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Biomedical subjects

K Mayer

Publications and source records attributed to K Mayer.

At least 145 records · Page 8Linked to original sources
PubMed1991

Detection of human immunodeficiency virus type 1 in semen from seropositive men using culture and polymerase chain reaction deoxyribonucleic acid amplification techniques.

We have demonstrated that the polymerase chain reaction is a valid and sensitive technique for the detection of human immunodeficiency virus type 1 (HIV-1) proviral deoxyribonucleic acid (DNA) in human semen. The combination of extraction, polymerase chain reaction, and liquid hybridization techniques used in this study was sensitive to a level of detection of one HIV-1 infected cell in 100,000 (or 3 infected cells/test sample). In a series of matched peripheral blood mononuclear cells (PBMC) and semen cells from 25 HIV-1 seropositive homosexual men, HIV-1 DNA was detected by polymerase chain reaction in 23 of 25 PBMC samples and 1 of 25 semen samples. By coculture on mitogen-activated peripheral blood leukocyte target cells, 19 of 24 PBMC and 4 of 24 semen samples were positive for infectious HIV-1. Of the four culture-positive semen samples, three were negative for the proviral form of the virus in the polymerase chain reaction assay. These data indicate that HIV-1 infected cells are not as prevalent in semen as in the peripheral blood. Furthermore, they indicate that the classical polymerase chain reaction approach, which only detects HIV-1 proviral DNA (infected cells), is not sufficient for clinical screening programs whose goal is the detection of HIV-1-infected semen samples. Accurate semen analysis by polymerase chain reaction may require enrichment of the infected cell population and/or a reverse transcriptase step to enable detection of the infectious ribonucleic acid form of the virus.

DNA↗
PubMed1990

Surface immunoglobulin-positive T lymphocytes in HIV-1 infection: relationship to CD4+ lymphocyte depletion.

T lymphocytes bound to autologous immunoglobulin (surface Ig + T cells) and serum antibodies that bind to allogeneic lymphocytes have been detected in HIV-1-infected individuals, but their significance in the immunopathogenesis of HIV-1 infection is uncertain. We tested peripheral blood from HIV-1-infected individuals to determine if surface Ig+ T cells are specific for HIV-1 infection and are associated with CD4+ lymphocyte depletion. The majority of HIV-1-infected individuals contained substantial numbers of circulating surface Ig+ T cells. The presence of such cells was restricted to seropositive individuals and not related to risk factors associated with the acquisition of HIV-1 infection. Autologous immunoglobulin was detected on both CD4+ and CD8+ cells in all patients tested. Most individuals with surface Ig+ T lymphocytes also had serum anti-T-lymphocyte antibodies. The presence of surface Ig+ T lymphocytes correlated significantly with lower absolute CD4+ lymphocyte counts only in asymptomatic, HIV-1-infected individuals.

Antigens, CD↗
PubMed1990

Functional and immunogenetic characterization of FcR-blocking antibody.

The characteristics and functional importance of FcR-blocking antibodies and their production were investigated after immunization with whole blood, "buffy coat" and purified platelets. We studied the presence of FcR-blocking antibody in haemodialyzed, transfused patients waiting for kidney transplantation, and we found strong correlation between the blocking effect and better graft survival. We suggest that this blocking antibody does not attack FcR as primary target. Investigation of blocking activity of ten different immune sera on 50 healthy panel cells showed that target antigen has some polymorphic varieties. On basis of family studies it seems that the target antigen is not linked to HLA haplotype. The blocking effect of sera could be removed by absorption of CD8+ cells, B lymphocytes, platelets and granulocytes, but not with erythrocytes, monocytes, CD8- cells and NK cells.

Absorption↗
PubMed1990

Differences in non-MHC restricted cytotoxic activities of human peripheral blood lymphocytes after transfusion with allogeneic leukocytes or platelets possessing class I and/or class II MHC molecules.

MHC-unrestricted cytotoxic activity of peripheral blood lymphocytes (PBL) from 4-6 healthy donors was investigated before and after transfusion with allogeneic leukocytes or platelets. Natural killer and lectin-dependent cellular cytotoxicity (LDCC) of PBL was tested against K562 and Raji target cells in a 4-h and 16-h 51Cr-release assay, respectively. After allotransfusion with leukocytes, we found increased cytotoxic activity of each donor's PBL against all the three targets on day 3 or 7. The highest non-specific cytotoxic activity was detected against the relatively NK resistant Raji target cells. The increase of cytotoxic activity was lowest against the LDCC target (PHA-treated Raji) cells. On the contrary, no changes in cytotoxic activity against any targets were observed after allotransfusion with platelets (possessing class I HLA antigens but no HLA class II molecules). Our results suggest that HLA class II molecules, presumably by inducing immune responses, are essential for activation/generation of non-specific killing of tumor targets after leukocyte transfusion. Thrombocytes, known to be less immunogenic than leukocytes, are not effective in in vivo enhancing of non-specific cytotoxicity. Cellular activation of PBL following leukocyte allotransfusion was confirmed by detection of elevated serum neopterin and beta-2-microglobulin levels on day 3. This was not the case after platelet allotransfusion. In addition, the expression of ICAM-1 antigen (as a molecule involved directly in MHC-unrestricted cytotoxicity) was also found to be increased in two donors' PBL on day 3 after leukocyte transfusion in contrast to transfusion with platelets.

Biopterins↗
PubMed1990

Selective effect of noncytotoxic blocking alloantibodies produced after platelet transfusions on MLC, and mitogen and soluble antigen-induced responses of human lymphocytes.

The transfusion of blood components (buffy coat and platelets) may induce characteristic alloimmune response or suppressive regulation that have, in certain cases, a beneficial effect on allograft survival. The blocking effect of the sera of donors immunized with platelets on mixed lymphocyte culture and on the response of lymphocytes to mitogen as well as soluble antigen (PPD, tetanus toxoid) stimulation was studied. Six sera from 7 volunteers displayed a strong and significant nonspecific MLC blocking effect that was detectable on the 10th day following the second platelet transfusion (PT). Incubation of isolated stimulator and effector cell population with this "blocking sera" showed that the latter are involved in the mediation of suppression in the MLC test. This inhibitory effect is associated with the serum IgG fraction lacking any correlation with either class I or class II specific cytotoxic antibodies. Selective blocking behavior was found on transformation activity induced by mitogens or soluble antigens. Thus, sera of platelet-transfused volunteers decreases the responsiveness of lymphocytes to phytohemagglutinin, while the response to concanavalin A, tetanus toxoid, and PPD was not suppressed. Separate treatment of T and B lymphocyte populations and monocytes with the blocking sera showed that only T and B lymphocytes are targets, and not the monocytes for the inhibition in the case of PHA-induced proliferation. Indirect evidence may support the notion that MLC-inhibiting and FcR-blocking antibodies may be analog products of a regulatory alloimmune response induced by leukocytes that are partially responsible for the beneficial transfusion effect in organ transplantation.

Antigens↗
PubMed1990

[Gerontoprosthesis. Concept of rebuilding old complete dentures].

If aged patients who have been wearing their full dentures without complications so far, need further prothetic treatment, the dentist must not replace the old denture by a completely new one. It is better to rebuild it step by step. This demand is based on the following theses: --Nobody but the patient himself is able to perform functional movements. --Unless bite and occlusion are correct, patients are not able to perform accurate functional movements. --When bite and occlusion have been checked and, if necessary, improved, bases and alveolar ridges must be congruent.

Aged↗
PubMed1990

Transfusion of the patient with acquired immunodeficiency syndrome.

Cytopenias are commonly found in patients infected with human immunodeficiency virus. Thrombocytopenia due to peripheral destruction of platelets is an early manifestation, normocytic anemia and neutropenia are late manifestations. Transfusions are required when symptoms become severe. Chemotherapy of patients with the acquired immunodeficiency syndrome (AIDS) is also cytotoxic and further contributes to the transfusion requirement. Patients with AIDS receiving treatment with zidovudine, in particular, have a high transfusion requirement. Empirically, many centers irradiate blood products transfused to AIDS patients to prevent possible graft-vs-host reaction in the immunologically compromised recipient. Attempts to correct the deficiency of helper T cells with lymphocyte transfusion and marrow transplantation have so far been ineffective. Similarly, therapeutic trials to treat this disease by apheresis of virus-bearing cells has been ineffective and has, therefore, been abandoned.

Acquired Immunodeficiency Syndrome↗
PubMed1989

[Importance of type I hypersensitivity to molds in autumnal respiratory allergies].

The authors examined by means of skin tests for moulds 108 patients with the diagnosis of pollen rhinitis and/or pollen bronchial asthma. All had maximum complaints at the end of summer and in autumn and were formerly hyposensitized only by pollen allergens. Sensitization to fungi and its polyvalent character was significantly greater in subjects unsuccessfully treated by pollen hyposensitization, as moulds acted obviously as an important allergen. The authors found a low sensitivity and specificity of USOL screening preparations "Outdoor moulds" (76% and 81%) and "Indoor moulds" (74% and 93%).

Adult↗
PubMed1988

Human immunodeficiency virus type 1 has an additional coding sequence in the central region of the genome.

Eight coding regions designated gag, pol, env, sor, R, tat, art/trs, and 3' orf have been identified in the genome of the human immunodeficiency virus type 1 (HIV-1). Several other open reading frames have the potential to encode additional viral proteins. In this study, we show that HIV-1 has another coding sequence whose product is expressed during natural infection. Unlike antibody to other HIV-1 proteins, the prevalence of antibody to the product encoded by this region is elevated in patients with acquired immune deficiency syndrome (AIDS). Because no analogous coding region has been identified in HIV-2, the antibody to the product of this coding region may serve as a marker to distinguish infection with HIV-1 from infection with HIV-2.

Acquired Immunodeficiency Syndrome↗
PubMed1988

Human immunodeficiency virus infection in patients with leukemia.

Eighteen human immunodeficiency virus (HIV)-seropositive patients were found among 211 previously treated adult patients with a variety of leukemias who had been multiply transfused before April 1985. Patients known to be homosexual or intravenous drug users were excluded from this study. The spouse of one HIV-seropositive patient became HIV infected and subsequently developed the acquired immune deficiency syndrome. Patients with leukemia who were multiply transfused before the availability of screening of blood products for HIV antibody should be counseled regarding their individual risks of HIV infection and the risk to sexual contacts.

Female↗
PubMed1988

Lack of evidence of prolonged human immunodeficiency virus infection before antibody seroconversion.

Recently, considerable concern has been raised regarding the possibility that antibody-based screening tests for the human immunodeficiency virus (HIV) may fail to detect certain high-risk individuals for prolonged periods of time. It has been proposed that testing for HIV-related antigen may be a necessary procedure to detect such individuals. To address this issue, we longitudinally studied two groups of homosexual men: direct sexual partners of acquired immunodeficiency syndrome (AIDS) or AIDS-related complex (ARC) patients and individuals who ultimately sero-converted. There was no evidence of prolonged infection with HIV in the absence of detectable antibody in these two groups. It appears at this time that, even among subjects at very high risk for HIV infection, currently available antibody-based assays are sufficient to identify infected individuals.

Acquired Immunodeficiency Syndrome↗
PubMed1987

Characterization of serum neutralization response to the human immunodeficiency virus (HIV).

To determine the clinical significance of human neutralizing antibodies to the human immunodeficiency virus (HIV), we measured serum neutralization in patients with different clinical outcomes following HIV infection. Serum neutralization titers ranged from less than 1:5 to 1:100. The neutralization response after HIV infection appeared slow, with neutralization titers remaining low, at or below 1:5, at 7 months following seroconversion. Comparison of 78 HIV seropositive subjects with AIDS, AIDS-related complex, or no symptoms failed to reveal any significant differences in titer which correlated with clinical status. However, a greater proportion of AIDS patients with Kaposi's sarcoma (11/12) had neutralization titers of 1:20 or greater than did AIDS patients with opportunistic infections (2/11). Serum samples were analyzed by Western blot for their reactivity to specific viral proteins. Clinical status could not be predicted by a particular serological profile. However, sera which reacted with the HIV major envelope glycoprotein gp120 tended to have higher neutralization titers, suggesting that gp120 may be a target of anti-HIV neutralizing antibody in man.

AIDS-Related Complex↗