Pulmonary embolism after hip or knee replacement: postoperative changes on pulmonary scintigrams in asymptomatic patients

Serial pulmonary imaging has proved to be effective in the evaluation of patients undergoing total joint arthroplasty. A clinical dilemma arises in asymptomatic patients whose postoperative pulmonary images differ from the preoperative images. The authors prospectively evaluated 403 patients with serial imaging to determine the significance of changed postoperative images in asymptomatic patients undergoing total hip or knee arthroplasty. Twenty-two (5.5%) patients had significant changes on postoperative images. Seventeen were asymptomatic; all but one underwent pulmonary angiography. Documented pulmonary emboli were demonstrated in 100% of patients whose postoperative images changed to indicate a high probability of pulmonary embolism, 71% whose images changed to a moderate probability, and 0% whose images changed to indeterminate probability. Overall, pulmonary emboli occurred in 76% of all asymptomatic patients with significantly change postoperative images. Asymptomatic pulmonary embolism is a significant occurrence after total hip or knee repair, and a changed lung scan with appropriate clinical evaluation is an accurate indicator of pulmonary emboli in asymptomatic postarthroplasty patients.     

Interaction of cefotetan and the metallo-beta-lactamases produced in Aeromonas spp. and in vitro activity

Aeromonas spp. are increasingly being recognized as human pathogens. The presence of metallo-beta-lactamases in these organisms represents a potential problem in antimicrobial therapy. Mechanism-based inactivators of beta-lactamases are used to overcome the resistance of clinical pathogens to beta-lactam antibiotics, but no clinical useful inhibitors of the metallo-beta-lactamases are presently known. Studying the interaction between cefotetan and Aeromonas spp. producing metallo-beta-lactamase activity, we observed that cefotetan behaved as a transient inactivator for both the crude extracts of Aeromonas strains and the purified enzymes from Aeromonas hydrophila AE036 and Aeromonas schubertii MNSA20. The direct hydrolysis of cefotetan showed that it was a poor substrate for both purified enzymes. In view of the minimum inhibitory concentrations, cefotetan shows to be a useful antimicrobial agent against Aeromonas spp.     

预激态补骨脂素抑制 K562细胞增殖的实验研究

本研究的目的是观察预激态补骨脂素对K562细胞增殖的影响，为补骨脂素的临床应用提供实验依据。取预激态补骨脂素和晚激态补骨脂素处理的细胞，在培养后检测台盼蓝拒染细胞数和白血病细胞集落，并对它们在台盼蓝拒染细胞抑制率(TBIR)、细胞增殖抑制率(CPIR)和集落形成抑制率(CFIR)方面的差异进行比较。结果表明：预激态补骨脂素对K562细胞增殖有抑制作用；随着预激态补骨脂素浓度的增加，其抑制作用也随之增强；预激态补骨脂素与晚激态补骨脂素的TBIR、CPIR、CFIR各值比的差异不显著；为使预激态补骨脂素要充分发挥对K562细胞的抑制作用，补骨脂素的紫外线照射时间应在10分钟以上；与K562细胞作用时间也应大于12小时；抑制作用会因预激态补骨脂素预激后搁置时间的延长而下降，在6小时内作用最强。结论：预激态补骨脂素和晚激态补骨脂素对K562细胞的增殖均表现出抑制作用，有望作为临床的抗肿瘤用药。     

Donor screening for antibody to hepatitis B core antigen and hepatitis B virus infection in transfusion recipients

BACKGROUND: Testing for antibody to hepatitis B core antigen (anti-HBc) as a surrogate for hepatitis C viremia is no longer needed for blood donor screening. Currently, the important question is how much its use supplements hepatitis B surface antigen (HBsAg) donor screening in preventing transfusion-transmitted hepatitis B virus (HBV) infection. STUDY DESIGN AND METHODS: In a study conducted in the 1970s, 64 blood donors were associated with 15 cases of HBV (1.0%) in 1533 transfusion recipients. Sera from 61 donors at donation and 29 follow-up visits were available for present-day assays for HBsAg, HBV DNA, anti-HBc, and antibody to HBsAg (anti-HBs). RESULTS: HBsAg was found in four previously negative blood donors; HBV DNA was limited to three of these four. Anti-HBc was detected in six HBsAg-negative donors. Two other donors were negative in all assays at donation, but positive for anti- HBc and anti-HBs 2 to 4 months later. The remaining donors were negative for all HBV markers, which left five recipient cases unexplained. No HBV transmission was observed when anti-HBs sample-to- negative control values were > or = 10. CONCLUSION: Some 33 to 50 percent of cases of hepatitis B that could be transmitted by transfusion of blood from HBsAg-negative donors are prevented by anti- HBc screening. Anti-HBc-positive donors unequivocally positive for anti- HBs should be considered noninfectious for HBV and should be allowed to donate. Anti-HBc screening of paid plasmapheresis donors, supplemented by anti-HBs testing, would reduce the amount of HBV to be processed by virus inactivation and increase the content of anti-HBs in plasma pools.     

Childhood Lead Poisoning on the US-Mexico Border: A Case Study in Environmental Health Nursing Lead Poisoning

Abstract Human exposure to environmental hazards is a major public health problem along the US-Mexico border due to socio-economic, cultural and political factors. Childhood lead exposure is endemic in areas of extreme poverty and substandard housing. Hispanic children of indigent, poorly-educated, disenfranchised families are at disproportionate risk. Risk management is contingent upon consideration of the interrelationships between socioeconomics, politics, and culture. This case study explains childhood lead poisoning in a colonia family living at subsistence level from such a perspective. The purpose of the study was to identify, explain, and ameliorate lead exposure pathways. Case study methodology was used to support or refute the proposition that these children were exposed to occupational lead. The children were the study sampling unit and the family a subunit. An embedded single case explanatory design was appropriate. Data were collected from exposure surveys, environmental and blood specimens, and review of medical records. Pattern-matching and explanation-building techniques were used to analyze data. The study illustrated how extreme poverty, lack of access to health services, social isolation, language and legal barriers, and hazardous occupations may be singularly common risk factors for Hispanic children on the US-Maxico border. The study is pertinent to public health nurses who work with this population.     

Percutaneous umbilical blood sampling and umbilical vein transfusions. Rapid serologic differentiation of fetal blood from maternal blood

Percutaneous umbilical blood samples (PUBS), obtained under ultrasound guidance, are used for prenatal diagnosis and management of hemolytic disease of the newborn (HDN) and other fetal disorders. Rapid testing at the time of sampling is vital to distinguish fetal from maternal blood. Blood typing was performed by slide technique in the treatment room during 38 procedures on 25 patients. Anti-I was used to test 50 presumed PUBS; venous I-positive maternal blood was tested in parallel. Because anti-I cannot detect fetal blood after umbilical vein transfusion (UVT) of I-positive donor blood, ABO and Rh blood typing reagents were used to test 29 samples when maternal and fetal or donor blood groups differed. Monoclonal reagents were used for optimal detection of weak AB antigens in fetal blood. Avid, chemically modified anti-D was used for Rh typing. Blood typing showed 27 (34%) of 79 samples to be maternal blood. Fetal blood was obtained in 8 of 10 cases investigated for fetal disorder and in 16 cases of potential HDN (anti-D, 5; -CD, 5; -cE, 2; -K, 2; -c; -E). The absence of HDN (antigen-negative fetus) was determined in 4 cases. UVT afforded live birth of 9 of 10 infants with HDN and was not indicated in two cases.     

Donor levels of serum alanine aminotransferase activity and antibody to hepatitis B core antigen associated with recipient hepatitis C and non- B, non-C outcomes

BACKGROUND: Hepatitis virus(es) that are neither hepatitis B (HBV) nor hepatitis C (HCV) (non-B, non-C [NBNC]) may be transmitted by transfusion. The present study assessed donor values for alanine aminotransferase (ALT) and antibody to hepatitis B core antigen (anti- HBc) for their association with HCV and NBNC hepatitis outcomes among allogeneic blood recipients. STUDY DESIGN AND METHODS: Data on blood donors and recipients enrolled in the Transfusion- Transmitted Viruses Study in four United States cities from 1974 through 1980 were supplemented by anti-HBc testing of donors and anti-HCV evaluation of recipients. Two statistical approaches estimated the value of these indirect tests in detecting donors associated with HCV seroconversion and NBNC hepatitis in recipients. RESULTS: For HCV cases, donor ALT alone (at > or = 60 IU/L) had a sensitivity and a specificity of 30 and 96 percent, respectively, and anti-HBc alone (at > or = 60% inhibition) had a sensitivity and specificity of 53 and 86 percent, respectively. The two markers combined had a sensitivity and a specificity of 69 and 83 percent. For NBNC hepatitis cases, each measure had low sensitivity (20%) that was not improved by using both (28%) [corrected]. CONCLUSION: The indirect tests proved to be equal in sensitivity to the first-generation anti-HCV tests. The positive predictive power of these indirect tests in the 1980s was sufficient to affect HCV incidence in studies during that period. Improved anti-HCV assays, however, replaced the need for indirect tests. The sensitivity of indirect tests for NBNC hepatitis contributed little.     

Taurocholate-stimulated leukotriene C4 biosynthesis and leukotriene C4-stimulated choleresis in isolated rat liver

Cysteinyl-containing leukotrienes seem to exert a cholestatic effect. However, leukotriene inhibitors were found to reduce bile salt efflux in isolated rat hepatocytes, suggesting a role for leukotrienes in bile flow formation. In the isolated rat liver, the effects of two different concentrations of leukotriene C₄ on bile flow and bile salt excretion are analyzed, as well as the possible effect of taurocholate on the hepatic production of cysteinyl-containing leukotrienes. Leukotriene C₄ (0.25 fmol) increased bile salt excretion (+22.2%; P < 0.05), whereas a much higher dose (0.25 × 10⁶ fmol) showed the known cholestatic effect, reducing bile salt excretion (−25.9%; P < 0.01). These dose-dependent biphasic effects were specific because they could be prevented by the simultaneous administration of cysteinyl-containing leukotriene antagonists. On the other hand, taurocholate administration induced a dose-dependent increase in biliary excretion of cysteinyl-containing leukotrienes. Furthermore, taurocholate increased messenger RNA levels of 5-lipoxygenase, a key enzyme in leukotriene biosynthesis. Taurocholate increase of hepatocyte intracellular calcium was not significant, suggesting that taurocholate effects are not mediated by stimulation of calcium metabolism. These results constitute evidence for the existence of a positive feedback mechanism by which bile salts stimulate the synthesis of leukotrienes that, in turn, stimulate bile salt excretion.