV (24.6 +/- 12.23 vs 36.00 +/- 11.01, p < 0.01), when compared with patients without LASEC. For group I, LAAEF, LAAMEV and LAAFV were smaller in patients with SEC than in patients without SEC (p < 0.005, p < 0.05, p < 0.01). However LAD values were similar for patients with and without SEC (53.67 +/- 8.75 vs 54.20 +/- 18.81, p = NS). Both LAAMEV and LAAMFV were related to SEC in patients with atrial fibrillation. However, LAD did not show the same trend. CONCLUSIONS: LASEC is more commonly observed in patients with rheumatic mitral stenosis or atrial fibrillation. Both LAAMEV and LAAMFV are associated with SEC in these patients.     

A patient with Graves' disease, thrombocytopenia and chronic hepatitis B

A 22-year-old Chinese man, a HBsAg carrier, presented with relapse of thyrotoxic Graves' disease complicated by thrombocytopenia and hepatitis. Platelet count and liver enzymes gradually improved following successful treatment of the thyrotoxicosis with radioactive iodine. Possible pathogenetic links and therapeutic implications are discussed.     

Fatal Campylobacter jejuni infection in a patient splenectomised for thalassaemia

A 35 year old man with a fatal Campylobacter jejuni infection is described. He had HbE/beta zero thalassaemia and had undergone splenectomy nine months previously for hypersplenism; he also had chronic hepatitis C infection. He presented with high grade fever but no gastrointestinal symptoms and rapidly progressed to septicaemic shock and hepatic encephalopathy despite treatment with penicillin, gentamicin, and, later, chloramphenicol and ceftazidime. Only one case of Campylobacter jejuni septicaemia occurring post-splenectomy has been reported previously, also in an iron overloaded thalassaemia patient. Unusual Gram negative bacilli must be covered by the chosen antibiotic regimen when splenectomised thalassaemic patients present with high grade fever.