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Biomedical subjects

H Eichler

Publications and source records attributed to H Eichler.

At least 19 recordsLinked to original sources
PubMed2004

Implementation of the INTERCEPT Blood System for Platelets into routine blood bank manufacturing procedures: evaluation of apheresis platelets.

BACKGROUND AND OBJECTIVES: The INTERCEPT Blood System for Platelets utilizes amotosalen-HCl (S-59) in combination with ultraviolet A (UVA) light to inactivate viruses, bacteria, protozoa and leucocytes that may contaminate platelet concentrates (PCs). To facilitate implementation of this technique into routine blood bank manufacturing procedures, this study evaluated the impact of different time settings of photochemical treatment on in vitro platelet function. MATERIALS AND METHODS: Platelets derived from apheresis (6.5-7.0 x 10(11) platelets) were resuspended in 240 ml of autologous plasma and 360 ml of platelet additive solution (PAS III) and split into two equal-sized PC units. Whereas one unit was not treated, the other was treated with 150 microm amotosalen and 3 J/cm2 UVA light followed by a compound adsorption device (CAD) step for reduction of residual amotosalen and photoproducts. In a first series of experiments (arm A, n = 7), PC units were photochemically treated after an overnight storage period of 16-23 h followed by a CAD step of 4 h. In a second series (arm B, n = 8), photochemical treatment occurred after a short storage time of 4 h with a subsequent CAD step of 16 h. Platelet function was evaluated by assaying blood gas analysis, glucose and lactate concentration, lactate dehydrogenase (LDH), hypotonic shock response (HSR) and the expression of CD62p, over a period of 7 days. RESULTS: Neither of the photochemical treatment procedures showed differences for pH, pCO2, pO2, HCO3, glucose consumption or platelet activation until the end of day 7. Increased lactate values detected for the treated units of arm A at the end of the storage period were independent from the PCT time setting. CONCLUSIONS: Photochemical pathogen inactivation with different initial resting periods between 4 and 23 h, and different CAD steps of 4 and 16 h, had no influence on the platelet in vitro function during 7 days of storage.

Adsorption↗
PubMed2003

Interventions for normal tension glaucoma.

BACKGROUND: Normal tension glaucoma is a clinical condition in which the optic nerve is pathologically excavated and the visual field is disturbed. Nevertheless it has been assumed that intraocular pressure plays a role in the progression of visual field defects in this disease, but other, mainly vascular factors, have been discussed as well. OBJECTIVES: The objective of this review is to assess the effects of medical and surgical treatments for normal tension glaucoma. SEARCH STRATEGY: Trials were identified from the Cochrane Central Register of Controlled Trials (CENTRAL) (which contains the Cochrane Eyes and Vision Group trials register), MEDLINE, EMBASE and BIOSIS Previews. Bibliographies of identified trials were searched to find additional trials. In addition, investigators and pharmaceutical companies were contacted. Date of last search: January 2001. SELECTION CRITERIA: This review includes randomised controlled trials in which medical or surgical interventions were compared to no treatment, placebo or other treatment in people with normal tension glaucoma. Two reviewers independently assessed the full text copies of the possibly relevant trials. Trial quality was assessed according to the methods set out in Section 6 of the Cochrane Reviewers' Handbook (Clarke 2000). DATA COLLECTION AND ANALYSIS: Data were extracted by two reviewers and results were compared for differences. Discrepancies were resolved by discussion. The heterogeneity of interventions, follow-up periods and outcomes did not allow for statistical combinations of the study results. MAIN RESULTS: According to the selection criteria on visual field loss, eight studies were included in this review. Only three studies focussed on patient relevant outcomes. In one trial a beneficial effect of lowering intraocular pressure was found, but only if data were corrected for cataract development. In two small studies a beneficial effect on visual field loss of brovincamine, a calcium antagonist was reported. REVIEWER'S CONCLUSIONS: In one study the effect of intraocular pressure lowering on visual field outcome was only significant when data were corrected for cataract development. The results for calcium antagonists are promising, but larger trials have to be performed. Studies that focussed on reduction of intraocular pressure or haemodynamic variables are not necessarily relevant for the outcome in people with normal tension glaucoma.

Antihypertensive Agents↗
PubMed2003

Effect of recombinant human deoxyribonuclease on the expression of cell adhesion molecules of thawed and processed cord blood hematopoietic progenitors.

BACKGROUND AND OBJECTIVES: The integrity of granulocytic cells and platelets is compromised within cryopreserved stem cell transplants, and consequent DNA release during the thawing procedure can therefore lead to clotting phenomena or microaggregate formation and that in turn may cause loss of progenitor cells. To circumvent this problem a new processing protocol was introduced using recombinant human deoxyribonuclease (rhDNase) to prevent cell aggregate formation. In addition, the impact of this new processing protocol on CD34+ umbilical cord blood (UCB) cells was assessed. MATERIALS AND METHODS: Fifty samples derived from 7 buffy coat (BC) volume reduced UCB units were cryopreserved, thawed, and processed with washing solutions that were supplemented with rhDNase in various concentrations. Thereafter, clotting and microaggregate formation was scored microscopically. In addition, expression of the adhesion molecules leukocyte function-associated antigen 1 (LFA-1, n = 6), intercellular adhesion molecule-1 (ICAM-1, n = 11), and L-selectin (n = 11) on CD34+ UCB cells was analyzed by flow cytometry after incubating the samples with either dimethyl sulfoxide (DMSO) 5.5%, rhDNase 10 or 50 U/mL, or a combination of DMSO 5.5% and rhDNase 50 U/mL. RESULTS: At a minimal concentration of 10 U rhDNase/mL, clotting or microaggregate formation could be prevented for all tested samples, whereas cell clots could be observed for concentrations up to 8 U/mL. The expression of adhesion molecules on untreated CD34+ UCB cells (L-selectin: 64.6 +/- 18.8%; LFA-1: 62.6 +/- 7.5%; ICAM-1: 14.8 +/- 4.1%) did not show any significant difference compared with cells that were incubated with up to 50 U/mL rhDNase (L-selectin: 62.2 +/- 19.3%; LFA-1: 63.1 +/- 5.9%; ICAM-1: 17.5 +/- 6.7%). However, after a combined treatment with DMSO 5.5% and rhDNase 50 U/mL, a slight but significant decrease in L-selectin expression could be observed (P < 0.03). CONCLUSION: The supplementation of rhDNase to a final concentration of 10 U/mL cell suspension proved to be effective in preventing clot formation under the conditions examined and did not lead to decreased expression levels of adhesion molecules. We therefore recommend the use of rhDNase for the prevention of clot formation and cell loss during the processing of thawed UCB transplants.

Antigens, CD34↗
PubMed2003

Tolerance of granulocyte donors towards granulocyte colony-stimulating factor stimulation and of patients towards granulocyte transfusions: results of a multicentre study.

Data of 507 granulocyte donations from 183 donors were evaluated. No severe granulocyte colony-stimulating factor (G-CSF)-related side-effects were observed. Three donors complained of severe itching following infusion of hydroxyethyl starch (HES). A high proportion (85%) of the donors stated that they would donate granulocytes again. The mean granulocyte yield was 4.3 x 10(10). High-molecular-weight HES resulted in a significantly higher yield compared with low-molecular-weight HES. Mild, but no severe, adverse transfusion reactions were observed in 16% of the recipients. A leucocyte alloimmunization rate of 24% was found. G-CSF stimulation and transfusion of G-CSF-mobilized granulocytes were well tolerated by donors and recipients, respectively.

Adolescent↗
PubMed2003

Optimized sensitivity of allele-specific PCR for prenatal typing of human platelet alloantigen single nucleotide polymorphisms.

PCR using sequence-specific primers (PCR-SSP) is widely employed for the genotyping of single nucleotide polymorphisms (SNPs) in both routine diagnosis and medical research. The human platelet alloantigens (HPAs) represent SNPs in platelet-specific glycoproteins, and HPA-1, -2, -3, and -5 are the most relevant in immunohematology. In most protocols, the respective HPA-SNPs are analyzed in allele-specific reactions, each with at least 100 ng DNA. In many cases, prenatal HPA typing in the diagnosis of neonatal alloimmune thrombocytopenia is often limited by the restricted amounts of fetal DNA that are obtainable. We developed a novel PCR-SSP technique to achieve accurate HPA genotypes using only 1 ng DNA per reaction. The concentration of HPA-specific primers was increased to 1 microM each and exhibited a higher sensitivity compared to a commercial PCR-SSP kit. The modified PCR-SSP technique enabled the identification of fetal HPA genotypes using only 0.5 mL amniotic fluid (from week 16 of gestation) and from a maternal plasma sample (from week 38 of gestation). The principle of the modified PCR-SSP technique may also be applied for the genotyping of other SNPs from limited amounts of DNA.

Amniocentesis↗
PubMed2002

Is prenatal HLA typing of uncultured amniocytes before the collection of related allogenic cord blood helpful?

The collection of related allogenic cord blood is gaining increasing importance in families with one child affected by haematopoietic disease. Within a family, there is only a 25% chance of a full HLA match between siblings. 50% of all collected cord blood samples cannot be used because of poor quality. Because of this, the determination of HLA type is useful for planning the collection of related allogenic cord blood transplants. We studied whether HLA typing is possible during late pregnancy if amniocentesis has not been performed during the first trimester. HLA -A, -B and -DRB loci were detected in amniotic fluid, as well as in corresponding cord blood and maternal blood using PCR-SSP. For the first time, HLA typing was performed from uncultured amniocytes. Unambiguous results were obtained from all samples. Fetal HLA-genotype in amniotic fluid was confirmed by typing results from corresponding cord blood. HLA typing of uncultured amniocytes during late pregnancy is a reliable and fast method. For the first time, prenatal HLA typing by amniocentesis after week 38 of gestation is possible in less than 8 h and without fetal risk.

Adult↗
PubMed2002

Use of recombinant human deoxyribonuclease (DNase) for processing of a thawed umbilical cord blood transplant in a patient with relapsed acute lymphoblastic leukemia.

This case report describes for the first time the use of a recombinant human enzyme deoxyribonuclease (rhDNase) containing solution for the processing of a thawed umbilical cord blood (UCB) unit prior to successful transplantation to avoid cell losses by clotting phenomena. A 6-year-old boy received an unrelated 2/6 HLA antigen mismatched UCB transplant for high-risk Burkitt type acute lymphoblastic leukemia. The UCB unit was provided as a volume-reduced sample after buffy coat separation with a final volume of 36 ml. To avoid the loss of nucleated cells due to cell clumping during thawing procedure cells were washed with a solution containing the rhDNase. No visible clotting of the resuspended unit occurred, and the patient was transplanted with 2.9x10(7) nucleated cells/kg body weight without any acute or chronic side effects due to rhDNase. On day +35, PCR analysis of bone marrow aspirate showed complete chimerism, and the child engrafted with an absolute neutrophil count greater than 0.5x10(9)/l on day +47. Platelet transfusion independence was achieved on day +120. In conclusion, the supplementation of rhDNase to the washing and resuspension solutions of a thawed UCB unit is effective to prevent cell losses prior to transplantation. However, further investigations must be performed to confirm the safety of this procedure.

Blood Transfusion↗
PubMed2002

Autologous concentrated platelet-rich plasma (cPRP) for local application in bone regeneration.

Platelets are rich in growth factors that may contribute to an accelerated tissue regeneration process. The therapeutic osteogenic effect of local platelet administration probably depends on the amount of growth factors delivered within. To improve platelet-derived factor preparations, the platelets have to be concentrated without loss of the granular growth factor load. An autologous procedure according to the Good Manufacture Practice (GMP) guidelines to prepare a high concentrate from platelet-rich plasma (cPRP) for clinical application in bone regeneration is presented. Platelet-rich plasma (PRP) was generated from the centrifugation supernatant of 250 ml anticoagulated autologous blood. The PRP was then further centrifuged at the day of operation to generate concentrated PRP (cPRP) in 8 ml plasma. The data from 34 patients (9 m, 25 f), ageing from 21 to 71 years (median 50.4) were evaluated. Both, the platelet counts as well as the TGF-beta1 concentrations in the cPRP were found to be 12-fold increased compared to the PRP values. Overall, a 17-fold increase in platelet concentrations was achieved compared to the patients' whole bloods and platelet counts correlated with increased levels of TGF-beta1 within the cPRP. These results give rise to quality control specifications for a safe and cost effective preparation of cPRP. The method has proven to be suitable for blood services to support the needs for treatment in oral and maxillofacial surgery.

Adult↗
PubMed2001

Prenatal HLA typing of uncultured amniocytes prior to the collection of related allogeneic cord blood.

DNA samples isolated from corresponding uncultured amniotic fluid, cord blood and maternal blood (n=5) were subjected to low resolution typing of the HLA-A, -B and -DRB loci by the polymerase chain reaction using sequence-specific primers (PCR-SSP). Furthermore, the effect of ethylene diamine tetraacetate disodium salt (EDTA) on the quality of genomic DNA isolated from amniotic fluid samples after long-term storage was evaluated. Unambiguous results of HLA typing could be achieved from all amniotic fluid samples stabilized with EDTA. PCR-SSP typing failed in DNA samples from amniotic fluid without the addition of EDTA. In all cases the fetal HLA type could be confirmed by the result from the corresponding cord blood typing. Contamination with maternal DNA led to additional weak PCR-SSP bands in one case, but data interpretation was still unambiguous. Reliable fetal HLA typing can be achieved directly from amniotic fluid and culturing of amniocytes is not required.

Amniocentesis↗
PubMed2001

Impact of plasmapheresis on platelet hemostatic capacity in healthy voluntary blood donors detected by the platelet function analyzer PFA-100.

Previous flow cytometry studies showed that platelet activation may occur during cytapheresis, cardiopulmonary bypass and hemodialysis. The aim of this pilot study was to determine if the impact of plasmapheresis leads to alterations in platelet hemostatic capacity. Plasmapheresis was carried out in 30 volunteers using an Autopherese C (Baxter) and an MCS3p (Haemonetics). Blood samples were collected and analyzed immediately before and after plasmapheresis. As a result of the plasmapheresis on the Autopherese C, the mean closure time (CT) for collagen/epinephrine (Col/Epi) increased from 118.2 +/- 25.1 to 149.9 +/- 35.0 s and from 88.7 +/- 16.9 to 98.5 +/- 26.3 s for collagen/ADP (Col/ADP), respectively. Seven subjects showed impaired CTs after plasmapheresis for Col/Epi. For Col/ADP, five subjects showed impaired CTs after apheresis. Statistical analysis (McNemar test) showed a significant difference before and after apheresis for Col/Epi (P = 0.024) but not for Col/ADP (P = 0.088). Similar results were shown for plasmapheresis carried out with the MCS3p. These findings show that plasmapheresis can cause an impairment of platelet function in healthy volunteers as measured by the PFA-100, an effect of so far unknown clinical significance.

Adult↗
PubMed2000

Cord blood as a source of autologous RBCs for transfusion to preterm infants.

BACKGROUND: This prospective study was conducted to gain experience as to whether it is technically possible to produce autologous RBCs in additive solution from cord blood (CB), to optimize the blood supply for preterm infants. STUDY DESIGN AND METHODS: CB was collected from 47 infants with a mean (+/- SD) birth weight of 1717 (+/- 699) g. Whenever possible, RBC components were prepared by standard centrifugation using a six-bag system. All samples were put in sterility testing quarantine for 5 days, and a maximum storage of 14 days from collection to transfusion was specified. The babies were given either the autologous RBCs or standard allogeneic RBC concentrates, if autologous blood was not available. RESULTS: In 81 percent of the samples, autologous RBC components could be processed (vol, 7-87 mL; Hct, 31-82%). But within the group of extremely low birth weight infants (body weight <1000 g), a mean CB net volume of only 37 mL was collected, and the RBC preparation was successful only in exceptional cases. Three CB samples (8.6%) tested positive in sterility testing. Of the 47 infants, 21 were treated with a total of 62 allogeneic and 4 autologous RBC transfusions. Most infants with a body weight over 1400 g did not need any RBC transfusion. CONCLUSION: The preparation of autologous RBCs from the CB of preterm infants is technically possible in principle. However, major concerns must be raised as to whether such preparations are of benefit in ensuring safe care of neonates with blood components, with respect to the high rate of bacterial contamination and the limited availability in babies with low birth weight.

Costs and Cost Analysis↗
PubMed1999

Novel Ras antagonist blocks human melanoma growth.

During past decades, knowledge of melanoma biology has increased considerably. Numerous therapeutic modalities based on this knowledge are currently under investigation. Advanced melanoma, nevertheless, remains a prime example of poor treatment response that may, in part, be the consequence of activated N-Ras oncoproteins. Besides oncogenic Ras, wild-type Ras gene products also play a key role in receptor tyrosine kinase growth factor signaling, known to be of importance in oncogenesis and tumor progression of a variety of human neoplasms, including malignant melanoma; therefore, it is reasonable to speculate that a pharmacological approach that curtails Ras activity may represent a sensible approach to inhibit melanoma growth. To test this concept, the antitumor activity of S-trans, trans-farnesylthiosalicylic acid (FTS), a recently discovered Ras antagonist that dislodges Ras from its membrane-anchoring sites, was evaluated. The antitumor activity of FTS was assessed both in vitro and in vivo in two independent SCID mouse xenotransplantation models of human melanoma expressing either wild-type Ras (cell line 518A2) or activated Ras (cell line 607B). We show that FTS (5-50 microM) reduces the amounts of activated N-Ras and wild-type Ras isoforms both in human melanoma cells and Rat-1 fibroblasts, interrupts the Ras-dependent extracellular signal-regulated kinase in melanoma cells, inhibits the growth of N-Ras-transformed fibroblasts and human melanoma cells in vitro and reverses their transformed phenotype. FTS also causes a profound and statistically significant inhibition of 518A2 (82%) and 607B (90%) human melanoma growth in SCID mice without evidence of drug-related toxicity. Our findings stress the notion that FTS may qualify as a novel and rational treatment approach for human melanoma and possibly other tumors that either carry activated ras genes or rely on Ras signal transduction more heavily than nonmalignant cells.

Animals↗
PubMed1999

High incidence of maternal HLA A, B and C antibodies associated with a mild course of haemolytic disease of the newborn. Group for the Study of Protective Maternal HLA Antibodies in the Clinical Course of HDN.

Mild courses of haemolytic disease of the foetus or newborn (HDN) due to Rh (D) blood group antibodies are associated with and may therefore be ameliorated by maternal antibodies reacting with human leucocyte antigens (HLA) of the child, an observation drawn from our own earlier data (Neppert J, Kissel K. Lancet 1992;339:1481). This study (i) corroborates this association; (ii) reveals shortcomings in the published data; and (iii) examines the characteristics of HDN cases when these shortcomings have been rectified. Samples from 51 women with antibodies against their child's blood group antigens of the Rh system were analysed for HLA A, B, C and DR antibodies during parturition. The mothers were divided into two groups, either severe or mild, dependent upon the clinical course of the HDN, and the incidence of HLA antibody production was determined for each group. HLA A, B, C and/or DR antibodies were detected in 85.2% of those women whose children had a mild course of HDN prenatally or perinatally (n=27). This is statistically greater than the incidence of 50.0% (Fisher's exact test: p=0.014) found in the group of women whose children had a severe HDN either pre- or perinatally (n=24) and is greater than the 35% (n=20; p=0.0001) found in women without Rh or other irregular antibodies. HLA DR antibodies were detected in three cases. The findings support our hypothesis that maternal anti HLA A, B and C antibodies may protect against a potential severe HDN. We therefore assume that those women will benefit who have already had a child with a severe HDN and in whom HLA antibodies were not previously detected, if HLA antibody production is provoked by subcutaneously inoculating with the father's leucocytes before or at the beginning of the new pregnancy.

Adult↗
PubMed1999

Micro-column affinity test and gel test: comparative study of two techniques for red cell antibody screening.

BACKGROUND AND OBJECTIVES: We describe the results of a comparative evaluation of a gel test (ID Micro Typing) and a micro-column affinity test (MCAT, Cellbind Screen) for red cell antibody screening and identification under routine conditions. MATERIALS AND METHODS: 3,000 serum samples of patients from the Mannheim University Hospital were tested in parallel by means of the gel test and the MCAT, using the low-ionic-strength-saline indirect antiglobulin test and the protein G affinity technique, respectively. Test cells used were the same in all tests. In addition, we performed titration studies with all detected antibodies as well as with 59 frozen sera containing antibodies of known specificity. RESULTS: A total of 154 antibodies (5.1%) were detected, 149 by gel test and 147 by MCAT. The overall sensitivity and specificity of the gel test was 96.8 and 96.5% and of the MCAT 95.5 and 97.2%. No significant differences between the gel test and MCAT were found when the titer scores of all 213 (fresh and frozen) antibodies were used to check the results. The mean scores for the gel test and the MCAT were 26.8 and 28.5, respectively. For anti-Fy(a) and anti-Kell, a significantly higher titration score could be obtained in the MCAT, whereas anti-Lu(a) showed a significantly higher score with the gel test. CONCLUSION: For the screening of unexpected red blood cell antibodies, the MCAT is as sensitive as the gel indirect antiglobulin test. The sensitivity and specificity of the two systems are more or less the same although it seems that IgM antibodies are better detected by the gel test.

Antibodies, Blocking↗
PubMed1998

Photometric evaluation of the solid-phase antiglobulin test using length measurement of the absorption curve.

BACKGROUND AND OBJECTIVES: The very sensitive solid-phase antiglobulin test is used widely in blood group serology. However, a disadvantage of the test is the sedimentation variability of indicator cells during centrifugation, which causes errors in the photometric evaluation. MATERIALS AND METHODS: To solve this problem a technique was developed which depends on the 'length measurement of the absorption curve' of the sedimented indicator cells. RESULTS: 9,075 sera were tested for the presence of alloantibodies on the basis of the visual type of measurement and the newly developed technique. The agreement between the two evaluation systems was 99.94%. No false-negative results were observed. CONCLUSION: The new method allows the complete automation of the solid-phase antiglobulin test, enabling the analysis and evaluation of the solid-phase microtiter plate assay to be more discriminating and safe.

Antibody Specificity↗
PubMed1998

5% Me2SO is sufficient to preserve stem cells derived from cord blood.

On the basis of historical findings, 10% dimethylsulfoxide is still used to cryopreserve stem cells. We studied a final concentration of 5% dimethylsulfoxide in cryopreservation of cord blood-derived stem cells in autologous plasma. In our opinion, a final concentration of 5% dimethylsulfoxide in autologous plasma without further additives is sufficient for cryopreservation of cord blood stem cells in a banking routine.

Blood Banks↗