Effacement of the fetal cisterna magna in association with myelomeningocele

The cisterna magna is effaced in association with myelomeningocele. The authors retrospectively investigated the size of the fetal cisterna magna as a predictor of fetal myelomeningocele in 67 pregnant women (17-38 menstrual weeks) referred for prenatal sonography because of an elevated serum alpha-fetoprotein level (n = 61) or a suspicion of fetal ventriculomegaly on previously obtained sonograms (n = 6). Twenty fetuses had myelomeningocele, 14 had isolated ventriculomegaly, and 33 were normal. A normal-sized cisterna magna (range, 4-9 mm in depth) was present in all normal fetuses. In 19 of 20 fetuses with myelomeningocele, the views of the posterior fossa were adequate, and in each of these the cisterna magna was effaced (n = 18) or very small (n = 1). The cisterna magna was effaced in five of 13 (38%) fetuses with isolated ventriculomegaly in whom the posterior fossa was adequately imaged. Although effacement of the cisterna magna is a nonspecific finding, the high negative predictive value of this sign is useful during routine screening of the fetal neural axis.     

Effect of menstrual cycle phase on dopamine D2 receptor availability in female cynomolgus monkeys

Sex differences have been reported in a variety of affective and neurodegenerative disorders that involve dysfunctional dopamine (DA) neurotransmission. In addition, there is evidence for differences in sensitivity to the abuse-related effects of psychostimulants across the menstrual cycle which may result from effects of ovarian hormones on DA function. The goal of the present study was to extend previous work examining menstrual cycle-related changes in DA D2 receptor availability in humans to drug-naive female cynomolgus monkeys (n=7) using the selective D2-like receptor ligand [(18)F]fluoroclebopride (FCP) and a high-resolution microPET P4 scanner. Menstrual cycle phase was characterized by daily vaginal swabs and measurements of serum progesterone levels. PET studies were conducted once during the luteal phase and once during the follicular phase. Regions of interest in the caudate nucleus, putamen, and cerebellum were defined on coregistered MRIs. Distribution volumes were calculated for FCP in each structure and the distribution volume ratio (DVR) for both brain regions relative to the cerebellum was used as a measure of D2 receptor availability. FCP DVRs were significantly higher in the luteal phase compared to the follicular phase in both the caudate nucleus (11.7% difference, p=0.02) and putamen (11.6% difference, p=0.03). These findings extend earlier work in humans and suggest that changes in DA receptor availability may be involved in the variation in symptoms of various neuropsychiatric disorders across the menstrual cycle, including differences in sensitivity to the abuse-related effects of stimulants.     

Paediatric use of intensive care

OBJECTIVES--To determine the number of children from a defined population who use intensive care facilities, to analyse bed occupancy data for those children, and to estimate the number of intensive care beds required to satisfy this demand throughout the year. DESIGN--Examination of admission data books from intensive care units within the four Birmingham health authorities and the neighbouring health authorities. RESULTS--Two hundred and ninety seven children resident within the four Birmingham health authorities used intensive care facilities in a calendar year. One hundred and forty one (47%) of these were admitted for specialist paediatric services. Of the remaining 156, 106 (68%) were cared for in adult intensive care units, 46 (29%) in a paediatric intensive care unit and four (3%) in a special care baby unit. Use of intensive care varied from none to 11 patients each day, and was lowest in the summer and highest during the winter months. During periods of peak demand, one in 19,000 (5.3/100,000) children were using intensive care facilities. CONCLUSIONS--These data provide a population based minimum need for paediatric intensive care beds. They are higher than previous estimates and do not include provision for children from outside Birmingham, or for those denied intensive care due to bed shortages. These factors and the marked seasonal variation in demand need to be considered when planning intensive care services for children if bed shortages are to be avoided.     

Medical treatment of hepatic amebic abscess: rare need for percutaneous drainage

Although amebic liver abscess can virtually always be successfully treated medically, percutaneous drainage has been advocated recently. In 96 recently treated patients, therapeutic aspiration and percutaneous drainage were rarely needed. Most cases were correctly diagnosed by means of clinical, laboratory, and sonographic findings. Abscesses in only 13 (13.5%) patients were diagnostically aspirated. An abscess in one patient was therapeutically aspirated because the patient was responding slowly to medical therapy. No patient required catheter drainage. The key to successful amebic abscess management is medical therapy. Therapeutic drainage is rarely needed. Successfully treated patients occasionally respond slowly to medical therapy, and successfully treated amebic abscesses may enlarge or become bizarre-appearing on sonograms. This should not prompt therapeutic drainage. Diagnostic aspiration is appropriate when amebic and pyogenic abscesses are indistinguishable using clinical and imaging findings. Rare indications for therapeutic aspiration or drainage include pyogenic superinfection and large, juxtacardiac abscesses (potential intrapericardial rupture).     

Decreased deformability of erythrocytes from smokers

The deformability of erythrocytes from smoking and non-smoking human subjects was examined by filtration through 3-mu pores and capillary viscometry of cell suspensions. In both cases, small but significant differences were found between the two groups that are consistent with a reduction in the surface area-to-volume ratio and/or a diminished membrane flexibility in erythrocyte from smokers. Additional evidence suggests that these findings represent a chronic rather than an acute effect of smoking on erythrocyte deformability.     

Myelinated and nonmyelinated nerves: comparison of proton MR properties

The magnetic resonance (MR) relaxation rates of protons were compared in the myelinated and nonmyelinated nerves of the garfish. The long, large olfactory nerve of the garfish, as an easily accessible source of nonmyelinated axons, is uniquely suited for such a comparison. The T1 and T2 measurements revealed distinct and consistent differences between nonmyelinated olfactory nerves and myelinated optic and oculomotor nerves. Comparisons between water content, lipid content, and relaxation rates indicated that the differences in MR properties represent complex differences in the distribution and physical environment of the constituent lipid and water protons.