Timing and course of neonatal intracranial hemorrhage using real-time ultrasound

Knowledge of the timing and course of neonatal intracranial hemorrhage is essential in determining the etiology of hemorrhage, since the key to preventing neurologic damage in newborns is to define preventable causes and to treat the complications of hemorrhage. In an intensive study of 49 neonates delivered less than or equal to 32 weeks gestation, the initial hemorrhage typically occurred in the first three days of life, with 36% occurring on day 1, 32% on day 2, and 18% on day 3. Most of the major hemorrhages (Grades III and IV) occurred on day 1, although ventricular enlargement occurred at a variable time after the initial insult. By the sixth day, 91% of all intracranial hemorrhage had occurred.     

Thromboembolic disease and air travel in pregnancy: a survey of advice given by obstetricians.

The objective of this study was to document the awareness of risk and the nature of advice given by obstetricians to pregnant women who intend to travel by air and to compare the results with the advice given in an opinion paper of the Royal College of Obstetricians and Gynaecologists. The results were based on a self-completed questionnaire. All registered members of the Royal College of Obstetricians and Gynaecologists comprising 1349 individuals, obtained from a list provided by the RCOG, were invited to participate. An anonymous postal questionnaire was completed by the individuals before publication of the opinion paper of the RCOG. A total of 862 (62%) questionnaires returned, and 690 (51%) were available for analysis; 67% of obstetricians regard flying as being safe throughout pregnancy, 33% only in the 2nd and 3rd trimester. Nearly all obstetricians advised on simple prophylactic measures such as mobilisation, fluid intake and leg exercise. Fifty-three per cent would advise the use of prophylactic aspirin (75 mg), 49% the use of compression stockings; 4% recommended heparinisation; 44% believed this advice to be applicable only for the 2nd and 3rd trimester, while the RCOG emphasises that the risk of developing venous thromboembolism begins in the 1st trimester. Obstetricians as well as other health professionals need to be made aware that advice on air travel in pregnancy needs to start in the 1st trimester. Further research is needed to explore the relevance of the duration of flight when considering the application of thromboprophylactic measures as well as the value and choice of pharmacological treatment such as aspirin and heparin.     

Factors influencing interocular blur suppression

An Important feauture of monovision correction is the ability of the binocular system to suppress blur from the defocused eye (interocular blur suppression). We conducted a study with three subjects and found that interocular blur suppression improved with higher levels of monocular defocus (addition powers in monovision) but was not affected by the eye defocused (sighting dominant or non-domninant) or by pupil size. The selection and management of monovision patients may be assisted by an understading of the understanding of the underlying suppression preocesses.     

Localisation of pseudohypoaldosteronism genes to chromosome 16p12.2- 13.11 and 12p13.1-pter by homozygosity mapping

Pseudohypoaldosteronism type 1 (PHA1, OMIM 264350) is a rare Mendelian disorder characterised by end-organ unresponsiveness to mineralocorticoids. Most steroid hormone insensitivity syndromes arise from mutations in the corresponding receptor, but available genetic evidence is against involvement of the mineralocorticoid receptor gene, MLR, in PHA1. A complete genome scan for PHA1 genes was undertaken using homozygosity mapping in 11 consanguineous families. Conclusive evidence of linkage with heterogeneity was obtained with a maximum two- locus admixture lod score of 9.9. The disease locus mapped to chromosome 16p12.2-13.11 in six families and to 12p13.1-pter in the other five families. The two chromosomal regions harbour genes for subunits of the amiloride-sensitive epithelial sodium channel: SCNN1B and SCNN1G on 16p and SCNN1A on 12p. Liddle's syndrome of hypertension and pseudoaldosteronism has been shown to arise from mutations in SCNN1B and SCNN1G. These results strongly suggest that PHA1 and Liddle's syndrome are allelic variants caused by mutations in genes encoding subunits of this sodium channel. These genes are of broad biological interest both in relation to sodium and water homeostasis in mammals and by virtue of their homology to the mec genes of Caenorhabditis elegans involved in mechanosensitivity and neuronal degeneration.      

Differential cholinergic influences on the immobility response in various strains of domestic fowl

A series of five experiments examined the effects of two anticholinergic drugs, atropine and scopolamine, on the duration of tonic immobility (TI) and susceptibility to the TI response in both Production Red and White Leghorn chickens (Gallus gallus), in an attempt to resolve previous contradictory findings about the effects of cholinergic manipulations on tonic immobility. These two anticholinergic drugs significantly reduced the duration of TI and, therefore, supported the conclusion that cholinergic systems are involved with the immobility response. However, the effects of these drugs on TI differed depending on the age, strain, local population, and handling experience of the individual birds.     

Spinal infection: evaluation with MR imaging and intraoperative US

Magnetic resonance (MR) images of the spine and/or intraoperative spinal ultrasound (US) in 24 patients with spinal infections were reviewed and correlated with clinical and pathologic data to determine their diagnostic value. In disk space infection with osteomyelitis and in retrospinal abscess, MR images showed characteristic findings, whereas in myelitis, MR images demonstrated nonspecific abnormalities. The appearance on MR images of epidural abscesses ranged from clearly identifiable extradural masses with high-intensity signal on spin-echo T2-weighted images to extensive inhomogeneous collections of mixed signal intensities, difficult to distinguish from adjacent meningitis. Myelography with high-resolution computed tomography (CT) and intraoperative spinal US was superior to MR imaging in demonstrating epidural abscesses when there was concomitant meningitis. With intraoperative spinal US, epidural abscesses could be located and their decompression monitored. MR imaging is recommended as the initial screening procedure in spinal infection; in those few patients with nondiagnostic MR images, myelography with high-resolution CT should be the supplementary study. If surgery is planned, intraoperative spinal US should be used.     

Syrinx-like artifacts on MR images of the spinal cord

Magnetic resonance (MR) imaging of the spinal cord frequently demonstrates, especially on sagittal sections, a central stripe that mimics a true syrinx. This syrinx-like manifestation of a truncation artifact occurs in objects having a width of only a few pixels and was demonstrated by calculations verified with phantom MR images. Healthy volunteers and two patients with a syrinx and cervical spondylosis, respectively, underwent MR imaging. By increasing the number of phase-encoding steps, decreasing the field of view, and switching phase- and frequency-encoding axes, the syrinx-like artifact can be eliminated.