Ferrite particles for bowel contrast in MR imaging: design issues and feasibility studies

Diverse materials with varying physical and magnetic properties have been evaluated as gastrointestinal contrast agents for magnetic resonance (MR) imaging. Uniform marking of the small bowel remains the greatest challenge. Ferrites are magnetically active iron oxide particles that are miscible with water and cause loss of signal on MR images. The decrease in MR signal intensity produced by ferrites occurs with a wide range of iron concentrations (0.1-10 mM) and with both T1- and T2-weighted pulse sequences. These effects of ferrites are explained by predominant T2 shortening with negligible T1 effects. The ferrite preparation used in this study was stable in vitro, with little iron solubilized by acid. Intragastric administration of ferrite (5 mg of iron per kg in 6 ml) routinely marked the small bowel of rats. The authors conclude that ferrites represent a promising new class of contrast agents for gastrointestinal MR imaging.     

Comparison of the structure of human intervertebral discs in the cervical,thoracic and lumbar regions of the spine

Posterior and anterior heights, cross-sectional area and shape were measured for all the intervertebral discs in four spines from elderly human cadavers. Disc height was a minimum at the T4-5 level; thoracic discs were less wedge-shaped than those in the cervical and lumbar regions. Cross-sectional area increased from the cranial to caudal extremity; at the L5-S1 level the nucleus pulposus occupied a high proportion of this area. Cervical discs tended to have an elliptical cross-sectional shape, thoracic discs were more circular and lumbar discs tended to have an elliptical cross-section which was flattened or re-entrant posteriorly. This shape distribution was quantified by defining a shape index which had a maximum value of 1 for a circular cross-section. Orientations of the reinforcing fibres in the outer lamellae of the anterior annulus fibrosus were measured from 27 discs by X-ray diffraction. For these measurements, C3-4, T7-8 and L2-3 were chosen as representative of cervical, thoracic and lumbar discs. The fibre tilt, with respect to the axis of the spine, was significantly less in the cervical discs (at 65 degrees) than in the thoracic and lumbar discs (about 70 degrees). These findings are interpreted in relation to differing functional requirements and possible mechanisms of failure in the cervical, thoracic and lumbar regions of the spine in the light of current knowledge on the biomechanics of the intervertebral disc.     

Fetal and infant outcome of pregnancies with very early rupture of membranes

Fetal and infant outcome was studied in 38 singleton pregnancies complicated by very early rupture of membranes (PROM), in gestational weeks 19-29, over a 4-year period, in a Swedish population. The pregnancies were managed according to a specified protocol, including postponement of delivery until 34 weeks of gestation if possible. Stillbirth occurred in 10 cases (26.3%), all with PROM before 26 completed weeks, while 6 other infants died in the neonatal period. Respiratory distress syndrome was evident in half (50.0%) of the 28 liveborn infants. The surviving 22 infants (57.9%) were followed up to 2 years of age. The rate of neurological sequelae at follow-up was 22.7% (5/22). The fetal outcome of the 20 pregnancies with rupture of membranes before 26 completed weeks was poor; only 7 infants of the 10 born alive survived the neonatal period. The short-term fetal outcome in the group with rupture of membranes in 26-29 completed weeks was better: 15 of the 18 infants survived, but 4 had neurological sequelae. PROM before 29 completed weeks of gestation is associated with severe short-term and long-term fetal complications, in cases where the pregnancy is prolonged for several weeks.     

Intrapartum fetal heart rate patterns in pregnancies complicated by hypertension. A cohort study

Intrapartum fetal heart rate patterns were investigated in pregnancies complicated by hypertension in a cohort study. The total number of live births was 2400 and the frequency of hypertension was 8.8%. The study group comprised 2023 normotensive and 200 hypertensive deliveries. Dates of all pregnancies were established at an ultrasound examination in week 17. Ominous intrapartum fetal heart rate patterns were significantly more common in hypertensive deliveries than in normotensive deliveries (20.5% versus 7.6%). The women with hypertension were compared with a group of control women matched for age, parity, induction of labor, and gestational week (20.5% versus 6.5%). In hypertensive women ominous fetal heart rate tracings were frequently associated with primiparity, induced labor, epidural block, delivery of a growth-retarded fetus, and beta 1-adrenergic receptor blockers. Ominous fetal heart rate patterns were less common in hypertensive women without these risk factors; still the significant differences in comparison with normotensive women remained. The hypertensive pregnancies accounted for no less than 21.0% of all ominous intrapartum fetal heart rate patterns, whereas 13% of all cases of ominous intrapartum fetal heart rate patterns could be attributed to the excess frequency in hypertensive pregnancies.     

Placental grading with ultrasound in hypertensive and normotensive pregnancies. A prospective, consecutive study

Placental grading was studied prospectively with real-time ultrasound in 654 consecutive pregnancies. The placental maturation was clearly demonstrated in both unselected and hypertensive pregnancies. No differences in placental grading were found between normotensive and hypertensive pregnancies. Fetal outcome was not associated with different placental grades and a grade III placenta was not predictive of an adverse outcome. The value of antenatal placental grading in unselective and hypertensive pregnancies could not be demonstrated.     

Outcome in congenital stridor (laryngomalacia)

Twenty-one children who had been diagnosed as having laryngomalacia by direct laryngoscopy in infancy were reviewed 7 to 12 years later. The natural history of the disease is documented. A wide variation in the time of onset and duration of the stridor was found and there was a high incidence of feeding difficulties. A previously reported association with mental retardation or cerebral palsy is not confirmed. 4 out of the 21 children had early speech problems.     

Menkes's syndrome. Report of a patient treated from 21 days of age with parenteral copper

In an infant with Menkes's steely-hair syndrome, early treatment (from 21 days of age) with parenteral copper failed to halt the disease. In addition to urinary tract abnormalities, panlobular emphysema was present a finding not previously noted in the syndrome.     

抗真菌药物的研究II.C-端含氧代赖氨酸二肽的合成及抗白念珠菌活性

引用违法传递概念设计合成了11个C-末端含氧代赖氨酸二肽,进行抗深部致病菌-白念珠菌活性试验,体外实验结果显示极强的抑菌活性,MIC在12.5～0.8μg/disk之间,较母体氧化赖氨酸大50～135倍(克分子比。