Search PubMed⌕ Search

Biomedical subjects

S Wendel

Publications and source records attributed to S Wendel.

33 records · Page 2Linked to original sources
PubMed1996

Evaluation of Rh monoclonal antibodies for flow cytometry tests.

As participants of the "III International Workshop on Monoclonal Antibodies against Human Red Blood Cells and Related Antigens", we tested 43 RH monoclonal antibodies by the flow cytometry technique. Besides the anti-D antibodies (not included in this paper), we tested the following antibodies: three (3) anti-C; one (1) anti-Cw; six (6) anti-c; eight (8) anti-E; three (3) anti-e; two (2) anti-G; one (1) anti-CcEe (total = 24 antibodies). These antibodies (from different lab sources) were tested against antigen positive cells (homozygous or heterozygous) and antigen negative cells. When available, some of them were tested against "rare" phenotypes like ryr, r' 'Gr, rGr, R2Rz. All the three anti-C tested, showed poor discrimination between positive and negative cells; from the six anti-c tested, only three had good results (Workshop n degree 18, 20, 21) with a superior performance of one of them (Workshop n degree 18). From the eight anti-E tested, we found two (Workshop n degree 139 and 153) with good performance; all the three anti-e were non reactive; the two anti-G failed to react with r'r red cells; the anti-Cw reacted better with R1wr cells than R1wR1; and the anti-CcEe antibody showed good results with all the phenotypes tested. From the 24 antibodies tested, we found six (25%) antibodies with a good performance.

Antibodies, Monoclonal↗
PubMed1995

Akv murine leukemia virus enhances bone tumorigenesis in hMT-c-fos-LTR transgenic mice.

hMt-c-fos-LTR transgenic mice (U. Rüther, D. Komitowski, F. R. Schubert, and E. F. Wagner. Oncogene 4, 861-865, 1989) developed bone sarcomas in 20% (3/15) of females at 448 +/- 25 days and in 8% (1/12) of males at 523 days. After infection of newborns with Akv, an infectious retrovirus derived from the ecotropic provirus of the AKR mouse, 69% (20/28) of female animals and 83% (24/29) of males developed malignant fibrous-osseous tumors. The tumors in infected transgenics developed with higher frequency and a 200-days shorter mean tumor latency period. The hMt-c-fos-LTR transgene was expressed in all the fibrous-osseous tumors. They also showed newly integrated Akv proviruses, but in most tumors Akv was detected and expressed in only a small number of the tumor cells. Wild-type C3H mice infected with Akv developed benign osteomas with an incidence of 33% and a latency period of 474 days. The data indicate that Akv exerts distinct pathogenic effects on the skeleton. In hMt-c-fos-LTR transgenic mice, predisposed to bone sarcomagenesis, Akv acts synergistically with the fos transgene, resulting in the development of fibrous-osseous tumors.

AKR murine leukemia virus↗
PubMed1995

Akv murine leukemia virus enhances lymphomagenesis in myc-kappa transgenic and in wild-type mice.

The contribution of endogenous retroviruses to the multistep process of lymphomagenesis was investigated in wild-type mice and in two different myc-kappa transgenic mouse lines by infection with Akv. This retrovirus is derived from the endogenous ecotropic provirus of the AKR mouse and was previously considered to be nonlymphomagenic. The mice of the two myc-k transgenic lines are predisposed to B-cell lymphomagenesis and were therefore considered to be more susceptible to Akv. For comparison, the same mouse strains were also infected with the exogenous Moloney murine leukemia virus (MoMuLV). Both MoMuLV and Akv increased the tumor incidence and shortened the tumor latency period in wild-type mice and in the transgenic mouse lines. The differences in pathogenicity, number of provirus integrations, and level of virus expression between MoMuLV and Akv indicate different mechanisms of lymphomagenesis: while MoMuLV induced tumors apparently by insertional mutagenesis involving common integration sites similar to previous reports, the enhancement of lymphomagenesis by Akv seems to be directed by other mechanisms.

AKR murine leukemia virus↗
PubMed1995

Absence of serological surrogate markers for Trypanosoma-cruzi-infected blood donors.

Specific serological screening tests for Trypanosoma-cruzi-infected donors are not yet available and thus not routinely performed in North America. With the recent increase of Latin-American immigration to North America and Europe, there is a risk of transmission by blood products. In this study, we evaluated the possibility whether any of the serological screening tests currently recommended by the AABB could be used as a surrogate marker for this protozoarium. A group of 26,365 blood donors (male = 21,053 and female = 5,312) was analysed for the correlation of T. cruzi antibodies (TcAb) with other serological markers (HIV, HBsAg, ALT, HTLV-I/II, HCV, Anti-HBc, syphilis and unexpected hemoglobins other than A1, A2 and F). Association could be demonstrated only between syphilis and TcAb in the female group (p = 0.005), but the low number of donors found with this association (n = 4) renders the effect of this correlation very small. A higher prevalence of TcAb was found in older age groups, with even gender distribution (p < 0.05), however, donors aged more than 54 years also represent a minority of the donor pool (4.83%) and the detection of positive donors in this age group also has a minor preventive effect on transfusion-transmitted Chagas disease. We conclude that when infected blood donors must be detected, specific serological screening for TcAb is essential and that currently no surrogate marker can be considered for detecting T. cruzi-infected blood donors.

Animals↗
PubMed1993

Chagas' disease and blood transfusion: a New World problem?

American trypanosomiasis (Chagas' disease) can be transmitted by blood transfusion. For almost 40 years, this transmission has been limited to Latin America, but recently, three cases have been reported in the USA and Canada. With increasing emigration to North America and Europe, Chagas' disease may be introduced to the Northern hemisphere by transfusion of blood from carriers. This review will focus on the discovery, biology and antigenic profile of Trypanosoma cruzi (the aetiological agent of Chagas' disease), including the invertebrate vectors, animal reservoirs and transmission to humans, with special reference to blood transfusion. Finally, diagnostic tests and prophylactic measures for the prevention of Chagas' disease will be discussed.

Animals↗
PubMed1990

Molecular analysis of the REV2 gene of Saccharomyces cerevisiae--a review.

The REV2 gene controls DNA repair, induced mutagenesis and, probably, some fidelity mechanism of replication. Of particular interest is the notion that it is inducible by DNA-damaging agents. We wanted to find molecular evidence for these results derived from numerous biological experiments. We cloned the REV2 gene from a yeast genomic DNA library based on the YCp50 centromere vector, sequenced it and studied its regulation on the transcriptional level. The coding region of the REV2 gene consists of a 1425 pb reading frame with a coding capacity for a polypeptide of 52 kD; no significant homology to any gene filed in available data bases was found. Examination of a hydrophobicity plot of the putative Rev2 protein predicts the existence of transmembrane helices. Quantitative Northern analysis confirmed the working hypothesis that DNA-damaging agents increase the level of REV2 gene expression in stationary cells. Thus, the REV2 gene seems to code for a membrane protein which is inducible by DNA-damaging agents and which controls processes of repair and mutagenesis in yeast.

Base Sequence↗
PubMed1990

A simplified method for purification, concentration and freezing of bone marrow cells for autologous transplantation.

Autologous bone marrow (BM) transplantation is being increasingly applied in hematological and oncological patients. However, because of the need to purify and preserve BM requiring high technology, such treatments are virtually concentrated in the "developed" countries. This paper examines methods of BM purification and freezing that could make the technique potentially applicable in developing countries. Hemapheresis is routinely applied for BM purification in our Dutch Centre, where the buffy coats obtained from routine blood donations were utilised in experimental settings. Using DMSO as cryoprotectant, semi-purified white cells were frozen in liquid N2 (LN2), by mechanical freezer or snap-frozen at -55 degrees C. Different types of containers were compared including plastic tubes and ordinary blood bags. After thawing the results show that snap-freezing had a deleterious effect but the cell yields and viability were similar in LN2 or the mechanical freezer where the tubes and the bag were equally effective as containers (86% cell recovery with 90% viability). In the purification/concentration stage, reduction of the volume of the material by extra centrifugation, thus requiring less DMSO, produced better results--96% cell yield and 90% viability after thawing. This simplified method was applied in a general hospital in Sao Paulo where four oncology patients underwent BM collection. BM was purified and concentrated within a blood bank facility. Hydroxyethyl starch sedimentation and centrifugation of the material in plastic blood bags gave 80% BM cell harvest. After thawing from the mechanical freezer 1 x 10(8) BM cells/kg were available for reinfusion to patients. There was no immediate untoward reaction. Three of the patients showed signs of bone marrow regeneration by three weeks, but one patient died 16 days after transplantation, of septicemia. We conclude that certain high-technology procedures for ABMT can be adapted for existing facilities in developing countries.

Bone Marrow Transplantation↗
PubMedDate not supplied

Reliability and validity of the Overeating Tension Scale.

This study presents the development and testing of the Overeating Tension Scale. Overeating tension was defined operationally as the total discrepancy score resulting from differences between subjects' ratings of actual and desired feelings before overeating. The 32-item Overeating Tension Scale, derived from Apter's Reversal Theory, measures reported overall tension and motivation-specific tension. The scale initially included 48 items, six items for each of eight motivational states. After two instrument development studies (N = 373, N = 208), items were refined and reduced to a total of 32, or four for each of eight motivational states. The final version of the instrument was tested in two additional studies (N = 330, N = 130) that provided evidence to support the internal consistency reliability of the Overeating Tension Scale. There was support for construct validity using contrasted groups (overweight and normal weight subjects), convergent validity, and factor analysis.

Adult↗
PubMedDate not supplied

[Anti-BHc determination in blood donors in São Paulo: should this test be adopted in Brazil?].

PURPOSE: to study the incidence of anti-HBc (core) as a surrogate marker for post-transfusion Non-A, Non-B Hepatitis (HNANB-PT) among blood donors in São Paulo, Brazil. TYPE: prospective, screening all blood donors from September to December, 1989 (nr. 2,773 donors). PLACE: Sírio-Libanês Hospital and 9 de Julho Hospital (São Paulo). PATIENTS: a total of 2,773 donors, 84% male and 16% female. METHOD: the tests used were competitive ELISA for Anti-HBc. MEASUREMENTS AND RESULTS: the repeated rah reactivity (RR) was 10.2% among all donors, with a higher incidence in males than in females (10.9% x 6.8% p less than 0.05 6y X2). Only 4.5% were borderlines, and 94.5% showed an absorbance/cut-off ratio less than 0.9. CONCLUSIONS: despite the lack of prospective studies correlating HNANB-PT to surrogate markers (e.g. ALT and anti-HBc) in this country, the high incidence of anti-HBc in donors allows to conclude that it might be as high as reported in other countries. Although the costs related to the adoption of this test, its indication in other countries and its association with the newly-developed specific test (anti-HCV) supports the idea of anti-HBc as a screening test for HNANB-PT in Brazil, at least in the most developed blood centers in the country.

Adolescent↗