结肠非低张双重造影的应用

本文应用结肠非低张双重对比灌肠造影诊断结肠病变,这是一种简单的方法。本文根据150例的实践径验介绍了技术、病人的准备、有关造影剂的问题和正常所见,并通过具体的病例阐述了结肠非低张双重对比检查的临床应用价值,并指出了本法的不足之处。     

Laboratory diagnosis of catheter-related bacteremia.

Semiquantitative culture of the external surface of catheter tips has become the currently most used method to detect catheter colonisation and catheter-related bacteremia; however, this method may fail to detect significant colonisation of the internal lumen of catheters, and several quantitative methods have been described for this purpose. Although 15 and 1000 CFU are used to define positive catheters, the sensitivity and specificity are not yet well known, and the definitive cut-off level for a positive result remains to be established. We studied prospectively 91 intravascular catheter tips removed because a catheter-related infection was suspected. The result of external and internal cultures with different cut-off levels, alone or combined, were correlated with clinical data in 22 bacteremic episodes which occurred in these patients, 12 of which were catheter-related. The semiquantitative culture of the external surface alone with a cut-off level of 25 CFU provided the best means of detecting catheter-related bacteremia. This method has 100% sensitivity and 81.1% specificity. We conclude that semiquantitative culture technique of the catheter tip alone is sufficient and this method should be employed for diagnosing catheter-related bacteremia in unselected populations.     

Lewis Histo-Blood Group System and Associated Secretory Phenotypes

This review summarises present knowledge of the chemistry, immunology, genetics and clinical significance of antibodies in the Lewis and secretor histoblood group systems. Although red cell serology has laid the foundations for these systems, more recent advances have been made by studying Lewis and related glycoconjugates with monoclonal antibodies, determining structures by mass spectrometry and NMR spectroscopy, identifying enzymes and their specificities, and identifying the genes by molecular biology. The expression of Lewis system antigens is dependent on Lewis and secretor loci. Fucosyltransferases coded by genes at these loci compete and interact with each other and with other transferases to determine an individual's Lewis and secretor phenotype. Exocrine epithelial cells, mostly of endodermal origin, synthesise the Lewis antigens which, as plasma glycolipids, are secondarily acquired by cells of the peripheral circulation. Phenotyping red cells is often regarded as a simple way of determining the Lewis and sometimes the secretor status of an individual; however, the red cell phenotype is influenced by many factors and may not necessarily reflect someone's Lewis and secretor genotypes. Two main red cell Lewis groups are usually found, Lewis negative and Lewis positive. In Lewis-negative individuals, the secretor genotype does not affect the Lewis phenotype, but in Lewis-positive individuals, the non-secretor genotype generates the Le(a+b–) phenotype, the secretor genotype causes the Le(a–b+) phenotype, and the partial secretor genotype gives rise to the Le(a+b+) phenotype.     

Prospective epidemiological study of invasiveHaemophilus influenzae disease in adults

The incidence and characteristics of invasiveHaemophilus influenzae disease were studied in 43 adult patients admitted to the acute care hospitals in El Vallés County (Barcelona, Spain) between January 1987 and June 1992. The annual incidence ofHaemophilus influenzae disease was 1.2 per 100,000 inhabitants. Pneumonia occurred in 24 patients, meningitis in five, intraabdominal infections in three, obstetric infections in two, epiglottitis in two and cellulitis in one. In six patients the source of infection was unknown. Ten (23 %) of the infections were hospital acquired. Underlying conditions were diagnosed in 30 (70 %) patients. NontypeableHaemophilus influenzae strains predominated in all adult age groups. Sixty-one percent of type b and 34 % of nontypeable strains were ampicillin resistant (p=0.08). Multiple antibiotic resistance was also high among type b (53 %) and nontypeable (18 %) strains. The mortality rate was significantly higher in patients with pneumonia, bactaeremia from an unidentified focus or shock at presentation.     

A note on the half-life of 209Po.

The widely adopted value of (102+/-5)a for the (209)Po half-life, which is based on a single determination reported in 1956, appears to be in error by a large factor. Decay data from two separate primary standardizations of a (209)Po solution standard, conducted approximately 12 years apart, are inconsistent with the adopted value and its assigned uncertainty. An estimated half-life, larger than the adopted value by about 25%, is more consistent with the standardization data. A longer half-life is also supported by measurements on a recently standardized (210)Pb solution standard.     

Detection and Characterization of Lewis Antigens in Plasma of Lewis-Negative Individuals Evidence of Chain Extension as a Result of Reduced Fucosyltransferase Competition

Nonacid plasma glycolipids from Lewis-negative individuals of nonsecretor, partial-secretor and secretor phenotypes were prepared and separated by thin-layer chromatography and immunostained with radiolabelled Lewis antibodies. Lewis-positive plasma and intestinal epithelial cell glycolipids from Caucasians representing the four recognized Lewis and secretor combined phenotypes were used as controls. By presenting these purified total glycolipids in a cell-free environment to Lewis antibodies we were able to demonstrate the presence of small amounts of Lewis antigens in Lewis-negative individuals. It is shown that lactotetraosylceramide and extended precursor glycolipids are present in all Le(a–b–) nonsecretors. Le^awas detected in 1 of the 3 Le(a–b–) nonsecretor plasmas and in the intestinal sample of the same phenotype. Lactotetraosylceramide was absent but H type 1 and Le^bwere both present in all group O Le(a–b–) secretors, and extended H type 1 reactive structures were also found in the partial secretor. These results clearly demonstrate that although the Lewis-negative phenotype exists at the serological level, this phenotype is not an 'all-or-nothing' phenomenon at the chemical level. We also show that in the presence of reduced fucosyltransferase activity, increased elongation of the precursor chain occurs, which allows us to postulate that fucosylation of the precursor prevents or at least markedly reduces chain elongation.