Search PubMed⌕ Search

Biomedical subjects

T Wagner

Publications and source records attributed to T Wagner.

At least 91 records · Page 5Linked to original sources
PubMed2000

Kell is not restricted to the erythropoietic lineage but is also expressed on myeloid progenitor cells.

Anti-Kell antibodies have been shown to suppress fetal erythropoiesis, but little is known about their effect on myelopoiesis. We analysed the effect of Kell-related antibodies on granulocyte-macrophage colony-forming units (CFU-GM) growth in semisolid medium using peripheral blood mononuclear cells (PBMNCs) from haematologically normal individuals. In addition to its inhibitory effect on erythroid burst-forming units (BFU-E) growth, anti-Kell antibodies significantly reduced CFU-GM colony formation from Kell-positive individuals but not from Kell-negative donors. Moreover, anti-cellano and anti-Kpb antibodies also inhibited the growth of CFU-GM from antigen-positive MNCs. These data indicate that Kell is not restricted to erythroid blood cells, but is also expressed on myeloid progenitor cells.

Antibodies↗
PubMed2000

Transfusion of platelet concentrates from pooled buffy-coats: comparison of bedside vs. prestorage leukofiltration.

Prestorage leucocyte filtration of platelet concentrates (PC) has been considered to be superior to bedside filtration with regard to the incidence of nonhaemolytic transfusion reactions (NHTR) or HLA-alloimmunization. It is currently a matter of debate whether prestorage leucocyte filtration has an impact on the storability of platelets and on the transfusion results of PC. In a clinical retrospective study we investigated the transfusion results of PC from pooled buffy-coats (PC-BC) in haematological patients without known refractoriness to platelets, and compared bedside filtration (n = 228/36 patients) vs. prestorage filtration (n = 271/25 patients). Leukocyte and platelet content of the PC, duration of storage, platelet count of the patient before transfusion and 20 h after transfusion were determined and platelet increment and corrected count increment (CCI) 20 h after transfusion were calculated. The mean leucocyte content of the bedside filtered PC was 66 +/- 50 x 106 and < 0.1 x 106 for the prestorage filtered PC (P < 0.001). Mean platelet content of the PC (2.6 x 1011 vs. 2.7 x 1011) and the duration of PC storage (2.7 vs. 2.6 days) were almost identical in both groups. The platelet increment after 20 h (14.6 x 109 L-1 vs. 14.9 x 109 L-1) was equal for both groups, but CCI values were significantly higher for the bedside filtered PC (14.1 +/- 9.5 vs. 11.4 +/- 6.8) (P = 0.008). Correlation with the storage time revealed that CCI levels were higher for bedside filtered PC after short-term storage (< 36 h) (P = 0.014), but declined more rapidly compared with prestorage filtered PC. A patient-based analysis including fewer cases revealed superior but nonsignificant results for bedside filtration. In conclusion, bedside filtered PC-BC resulted in better CCI results after short-term storage, but values equalized with prestorage filtered PC-BC after longer storage intervals. Prestorage-leucocyte filtration did not improve platelet recovery in vivo, but CCI values decreased only moderately throughout storage. Both preparations showed excellent transfusion results even after a 5-day storage interval.

Blood Preservation↗
PubMed2000

Severe HDN due to anti-Ce that required exchange tranfusion.

BACKGROUND: Rh system antibodies are commonly encountered in blood bank practice as well as during pregnancy. Nevertheless, no examples of anti-Ce (RH7) have been reported as a cause of HDN that requires exchange transfusion. CASE REPORT: A 38-year-old woman in her fourth pregnancy was typed as blood group O D+, C-, c+, E+, e-. Anti-C and anti-e were detected in her serum during a routine prenatal work-up. Further evaluation, including flow cytometric analysis, revealed the presence of a strong anti-Ce and a weak anti-e. Her partner was typed as group A D+, C+, c-, E-, e+. A seemingly healthy male infant was delivered at 40 weeks of gestation. The infant's RBCs were typed as group O D-, C+, c+, E+, e+ with a positive DAT (titer 128). Twenty-five hours after birth, the baby had to be transferred to the neonatal intensive care unit because of rapidly rising total serum bilirubin. Despite intensive treatment, including double phototherapy, albumin infusion, and the administration of furosemide and IVIG, the total serum bilirubin level increased during the following day and exchange transfusion with 2 units of type O D-, C-, c+, E+, e- had to be performed; this resulted in a prompt decrease in total serum bilirubin without relapse. CONCLUSION: Anti-Ce caused severe HDN requiring exchange transfusion. This highlights the need for a close follow-up throughout pregnancy if unexpected RBC antibodies are present, to permit the provision of compatible blood in case of a rare antibody.

Adult↗
PubMed2000

Suprabasal expression of the human papillomavirus type 16 oncoproteins in mouse epidermis alters expression of cell cycle regulatory proteins.

Human papillomavirus (HPV) survives by reactivating DNA replication in post-mitotic cells. In the present study, we describe a mouse model of HPV-dependent disease. In these mice, DNA synthesis is activated in suprabasal keratinocytes, leading to acanthosis, parakeratosis and enhanced desquamation. The full-length E6/E7 transcript and two alternately spliced products are produced and in most lines the predominant product is E6*. In the present study, we examine the effects of E6/E7 on cell cycle regulatory protein expression. E6/E7 expression in mouse epidermis is correlated with increased levels of the p53, p21, p27, cdk2, cdk4, cdk6, cyclin D1 and cyclin E regulatory proteins. Hyperproliferation is also observed in the buccal mucosa and the tongue epithelia of E6/E7 mice, and p53 levels are markedly increased in these epithelia. These results suggest that the major changes in cell cycle regulatory protein expression are in response to the presence of E7 and that E6 has a lesser impact.

Animals↗
PubMed2000

Differentiated therapy with prostaglandin E1 (alprostadil) after orthotopic liver transplantation: the usefulness of procalcitonin (PCT) and hepatic artery resistive index (RI) for the evaluation of early graft function and clinical course.

Increasing demand for donor organs has led to new pharmacological concepts for reducing ischemia-reperfusion injury (I/R) of the graft after liver transplantation to prevent primary non-functioning of the organ. Prostaglandins have proved to be cytoprotective in several experimental models of ischemia and transplantation. The prophylactic administration after orthotopic liver transplantation is still a subject of controversial discussion. The aim of our study was the evaluation of the post-transplant hepatic artery resistive index (RI) measured by color Doppler imaging, in combination with postoperative elevation of transaminases, as parameters indicating the need for a differentiated systemic therapy with prostaglandin E1 (PGE1) (alprostadil). In addition, the value of serum procalcitonin (PCT) as a postoperative parameter for the extent of I/R is investigated. In the case of post-transplant elevated hepatic artery RI (RI > 0.75), the administration of PGE1 led to a significant reduction of transaminases (p < 0.05) and a decline of the RI. In addition, postoperative PCT levels could be reduced significantly by PGE1 application. These results suggest that determination of RI is feasible for indicating a need for therapy with PGE1. Its targeted application reduces hepatocellular damage due to I/R after liver transplantation.

Alprostadil↗
PubMed2000

Toxicity and in vitro metabolism of t-permethrin in eastern subterranean termite (Isoptera: Rhinotermitidae).

Toxicity and metabolism of t-permethrin were evaluated in two colonies (UF and ARS) of the eastern subterranean termite, Reticulitermes flavipes (Kollar), collected in Gainesville, FL. The UF colony (LC50 = 1.86 micrograms per vial) was approximately twofold more tolerant of t-permethrin than the ARS colony (LC50 = 0.89 microgram per vial) at the LC50. The synergists piperonyl butoxide and S,S,S-tributylphosphorotrithioate increased t-permethrin toxicity four- and threefold (at the LC50) in the UF and ARS colonies, respectively. Despite these differences in t-permethrin susceptibility, microsomal oxidase activities toward surrogate substrate (aldrin epoxidase, and methoxyresorufin O-demethylase), cytochrome P450 content, and microsomal esterase activity toward alpha-naphthyl acetate did not differ significantly between the colonies. Moreover, no significant differences in qualitative and quantitative metabolism of [14C]t-permethrin were observed between the UF and ARS colonies for three enzyme sources (microsomal oxidase, microsomal esterase, and cytosolic esterase). Based on in vitro metabolism assays, the major detoxification route of t-permethrin in the UF and ARS termite colonies appears to be hydrolysis catalyzed by microsomal esterases.

Animals↗
PubMed2000

Locally advanced breast carcinoma: computer assisted semiquantitative analysis of color Doppler ultrasonography in the evaluation of tumor response to neoadjuvant chemotherapy (work in progress).

We aimed to evaluate objectively the value of color Doppler flow imaging in the assessment of response of locally advanced breast cancer to primary medical treatment by using a computer assisted semiquantitative method. Prior to and after neoadjuvant treatment, 17 patients with locally advanced breast carcinoma were prospectively evaluated by physical examination and computer assisted semiquantitative color Doppler ultrasonography. The results of clinical and color Doppler examination were finally correlated to the histopathologic evaluation of tumor response. The degree of concordance between posttherapeutic histopathologic results, clinical examination, and color Doppler assessment was evaluated by kappa statistics. Concordance was 0.474 (0.135-0.813) between histopathologic results and clinical posttherapeutic assessment and 0.870 (0.627-1.113) between histopathologic results and semiquantitative color Doppler examination. Objective semiquantitative assessment of tumor vascularity as displayed by color Doppler ultrasonography has potential as a functional tool for measuring tumor response to neoadjuvant chemotherapy.

Adult↗
PubMed2000

Amplification of the MLL gene on double minutes, a homogeneously staining region, and ring chromosomes in five patients with acute myeloid leukemia or myelodysplastic syndrome.

Gene amplification is one of the mechanisms for activating proto-oncogenes resulting in an enhanced expression of the corresponding gene product. By fluorescence in situ hybridization (FISH), amplification of the proto-oncogene MLL has been described only in seven patients with acute myeloid leukemia (AML). We report five new patients (four had de novo AML, one had a de novo myelodysplastic syndrome) displaying different mechanisms of MLL amplification, suspected by G-banding and confirmed by FISH analysis. In two patients, MLL was amplified on double-minute chromosomes (dmins). In both cases, an interstitial deletion in 11q23 including the MLL gene was associated with the occurrence of the dmins containing MLL. As a rarely described mechanism, MLL amplification in the form of size-variable ring chromosomes was observed in two patients. Remodeling of the ring chromosomes leads to multiple copies of MLL and obviously provided a selective growth advantage. In one of the two cases with ring chromosomes, the centromeric alpha-satellite DNA of the ring chromosome was not detectable. Our fifth patient showed the unique finding of MLL amplification within a uniformly (homogeneously?) stained region in interaction with amplified ribosomal DNA sequences. Also, one of the patients with ring chromosomes exhibited the amplification of ribosomal DNA on the ring chromosomes. The transcriptionally active genes for ribosomal RNA could probably enhance the expression of MLL. In one of our five patients, we found the new combination of concomitant amplification of the proto-oncogenes MLL and MYC.

Adult↗
PubMed2000

Metabolism of ifosfamide to chloroacetaldehyde contributes to antitumor activity in vivo.

Metabolic activation of ifosfamide (IFO) leads to the active 4-hydroxy-metabolite and to a substantial liberation of chloroacetaldehyde (CAA). CAA has been presumed responsible for side effects of IFO. We recently have shown cytotoxic effects of CAA against human tumor cells in vitro. The aim of this study was to demonstrate antitumor effects of CAA in vivo, and to compare its potency to 4-OH-IFO. Pharmacokinetics of IFO and metabolites were evaluated after infusion of 250 mg/kg IFO in mice. The area under the curve (AUC) for 4-hydroxyifosfamide (4-OH-IFO) and CAA were 138. 5 and 102.4 micromol. h/liter, respectively. To compare pharmacokinetics and antitumor effects, the mice received isolated infusion of 4-OH-IFO or CAA in equimolar doses to IFO. Administration of 4-OH-IFO yielded AUC values comparable with those obtained after administration of the parent drug. In contrast, infusion of isolated CAA via tail vein gave a low AUC value of 51.5 micromol. h/liter due to slow flow in the tail vein and rapid degradation. Administration of the parent drug gave highly cytotoxic intratumoral peak concentrations of 25 and 12 micromol/kg tumor weight for 4-OH-IFO and CAA in MX1 xenotransplanted nude mice. Both IFO and isolated 4-OH-IFO led to complete remissions. Administration of isolated CAA (75 mg/kg) delayed tumor growth significantly. The equitoxic dose of isolated 4-OH-IFO was 40 mg/kg. On a molar basis CAA was seven times less potent as 4-OH-IFO. However, on the basis of achieved AUC values, CAA seems to exhibit a similar antitumor activity to 4-OH-IFO.

Acetaldehyde↗
PubMed2000

[Cytokine combinations for in vivo and ex vivo expansion of hematopoietic progenitor cells].

The critical role of hematopoietic progenitor cells (HPC) for the formation of mature blood cells is well established. Interleukin-3 (IL-3), stem cell factor (SCF), and flt3-ligand (FL) are potential candidates for expansion strategies due to their early acting and lineage-unspecific hematopoietic stimulation. In preclinical and clinical models IL-3, SCF, and FL induced in-vivo expansion of the progenitor cell pool has been shown to be associated with increased HPC-mobilization by G-CSF, reduction in the number of leukaphereses required to obtain adequate HPC-numbers and the potentiation of lineage-specific growth factors. Early acting cytokines are also crucial for ex-vivo expansion strategies and are here important partner molecules for IL-1, IL-6 and IL-10. In-vivo as well as ex-vivo expanded HPC are able to reconstitute hematopoiesis in patients following myeloablative chemoradiotherapy. Thus expanded HPC will be increasingly used for clinical purposes and facilitate therapeutic strategies which are currently limited by the problem of insufficient HPC-numbers.

Animals↗
PubMed2000

Fluoride release from a toothbrush.

The purpose of the present study was to evaluate the fluoride concentration in unstimulated saliva after using a toothbrush with 9,048 ppm fluoride as sodium fluoride incorporated in the bristles. A toothpaste with 1,500 ppm fluoride served as the positive control. Twelve volunteers took part in the single-blind crossover study. In a pre-test phase of 14 days, the subjects refrained from eating fluoride-rich foods and did not use any fluoride-containing products for oral hygiene measures. This was followed by a test period of four weeks. At day one and after 14 and 28 days, unstimulated saliva was collected and analyzed for its fluoride content. Saliva was collected immediately after toothbrushing and after 15, 30, 60, 90, 120 150, and 180 minutes. On day one, the fluoride toothbrush released significant amounts of fluoride immediately after the brushing, and after 15 and 30 minutes (p < 0.01). After 14 days of use, this could be found immediately after brushing and after 15 minutes (p < 0.01 or p < 0.05, respectively). After 28 days, a significant fluoride release was only found immediately after brushing (p < 0.05). On all days, compared to the positive control, the fluoride release from the fluoride toothbrush was generally lower immediately after brushing and after 15 minutes (p < 0.001, p < 0.01 or p < 0.05, respectively). It may be concluded that a toothbrush with incorporated sodium fluoride could act as a fluoride-releasing. device.

Cariostatic Agents↗
PubMed1999

Denaturing high-performance liquid chromatography detects reliably BRCA1 and BRCA2 mutations.

Denaturing high-performance liquid chromatography (DHPLC) is a recently developed method of comparative sequencing based upon heteroduplex detection. To assess the reliability of this method, 180 different mutations (54 deletions, 12 insertions, and 117 single base substitutions) in BRCA1 and BRCA2 were tested. Second, 25 index individuals with complete DHPLC analysis of BRCA1 were reanalyzed by dye-terminator sequencing. Third, 41 index individuals were analyzed concomitantly by both DGGE and DHPLC. Of the 180 different BRCA1 and BRCA2 mutations, 179 showed heterozygous DHPLC elution profiles. Dye-terminator sequencing of the entire BRCA1 gene, including 5592 bp of coding sequence and 5206 bp of flanking noncoding sequence, in 25 index individuals did not reveal additional variants missed by DHPLC. The concomitant analysis of 41 index cases showed that 4 probably disease-associated mutations were identified by DHPLC while only 3 of those 4 sites were detected by denaturing gradient gel electrophoresis. We conclude that DHPLC is a sensitive and cost-effective method for the screening of BRCA1 and BRCA2.

BRCA1 Protein↗
PubMed1999

Injection of encapsulated cells producing an ifosfamide-activating cytochrome P450 for targeted chemotherapy to pancreatic tumors.

The prognosis of pancreatic cancer is poor, and current medical treatment is mostly ineffective. The aim of this study was to design a new treatment modality in an animal model system. We describe here a novel treatment strategy employing a mouse model system for pancreatic carcinoma. Embryonal kidney epithelial cells were genetically modified to express the cytochrome P450 subenzyme 2B1 under the control of a cytomegalovirus (CMV) immediate early promoter. This CYP2B1 gene converts ifosfamide to its active cytotoxic compounds, phosphoramide mustard, which alkylates DNA, and acrolein, which alkylates proteins. The cells were then encapsulated in a cellulose sulphate formulation and implanted into preestablished tumors derived from a human pancreatic tumor cell line. Intraperitoneal administration of low-dose ifosfamide to tumor bearing mice that received the encapsulated cells results in partial or even complete tumor ablation. Such an in situ chemotherapy strategy utilizing genetically modified cells in an immunoprotected environment may prove useful for solid tumor therapy in man.

Animals↗
PubMed1999

Chemical etiology of nucleic acid structure: comparing pentopyranosyl-(2'-->4') oligonucleotides with RNA.

All four members of the family of pentopyranosyl-(2'-->4') oligonucleotide systems that contain beta-ribo-, beta-xylo-, alpha-lyxo-, or alpha-arabinopyranosyl units as repeating sugar building blocks are found to be much stronger Watson-Crick base-pairing systems than RNA. The alpha-arabinopyranosyl system is the strongest of all and in fact belongs to the strongest oligonucleotide base-pairing systems known. Whatever the chemical determinants by which nature selected RNA as a genetic system, maximization of base-pairing strengths within the domain of pentose-derived oligonucleotide systems was not the critical selection criterion.

Arabinose↗
PubMed1999

Randomized in vitro and in vivo evaluation of different biopsy needles and devices for breast biopsy.

In an experimental study (in vitro and in vivo) we evaluated the efficacy of various biopsy needles/devices for breast biopsy. In vitro, biopsies of five human cadaveric breast specimens were performed using 33 different needles/devices ranging from 14 to 20-gauge. Of these 33 needles/devices, 22 optimally performing needles were selected for the in vivo study. In the clinical part of the study, 44 breast lesions were randomly biopsied with each of the 22 needles/devices under stereotactic guidance. Tissue specimens were analysed quantitatively and qualitatively. Several automatic long-throw guns (Acecut, Asap, Biopty, Magnum) obtained greater tissue areas and had a better histopathologic score than the conventional type of a side-notch needle like Trucut, an aspiration needle like Surecut, or an end-cut needle like Autovac. The automatic long-throw guns performed better than the short-throw Monopty gun. Regardless of needle size (14-20-gauge), breast biopsies should be routinely performed with automated long-throw side-notch guns (Acecut, Asap, Biopty, Magnum).

Adult↗
PubMed1999

Course of molecular hemostatic markers during and after different surgical procedures.

STUDY OBJECTIVE: To establish the most vulnerable time of thrombi formation with regard to the plasmatic (noncellular) part of the coagulatory and fibrinolytic systems. DESIGN: Nonrandomized observational study. SETTING: A surgical and an orthopedic unit and the central laboratory of a university hospital. PATIENTS: 61 consenting ASA physical status I and II inpatients undergoing four different types of surgery: total hip replacement (THR): 16 patients; hemicolectomy: 15 patients; endoscopic cholecystectomy: 15 patients; subtotal thyroid resection: 15 patients. INTERVENTIONS: The time course of 11 procoagulatory and fibrinolytic parameters was examined during the different types of surgery. Blood samples were drawn on the day before surgery, directly before the induction of general anesthesia, 1 to 2 hours postoperatively, and on the mornings of postoperative days 1, 2, 3, 4, and 5. MEASUREMENTS AND MAIN RESULTS: The coagulation samples were centrifuged within 1 hour of collection at 2,300 g for 15 minutes at 4 degrees C. Hemoglobin, hematocrit, platelets, fibrinogen, prothrombin time, activated partial thromboplastin time, thrombin time, antithrombin III, and protein C were determined immediately on laboratory arrival of the samples. The samples were aliquoted at -70 degrees C. They were thawed within 2 weeks and prepared for the following assays: thrombin-antithrombin III complexes (TAT-complexes), D-dimers, and plasminogen activator inhibitor type 1. Maximum activation of coagulation is not reached until 2 hours postoperatively and slowly decreases until normal values are reached around the fifth postoperative day. Parameters displaying the greatest changes are TAT-complexes and D-dimers. The type of surgery with the most pronounced changes was total hip replacement, followed by hemicolectomy, cholecystectomy, and subtotal thyroid resection. CONCLUSION: The total hip replacement and hemicolectomy groups show similar and strong activation of the procoagulatory and fibrinolytic systems. Much less pronounced are the changes during endoscopic cholecystectomy and subtotal thyroid resection. Maximum activation occurs 1 to 2 hours postoperatively.

Adult↗
PubMed1999

The cytotoxicity of mafosfamide on G-CSF mobilized hematopoietic progenitors is reduced by SH groups of albumin--implications for further purging strategies.

The efficacy of mafosfamide purging depends on factors like incubation time, drug and erythrocyte concentration. To determine the influence of protein-bound SH groups in the incubation medium, the cytotoxicity of mafosfamide on G-CSF mobilized CD34+/- cells was evaluated by short-term culture assays and drug concentration measurements. 100 micromol/ml mafosfamide was incubated for 30 min in five buffers (PBS, PBS with 1%, 5% and 10% BSA and plasma). The mean calculated areas under the concentration-time curves (AUC) were 2489 +/- 198, 1561 +/- 286, 976 +/- 201, 585 +/- 62 and 605 +/- 196 micromol/l/min. The mean reductions of CFU-GM growth were 79.4%, 73.0%, 62.5%, 30.3%, 6.2% respectively. Similar results were obtained for BFU-E. Regression analysis showed a good correlation between cytotoxicity and AUCs (CFU-GM: r = 0.8195; BFU-E: r = 0.8207). This effect is well explained by the different concentrations of SH moieties in the incubation medium resulting in a higher drug binding capacity. The profound difference between AUCs and CFU-GMs in plasma and 10% BSA cannot be explained by the quantity of SH-groups. It is probably due to an additional enzymatic drug degeneration by the 3'-5'exonuclease subsite of plasma DNA polymerase. In conclusion, the concentration of albumin-associated SH groups strongly influences the cytotoxicity of mafosfamide. It has to be considered as a new and important aspect in ex vivo bone marrow purging.

Albumins↗