PubMed Health⌕ Search

Biomedical subjects

E Strobel

Publications and source records attributed to E Strobel.

At least 37 records · Page 2Linked to original sources
PubMed1998

Detection of HIV-1 infection in dried blood spots from a 12-year-old ABO bedside test card.

BACKGROUND AND OBJECTIVES: We tested dried blood from an ABO bedside test card which had been stored at room temperature for 12 years, to prove that a patient with HIV-1 infection had been infected by blood transfusion. MATERIALS AND METHODS: Immunoblots for HIV-1 antibodies and threefold PCRs with half-nested primers for the HIV-1 integrase gene were done with eluates from the dried blood spots. RESULTS: HIV-1 antibodies and HIV-1 DNA could be detected in the sample from one unit of blood, but not from the two other units or from the recipient before transfusion. CONCLUSION: Further studies should be done on the validity of stored dried blood as an alternative to the storage of frozen donor serum for several years for 'look-back' studies.

ABO Blood-Group System↗
PubMed1996

Rationally designed non-peptides: variously substituted piperazine libraries for the discovery of bradykinin antagonists and other G-protein-coupled receptor ligands.

Molecular modeling studies of potent decapeptide bradykinin antagonists suggested the de novo design of peptide mimetics based on a 1,2,3,4-tetrasubstituted 1,4-piperazin-6-one scaffold. These de novo-designed antagonists exhibited only modest potency (IC50 approximately 55 microM) on a cloned human B2 receptor and antagonist activity in an in vitro human-cell functional assay. The success of these structures led to the creation of prototype libraries based on variously substituted 1,4-piperazine scaffolds, which allowed a rapid and general search of pharmacophores attached to a piperazine scaffold. The parent piperazinedione structures and fully reduced piperazine libraries differ from recently reported diketopiperazine libraries in the use of diverse nonnatural amino acids, on-resin-submonomer synthesis to provide more diverse N-substituted structures, and the adaptation of simultaneous ring closure and resin cleavage to drive the formation of highly hindered amide bonds. Using this chemistry, a rationally directed non-peptide library of approximately 2500 N,N'-disubstituted piperazines and piperazinediones was synthesized and screened for ligand affinity on bradykinin, neurokinin, and opioid receptors. A number of lead structures were identified. Notably, a bradykinin antagonist lead, CP-2458, with good receptor selectivity and antagonist activity in human-cell assays was identified and is undergoing optimization by traditional and combinatorial methods.

Acetylation↗
PubMed1996

[Suitability of monoclonal reagents in determination of ABO blood group of newborn infants].

BACKGROUND: Weak expression of ABO antigens in newborns has been known for many years. In the near future reduced availability of polyclonal sera for ABO testing is to be expected. Therefore, it was the aim of our study to compare the suitability of monoclonal reagents for ABO testing of newborns to that of polyclonal sera. MATERIAL AND METHODS: One monoclonal and 1 polyclonal reagent of each of the specificities anti-A, and anti-B and anti-AB from 7 manufacturers were tested by titration with blood from 5 newborns of blood group A, 5 of blood group B, and 3 of blood group AB. RESULTS: All monoclonal anti-A reagents showed better results than the polyclonal sera (for newborns of blood group A on the average of the 7 pairs of reagents 1.3 geometrical titration steps). Most of the monoclonal anti-B reagents showed higher titers than the polyclonal sera (on the average for newborns of blood group B 0.7 titration steps). Also most monoclonal anti-AB reagents were stronger than the polyclonal sera in testing newborns of blood group B the monoclonal anti-AB-reagents were slightly weaker than the polyclonal sera (on the average 0.4 titration steps). CONCLUSION: Use of monoclonal reagents for ABO testing of newborns shows some advantages in comparison to the use of polyclonal sera.

ABO Blood-Group System↗
PubMed1995

[Preventive anti-D after massive fetomaternal hemorrhage].

In the 36th week of gestation intrauterine death of both twins occurred in a 31-year old primigravida. The examination of the C- and the D-antigen of the mother's blood (result of previous testing: AB Rhesus negative) immediately before delivery showed a mixed field agglutination which pointed to a fetomaternal macrotransfusion. Fetal haemoglobin in the mother's circulation was 7.8% of her total haemoglobin, so that a fetomaternal haemorrhage of about 440 ml whole blood had to be suspected. For Rhesus-prophylaxis 17 standard doses of anti-D-immunoglobulin were administered intramuscularly distributed over 4 days. No adverse effects were seen; fetal haemoglobin dropped to 2.0% 5 days and to 0.1% 15 days after the beginning of the treatment. A control examination after 9 months showed no signs of a Rhesus-(D)-sensitisation of the patient.

Female↗
PubMed1995

[Suitability of monoclonal reagents for antigen determination in T-antigen activation].

BACKGROUND: The lack of additional antibodies--for example anti-T--which can be contained in test sera of human origin has been pointed out as an advantage of monoclonal reagents in blood group serology. It was the aim of our study to examine whether the reactions of monoclonal reagents are nevertheless disturbed by T activation of red blood cells or not. MATERIALS AND METHODS: Monoclonal reagents of several manufacturers of the specificities anti-A, -B, -AB, -A1, -H, -C, -c, -D, -E, -e, -K, -Jka, -Jkb, -Lea, -Leb, -M, and -N were tested. For this study we examined sialidase-treated and not treated red blood cells with and without the tested blood group antigen by the reagent using the tube centrifugation method. RESULTS: We found no significant disturbances for the monoclonal reagents of the AB0-system, A subgroups, Rhesus system, Kidd system, Kell antigen, and Leb antigen. Monoclonal anti-M and anti-N showed missing reactivity with sialidase-treated erythrocytes, which is already known from polyclonal test sera. Most of the monoclonal anti-Lea reagents showed strong false-positive reactions with T-positive Le(a-) erythrocytes. After several absorptions of one of the monoclonal anti-Lea reagents with T-activated Le(a-b-) red blood cells, the reactivity of the reagent with the Lea antigen and the T antigen had disappeared. CONCLUSIONS: In contrast to the other monoclonal reagents for most of the monoclonal anti-Lea reagents the lack of additional anti-T antibodies does not indicate the lack of false-positive reactions. This cross-reactivity might be caused by the fact that the type 1 chain antigen Lea and the type 3 chain antigen T have the same terminal saccharide (galactose) in beta 1-->3 connection to the preterminal saccharide of their peripheral core structure.

Antibodies, Monoclonal↗
PubMed1995

Biotin in vitro translation, nonradioactive detection of cell-free synthesized proteins.

In vitro translation of mRNAs into proteins is frequently used to study the coding capacity of RNAs or cDNAs and the functional effects of mutations. In vitro translation assays have traditionally been monitored by following the incorporation of a radiolabeled amino acid into newly synthesized protein. We have optimized an alternative nonradioactive biotin-labeling method. tRNALys is first aminoacylated with lysine, which is then chemically labeled with biotin. When biotin-lysine-tRNALys is added to translation systems, the biotinylated lysine is incorporated into the growing polypeptide chain. After electrophoresis and transfer to a blotting membrane, the biotin-labeled translation products are detected by a chemiluminescent reaction of luminol/iodophenol with streptavidin-coupled horseradish peroxidase. This nonradioactive method yields results equivalent to those obtained using the radioactive method. Biotin-labeled translation products are also biologically functional: (i) biotinylated precursor proteins are transported and processed correctly by dog pancreas microsomes; (ii) transcription factors synthesized by biotin in vitro translation bind specifically to their DNA recognition sequence; and (iii) biotin-modified luciferase keeps its enzymatic activity. The major advantage of the biotin in vitro translation system is that no radioactivity is required, and the method is easy, economical, reproducible and fast--the whole nonradioactive procedure, from translation to detection, can be completed within six hours.

Animals↗
PubMed1995

[Observations on antibody determination and differentiation with papain test erythrocytes using the gel centrifugation technique (ID-Microtyping System)].

BACKGROUND: The gel centrifugation system (ID Microtyping System, Fa. Diamed, Bensheim, FRG) is one of several new methods, which has become commercially available within the last few years for the detection of antibodies against red blood cell antigens. MATERIALS AND METHODS: During 1 year we used the gel centrifugation method for antibody screening in our routine laboratory by performing 3 tests each time: 1. NaCl card (room temperature) with untreated red cells; 2. NaCl card (37 degrees C) with papain-treated red cells, and 3. Liss-Coombs card (37 degrees C) with untreated red cells. RESULTS: The two-stage papain test revealed some interesting phenomena: 1. In some cases the sensitivity of the papain gel test is higher than that of all other methods tested in this study, namely in the gel centrifugation technique and in the tube centrifugation technique. 2. There are reactions which seem to be directed against patients' own antigens (in the Rhesus or Kidd system), but there are no positive direct antiglobulin test and no clinical signs of hemolysis. 3. Some sera show reaction patterns which seem to have a distinct specificity, but they cannot be assigned to any of the antigens in the manufacturer's antigenogram. CONCLUSIONS: Before a general recommendation for antibody screening with the two-stage papain test in the gel centrifugation method can be given, further investigations about the clinical value of those antibodies which are detectable only by this technique are necessary. For antibody identification further declarations in the work sheet of the panel would be desirable.

Adult↗
PubMed1995

[Detection and side effects of isoantibodies in intravenously administered immunoglobulin preparations].

BACKGROUND: Intravenous immunoglobulins (IvIg) contain not only the declared antibodies against pathogenic microorganisms, but also all the other antibodies of the blood donors, e.g. against erythrocytic antigens. MATERIALS AND METHODS: We tested 14 IvIg from 7 manufacturers (a total of 40 charges) for isoantibodies and irregular antibodies. To improve the reading of our tests we used the gel centrifugation method (ID-Microtyping-System, Fa. Diamed, Bensheim, Germany). RESULTS: The highest isoantibody titers were (in 8 charges) 1:32 or 1:64 in the Liss-Coombs test. Irregular antibodies were found in 5 IvIg (maximal titer 1:8). CONCLUSIONS: Isoantibodies in the IvIg can influence blood group serologic tests. With an example of a newborn who had received IvIg we point to the potential danger of misinterpretation of a positive direct antiglobulin test after administration of IvIg. Therefore we recommend to carry out the direct antiglobulin test before administration of IvIg and to examine all eluates after a positive direct Coombs test not only with 0 RBCs but also with A or B RBCs of the AB0 blood group of the patient.

ABO Blood-Group System↗
PubMed1995

[Suitability of monoclonal test sera for determination of blood group markers in positive direct Coombs test].

BACKGROUND: Monoclonal reagents of the IgM type allow to test some red blood cell antigens (K; Jka; Jkb) by the tube centrifugation method at room temperature, for the examination of which the indirect antiglobulin test was necessary in the past. This permits to test antigens also when the direct antiglobulin test is positive, provided the sera do not contain too much supplement. MATERIALS AND METHODS: We tested a choice of monoclonal reagents of different manufacturers (for the ABO system, A subgroups, the Rhesus, MN, Kell, Kidd and Lewis system) for their ability to examine antibody-coated erythrocytes. To recognize false-positive reactions of the reagents, erythrocytes without the particular antigen were coated with an incomplete antibody, and then the reagent was tested with these self-made Coombs control cells. RESULTS: We found no false-positive reactions for all tested anti-A, anti-B, anti-AB, and anti-A1 reagents. Some anti-C, anti-c, anti-E, anti-e and anti-N reagents showed weak false-positive reactions, some anti-H, anti-D, anti-K, anti-Jka, anti-Jkb, anti-Lea, anti-Leb and anti-M reagents stronger false-positive reactions.

Antibodies, Monoclonal↗
PubMed1994

[Acute intravasal hemolysis in Clostridium perfringens sepsis. Differential diagnosis of hemolytic episodes].

A 19-year-old man with acute lymphoblastic leukaemia developed fever, general deterioration and somnolence 3 days after a cycle of cytostatic treatment. He had anaemia (haemoglobin 6.6 g/dl), leukopenia (100/microliters) and thrombocytopenia (7,000/microliters). As an acute septicaemia was suspected he received broad spectrum antibiotic therapy, together with two units of red cell and platelet concentrates. However, his condition worsened rapidly over the next 5 hours (meningism, seizures, fever to 41.1 degrees C, dyspnoea). Another blood count revealed severe haemolysis. Computed tomography of the skull demonstrated multilocular intraparenchymal gas formation. Although the antibiotic treatment was extended the patient died several hours later. Retrospective examination for suspected transfusion mismatch provided no evidence for erythrocyte incompatibility. But there was liberation of T-antigen as sign of a bacterial cause of erythrocyte damage. An anaerobic blood culture grew Clostridium perfringens. This case demonstrates that acute intravascular haemolysis in septicaemia should be considered in the differential diagnosis of transfusion mismatch.

Adult↗