An electric bottle for colloids.

Particle concentration is a dominant control parameter for colloids and other soft matter systems. We demonstrate a simple technique, "dielectrophoretic equilibrium," implemented as an "electric bottle," a planar capacitor in a larger volume. The uniform field in the capacitor traps particles in this force-free region at a higher density than in the zero field regions outside. We show how the technique measures the equation of state and we initiate and grow colloidal crystals. "Dielectrophoretic equilibria" enable the study of a complete concentration-dependent phase diagram from a single microscopic sample, obviating the previous need for preparing a large number of samples.

Surveillance of HIV-1 genetic subtypesand diversity in the US blood supply.

BACKGROUND: Recent reports of variant (non-subtype B) HIV infections in US populations have raised concerns about the sensitivity of subtype B virus-based donor screening and diagnostic assays. This study was designed to determine the prevalence and genetic diversity of HIV subtypes in US blood donors over the last two decades. STUDY DESIGN AND METHODS: Three groups were studied: hemophiliacs infected by clotting factor concentrates in the early 1980s (n = 49), blood donors retrospectively identified as being seropositive in 1985 (n = 97), and blood donors identified as seropositive between 1993 and 1996 (n = 405). Subtype assignment was based primarily on heteroduplex mobility analysis (HMA) of HIV-1 env, with DNA sequence confirmation of selected specimens. HIV peptide-based EIA serotyping was used to rule out HIV-2 and group O infections and to serotype HMA-refractory specimens. RESULTS: Of 551 specimens, 535 (97%) were assigned subtypes; 532 (99%) of these were subtype B. Three postscreening donations (1%) were assigned non-B subtypes (2 A, 1 C). Two of these three donors were born in Africa; the third was born in the United States and reported no risk factors other than heterosexual activity. HMA distribution plots showed an increase in env diversity among HIV-1 group B strains over time. CONCLUSION: The results support the need for continued surveillance of HIV subtype diversity and ongoing validation of the sensitivity of HIV diagnostic assays to non-B subtype infections.

Effectiveness of functional communication training with and without extinction and punishment: a summary of 21 inpatient cases.

Functional communication training (FCT) is a frequently used treatment for reducing problem behavior exhibited by individuals with developmental disabilities. Once the operant function of problem behavior is identified by a functional analysis, the client is taught to emit an appropriate communicative response to obtain the reinforcer that is responsible for behavioral maintenance. Studies on FCT have typically used small numbers of participants, have reported primarily on clients for whom FCT was successful, and have varied with respect to their use of other treatment components. The main purposes of the present study were to evaluate the efficacy of FCT for treating severe problem behavior in a relatively large sample of individuals with mental retardation (N = 21) and to determine the contribution of extinction and punishment components to FCT treatment packages. FCT with extinction was effective in reducing problem behavior for the majority of clients and resulted in at least a 90% reduction in problem behavior in nearly half the applications. However, when demand or delay-to-reinforcement fading was added to FCT with extinction, treatment efficacy was reduced in about one half of the applications. FCT with punishment (both with and without fading) resulted in at least a 90% reduction in problem behavior for every case in which it was applied.

Identification and characterization of an HIV-2 antibody-positive blood donor in the United States.

BACKGROUND: As of June 1, 1992, the Food and Drug Administration recommended that all donated blood be screened for antibodies specific to HIV-2. Despite broad serologic surveillance, only two cases of HIV-2 infection had been detected among potential blood and plasma donors since the implementation of the test. CASE REPORT: The identification of a third HIV-2 antibody-positive blood donor is reported. The first-time donor was identified by routine screening procedures as anti-HIV-1/HIV-2-reactive, and that status was confirmed by licensed HIV-1 Western blot. Concurrent whole-virus lysate enzyme immunoassay and Western blot for HIV-2 were strongly positive, but the possibility of HIV-1 cross-reactivity could not be eliminated. The donor was notified, counseled, and deferred from future donation. He subsequently enrolled in a Centers for Disease Control and Prevention-sponsored epidemiologic study of HIV-positive former donors. When it was revealed during the standardized interview that he was a native of an HIV-2-endemic region, follow-up samples were submitted to the Centers for Disease Control and Prevention. Investigational HIV-1 and HIV-2 peptide enzyme immunoassays indicated that this infection was due to HIV-2 only. CONCLUSION: Enzyme immunoassays for antibodies to synthetic peptides of HIV-1 and HIV-2 may be useful in differentiating the two viruses in individuals with ambiguous Western blot results and risk factors for HIV-2 infection.

Assessment of motivations for return donation among deferred blood donors. American Red Cross ARCNET Study Group.

BACKGROUND: The recent addition of a computerized donor deferral registry to American Red Cross blood donation procedures has enabled blood center staffs to identify, before donation, persons who attempt to donate despite previous deferral. The current study investigated reasons that deferred donors return to donate, despite having been notified that they are ineligible. STUDY DESIGN AND METHOD: Anonymous mail surveys requesting demographic information, details of last donation or attempted donation, and assessments of incentives for donating were sent to 311 donors presenting inappropriately at blood drives and 849 matched controls in three American Red Cross regions between April and July 1996. RESULTS: Responses were received from a total of 113 deferred donors and 388 matched controls. Analysis of the 49 permanently deferred donors indicated that they were more likely than controls to donate blood to receive test results or to be awarded community service credit. Responses also revealed that some deferred donors may return to donate blood because of a misunderstanding of the deferral message or erroneous recruitment by blood center staff. CONCLUSION: There is a need before donation for the provision of educational materials regarding the window period of infection and for careful consideration of the use of incentives to attract donors to blood centers. It is also important to provide to donors a clear and consistent message regarding their test results and deferral status.

Lamivudine therapy for chronic hepatitis B: a six-month randomized dose-ranging study.

BACKGROUND & AIMS: Lamivudine inhibits hepatitis B virus replication. This study investigated 6 months of lamivudine treatment at three doses. METHODS: Fifty-one patients (43% white, 49% Asian) with chronic hepatitis B were randomly assigned to receive 25, 100, or 300 mg of lamivudine orally once daily for 24 weeks with 24 weeks' follow-up. RESULTS: Serum hepatitis B DNA by liquid hybridization decreased in all patients and was undetectable at the end of the treatment in 7 of 12 (58%, 25 mg), 13 of 14 (93%, 100 mg), and 14 of 16 (88%, 300 mg) patients. Of the 36 patients with abnormal alanine aminotransferase (ALT) levels at baseline, 7 of 11 (64%, 25 mg), 5 of 11 (45%, 100 mg), and 5 of 14 (36%, 300 mg) normalized ALT at treatment completion. Quantitative decreases hepatitis Be antigen and hepatitis B surface antigen concentrations were observed at all doses. In most patients, markers of replication returned after treatment. Two patients (4%) were anti-HBe positive at the end of follow-up. Lamivudine was well tolerated. The incidence of adverse events was similar across all dose groups. However, 2 patients developed temporary hepatic decompensation after increase in transaminase levels after treatment. CONCLUSIONS: Lamivudine was well tolerated and induced sustained suppression of hepatitis B replication during treatment in all patients at all doses. These data support investigation of longer treatment durations of 100 mg once daily.

Prevalence of antibodies to hepatitis C virus and other markers in Jamaica.

Three population groups, 1500 blood donors, 513 antenatal women representing a normal population group and 250 sicklers representing a multiply transfused group were studied to determine the prevalence of hepatitis C viral (HCV) infection in Jamaica. The relationship to liver enzyme levels, hepatitis B infection, syphilis and HIV infection was also investigated. Sera were screened by enzyme-linked immunoassay (EIA) for anti-HCV C100-3 and subsequently tested by a supplementary second generation recombinant immunoblot assay (RIBA). In the blood donors, the prevalence of anti-HCV was low, 0.3%-0.4%, the same level as that reported by several European countries. In the multiply transfused sicklers, the prevalence was more than seven times higher. No HCV infection was detected in the antenatal group. There was little correlation between HCV infection and surrogate markers alanine aminotransferase (ALT) and antibody to hepatitis B core antigen (anti-HBc) and no correlation with sexually transmitted diseases.

Prevalence of antibodies to hepatitis C virus and other markers in Jamaica

Three population groups, 1500 blood donors, 513 antenatal women representing a normal population group and 250 sicklers representing a multiply transfused group were studied to determine the prevalence of hepatitis C viral (HCV) infection in Jamaica. The relationship to liver enzyme levels, hepatitis B infection, syphilis and HIV infection was also investigated. Sera were screened by enzyme-linked immunoassay (EIA) for anti-HCV C100-3 and subsequently tested by a supplementary second generation recombinant immunoblot assay (RIBA). In the blood donors, the prevalence of anti-HCV was low, 0.3 per cent - 0.4 per cent, the same level as that reported by several European countries. In the multiply transfused sicklers, the prevalence was more than seven times higher. No HCV infection was detected in the antenatal group. There was little correlation between HCV infection and surrogate markers alanine aminotransferase (ALT) and antibody to hepatitis B core antigen (anti-HBc) and no correlation with sexually transmitted diseases.

Prevalence of antibodies to hepatitis C virus and other markers in Jamaica

Three population groups, 1500 blood donors, 513 antenatal women representing a normal population group and 250 sicklers representing a multiply transfused group were studied to determine the prevalence of hepatitis C viral (HCV) infection in Jamaica. The relationship to liver enzyme levels, hepatitis B infection, syphilis and HIV infection was also investigated. Sera were screened by enzyme-linked immunoassay (EIA) for anti-HCV C100-3 and subsequently tested by a supplementary second generation recombinant immunoblot assay (RIBA). In the blood donors, the prevalence of anti-HCV was low, 0.3 per cent - 0.4 per cent, the same level as that reported by several European countries. In the multiply transfused sicklers, the prevalence was more than seven times higher. No HCV infection was detected in the antenatal group. There was little correlation between HCV infection and surrogate markers alanine aminotransferase (ALT) and antibody to hepatitis B core antigen (anti-HBc) and no correlation with sexually transmitted diseases. (AU)

Transfusion-transmitted retrovirus infection.

This article reviews the history, classification, and disease associations of the known human retroviruses and outlines their profound effects on the practice of transfusion medicine. The immunodeficiency viruses, HIV-1 and HIV-2, produce a cytolytic effect on infected lymphocytes, and are the causative agents of AIDS. In contrast are the oncoviruses, including HTLV-I and HTLV-II, which are typically lymphoproliferative and able to induce cellular transformation. Human foamy viruses, more recently recognized as a potential human neuropathogen, resemble the other retroviruses with their complex genome organization and structure.

Analysis of glycosphingolipid glycosyltransferase products on TLC plates by combined storage phosphor and immunostaining techniques.

Measurement of glycosyltransferase activity in whole cell extracts is often complicated by the fact that several enzymes in an homogenate are capable of using the same nucleotide sugar donor, thereby generating a range of products from both an exogenous and any endogenous acceptors. We report the use of a novel combination of techniques to simultaneously identify and quantify the products generated from a whole cell extract in a single experiment. Several radiolabeled glycosphingolipid products were generated by the addition of UDP-[14C]Gal to a reaction mixture containing an homogenate from a human leukemia cell line, THP-1. After the 14C-labeled products were separated on a TLC plate, storage phosphor technology and immunostaining (with carbohydrate sequence-specific monoclonal antibodies) were used sequentially on the same plate to simultaneously identify and quantify each of the glycosyltransferase products. This method allows product identification and quantification in the femtomole range. Thus, low levels of endogenous acceptors were easily detected. We have used a similar method with UDP-[3H]Gal to obtain glycosyltransferase product profiles from several human leukemia/lymphoma cell lines and subsequently identify two galactosyltransferase activities in these cell lines: UDP-Gal:Gal beta 1-4Glc beta 1-1Cer alpha 1,4galactosyltransferase; and UDP-Gal:GlcNAc beta 1--3Gal beta 1--4Glc beta 1--1Cer beta 1,4galactosyltransferase. In addition to product characterization, this method was used with reaction mixtures at different pH to demonstrate the usefulness of the method for characterizing multiple enzyme activities simultaneously.

Prevalence of antibodies to hepatitis C virus and other markers in Jamaica - abstract

Three population groups, 1500 blood donors, 513 antenatal women representing a normal population group and 250 sicklers representing a multiply transfused group, were studied to determine the prevalence of Hepatitis C Viral (HCV) infection in Jamaica. The relationship to liver enzyme levels, hepatitis B infection, syphilis and HIV infection was also investigated. Sera were screened by EIA for anti-HCV C100-3 and subsequently tested by a supplementary second generation recombinant immunoblot assay (RIBA). In the blood donors, the prevalence of anti-HCV was low, 0.3 percent - 0.4 percent, the same level as that reported by several European countries. In the multiply transfused sicklers, the prevalence was more than seven times higher. No HCV infection was detected in the antenatal group. There was little correlation between HCV infection and surrogate markers alanine transferase (ALT) and antibody to hepatitis B core antigen (anti-HBc) and no correlation with sexually transmitted diseases (AU)

Human T-lymphotropic virus (HTLV) types I and II infection in sexual contacts and family members of blood donors who are seropositive for HTLV type I or II. American Red Cross HTLV-I/II Collaborative Study Group.

Interviews and laboratory testing were conducted for 168 contacts referred by former blood donors identified as seropositive for antibody to human T-lymphotropic virus type I (HTLV-I) or type II (HTLV-II). Thirty-two (28%) of 114 heterosexual contacts of seropositive donors, including 12 women and 20 men, were found to be antibody positive. None of 40 offspring (except one adult man who reported sexual contact in Puerto Rico) or 14 other (nonspousal) family members were seropositive. Thirty-one of the seropositive contacts were typeable as having either HTLV-I (52%) or HTLV-II (48%). Assessment of couples found that the median duration of the sexual relationship was significantly longer (p = 0.03) for those in which both partners were infected than in discordant pairs. Analysis of risk history data for 22 infected couples revealed that, in three cases, risk factors (Japanese ancestry or sexual contact with an injecting drug user) could be identified in the women, but not in their male partners. Among couples in which the male had the greater risk history, the risk factor was either a history of transfusion, birth or sexual exposure in an endemic area, or injected drug use. Counseling strategies for individuals with HTLV-I or HTLV-II infection should take into account the relatively high seroprevalence in their partners and should address the potential for sexual transmission in both directions.

Evaluation of an indirect immunofluorescence assay for confirmation of human immunodeficiency virus type 1 antibody in U.S. blood donor sera.

An indirect immunofluorescence assay (IFA) was evaluated as a confirmatory test for antibody to human immunodeficiency virus type 1 in U.S. blood donor sera previously found to be repeatedly reactive by enzyme immunoassay. IFA results were 100% concordant with a licensed Western blot (immunoblot) for 53 negative and 49 positive samples. Four samples which exhibited antibody to viral proteins from more than one gene, yet were indeterminate by Western blot by the manufacturer's criteria, were also reactive by IFA, whereas 49 additional indeterminate samples were IFA negative.

Electrophoretic resolution and fluorescence detection of N-linked glycoprotein oligosaccharides after reductive amination with 8-aminonaphthalene-1,3,6-trisulphonic acid.

The relative mobilities of various N-linked oligosaccharides reductively aminated to the charged fluorophore 8-amino-naphthalene-1,3,6-trisulphonic acid (ANTS) were determined by electrophoresis on high-density polyacrylamide slab gels. Each ANTS-derivatized oligosaccharide was assigned a relative migration index (RMI) expressed in terms of glucose equivalents, which was conveniently estimated by reference to a homologous series of ANTS--maltooligosaccharides run on each gel as oligosaccharide size standards. High-mannose-, complex- and hybrid-type structures were generally well resolved and easily visualized at picomole levels by simple UV light excitation. Application of these methods for the qualitative analysis of the oligosaccharides released from bovine fetuin and bovine asialofetuin by peptide-N-glycosidase F illustrates the usefulness of these techniques as fast, simple, and inexpensive tools for the characterization of N-linked oligosaccharides attached to glycoproteins.

Transmission of human T-lymphotropic virus types I and II by blood transfusion. A retrospective study of recipients of blood components (1983 through 1988). The American Red Cross HTLV-I/II Collaborative Study Group.

We studied results of a "lookback" program involving laboratory testing and interviews of 133 recipients of prior donations from blood donors seropositive for human T-lymphotropic virus types I and II (HTLV-I/II) identified at 28 American Red Cross blood centers. The study was designed to explore the natural course of posttransfusion HTLV-I/II infection among individuals who received blood components from donors subsequently identified as being HTLV-I/II seropositive. Seventeen recipients were seropositive, an apparent transmission rate of 12.8%. Red blood cells and platelets were the implicated components, and red blood cells that were less than 6 days old had a transmission efficiency of 80%. Virus typing enabled documentation of primary and secondary transfusion transmission of HTLV-I and HTLV-II, including the direct transmission of HTLV-II by a donor with a history of intravenous drug use. We conclude that transfusion transmission of HTLV-I/II to approximately 700 recipients per year occurred in the United States before routine donor testing began in 1988.