A randomized clinical trial of daily nonstress testing versus biophysical profile in the management of preterm premature rupture of membranes

OBJECTIVE: Our purpose was to evaluate the ability of 2 different antepartum testing modalities to predict infectious morbidity in patients with preterm premature rupture of membranes. STUDY DESIGN: During a 36-month period, patients with preterm premature rupture of membranes (at 23 to 34 weeks of gestation) were randomly assigned to either a daily nonstress test or a biophysical profile, after a 24-hour observational period. We used the original scoring system of Manning et al for the biophysical profile, with a score of 相似文献   

Validation of a thermographic guidewire for endoluminal mapping of atherosclerotic disease: an in vitro study.

Temperature heterogeneity along the inner surface of an artery may be a surrogate marker of impending plaque rupture and has been associated with an increased likelihood of future coronary events. Initial studies using catheter-based thermographic devices have demonstrated that the changes in temperature are subtle, while the effects of coronary flow on measured temperature have not yet been examined. A novel guidewire-based system (ThermoCoil, Imetrx) designed to measure surface temperature in coronary arteries was used to study the effects of heat source intensity and flow on measured temperature. An in vitro model of a focal, eccentric, heat-generating lesion demonstrated that a guidewire-based system can detect changes in surface temperature with a precision of less than 0.08 degrees C. In this model, temperature measurements increased linearly with source temperature and decreased with increases in flow by an exponent of -0.33 (P < 0.001 for both). Flow rates and heat source properties can significantly influence the measurement and interpretation of thermographic data. The incorporation of 2D thermographic images may contribute further to the characterization of metabolically active plaques likely to cause acute coronary syndromes.     

Detection of glutamate/glutamine resonances by 1H magnetic resonance spectroscopy at 0.5 tesla

Midfield proton magnetic resonance spectroscopy (MRS) provides a noninvasive method to monitor glutamate and glutamine (Glx) levels in vivo. Experiments to detect the γ and β resonances of Glx have been performed by using commercial 0.5 T and 1.5 T MR scanners on seven patients with elevated blood ammonia and eight normal volunteers. Compared with the spectral sensitivity obtained on an otherwise identical system operating at 1.5 T, the singlet resonance of N-acetyl aspartate (NAA) was decreased by a factor of 1.48, which is significantly less than expected using the ratio of Boltzman populations at the two field strengths. However, the resonances of Glx at 0.5 T increased in signal-to-noise ratio (SNR) by a factor of 2. The increased SNR of Glx is principally due to improved B ₀ main-field homogeneity and collapse of the strongly J -coupled Glx resonances. Our preliminary results suggest that midfield proton MRS will provide significant clinical utility in the detection of Glx levels in human brain.     

Imaging in chronic achilles tendinopathy: a comparison of ultrasonography,magnetic resonance imaging and surgical findings in 27 histologically verified cases

 Objective. To compare information gained by ultrasonography and magnetic resonance imaging (MRI) in chronic achilles tendinopathy with regard to the nature and severity of the lesion. Design. Imaging of both achilles tendons with ultrasonography and MRI was performed prior to unilateral surgery. Operative findings and histological biopsies together served as a reference. Patients. Twenty-seven patients (22 men, 5 women; mean age 44 years; 21 athletes) suffering from chronic achilles tendinopathy participated in the study. Eighteen patients had unilateral and 9 had bilateral symptoms. Results and conclusions. Surgical findings included 4 partial ruptures, 21 degenerative lesions and 2 macroscopically normal cases. Microscopy revealed tendinosis (degeneration) in all tendon biopsies, including cases with a partial rupture, but only slight changes in the paratendinous tissues (paratenon). Ultrasonography was positive in 21 of 26 and MRI in 26 of 27 cases. Severe intratendinous abnormalities and a sagittal tendon diameter >10 mm suggested a partial rupture. In tendons with a false negative result histopathological changes were mild and a tendency towards a better clinical outcome was noted in the sonographic cases. Assessment of the paratenon was unreliable with both methods. Ultrasonography and MRI give similar information and may have their greatest potential as prognostic instruments.     

Morphological comparison and functional reconstitution of rat hepatic parenchymal cells on various matrices

Four types of materials, type I collagen coat (Coat), acid-soluble type I collagen gel (Hardgel), pepsin-treated acid-soluble type I collagen gel (Softgel), and an extract of extracellular matrix of the murine Engelbreth-Holm-Swarm sarcoma (Matrigel), were used as matrices to culture rat hepatic parenchymal cells, and their morphological changes and adhesion were compared to the matrices by electron microscopic observations. Hepatic parenchymal cells cultured on Coat and Hardgel were extended and flattened, whereas cells cultured on Softgel and Matrigel assembled and formed aggregates. Such aggregates consisted of several hepatic parenchymal cells, with a recognizable bile duct-like alveolus on the inside. Morphologically, the aggregates were more spherical on Matrigel and oval shaped on Softgel. Microvilli of the cell surface were parallel to the matrix on Matrigel, but invaded into the gel on Softgel. Subsequently, investigation into how these morphological features affected the liver-specific functions, including secretion of albumin and induction of P450 by 3-methylcholanthrene, demonstrated that a high level of liver function was maintained in a long-term culture in hepatic parenchymal cells on Softgel. These results suggest that hepatic parenchymal cell interactions were stronger with Softgel than with Matrigel, and that Softgel appears to closely mimic the in vivo environment.     

The effect of hyperosmotic solutions on the hepatic blood flow,

Summary. The present study was undertaken in order to measure the effect of hyperosmotic solutions on portal and hepatic blood flow. In five anaesthetized pigs without arterial blood supply to the liver, portal blood flow rate was measured (electromagnetic flowmeter) during 5 min lasting intravenous infusions of hyperosmotic galactose (50%, 84–100 ml) and mannitol (25%, 100 ml), with physiological saline (100 ml) as control. Portal blood flow increased to a peak value of (39% [P= 0–06] galactose and 37%, [P= 0–06], mannitol) soon after stop of the hyperosmotic infusion. For galactose the change ended somewhat earlier than for mannitol. Saline induced a minor increase (15%). Similarly, increments of, on average, 144% of the hepatic blood flow rate was seen in six patients with cirrhosis, following infusion of hyperosmotic galactose, the increase being more pronounced than in the pigs. The causes for these osmotic effects are not known, but they have to be taken into consideration in studies of the portal and hepatic blood flow.     

The human drug metabolizing cytochromes P450

The superfamily of heme-thiolate proteins known as the cytochromes P450 is responsible for the oxidative metabolism of the majority of drugs. Thus, the phenotypes of individuals with respect to their levels of catalytically active cytochromes P450 determines to a large part the substantial interindividual variation observed in the metabolic clearance of drugs. Over the past 10 years 15 different human cytochromes P450 involved in drug metabolism have been isolated and characterized to varying degrees. This brief review discusses the characterization of these cytochromes P450 and how this knowledge has been used by the pharmaceutical industry to aid in the development of new drugs.