Retention of "safe" blood donors. The Retrovirus Epidemiology Donor Study

BACKGROUND: There are obvious advantages to increasing donor retention. However, for reasons of blood safety, certain donors may, in fact, be more desirable to retain than others. “Safe” donors are defined as those who provided a blood donation that was negative on all laboratory screening tests and who subsequently reported no behavioral risks in response to an anonymous survey. This study identifies the most important factors affecting the intention of “safe” donors to provide another donation. STUDY DESIGN AND METHODS: An anonymous survey asking about donation history, sexual history, injecting drug use, and recent donation experience was mailed to 50,162 randomly selected allogeneic donors (including directed donors) who gave blood from April through July or from October through December 1993 at one of the five United States blood centers participating in the Retrovirus Epidemiology Donor Study. Before mailing, questionnaires were coded to designate donors with nonreactive laboratory screening tests at their most recent donation. RESULTS: A total of 34,726 donors (69%) responded, with substantially higher response among repeat donors. According to reported intentions only, the vast majority of “safe” donors indicated a high likelihood of donating again within the next 12 months. Only 3.4 percent reported a low likelihood of donating again. A comparison of those likely to return and those unlikely to return reveals significant differences in demographics and in ratings of the donation experience. A higher proportion of those unlikely to return were first-time donors, minority-group donors, and donors with less education. The highest projected loss among “safe” donors was seen for those who gave a fair to poor assessment of their treatment by blood center staff or of their physical well-being during or after donating. CONCLUSION: These data suggest that efforts to improve donors' perceptions of their donation experience, as well as attention to the physical effects of blood donation, may aid in the retention of both repeat and first-time donors.     

Pediatric nutrition surveillance system--United States, 1980-1991.

The CDC Pediatric Nutrition Surveillance System (PedNSS) monitors the general health and nutritional characteristics of low-income U.S. children who participate in multiple public health programs. This system is intended to characterize trends and patterns in key indicators of nutritional status so that the information can be used for program planning and targeting. The indicators monitored by PedNSS are birth weight, childhood growth status, anemia, and breast-feeding patterns. From 1980 through 1991, the trends for low birth weight, low height-for-age (shortness), low weight-for-height (thinness), and high weight-for-height (overweight) were stable for all children monitored by the PedNSS, with the exception of Asian children, who were predominantly of Southeast Asian refugee background. In the early 1980s, the prevalence of low birth weight and shortness was higher among Asian children than among children of other racial or ethnic groups who were monitored by the PedNSS. However, these prevalences declined steadily from 1980 through 1991. By 1991, the prevalences of low birth weight and shortness for Asian children were similar to those observed for children of other races/ethnic groups. Overall, low-income U.S. children had a slightly lower height-for-age than expected, indicating that some of these children were at a health and nutritional disadvantage. The prevalence of overweight varied among different racial/ethnic groups; Hispanic and Native American children had the highest prevalences of overweight. The 20%-30% prevalence of anemia among low-income children monitored by the PedNSS was higher than among the general population, reflecting in part the preferential enrollment and retention of anemic children by public health nutrition programs and also indicating that many children had inadequate iron nutrition. From 1980 through 1991, the prevalence of anemia declined > 5% for most of the age- and race/ethnicity-specific groups monitored by PedNSS. That decline represents an improvement in iron nutritional status. PedNSS is a useful system for the monitoring and characterization of the nutrition status of low-income children at both state and national levels.     

Rupture of the posterior tibial tendon: CT and surgical findings

Computed tomography (CT) was performed in 42 patients with 49 clinically suspected tears of the posterior tibial tendon. Twenty-eight of the 49 suspected tears were subsequently surgically explored and repaired. Three patterns of tendon abnormalities were recognized on CT scans: type I-intact, hypertrophied, heterogeneous tendon; type II-attenuated tendon; and type III-absence of a portion of a tendon. Types I and II correlated with partial rupture seen during surgery, and type III correlated with complete rupture of the tendon. CT findings were accurate in 96% of the patients who underwent surgery. In four cases (14%), tendon rupture was seen on CT scans, but the extent of the injury was underestimated and the rupture was misclassified. Reactive periostitis of the distal tibia was seen in 71% of diseased tendons and may represent an important factor in the diagnosis of tendon rupture.     

Coronary thrombosis and platelet/fibrin microemboli in death associated with acute myocardial infarction.

The frequency and clinical significance of platelet/fibrin microemboli in the microcirculation were investigated in 24 patients whose deaths (before and during hospital admission) were associated with acute myocardial infarction. An acute coronary thrombus was present in all the hearts. In nine hearts an acute thrombus was found in more than one major epicardial coronary artery. A total of 35 acute thrombi were found in the 24 hearts. Platelet/fibrin microemboli were found in 19 (79%) hearts. Eighteen patients died in hospital. The hearts of 16 of these cases showed microemboli; 16 had important arrhythmias or various forms of heart block; 13 showed acute pathological changes in the conduction system. Fourteen of the deaths in hospital were primarily the result of cardiogenic shock and four were primarily caused by arrhythmia. Six of the deaths that occurred before admission to hospital were regarded as being arrhythmic in origin. Three of these showed microemboli and the other three had acute pathological changes in the conduction system. Microemboli were found in two (24%) of 12 control hearts. Coronary thrombosis was found in most deaths caused by acute myocardial infarction and platelet/fibrin microemboli were present in the majority of such hearts. These may arise from the coronary thrombus in the larger upstream vessel supplying the microcirculation.     

A method for evaluating systems of epidemiological surveillance

Epidemiological surveillance is the systematic collection, analysis and dissemination of health data for the planning, implementation and evaluation of public health programmes. Established surveillance systems should be regularly reviewed on the basis of explicit criteria of usefulness, cost and quality; systems should be modified as a result of such review. Attributes of quality include: (i) sensitivity, (ii) specificity, (iii) representativeness, (iv) timeliness, (v) simplicity, (vi) flexibility and (vii) acceptability. To date, evaluation of surveillance systems has been limited in scope and content. The evaluation method proposed in this article offers an organized approach to the evaluation of epidemiological surveillance systems. The usefulness of a surveillance system is measured by whether it leads to prevention or control or a better understanding of adverse health events. The measure can be qualitative, in terms of the subjective views of those using the system, or quantitative in terms of the impact of surveillance data on policies, interventions or the occurrence of a health event. The cost of a system includes indirect as well as direct costs, and should be measured in relation to the benefits obtained, such as reduction of medical-care expenses and of time lost from work. All elements of the system should be included in the cost: data collection, analysis and dissemination. The sensitivity of a surveillance system is its ability to detect health events (completeness of reporting). Its specificity is inversely proportional to the number of false positives it reports. Reports of a disease that do not meet the case definition are false positives, and may result in resources being wasted in investigating them.(ABSTRACT TRUNCATED AT 250 WORDS)     

Immunological properties of murine thymus-dependent lymphocyte surface glycoproteins.

The immunological properties of two murine thymus-dependent (T) lymphocyte surface glycoproteins, T200 and T25, were investigated. T200 is a lymphocyte-specific antigen with a high degree of species specificity. It shares antigenic determinants with molecules present on thymus-independent (B) lymphocytes. T25 has antigenic determinants which cross-react with antigens on mouse brain, rat thymocytes and rat brain. An antiserum against a purified rat brain glycoprotein which carries Thy-1.1 reacts with T25. Absorption of this antiserum with BALB/c thymocytes or brain homogenate produces a Thy-1.1 specific serum which reacts with T25 from AKR/J thymocytes but not with T25 from AKR/Cum thymocytes. These results confirm that T25 is the molecule on the surface of mouse T cells which carries the Thy-1 antigen. T25 also carries antigenic determinants, recognized by anti-thymocyte serum (ATS), which were found on secondary mouse embryo fibroblasts and untransformed fibroblast cell lines but which were not detected on fibroblast cell lines transformed with murine sarcoma virus (MSV) or with Simian virus 40 (SV40).     

Arenaviruses: Cellular Response to Long-Term In Vitro Infection with Parana and Lymphocytic Choriomeningitis Viruses

Persistent infections were established in suspension cultures of BHK21/13S cells with both Parana and lymphocytic choriomeningitis viruses. Four generations after infection with either virus, more than 90% of the cells scored as infective centers, with concomitant peaks in extracellular virus yields. In both cultures the synthesis of detectable plaque-forming units (PFU) ceased about the 50th generation postinfection, and this condition was maintained until the 350th cell generation when the cultures were discontinued. The generation time of each culture was identical to that of uninfected parent controls, and at no time were cytopathic effects evident. In spite of the absence of infectivity, over 90% of the cells sampled at various times contained viral antigen demonstrable by immunofluorescence. When either of these persistently infected cell lines was substituted for normal cells in the standard plaque assay, very low efficiencies of plating were observed for homotypic and heterotypic viruses. Plaque formation by several heterologous viruses was virtually unaffected. The mechanism of homotypic plaque exclusion in both cell lines was shown to occur beyond the virion adsorption stage. The original infecting virus genome persisted in both cell lines after standard virus was no longer detectable. This was shown with the lymphocytic choriomeningitis virus-infected cells after storage in liquid nitrogen. After thawing, such cells were found to synthesize standard virus for a brief period. Although the Parana virus-infected cells did not behave this way, the growth medium from these cells would initiate PFU synthesis in normal cells within 36 hr after infection.