Correction to: Pigment Epithelium-Derived Factor Improves Paracellular Blood-Brain Barrier Integrity in the Normal and Ischemic Mouse Brain

The original version of the article unfortunately contained an error in the unit of the protein concentrations under 'Stereotactic Intraparenchymal Injections' subsection in 'Methods' section.

Visualization of cell death in mice with focal cerebral ischemia using fluorescent annexin A5, propidium iodide, and TUNEL staining

To monitor stroke-induced brain damage and assess neuroprotective therapies, specific imaging of cell death after cerebral ischemia in a noninvasive manner is highly desirable. Annexin A5 has been suggested as a marker for imaging cell death under various disease conditions including stroke. In this study, C57BL6/N mice received middle cerebral artery occlusion (MCAO) and were injected intravenously with either active or inactive Cy5.5-annexin A5 48 hours after reperfusion. Some mice also received propidium iodide (PI), a cell integrity marker. Only in mice receiving active Cy5.5-annexin A5 were fluorescence intensities significantly higher over the hemisphere ipsilateral to MCAO than on the contralateral side. This was detected noninvasively and ex vivo 4 and 8 hours after injection. The majority of cells positive for fluorescent annexin A5 were also positive for PI and fragmented DNA as detected by terminal deoxynucleotidyl transferase-mediated 2'-deoxyuridine 5'-triphosphate-biotin nick end labeling (TUNEL) staining. This study demonstrates the high specificity of annexin A5 for visualization of cell death in a mouse model of stroke. To our knowledge, this is the first study to compare the distribution of injected active and inactive annexin A5, PI, and TUNEL staining. It provides important information on the experimental and potential clinical applications of annexin A5-based imaging agents in stroke.

Measuring the economic costs of antimicrobial resistance in hospital settings: summary of the Centers for Disease Control and Prevention-Emory Workshop

Health systems administrators and clinicians need refined calculations of the attributable cost of infections due to drug-resistant microorganisms to develop and assess cost-effective prevention strategies that deal with these infections. To date, however, efforts to provide this information have yielded widely variable and often conflicting estimates. This lack of reproducibility is largely attributable to problems in study design and in the methods used to identify and measure costs. Addressing these methodological issues was the focus of a workshop that included participants from a broad range of backgrounds, including economics, epidemiology, health care management, health care outcomes research, and clinical care. This workshop summary presents the advantages and disadvantages of various research designs as well as particular methodological issues related to the measurement of the economic cost of resistance in health care settings. Suggestions are made for needed common definitions and approaches, study areas for future research are considered, and priority investigations are identified.

Safety of blood donations following a natural disaster

To evaluate the relative safety of blood donations given in response to a major disaster, donor demographics and infectious disease test results were compared for donations made during the 10 days following the October 17, 1989, San Francisco Bay Area earthquake and those made during the preceding 6 months. These comparisons were made for donations given to the regional blood center in the area that was immediately affected by the disaster (Irwin Memorial Blood Centers) and for those given in an unaffected region (Los Angeles/Orange Counties Region, American Red Cross Blood Services). The rate of donation increased more than 200 percent during the 5 days following the earthquake in both the disaster-affected and unaffected regions. Both the disaster-affected and unaffected regions observed significant increases in the proportions of donations by first-time donors, by persons aged 20 to 39 years, and by women. The rates of confirmed positivity for infectious disease markers for post-earthquake donations did not differ significantly from rates for homologous donations given during the preceding 6 months, particularly when the rates were adjusted for the increased representation of first-time donors. Approximately 39 percent of post-earthquake first-time donors gave blood again within the following 6-month period. It is concluded that donations given after major disasters are essentially as safe as routine donations and that active efforts to recruit these donors again can be undertaken without reservation.

Specificity of enzyme immunoassay for hepatitis B core antibody used in screening blood donors

Hepatitis B core antibody (anti-HBc) is currently tested by a competitive inhibition enzyme immunoassay (EIA), using recombinant DNA-produced core antigen. We have used the anti-HBc assay in routine screening of voluntary blood donors in San Francisco. The detection rate of anti-HBc was 2.08 percent. The specificity of the antibody test was established by an absorption method using purified HBc antigen (HBcAg) produced by recombinant DNA technology and covalently coupled to Sepharose 4B. Bovine serum albumin was used in the preparation of a control conjugate. The absorption test demonstrated that out of 98 anti-HBc-positive specimens, 97 could be specifically neutralized. Only one specimen was indeterminate. The absorption test was particularly useful in confirming the specificity of EIA in eight specimens inconsistently positive for anti-HBc. We conclude that the current EIA for anti-HBc is highly specific and we are of the opinion that it could be used as a rational basis for donor deferral since it gives evidence of active or previous HBV infection.

Transient ischemic attacks due to atherosclerosis. A prospective study of 160 patients

Patients with transient ischemic attacks (TIAs) due to atherosclerosis were studied by aortocranial arteriography. Onset of TIAs was before age 55 in 24% and between 55 and 64 in 47%. Men exceeded women by two to one. Of 160 patients, 77 were treated medically and 82 surgically. Five died in the immediate postoperative period. In the survivors, mortality has been the same in the medically and surgically managed groups. For patients with multiple lesions, surgical reconstruction of the carotid arteries was associated with very high surgical risk. In the medically treated group, anticoagulant therapy reduced the frequency of TIAs, but did not appear to protect patients from stroke. Mortality was 23% at four years, 57% of deaths being attributable to myocardial infarction and 38% to stroke.