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Biomedical subjects

T F Zuck

Publications and source records attributed to T F Zuck.

At least 19 recordsLinked to original sources
PubMed2000

Evaluation of the safety of Rh immunoglobulin by monitoring viral markers among Rh-negative female blood donors.

BACKGROUND AND OBJECTIVES: Although immunoglobulin (Ig) preparations including RhIg have been noted for their record of safety, recent reports of hepatitis C virus (HCV) transmission by some Ig preparations have raised concern. This analysis examined the safety of RhIg manufactured in the US by comparing the prevalence and incidence of viral markers in Rh-negative and Rh-positive female blood donors. MATERIALS AND METHODS: Demographic and viral marker data were analyzed for allogeneic donations collected from female donors of childbearing age (17-49 years of age) from April 1992 to May 1996. Prevalence and incidence rates were calculated for HCV, human immunodeficiency virus (HIV), and hepatitis B surface antigen (HBsAg). RESULTS: Of the 624,939 female donors included in the study, 96,355 (15.4%) were Rh-negative and 528,584 (84.6%) Rh-positive. There were no significant differences in the prevalence of HCV and HIV between Rh-negative and Rh-positive female donors. HBsAg prevalence was significantly higher among non-white compared to white donors. Following implementation of the more sensitive EIA 2.0 screening test for HCV in April 1992, prevalence and incidence rates declined over time at similar rates for Rh-negative and Rh-positive female donors. CONCLUSIONS: Rh-negative female donors had similar prevalence and incidence rates for most viral markers compared to Rh-positive female donors. This analysis supports the historical safety of RhIg.

Adolescent↗
PubMed1996

Blood safety decisions, 1982 to 1986: perceptions and misconceptions.

Although blood bankers and those who treat persons with hemophilia are supportive of most of the recommendations of the Report, the manner in which the analysis was conducted and some of the general conclusions that were reached appear flawed. The flaws may reflect the deficiencies in the process by which the Committee gathered data more than any bias on the part of its members themselves. The Report may accurately reflect the testimony heard, but it is biased by the committee's acceptance as fact the opinions of critics who claim the AIDS epidemic was mismanaged by the blood-collecting agencies, professional organizations, hemophilia organizations, and the federal government. Countervailing views on the various issues are ignored or incompletely discussed. Much testimony was taken from the victims of the transfusion-associated AIDS epidemic. Reliance seems to have been placed upon hindsight testimony (taken 10 years after the events), rather than on documentation of what was known at the time when events unfolded. The Report states that "[t]he Committee's charge did not include the development of assertions about what should have been done at the time,"l(pl:4) yet that is precisely what was done. These comments address just a few of the misconceptions we perceive in the Report. They are based on our understanding of the state of knowledge--or ignorance--at the time that decisions about the safety of the blood supply were made. If we are to avert future threats to the blood supply from emerging infectious diseases, a goal that is universally embraced, we must learn the lessons the past can teach us, as painful as they may be. However, the hazards of judging history in hindsight should be avoided. Neither allegations nor opinions should be accepted as facts without critical examination and without placement in the context of contemporary knowledge; to accept a lesser standard does a great injustice to all who were touched by this tragedy.

Blood Banks↗
PubMed1996

Relationship between antibody to hepatitis B core antigen and retroviral infections in blood from volunteer donors.

BACKGROUND: The value of the test for antibody to hepatitis B core antigen (anti-HBc) as a surrogate screening assay in the time before sensitive, virus-specific screening tests were available has been well established. There is significant debate, however about the residual value of anti-HBc screening after the implementation of human immunodeficiency virus (HIV)-, human T-lymphotrophic virus (HTLV)-, and hepatitis C virus (HCV)-specific assays and, in particular, about its utility as a lifestyle marker to identify persons at risk for retrovirus infections. STUDY DESIGN AND METHODS: Screening tests for antibodies to HIV, HTLV, and HBc, as well as confirmatory or supplemental test results for anti-HIV and anti-HTLV, were obtained from approximately 2.8 million donations collected from 1991 through 1993 by five blood centers within the United States. The sensitivity, positive predictive value, and relative prevalence of anti-HBc for each retrovirus were calculated and compared among demographic subgroups. RESULTS: The overall relationship between anti-HBc and anti-HIV was similar to that between anti-HBc and anti-HTLV. When calculated from the measured endpoint of the prevalence of anti-HIV-positive and anti-HTLV-positive donations, the sensitivities were 31.1 and 26.2 percent, the positive predictive values were 0.18 and 0.21 percent, and the relative prevalences were 30.1 and 23.8, respectively. Among 27 anti-HIV-seroconverting donors and 9 anti-HTLV-seroconverting donors, the sensitivities were 7.4 percent (95% CI: 0.9-24.3%) and 0 percent (95% CI: 0.0-28.3%), respectively. It was estimated that for each HIV-infected window-period donation detected by anti-HBc, from 19,000 to 81,000 HIV-noninfected donations are discarded. Similarly, more than 33,000 HTLV-noninfected donations are likely to be discarded for each HTLV-infected donation detected by anti-HBc. CONCLUSION: Although anti-HBc-reactive donations are more likely to be seropositive for a retrovirus than are anti-HBc-nonreactive donations, the low positive predictive value limits the test's effectiveness. If the anti-HBc test is retained in the blood donor setting, efforts should be focused on reducing the number of false-positive results.

Adolescent↗
PubMed1996

The applicability of cGMP to cord blood cell banking.

The Food and Drug Administration will regulate cord blood cells stringently as a distinct category of somatic cells. The FDA has declared that cord blood cell products are subject to licensure and will require a claimed exemption for an investigational new drug (IND) to undertake clinical trials. This regulatory approach will require both establishment and product licenses, requirements that will pose significant difficulties for regulated establishments. The manufacture of cord blood cell products will be divided between delivery rooms or attached laboratories and regional cord cell processing laboratories. It is possible that cooperative manufacturing arrangements, perhaps using a short supply agreement model, will be the most practical way for FDA to regulate cord blood cell product manufacture. Without regard to regulatory or business arrangements for providing cord blood cell products, it is clear that current good manufacturing practices (cGMP) will be required in both the delivery suite and the processing laboratory. The concepts of cGMP will be foreign to many medical practitioners, but embracing them will be crucial to comply with FDA regulatory expectations and will concomitantly ensure uniform product quality.

Blood Banks↗
PubMed1994

Demographic characteristics and prevalence of serologic markers among donors who use the confidential unit exclusion process: the Retrovirus Epidemiology Donor Study.

BACKGROUND: Most blood centers utilize a confidential unit exclusion (CUE) process, intended to reduce the risk of transfusion-associated infectious diseases by allowing high-risk donors confidentially to exclude their blood from use for transfusion. The effectiveness of this method remains controversial. STUDY DESIGN AND METHODS: Confirmatory or supplemental test results for antibodies to human immunodeficiency virus, human T-lymphotropic virus type I, and hepatitis C virus, as well as hepatitis B surface antigen and syphilis and screening test results for antibodies to hepatitis B core (antigen) and alanine aminotransferase levels were obtained for approximately 1.8 million units donated during 1991 and 1992 at five blood centers within the United States. The prevalences of these infectious disease markers in units that the donors confidentially excluded (CUE+) and units that the donors did not exclude (CUE-) were calculated and examined within demographic subgroups. RESULTS: Units that were CUE+ were 8 to 41 times more likely to be seropositive for antibodies to human immunodeficiency virus and hepatitis C virus, hepatitis B surface antigen, and syphilis and three to four times more likely to react for antibody to hepatitis B core (antigen) or to have elevated alanine aminotransferase levels than units that were CUE- (p < 0.001). The positive predictive value of CUE (the percentage of CUE+ units that were confirmed seropositive for any marker) was 3.5 percent, and the sensitivity of CUE (the percentage of confirmed-seropositive units that were CUE+) was 2.3 percent. CONCLUSION: The current CUE process has low sensitivity and apparently low positive predictive value, and in many cases, it appeared that donors misunderstood it. Yet, CUE was not a "random process," as CUE+ units were more likely to be seropositive for any infectious disease marker than CUE- units. This suggests that efforts to improve the CUE system may be warranted. As risk factors for transfusion-transmitted infection become more difficult to identify by history-based screening, however, such efforts may have limited effect.

Adolescent↗
PubMed1994

Current status of injectable oxygen carriers.

In this review the current status of what commonly are termed "blood substitutes" is discussed. The term blood substitute is a misnomer because the formulations under development at this time transport respiratory gases but do not perform the metabolic, regulatory, and protective functions of blood. Either hemoglobin or a perfluorochemical form the base to transport oxygen; the advantages and disadvantages of each base are discussed. The availability of a blood substitute in the U.S. will require approval by the Food and Drug Administration (FDA) and, by law, both its efficacy and safety must be demonstrated prior to approval. Showing efficacy of any blood substitute is complicated by the oxygen reserve and the compensatory mechanisms to acute blood loss in man. The challenge is to prove that the administration of these formulations offer clinical advantages compared with replacement of volume alone. Several efficacy models, the most attractive among them being perioperative hemodilution, should provide data that would bring these formulations into clinical practice. When hemoglobin is not within the favorable environment of the red cell, whether the hemoglobin is derived from expression vectors developed through recombinant biotechnology or from lysed human red cells, it acquires a left-shifted oxygen disassociation curve. Further, because the tetramer disassociates when injected intravenously and the resulting dimers are cleared rapidly from the circulation by the kidneys, intravascular dwell time is brief. Hemoglobins have been modified chemically and linked intramolecularly, intermolecularly, and to macromolecules to correct these problems. While these manipulations have normalized the p50 and extended the dwell time significantly, some toxicity problems remain unresolved. The binding of nitric oxide to hemoglobin preparations and the presumably resultant systemic and pulmonary hypertension observed in animals may be the most difficult to overcome, although the implications of these reactions in man is poorly understood. Perfluorochemicals (PFC) provide a fundamentally different and simpler approach to oxygen transport than hemoglobin formulations. Typically, the PFCs used are liquids composed of 8 to 10 carbon atoms that dissolve oxygen and obey Henry's law. Thus, the recipient's inspired oxygen and cardiac output assume importance. Because they are insoluble in water, PFCs are administered as emulsions, that is, as small droplets about 0.1 to 0.2 microns in diameter. In this respect, they are very similar to the lipid emulsions widely used for parenteral nutrition. Egg yolk phospholipid and poloxamers are most commonly used as emulsifiers. PFCs are not metabolized and are excreted unchanged by the lungs, following temporary storage by the monocyte-macrophage system (MMS).(ABSTRACT TRUNCATED AT 400 WORDS)

Blood Substitutes↗
PubMed1994

Difficulties in demonstrating efficacy of blood substitutes.

Currently, the fear of infectious disease transmission by allogenic blood transfusions has spurred interest in developing a blood substitute FDA approval requires that a sponsor demonstrate that the substitute is effective. The challenge in designing efficacy studies in man is proving that the substitute offers significant advantages over conventional therapies for acute blood loss. This task is complicated by the oxygen reserve and the response to hemodilution following treatment of acute blood loss in man. Paradoxically, the technique that relies on these protective physiologies-isovolemic perioperative hemodilution-many offer the best experimental model to establish efficacy of a blood substitute in man.

Animals↗
PubMed1990

Experience with a transfusion recipient education program about hepatitis C.

Shortly after test kits for antibodies to the hepatitis C virus (HCV) were licensed in May of 1990, our medical community undertook a public education program encouraging previous transfusion recipients to see their physicians about the wisdom of being tested for anti-HCV. In response, 1034 samples were received for testing. All samples repeatably reactive (RR) with anti-HCV enzyme-linked immunoassay (EIA) were tested further with a research recombinant immunoblot assay (RIBA). Overall, 76 of the 1034 (7.4%) recipient samples were RR and 64 of these (84.2%) were reactive with RIBA. Recipients transfused prior to surrogate testing (alanine aminotransferase [ALT] and anti-hepatitis B core [anti-HBc]) in 1986 showed a 8.6 percent reactivity with RIBA and those transfused after surrogate testing showed a 4.8 percent reactivity, a 44 percent reduction. Of the 57 recipient samples reactive with RIBA and suitable for assay, 11 (19.3%) had an elevated ALT. Among 76 randomly selected blood donors with RR EIAs studied for comparison with recipients, 20 (26.3%) were reactive with RIBA, 9 of which had an abnormal surrogate test that would have disqualified them. ALT concentrations were abnormal in 6 (30%) of the donors who were reactive on RIBA. We conclude that an education program that encourages previous transfusion recipients to seek medical advice about anti-HCV testing is practical from the standpoint of the blood center. We believe more widespread implementation of similar programs should be considered.(ABSTRACT TRUNCATED AT 250 WORDS)

Antibodies, Viral↗
PubMed1990

Legal liability for transfusion injury in the acquired immunodeficiency syndrome era.

The emergence of the acquired immunodeficiency syndrome has wrought changes that have affected not only medicine and science, but many aspects of our social and political structures. In 1983 when it clearly became evident that acquired immunodeficiency syndrome could be transmitted by transfusions of blood components and products, blood banks became the focus of intense scrutiny by the public as well as by the mass media. Suddenly it was known that people could contract acquired immunodeficiency syndrome even though they had not engaged in activities known to place them at increased risk for acquiring infection with the human immunodeficiency virus type 1. In many ways the general fear evoked was, and remains, disproportionate to the risks posed by transfusions. This fear coupled with a general distrust of blood banks may also be reflected in the legal response to people infected with human immunodeficiency syndrome type 1 through transfusions. Further, whether the fault system of our tort law is an appropriate way to determine compensation for people injured by transfusion has been brought into question. For those people injured prior to our recognition of acquired immunodeficiency syndrome, the failings of the current system are most obvious.

Acquired Immunodeficiency Syndrome↗