Search PubMed⌕ Search

Biomedical subjects

H Wolf

Publications and source records attributed to H Wolf.

At least 127 records · Page 7Linked to original sources
PubMed1999

Expression of transforming growth factor alpha and epidermal growth factor receptor in human bladder cancer.

We analysed the expression of epidermal growth factor receptor (EGFr) and transforming growth factor alpha (TGF-alpha) in human bladder tumours. Tumour biopsies were obtained from 54 patients with primary bladder cancer (18 stage T1 and 36 stage T2-4). The protein and mRNA expression of EGFr and TGF-alpha were quantified by ELISA and competitive RT-PCR, respectively. The EGFr protein level was significantly increased in T2-4 tumours (0.44 x 10(-11); 0.0-27.5 x 10(-11) mol/g) compared with T1 tumours (0.0; 0.0-2.0 x 10(-11) mol/g) (median; range; 2p<0.01). The EGFr protein and mRNA level correlated (Spearman r=0.45, 2p<0.005, n=40). Co-expression of TGF-alpha protein and EGFr protein was significantly associated with muscle invasive tumours (T2-4) (chi-squared=7.9, df=3, p<0.05) and the TGF-alpha protein level correlated significantly with EGFr protein expression (Spearman r=0.56, 2p<0.0001, n=54). While tumour stage correlated with survival, no correlation was observed between survival and the expression of EGFr and/or TGF-alpha. In conclusion, human bladder tumours express both EGFr and TGF-alpha. The expression of EGFr and TGF-alpha are closely correlated, and the expression of EGFr and co-expression of EGFr and TGF-alpha correlate with tumour stage.

Enzyme-Linked Immunosorbent Assay↗
PubMed1999

Proteomic strategies in bladder cancer.

Here we review our current strategy for identifying phenotypic changes in the urothelium of bladder cancer patients with invasive disease, using a combination of proteomic technologies and immunowalking. This approach, which in principle can be applied to the study of any type of bladder cancer, makes use of proteomic technologies (for more information see http://biobase.dk/cgi-bin/celis) to reveal and identify proteins that are differentially expressed in fresh tumors and normal urothelium. Thereafter, specific antibodies against the differentially expressed proteins are used (immunowalking) to stain serial cryostat sections of cystectomies obtained from tumor-bearing patients who have undergone removal of the bladder for invasive disease. Since bladder cancer is a field disease--that is, a large part of the bladder lining is involved-the urothelium of these patients is expected to exhibit a spectrum of abnormalities, ranging from early stages of transformation to invasive disease. Besides highlighting the problems one faces when applying powerful proteomic technologies to the study of heterogeneous biopsy material, these studies show that it is feasible to study bladder cancer under experimental conditions that closely resemble the in vivo situation.

Animals↗
PubMed1999

A case of severe chronic active infection with Epstein-Barr virus: immunologic deficiencies associated with a lytic virus strain.

Infectious mononucleosis (IM) is a self-limiting, lymphoproliferative disease induced by primary infection with the Epstein-Barr virus (EBV). Infection with EBV leads in general to lifelong asymptomatic persistence of the virus. We report the case of a woman who acquired IM at the age of 15 years and then suffered from recurrent high fever, fatigue, and signs of immunologic disorder for more than 12 years until she died of liver failure. In an attempt to describe and to define the course of chronic active infection with EBV, we performed immunologic and molecular assays that demonstrated lytic replication of EBV in the B and T cells of the peripheral blood. In addition to signs of humoral and cellular immune deficiency, we detected an EBV strain with an impaired capability to immortalize B cells and a tendency to lytic replication, thus contributing to the pathogenesis of this chronic active infection.

Adult↗
PubMed1999

Glutathione S-transferases as risk factors in prostate cancer.

Glutathione S-transferases are enzymes involved in the metabolism of carcinogens and in the defence against reactive oxygen species. Genetic polymorphisms have been detected in glutathione S-transferases M1, T1 and P1, and some of these polymorphisms have been associated with an increased risk of cancer. In a case-control study (153 cases and 288 controls) the effect of these genetic polymorphisms on the risk of prostate cancer was investigated. Homozygote deletion of either GSTM1 or GSTT1 was not associated with a statistically significant increased risk, odds ratio (OR) 1.3; 95% confidence intervals (CI) 0.9-1.9 and 1.3; 0.8-2.2, respectively. Deletion of both GSTM1 and GSTT1 gave a near-significant increased risk (OR 1.7; 95% CI 0.9-3.4). Two allelic variants of GSTP1 (codon 105) have been reported. This polymorphism was not linked to an increased risk (OR 0.8; 95% CI 0.5-1.1). Smokers that lack either GSTM1 or GSTT1 activity had a slightly higher risk of prostatic cancer than smokers expressing the genes, OR 1.4 (95% CI 0.6-3.3) and 1.6 (0.6-3.9), respectively. Our results show that differences in enzymes involved in the metabolism of carcinogens slightly modify prostate cancer risk, especially in people exposed to carcinogens that are detoxified by these enzymes.

Adult↗
PubMed1999

Infection of apheresis cells by parvovirus B19.

Parvovirus B19 is the only member of the Parvoviridae family known to cause disease in humans. Owing to the high level of cell tropism the virus can only replicate in proliferating and differentiating erythroid precursor cells, which are present in human bone marrow and foetal liver. As human bone marrow is very difficult to obtain, an alternative in vitro system for the propagation of B19 virus has been developed, based on the application of mobilized haemapoietic progenitor (apheresis) cells. These cells are routinely harvested from cancer patients after treatment with recombinant human granulocyte/macrophage colony-stimulating factor. Replication of parvovirus B19 in vitro is possible in these cells after stimulation with erythropoietin. Therefore, this system is an easily, accessible alternative to the use of human bone marrow in parvovirus B19 infection assays.

Blood Component Removal↗
PubMed1999

Vaginal delivery compared with caesarean section in early preterm breech delivery: a comparison of long term outcome.

OBJECTIVE: To determine the optimum mode of delivery of the early preterm fetus in breech presentation. DESIGN: Retrospective comparison of two cohorts of preterm breech fetus. SETTING: Two tertiary care centres: at one centre the preferred management for preterm breech presentation was vaginal delivery; at the other centre, the preferred method was caesarean section. POPULATION: All singleton infants delivered after breech presentation from 1984 through 1989, at a gestational age of 26 to 31 weeks. Those with lethal congenital abnormalities, placenta praevia, placental abruption, fetal death or fetal distress before the onset of labour were excluded. MAIN OUTCOME MEASURES: Survival without disability or handicap documented at two years corrected age. The influence of a number of relevant variables on this outcome was assessed by logistic regression analysis. RESULTS: There was no difference in survival without disability or handicap between the centres (odds ratio 1.5, 95% CI 0.6-3.9 vaginal delivery compared with caesarean section). Survival without disability or handicap was positively influenced by increasing birthweight and corticosteroids > 24 h before birth, and negatively influenced by footling presentation. CONCLUSION: A policy of caesarean section for early preterm (26-31 weeks) breech delivery is not associated with increased survival without disability or handicap.

Adult↗
PubMed1999

Dose reduction in CT by anatomically adapted tube current modulation. II. Phantom measurements.

Theoretical considerations and simulation studies have led to the expectation that patient dose in CT (computed tomography) can be reduced significantly without a concomitant loss in image quality if tube current is modulated according to rotation angle-dependent x-ray attenuation. In this study, the simulation results presented in Part I were validated with phantoms. We used one cylindrical, two oval, and one elliptical phantom, available both as mathematical descriptions and in physical form, to mimic different parts of the human anatomy. Prototype hardware was available to control tube current on a commercial clinical CT scanner. The potential for dose reduction was evaluated for sinusoidal and attenuation-based current modulation for variable modulation amplitudes. Agreement between simulations and measured results was better than within 10%. Dose reduction values of 8%-56% were found depending on the phantom geometry and tube current modulation function. Attenuation-based tube current modulation consistently yielded higher reduction than fixed-shape sinusoidal modulation functions. For the shoulder phantom and 70% modulation amplitude, 44.6% dose reduction was measured as compared to 34.1% for sinusoidal modulation. A maximum of 56% was measured for the shoulder phantom including inserts. Specifying mAs reduction as an estimate for dose reduction proved to be a valid and conservative estimate; measured dose is reduced more strongly than the total mAs product both centrally and on average. First patient studies confirm the results of simulation and phantom studies. We conclude that attenuation-based online tube current control has great potential for reducing patient dose in CT and that it should be made generally available for clinical use.

Air Pollutants, Radioactive↗
PubMed1999

Dose reduction in CT by anatomically adapted tube current modulation. I. Simulation studies.

Tube current modulation governed by x-ray attenuation during CT (computed tomography) acquisition can lead to noise reduction which in turn can be used to achieve patient dose reduction without loss in image quality. The potential of this technique was investigated in simulation studies calculating both noise amplitude levels and noise distribution in CT images. The dependence of noise on the inodulation function, amplitude of modulation, shape and size of the object, and possible phase shift between attenuation and modulation function were examined. Both sinusoidal and attenuation-based control functions were used to modulate tube current. Noise reduction was calculated for both ideal systems and for real systems with limited modulation amplitude. Dose reductions up to 50% can be achieved depending on the phantom geometry and tube current modulation function. Attenuation-based tube current modulation yields substantially higher reduction than fixed-shape modulation functions. Optimal results are obtained when the current is modulated as a function of the square root of attenuation. A modulation amplitude of at least 90% should be available to exploit the potential of these techniques.

Air Pollutants, Radioactive↗
PubMed1999

Serodiagnosis of Epstein-Barr virus infection by using recombinant viral capsid antigen fragments and autologous gene fusion.

Using recombinant 15- to 30-kDa fragments and fusion with glutathione S-transferase (GST), we investigated the seroreactivity of three large structural proteins of Epstein-Barr virus (EBV), p150 (BcLF1, capsid), p143 (BNRF1, tegument), and gp125 (BALF4, membrane) in Western blots. None of 13 fragments tested, however, was qualified for diagnostic application. In contrast, the two small viral capsid antigens (VCA), p18 (BFRF3) and p23 (BLRF2), demonstrated sensitive (100%) EBV-specific immunoglobulin G (IgG) reactivities. While p18 additionally showed maximum sensitivity for IgM detection, the IgM sensitivity of p23 was restricted (44%). An autologous fusion protein, p23-p18, which consists N-terminally of full-length p23, followed by the carboxy half of p18, was constructed. This antigen was subjected to indirect VCA enzyme-linked immunosorbent assays (ELISAs), for IgG and IgM, as well as to a micro-capture (microc) IgM ELISA. All assays were found to be 100% specific when EBV-negative sera were tested. Using sera from previously infected individuals, the p23-p18 fusion revealed an improved IgG sensitivity of 99% compared to sensitivities of 97 and 93% for the single antigens p18 and p23, respectively. The sensitivity and specificity of the indirect IgM ELISA with samples of primary and past infections, respectively, were 100%. The microc principle for IgM overcame completely the interference by rheumatoid factors. Compared to the specificity of the indirect IgM version, the specificity with sera collected from rheumatoid arthritis patients increased from 48 to 100%. In summary, the p23-p18 IgG and microc IgM ELISAs showed excellent performances and are promising new diagnostic tests for the detection of EBV-specific antiviral capsid antibodies.

Antibodies, Viral↗
PubMed1999

Transforming potential of the adenovirus type 5 E4orf3 protein.

Previous observations that the adenovirus type 5 (Ad5) E4orf6 and E4orf3 gene products have redundant effects in viral lytic infection together with the recent findings that E4orf6 possesses transforming potential prompted us to investigate the effect of E4orf3 expression on the transformation of primary rat cells in combination with adenovirus E1 oncogene products. Our results demonstrate for the first time that E4orf3 can cooperate with adenovirus E1A and E1A plus E1B proteins to transform primary baby rat kidney cells, acting synergistically with E4orf6 in the presence of E1B gene products. Transformed rat cells expressing E4orf3 exhibit morphological alterations, higher growth rates and saturation densities, and increased tumorigenicity compared with transformants expressing E1 proteins only. Consistent with previous results for adenovirus-infected cells, the E4orf3 protein is immunologically restricted to discrete nuclear structures known as PML oncogenic domains (PODs) in transformed rat cells. As opposed to E4orf6, the ability of E4orf3 to promote oncogenic cell growth is probably not linked to a modulation of p53 functions and stability. Instead, our results indicate that the transforming activities of E4orf3 are due to combinatorial effects that involve the binding to the adenovirus 55-kDa E1B protein and the colocalization with PODs independent from interactions with the PML gene product. These data fit well with a model in which the reorganization of PODs may trigger a cascade of processes that cause uncontrolled cell proliferation and neoplastic growth. In sum, our results provide strong evidence for the idea that interactions with PODs by viral proteins are linked to oncogenic transformation.

Adenovirus E1A Proteins↗
PubMed1999

Generation of neutralizing human monoclonal antibodies against parvovirus B19 proteins.

Infections caused by human parvovirus B19 are known to be controlled mainly by neutralizing antibodies. To analyze the immune reaction against parvovirus B19 proteins, four cell lines secreting human immunoglobulin G monoclonal antibodies (MAbs) were generated from two healthy donors and one human immunodeficiency virus type 1-seropositive individual with high serum titers against parvovirus. One MAb is specific for nonstructural protein NS1 (MAb 1424), two MAbs are specific for the unique region of minor capsid protein VP1 (MAbs 1418-1 and 1418-16), and one MAb is directed to major capsid protein VP2 (MAb 860-55D). Two MAbs, 1418-1 and 1418-16, which were generated from the same individual have identity in the cDNA sequences encoding the variable domains, with the exception of four base pairs resulting in only one amino acid change in the light chain. The NS1- and VP1-specific MAbs interact with linear epitopes, whereas the recognized epitope in VP2 is conformational. The MAbs specific for the structural proteins display strong virus-neutralizing activity. The VP1- and VP2-specific MAbs have the capacity to neutralize 50% of infectious parvovirus B19 in vitro at 0.08 and 0.73 microgram/ml, respectively, demonstrating the importance of such antibodies in the clearance of B19 viremia. The NS1-specific MAb mediated weak neutralizing activity and required 47.7 micrograms/ml for 50% neutralization. The human MAbs with potent neutralizing activity could be used for immunotherapy of chronically B19 virus-infected individuals and acutely infected pregnant women. Furthermore, the knowledge gained regarding epitopes which induce strongly neutralizing antibodies may be important for vaccine development.

Amino Acid Sequence↗
PubMed1999

Phase-dependent presynaptic modulation of mechanosensory signals in the locust flight system.

In the locust flight system, afferents of a wing hinge mechanoreceptor, the hindwing tegula, make monosynaptic excitatory connections with motoneurons of the elevator muscles. During flight motor activity, the excitatory postsynaptic potentials (EPSPs) produced by these connections changed in amplitude with the phase of the wingbeat cycle. The largest changes occurred around the phase where elevator motoneurons passed through their minimum membrane potential. This phase-dependent modulation was neither due to flight-related oscillations in motoneuron membrane potential nor to changes in motoneuron input resistance. This indicates that modulation of EPSP amplitude is mediated by presynaptic mechanisms that affect the efficacy of afferent synaptic input. Primary afferent depolarizations (PADs) were recorded in the terminal arborizations of tegula afferents, presynaptic to elevator motoneurons in the same hemiganglion. PADs were attributed to presynaptic inhibitory input because they reduced the input resistance of the afferents and were sensitive to the gamma-aminobutyric acid antagonist picrotoxin. PADs occurred either spontaneously or were elicited by spike activity in the tegula afferents. In summary, afferent signaling in the locust flight system appears to be under presynaptic control, a candidate mechanism of which is presynaptic inhibition.

Afferent Pathways↗
PubMed1999

Thrombogenesis in myocardial infarction and related syndromes: the role of molecular markers in diagnosis and management.

Anticoagulant therapy has undergone some major developments in recent years. Conventional drugs that produce anticoagulant effects such as heparin and oral anticoagulants are no longer considered the only candidates for the anticoagulant/antithrombotic management of patients. Recombinant hirudin, glycoproteins IIb/IIIa targeting antibodies, synthetic peptides such as Hirulog and efegatran are being tested for their efficacy. These drugs produce their effects at different sites. To monitor their overall effects on the hemostatic system, molecular markers offer a practical and reliable approach. Markers of thrombin generation are useful for the monitoring of antithrombin drugs whereas, the efficacy of antiplatelet drugs can be assessed by monitoring the platelet release products. Furthermore, polytherapy using several anticoagulant and antithrombotic drugs in combination has been considered. In these situations, the use of molecular markers may also prove to be invaluable. The introduction of simple technology such as the test strip or particle agglutination methods may be available for the measurement of many of these markers in the near future. This will be useful for ready availability and reduced cost for individual marker testing. Furthermore, this type of technology can be used at bedside, off-site, and in doctor's offices. It is clear that the molecular marker profiling provides useful information on the nature of pathophysiology of a given thrombotic disorder. However, for practical use, a cost-effective and simpler assay-based approach will enhance their use, and these tests will be readily accepted at the laboratory and clinical levels.

Animals↗
PubMed1999

Construction and characterization of recombinant VLPs and Semliki-Forest virus live vectors for comparative evaluation in the SHIV monkey model.

For testing of recombinant virus-like particles (VLPs) in the SHIV monkey model, SIVmac239 Pr56gag precursor-based pseudovirions were modified by HIV-1 gp160 derived peptides. First, well-characterized epitopes from the HIV-1 envelope glycoprotein were inserted into the Pr56gag precursor by replacing defined regions that were shown to be dispensable for virus particle formation. Expression of these chimeric proteins in a baculovirus expression system resulted in efficient assembly and release of non-infectious, hybrid VLPs. In a second approach the HIV-1IIIB external glycoprotein gp120 was covalently linked to an Epstein-Barr virus derived transmembrane domain. Coexpression of the hybrid envelope derivative with the Pr56gag precursor yielded recombinant SIV derived Pr56gag particles with the HIV-1 gp120 firmly anchored on the VLP surface. Immunization of rhesus monkeys with either naked VLPs or VLPs adsorbed to alum induced substantial serum antibody titers and promoted both T helper cell and cytotoxic T lymphocyte responses. Furthermore, priming macaques with the corresponding set of recombinant Semliki-Forest viruses tended to enhance the immunological outcome. Challenge of the immunized monkeys with chimeric SHIV resulted in a clearly accelerated reduction of the plasma viremia as compared to control animals.

Amino Acid Sequence↗
PubMed1999

Intracellular and extracellular, ionized and total magnesium in pre-eclampsia and uncomplicated pregnancy.

Magnesium (Mg) and calcium (CA) concentrations in women with pre-eclampsia, women with an uncomplicated pregnancy and non-pregnant women were compared. Ionized serum magnesium and calcium concentrations and intracellular magnesium concentrations were measured in 15 pregnant women with severe pre-eclampsia, 34 uncomplicated pregnant women early, at midterm and preterm in their pregnancy and 24 non-pregnant women. The ionized calcium concentration did not chance during normal pregnancy or during pre-eclampsia relative to non-pregnant women. In contrast, elevated total and ionized magnesium serum concentrations were found in women with severe pre-eclampsia (total Mg = 0.85+/-0.11 mM, ionized Mg = 0.61+/-0.06 mM) relative to uncomplicated pregnant women (total Mg = 0.72+/-0.06 mM, ionized Mg = 0.53+/-0.03 mM). Total magnesium in pre-eclamptic women were similar to non-pregnant women. Intracellular ionized and total magnesium concentrations in mononuclear blood cells and erythrocytes were similar in pre-eclamptic women and women with uncomplicated pregnancy. Serum magnesium concentrations are elevated in severe pre-eclamptic women relative to women with uncomplicated pregnancy and are related to birth weight and gestational age at delivery. There may be a causal relationship since magnesium is involved in blood pressure regulation through an intracellular inhibition of NO synthase in endothelial cells.

Calcium↗
PubMed1999

Immunostimulatory CpG motifs trigger a T helper-1 immune response to human immunodeficiency virus type-1 (HIV-1) gp 160 envelope proteins.

Bacterial DNA sequences containing unmethylated CpG motifs have recently been proposed to exhibit immunostimulatory effects on B-, T- and NK cells, leading to the induction of humoral and cell-mediated immune responses. In the present study we investigated the immunomodulatory effects of a CpG-containing oligodeoxynucleotide (CpG ODN) to the HIV-1 gp 160 envelope (Env) protein in the BALB/c mouse model. Priming and boosting of mice with gp 160 adsorbed to aluminium hydroxide (Alum) induced a typical T helper-2 (Th2)-dominated immune response with high titers of gp 160-specific immunoglobulin (Ig)G1 isotypes but a weak IgG2a response. Specifically re-stimulated splenocytes from these mice predominantly secreted interleukin (IL)-5 but only minute amounts of interferon-gamma (IFN-gamma) upon specific re-stimulation. In contrast, a boost immunisation of gp 160/Alum primed mice with a gp 160/Alum/CpG combination resulted in a seven times higher production of IgG2a antibodies, without affecting the titers of IgG1 isotypes. Furthermore, approximately 10-fold increased levels of IFN-gamma, but significantly reduced amounts of IL-5, were secreted from gp 160-restimulated splenic cells. A further greater than 30-fold increase in the levels of specific IgG2a responses and a substantially elevated secretion of IFN-gamma were observed when the mice received gp160/Alum/CpG combinations for priming and boost injections. Thus, CpG ODNs are useful as an adjuvant to induce a typical Th0/Th1 response to HIV gp 160 proteins. However, despite the induction of a more Th1-like immune response, gp 16O/Alum/CpG combinations were not sufficient to prime an Env-specific cytotoxic T-cell (CTL) response.

AIDS Vaccines↗
PubMed1999

Pharmacologic profile of certoparin.

The low molecular weight heparins (LMWHs) are now not only used for the prophylaxis and treatment of deep vein thrombosis (DVT), but also for the management of acute coronary syndromes. Beside these approved usages, the LMWHs have been developed for indications such as thrombotic and ischaemic stroke, cancer-associated thrombotic and vascular disorders, Alzheimer's disease and a variety of inflammatory disorders. In the United States, there are three approved LMWHs (enoxaparin, dalteparin and ardeparin). In Canada, reviparin and tinzaparin are also approved. The European Union has taken the lead; eight LMWHs are approved for various indications. Certoparin represents one of the earlier LMWHs used for DVT prophylaxis and treatment, with additional indications currently under development. Certoparin represents an isoamyl nitrite depolymerised LMWH with comparable structural characteristics to other nitrous acid depolymerised products such as nadroparin and reviparin. While comparable in structure to dalteparin, this agent differs in function due to a secondary purification process that is employed in the manufacture of dalteparin. The preclinical pharmacology of this drug has been extensively investigated. Although indication specific dosing and the optimisation of use in, for example, acute coronary syndromes and thrombotic stroke, may be require, certoparin represents a typical LMWH with comparable performance characteristics to some other agents. This chapter describes some of the preclinical and clinical pharmacologic characteristics of this drug. This information will be useful in designing clinical trials for newer indications of this drug.

Journal Article↗