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D Schönitzer

Publications and source records attributed to D Schönitzer.

At least 19 recordsLinked to original sources
PubMed2006

Up to 21-day banked red blood cells collected by apheresis and stored for 14 days after automated wash at different times of storage.

BACKGROUND AND OBJECTIVES: A closed-system technology (ACP-215, Haemonetics, Braintree, MA) enables automated washing and extended storage of frozen red blood cells (RBC). This technology was applied to wash banked RBC for removal of undesirable protein and metabolites before transfusion. We studied protein and metabolite depletion as well as RBC metabolism and viability up to 14 days postwash with regard to various pre-storage times. MATERIALS AND METHODS: Thirty RBC units were collected by means of apheresis and subdivided into three arms based on prewash storage time period (6 days/group 1, 14 days/group 2, 21 days/group 3). Wash efficacy (protein depletion, IgA), RBC metabolism (pH, lactate, potassium, haemolysis) and cell viability (ATP) were analysed immediately and 14 days after washing. RESULTS: Total protein and IgA postwash were lowered by automated wash in all groups and uniformly met EC guidelines. Potassium (mmol/l) was below 1.2 mmol/l postwash and significantly below prewash values in all groups, even after 14 days of storage (prewash vs. postwash; P < 0.05). RBCs washed after 14 and 21 days, respectively, showed significantly lower pH values and lower ATP content than RBCs washed after only 6 days of storage. Haemolysis rate remained significantly below 0.8%, the maximum level recommended by the EC guidelines, immediately and 14 days after washing in all units. CONCLUSION: Our data confirm that RBC units banked up to 21 days can be effectively protein- and potassium-depleted with the ACP-215 independent from prewash storage time. With respect to high ATP levels and pH, postwash storage of 2 weeks should be limited to units not older than 7 days before wash. This new washing technology ensures better standardization in washed RBC and provides blood centres with a logistical alternative to 24-h washed RBC products.

Blood Component Removal↗
PubMed2001

Prostate cancer mortality after introduction of prostate-specific antigen mass screening in the Federal State of Tyrol, Austria.

OBJECTIVES: To monitor the impact of screening in a natural experiment by comparing prostate cancer mortality in Tyrol, where prostate-specific antigen (PSA) testing was introduced at no charge, with the rest of Austria, where it was not introduced. METHODS: In 1993, PSA testing was made freely available to men aged 45 to 75 years in the Federal State of Tyrol, Austria. At least two thirds of all men in this age range have been tested at least once during the first 5 years of the study. Initially, only total PSA was measured, but free PSA measurement was added in 1995. The IMX assay was used. Digital rectal examination was not part of the screening examination. RESULTS: Significant migration to lower stages has been observed since the introduction of this screening program. A reduction in mortality rates in the rest of Austria from 1993 onward has occurred, with the reduction in Tyrol much greater; the mortality remained fairly constant between 1993 and 1995 and subsequently fell. The trends in prostate cancer mortality rates since 1993 differ significantly between Tyrol (P = 0.006) and the rest of Austria. On the basis of the age-specific death rates averaged from 1986 to 1990, the difference between the number of expected and observed deaths from prostate cancer in Tyrol was 22 in the group aged 40 to 79 years in 1998 and 18 the following year. CONCLUSIONS: These findings are consistent with the hypothesis that the policy of making PSA testing freely available, and the wide acceptance by men in the population, is associated with a reduction in prostate cancer mortality in an area in which urology services and radiotherapy are available freely to all patients. It is our opinion that most of this decline is likely to be due to aggressive downstaging and successful treatment and that any contribution from detecting and treating early cancers will only become apparent in the years to come.

Aged↗
PubMed2001

PCR screening for common weak D types shows different distributions in three Central European populations.

BACKGROUND: DNA sequencing showed RHD mutations for all weak D phenotypes investigated in a study from Southwestern Germany. Molecular classification of weak D offers a more reliable basis than serotyping and is relevant for optimal D transfusion strategies. STUDY DESIGN AND METHODS: Sequence-specific primers were designed to detect weak D types 1 to 5 and the partial D phenotype HMi in a modular set for conventional PCR analysis. Alternatively, all reactions were multiplexed into a single tube, and the products were identified after automated capillary electrophoresis by their size and fluorescence. Weak D phenotype samples from 436 donors in the Tyrol (Austria) and Northern Germany were investigated by PCR. RESULTS: More than 90 percent of the weak D types identified by PCR represented type 1, 2, or 3. The distribution among the common types varied between the Tyrol and Northern Germany (p<0.0001). Three new RHD alleles were identified. CONCLUSION: A PCR method of detecting the common weak D types was validated. This PCR system introduces a simple and rapid tool for routine DNA typing of weak D samples. The results confirmed that all weak D phenotype samples identified by current serologic criteria carry altered D proteins.

Alleles↗
PubMed2001

Prolonged iron depletion after allogeneic 2-unit RBC apheresis.

BACKGROUND: Allogeneic 2-unit RBC apheresis is a safe procedure offering many advantages for donors and blood banks. A controlled study was performed to determine whether the recommended minimum interval of 4 months between 2-unit RBC apheresis donations is appropriate in terms of the recovery of RBCs and the regeneration of iron stores. STUDY DESIGN AND METHODS: Twenty male subjects each donated 2 units of RBCs by apheresis. The RBC count, reticulocyte count, EPO, and measures of iron status were analyzed before and during the 4 months after donation. RESULTS: A significant decrease in Hb (15.89 +/- 0.82 [mean +/- SD] vs. 14.08 +/- 0.97 mg/dL, baseline vs. Day 7; p<0.001) was equalized within 2 months. In contrast, ferritin values declined significantly from 54.2 +/- 33.7 to 23.42 +/- 21.94 microg per L (predonation vs. Day 30) and remained significantly below predonation values, but within the normal range, until the end of the study period. CONCLUSION: A donation interval of 4 months is appropriate in terms of RBC recovery, but may not be appropriate in terms of iron store regeneration. The tendency to shorten the donation interval should be reconsidered in light of the measurements of iron storage. The use of ferritin levels is recommended as a preselection criterion for allogeneic 2-unit RBC apheresis.

Adult↗
PubMed2000

Unimpaired dendritic cells can be derived from monocytes in old age and can mobilize residual function in senescent T cells.

Dendritic cells (DC) are powerful antigen presenting cells, which have the unique capacity to stimulate naive T cells. In spite of the well-known decline of T cell function in old age, little information is available on whether DC are also affected by the aging process. This is mainly due to problems with the isolation and purification of DC. Rapid progress in the characterization of DC has been made in recent years, as simple methods to generate large numbers of DC from precursors have been developed. It was the aim of the present study to compare monocyte derived DC from old and young healthy persons. The generation of DC from blood monocytes in response to GM-CSF and IL-4 treatment was similar in cells from young and old persons. The DC population thus obtained had a typical dendritic morphology and expressed DC surface markers, such as HLA class II, CD1a, CD11c, CD54, CD80 and CD86, but not CD14 for a period of up to three weeks in culture. DC from young and old persons produced IL-12 and TNF-alpha and responded equally well to maturation-inducing stimuli. DC maturation was stimulated by purified protein derivative (PPD) of Mycobacterium tuberculosis, whole inactivated influenza virus and by influenza split vaccine, but not by purified viral RNA. When tested for their antigen-presenting capacity, DC from young and old persons were capable of stimulating the proliferation and the cytokine production of T cells. It was of particular interest that CD45RA(+) as well as CD45RO(+) T cells from aged donors were unable to respond to stimulation with influenza proteins presented by monocytes, but were triggered to proliferate and to produce cytokines when antigen was presented by DC. The results demonstrate that DC from old persons (a) may still function as powerful antigen-presenting cells provided the right differentiation and maturation stimuli are present; (b) are capable of mobilizing residual capacity in senescent T cells and (c) may therefore represent a potent tool for immunotherapy and vaccines in old age.

Adult↗
PubMed1999

Neutralization of HIV type 1 by alloimmune sera derived from polytransfused patients.

Antibodies (Abs) against HLA and other cell surface molecules, which HIV-1 acquires during the budding process at the host cell surface, neutralize HIV-1 in vitro. Macaques were protected against infection by SIV grown in human cells after xenoimmunization with human MHC molecules. Besides the immune responses arising against xenogeneic antigens, the highly polymorphic character of the HLA antigens enables the induction of alloresponses after exposure to allogeneic HLA molecules. Since polytransfused (PT) patients develop alloresponses, including humoral anti-HLA responses, we assumed that sera derived from PT patients may neutralize HIV-1. In a model system two PT sera out of a panel of 12 PT and 6 normal control sera neutralized HIV IIIB in vitro. Neutralizing activity of the PT sera was comparable to the efficacy of anti-HIV sera. The neutralizing capacity coincided with strong IgG reactivity against (HIV-infected) cell lines, which were used for virus production, and recognition of cell-free viral particles. Active human complement enhanced HIV neutralization mediated by the sera. Our results suggest an IgG-mediated neutralization based on recognition of allogeneic HLA molecules expressed on the viral surface. A vaccination strategy based on alloimmunization appears conceivable and requires further investigation.

Blood Transfusion↗
PubMed1999

Molecular basis of weak D phenotypes.

A Rhesus D (RhD) red blood cell phenotype with a weak expression of the D antigen occurs in 0.2% to 1% of whites and is called weak D, formerly Du. Red blood cells of weak D phenotype have a much reduced number of presumably complete D antigens that were repeatedly reported to carry the amino acid sequence of the regular RhD protein. The molecular cause of weak D was unknown. To evaluate the molecular cause of weak D, we devised a method to sequence all 10 RHD exons. Among weak D samples, we found a total of 16 different molecular weak D types plus two alleles characteristic of partial D. The amino acid substitutions of weak D types were located in intracellular and transmembraneous protein segments and clustered in four regions of the protein (amino acid positions 2 to 13, around 149, 179 to 225, and 267 to 397). Based on sequencing, polymerase chain reaction-restriction fragment length polymorphism and polymerase chain reaction using sequence-specific priming, none of 161 weak D samples investigated showed a normal RHD exon sequence. We concluded, that in contrast to the current published dogma most, if not all, weak D phenotypes carry altered RhD proteins, suggesting a causal relationship. Our results showed means to specifically detect and to classify weak D. The genotyping of weak D may guide Rhesus negative transfusion policy for such molecular weak D types that were prone to develop anti-D.

Alleles↗
PubMed1999

Unusual association of the DRB4 null allele, DRB4*0103102N, with HLA DRB1*0402 in a sample of Austrian patients.

Tissue typing for HLA class II antigens is routinely performed by serological, and/or DNA-based methods. Accuracy, absence of cross-reactivity and controllable level of resolution are striking advantages of molecular methods. However, a disadvantage of molecular typing, compared to serological methods, is the identification of unexpressed alleles. Whereas serology allows a more or less direct insight into antigen presence, molecular biology is an indirect method and results must also be interpreted by considering the biological pathways of protein expression. We believe that identification of nonexpressed MHC alleles is of importance for transplantation, since nonexpressed MHC allele positive individuals could give rise to antibody formation against the respective expressed MHC product in donor tissue. Usually, the nonexpressed DRB4*0103102N is encountered in association with DRB1*0701-DQB1*03032, which facilitates correct DNA typing. Here we describe the unusual association of this unexpressed DRB4*0103102N, with DRB1*0402-DQB1*0302 in a sample of Austrian patients.

Adult↗
PubMed1998

Environmental influence on age-related changes of human lymphocyte membrane viscosity using severe combined immunodeficiency mice as an in vivo model.

Peripheral blood lymphocytes (PBL) of healthy elderly people show increased plasma membrane viscosity compared to young subjects, that inversely correlates with lymphocyte proliferation after mitogen stimulation in vitro. Maintenance of a constant membrane viscosity, which is necessary for proper cell function, is crucially dependent on the membrane lipid composition. The cellular lipid metabolism, and thus lymphocyte function, may be subject to modulation by diet or drugs. To study the susceptibility of membrane viscosity to environmental conditions, we established an in vivo model using severe combined immunodeficiency (SCID) mice: human peripheral blood lymphocytes from healthy young and old subjects were engrafted for three days intraperitoneally into SCID mice to offer identical environmental conditions. First, we demonstrate that human lymphocytes can take up and utilize murine lipoproteins: engrafted human PBL can participate in the mouse lipid metabolism, and an exchange of membrane lipids in vivo is, therefore, possible. Second, plasma membrane viscosity was determined before and after engraftment: before engraftment, PBL from the elderly showed a significantly higher membrane viscosity than that from young controls, but this difference vanished during engraftment into SCID mice, wherein cells from both age groups exhibited nearly identical values. It was, therefore, concluded that lymphocyte membrane viscosity is influenced by environmental factors, and that the age-related increase is, in principle, reversible.

Adult↗
PubMed1998

Dendritic cell responsiveness to stimulation with influenza vaccine is unimpaired in old age.

We have previously demonstrated that whole virus influenza vaccine can activate dendritic cells (DC). In the present study we analyzed whether DC activation was affected by the aging process. For this reason the expression of immunoregulatory molecules and the production of cytokines were compared in blood-derived DC from old and young healthy individuals following stimulation with inactivated influenza virus. Unstimulated DC from young and old individuals had a similar surface expression of MHC class II and CD54 and secreted moderate amounts of IL-12 and TNF-alpha. Stimulation with influenza vaccine led to a marked increase in the production of surface molecules and cytokines. These changes were equally pronounced in cells from young and old individuals. Our results demonstrate that DC responsiveness to stimulation with a viral vaccine is unimpaired in old age. DC may, therefore, represent a potent tool for immunotherapy and may increase the efficacy of vaccines in the elderly.

Adult↗
PubMed1997

PSA-based screening for prostate cancer in asymptomatic younger males: pilot study in blood donors.

BACKGROUND: The efficacy and success of a screening program for prostate cancer in young and healthy asymptomatic volunteers are described. METHODS: In the present study, prostate specific antigen (PSA) samples obtained from 2,272 males (aged 40-65 years) who donated blood at the local Red Cross Blood Bank were evaluated. Two groups of donors were distinguished, which were investigated in different ways. Group 1 comprised individuals aged 40-49 years (n = 568), while group 2 consisted of males aged 50-65 years (n = 1,704). Volunteers in group 2 who had PSA levels greater than 4 ng/ml (n = 302) were referred for ultrasound guided biopsy irrespective of findings on digital rectal examination (DRE). In group 2, individuals with PSA levels exceeding 4 ng/ml and positive DRE findings biopsy specimen was ordered (n = 2). In patients with unremarkable findings on DRE, serum PSA was determined 1 year later and in case of more than 20% increase in the PSA level biopsy was obtained under ultrasound guidance. RESULTS: The biopsy specimen yielded prostatic carcinoma in 58 patients in group 1. As a screening test, serum PSA determination was superior to digital rectal examination. On digital palpation only 2 presented with abnormal prostates. These 58 patients underwent radical prostatectomy and histological examination revealed organ-confined disease in all but 8. In group 2, in 4 of 12 males the biopsy specimen yielded prostatic carcinoma. CONCLUSIONS: This study shows that PSA measurement in blood donors is a useful method for recruiting screening volunteers, and therefore represents an additional possibility for early detection of prostate cancer in asymptomatic younger males. Furthermore, it represents an effective tool for following relatively young patients known to have a significant risk of prostate cancer.

Adult↗
PubMed1997

RHD/CE typing by polymerase chain reaction using sequence-specific primers.

BACKGROUND: Current DNA-based Rh system typing strategies may detect the two RH genes and their prevalent alleles, but they are known to fail sometimes, when rare RH alleles (e.g., D category phenotypes) are encountered. It is almost impossible to find a single DNA-based method that can accommodate the great heterogeneity within the human Rh system. STUDY DESIGN AND METHODS: An easy-to-perform DNA-based method for the detection of the two RH genes and their alleles, including variant RHD alleles, was developed. By the use of one RHD/C-, seven RHD-, and four RHCE-specific polymerase chain reactions, all triggered to work at identical thermocycling conditions, the DNA of 77 blood donors carrying weak D and that of 200 random donors with common D phenotype was investigated. In addition, 77 selected samples of ccDee and rare Rh system phenotypes were examined. RESULTS: Among 77 samples of weak D, one Rh33 and six DVI categories were detected, one of which showed new RHD-specific nucleotide patterns. In DFR and CCee samples, novel variant RHD alleles were found. RHD DNA types of 200 random donors were found to be concordant with their D phenotype. For RHE and RHe genotyping, a full correlation with serologic phenotypes was found. Our method for genotyping RHC and RHc failed in some cases, because of an already published RHc allelic variation, which we have called RHc(cyt48). An estimate of the frequency of this RHc(cyt48) allele in a white population was made. CONCLUSION: The presented exon-scanning RHD/CE polymerase chain reaction using sequence-specific primers complements current DNA-based Rh system typing strategies and is superior in the detection of variant RHD alleles.

Blood Donors↗
PubMed1997

[Extensive plasma exchange in treatment of acute vascular graft rejection of the kidney and pancreas].

Twenty-eight histologically proven severe acute vascular rejection episodes in renal grafts were reversed in 22/28 (78%) cases by extensive plasma exchange, which was well-tolerated by all but one patient. CMV infection was the most frequent complication. As 1-year survival of 93% (patient) and 71% (graft) is considered a good result in this severe immunological complication, the extensive plasma exchange can be recommended for the treatment of acute vascular rejection.

Adolescent↗
PubMed1996

Properties of low density lipoproteins relevant to oxidative modifications change paradoxically during aging.

Atherosclerosis is a common problem among the elderly. Because lipid peroxidation is considered a contributor to the development of atherosclerosis, we compared oxidative properties of lipoproteins in an otherwise healthy (SENIEUR-classified) aged population (65-74 years) with young controls (18-30 years). Relative amounts of oxidatively altered low density lipoprotein (LDL), estimated by means of an antibody against LDL modified by 4-hydroxynonenal, a product of lipid peroxidation, were increased marginally in serum from the elderly (9.8 vs. 7.4%, P = 0.07). In contrast, isolated LDL from the elderly revealed a decreased susceptibility to in vitro oxidation: the lag time was increased (2.34 vs. 2.10 h, P < 0.01), and the maximal rate of LDL oxidation decreased (0.88 vs. 1.01 O.D./h, P = 0.001). However, there were no age-related changes in lipid composition of native LDL and consumption of fatty acids during in vitro oxidation. The serum concentrations of ascorbic acid and most lipophilic anti-oxidants (the latter expressed per g serum lipids) were significantly decreased in the elderly except tocopherols which tended to be higher. In conclusion, our data reveal paradox age-related alterations of LDL as to its behaviour in oxidation in vivo vs. in vitro.

Adolescent↗
PubMed1996

ABO glycosyltransferase genotyping by polymerase chain reaction using sequence-specific primers.

Serological typing for the classical ABO blood groups is routinely performed using anti-A and anti-B antisera of polyclonal or monoclonal origin, which are able to distinguish four phenotypes (A, B, AB, and O). Modern molecular biology methods offer the possibility of direct ABO genotyping without the need for family investigations. Typing can be done with small amounts of DNA and without detection of blood group molecules on the surface of red blood cells. We developed a system of eight polymerase chain reactions (PCR) to detect specific nucleotide sequence differences between the ABO alleles O1, O2, A1, A2, and B. PCR amplification using sequence-specific primers and detection of amplification products by agarose gel electrophoresis is one of the fastest genotyping methods and is easy to handle. With our method we tested the A1,2BO1,2 genotypes of 300 randomly chosen persons out of a pool of platelet donors and found the results to be consistent with ABO glycosyltransferase phenotypes. We also identified a presumably new ABO allele, which may be the result of a crossing-over event between alleles O1 and A2.

ABO Blood-Group System↗