Search PubMed⌕ Search

Biomedical subjects

H Wolf

Publications and source records attributed to H Wolf.

At least 145 records · Page 8Linked to original sources
PubMed1999

Determination of phage antibody affinities to antigen by a microbalance sensor system.

Over the past decade, phage display has maturated to be a frequently used method for the generation of monoclonal antibodies of human origin. The essential step of this method is the "biopanning" of phage carrying functional antibody fragments on their surface on an immobilized antigen. The screening of large combinatorial gene libraries with this method usually leads to a set of diverse clones specifically binding to the antigen that need to be characterized further. Beside its specificity, the key parameter to be determined is the affinity of the recombinant antibody fragment to its antigen. Here, we present a mass sensitive microsensor method that allows the estimation of antibody affinity directly from the phage supernatant. Binding of phage antibodies to the antigen immobilized on a quartz crystal microbalance (QCM) induced a mass dependent decrease in frequency. This principle was used to determine the apparent affinity of a single-chain (sc)Fv antibody against the RNA polymerase of Drosophila melanogaster presented on the surface of a filamentous phage (M13) from its association and dissociation rates. The apparent affinity obtained is in accordance with the affinity of the scFv fragment as determined by conventional equilibrium enzyme-linked immunosorbent assay (ELISA) and plasmon resonance methods.

Animals↗
PubMed1999

Lewis antigen mediated adhesion of freshly removed human bladder tumors to E-selectin.

PURPOSE: Twenty fresh surgical specimens of human bladder tumors were tested for their ability to adhere to recombinant P and E-selectin. The adhesion was correlated to immunological detection of carbohydrate structures. MATERIALS AND METHODS: A static titertray assay with immobilized selectins and appropriate controls was used for bladder tumor cell adhesion. On the same tumors expression of carbohydrate structures was examined by immunohistochemistry and Western blotting. RESULTS: No tumor bound to P-selectin. Nine tumors showed a high number of cells binding to E-selectin, 5 showed intermediate binding, and 6 showed only rare binding. The specificity of the binding was verified by inhibition with EDTA, by blocking antibodies to E-selectin, and by an acrylamide based sLe(x) (Galbeta1-4 [Fucalpha1-3]GlcNAc-) polymer. The binding was significantly more frequent (p <0.045) in superficial tumors than in invasive tumors. The binding property was correlated to the detection of carbohydrate structures in Western blots and tissue sections of the same tumors, using six different monoclonal antibodies: anti-sLe(a), anti-sLe(x), anti-Le(a), anti-Le(x) (two different clones) and anti-Le(b). Most blot-stainings were smeared indicating a mucin-type carrier molecule, but 115, 55 and 40 kDa bands carrying Le(a) and/or Le(b) epitopes were present in all tumors that bound. The Le(a) structure, as detected by blotting, was the only structure necessary for binding in the center of the wells (p <0.001), and was correlated to number of bound cells (p <0.006). A weaker correlation was found between Le(b) and number of bound cells (p <0.032), whereas it was remarkable that no correlation was found with Le(x) or sLe(x). Immunohistological staining of Le(a) on cell membranes correlated with frequent binding (p <0.003), whereas no correlation was found to secretor and Lewis genotypes. CONCLUSIONS: These data on clinical specimens indicate that Lewis antigen mediated E-selectin adhesion may play a role in the human bladder cancer disease.

Blotting, Western↗
PubMed1999

Comparison of 3,000 IU aXa of the low molecular weight heparin certoparin with 5,000 IU aXa in prevention of deep vein thrombosis after total hip replacement. German Thrombosis Study Group.

BACKGROUND: The aim of this randomized, double-blind and prospective clinical trial was to investigate whether an increase of the conventional daily dosage (3,000 IU aXa) of the low molecular weight heparin certoparin up to 5,000 IU aXa/day might lower the incidence of deep vein thrombosis (DVT) in patients undergoing elective hip surgery. METHODS: The main criterium of this trial was the incidence of DVT diagnosed by bilateral ascending venography, which was performed either if DVT was clinically suspected or in each remaining patient between the 12th and the 14th postoperative day. A total number of 172 patients were enrolled to receive the conventional dosage of 3,000 IU aXa (Mono-Embolex NM) and 169 patients to receive the high dosage form (5,000 IU aXa) once daily. The mean age (+/-SD) was 69.6+/-9.5 and 67+/-11.7 years. RESULTS: No relevant differences were found concerning predisposing risk factors. The duration of surgery was 93+/-25.2 and 88+/-21.4 min (mean+/-SD). Surgical type and approach were not different between the groups. Deep vein thrombosis was detected in 17 patients (9.9%) in the conventional dose group and in 16 patients (9.5%) in the high dose group (intent-to-treat analysis; n.s.). The rate of bleeding complications was not significantly different except the cell saver volumes (770+/-136 vs 475+/-186 ml; p<0.001). No significant difference was found in the serious adverse event reporting along the lines of EC-GCP (10 vs 8 events; p=0.65). CONCLUSIONS: This clinical trial confirmed that the conventional dosage (3,000 IU aXa/day) of certoparin ensures maximal antithrombotic activity.

Adult↗
PubMed1999

Lipoprotein(a) concentrations in women with a history of severe preeclampsia--a case control study.

A high concentration of lipoprotein(a) is associated with atherosclerotic disease. Atheroma may develop in spiral arteries in both preeclamptic and normal pregnancies, but they are much more common in preeclampsia, particularly in the decidual segments. We hypothesized that a high concentration of lipoprotein(a) is associated with the development of preeclampsia. We studied 40 women with a history of severe preeclampsia, 35 women with a history of preeclampsia and the (H)ELLP syndrome and 67 controls with a normal obstetric history. Lipoprotein(a) levels were measured at least 10 weeks post partum in the second half of a normal menstrual cycle. None of the women in the study or the control group were pregnant or used oral contraceptives. Lipoprotein(a) levels over the 90th percentile of the lipoprotein(a) distribution of our control group (420 mg/l) were defined as abnormal. There was a statistically significant higher prevalence of abnormal levels of lipoprotein(a) in women with a history of severe preeclampsia (33%) in comparison with women with a history of preeclampsia and (H)ELLP syndrome (9%) and with the control group (10%). We found that a history of severe preeclampsia and spontaneous abortion was associated with elevated lipoprotein(a) levels as a post-hoc finding. Whether spontaneous abortion and high levels of lipoprotein(a) are related remains to be demonstrated.

Adult↗
PubMed1999

Characterization of a MAb to ovarian cancer and its possible diagnostic application.

We report the distribution pattern of the target antigen of an IgG1 monoclonal antibody, Ki-OC III raised in BALB/C mice against solubilised ovarian adenocarcinoma, in normal tissue and in a collection of human tumour types. Special reference was made to benign and malignant ovarian tumours. The reactive antigen protein purified to homogeneity for a planned amino acid analysis showed three bands between 37-40 kDa. Immunohistochemical analysis revealed a specificity of 98% and a sensitivity of 77%. The tracer kinetics of the radiolabelled antibody were tested on a human ovarian carcinoma cell line in athymic mice. The results were compared to cell lines derived from breast and stomach carcinomas as well as to a human glioblastoma cell line. The results show the preferential uptake by ovarian cancer cells followed by breast cancer cell lines. In animal models, scintigraphic monitoring and direct measurement of the radio-labelled monoclonal antibody showed a preferential accumulation in tumours, in addition to high level signals in the liver, kidney, spleen and heart which were related to degradation, excretion and high circulation. The Ki-OC III reactive antigen could be a potential candidate for immunomonitoring of ovarian and possibly also of breast cancer, for in vivo tumour imaging as well as for histopathologic examinations.

Amino Acid Sequence↗
PubMed1999

[Extract of the Echinacea purpurea herb: an allopathic phytoimmunostimulant].

In Northamerican folk medicine Echinacea purpurea L. Moench (purple coneflower) was used as a medicinal plant. Nowadays various formulations containing stabilized or dried pressed juice from Echinacea purpurea as an active ingredient are often administered to treat common colds. These preparations are very well tolerated and safe. Allergic reactions, mainly reversible skin reactions, may occur especially in persons showing hypersensibility after contact with plants from the Compositae family. Pharmacological data let assume purple coneflower pressed juice preparations stimulate the innate immune system and increase the resistance to common colds. In this context the stimulation of the oxidative burst as well as the modulation on monokine secretion by the pressed juice of purple coneflower are reviewed. Also relevant clinical studies are presented concerning the treatment of infections respectively of common cold.

Adjuvants, Immunologic↗
PubMed1999

Reference values and biological variation for tumor marker CA 19-9 in serum for different Lewis and secretor genotypes and evaluation of secretor and Lewis genotyping in a Caucasian population.

The concentration of the tumor marker CA 19-9 is influenced by the patient's secretor status and Lewis genotype. The aim of this study was to establish novel reference intervals for CA 19-9 in serum based on secretor and Lewis genotypes, to investigate the biological variation of CA 19-9, and to evaluate the utility of Lewis and secretor genotyping on a group of individuals with serologically defined Lewis phenotypes. CA 19-9 was measured in serum of 500 healthy individuals. Secretor and Lewis genotypes were determined by sequencing and PCR-cleavage methods. Significant differences were found between subgroups with different Lewis and secretor genotypes. Genotype-based reference intervals for CA 19-9 are presented. The upper reference limit for all individuals was 28.7 kilounits/L; for secretors and nonsecretors, the upper reference limits were 12.4 and 61.2 kilounits/L, respectively. The analytical imprecision (CVA) was 9.8%, the within-subject variability (CVI) was 15.8%, and the between-subject variability (CVG) was 102.2%. Good agreement was found between Lewis and secretor genotyping and conventional blood grouping. Genotype-based reference intervals may be a way to increase the clinical utility of CA 19-9. On the basis of the calculation of a critical difference for sequential values (significant at P </=0.05) of 51.5%, a 40-50% change in marker concentration is suggested as the limit for significant change when the marker is used for follow up. PCR-based genotyping is a reliable method for secretor and Lewis histo-blood grouping.

Adult↗
PubMed1998

Pronounced microsatellite instability in transitional cell carcinomas from young patients with bladder cancer.

Microsatellites may show loss of heterozygosity as well as instability of the repeats. We examined 22 different microsatellites in 14 bladder tumours (7 grade II non-invasive, 7 grade III/IV invasive) and found altered CA repeat length compared with leukocytes, indicating instability, in several microsatellites in all tumours. Instability was significantly more frequent in low stage tumours compared with high stage tumours. The number of new bands occuring was also significantly higher in low stage tumours (median 7.2) compared with high stage tumours (median 3.3). Furthermore, patients with a disease course > or = 1 year had significantly more unstable microsatellites (10.83) than those with a disease course < 1 year (mean 8.88). Examination of biopsies from normal bladder mucosa showed no instability. In 2 cases in which selected site biopsies were taken, alterations differed from the tumours, pointing at a different clonal development. LOH was most frequent in 9p markers in low stage tumours. In a group of markers located at 2p, 17p (p53), 9q, 5q and 10p, LOH was significantly more frequent in high stage tumours. Microsatellites placed at MSH2 and MLH1 loci showed LOH in several cases, indicating that the profound microsatellite instability could partly be an effect of damage to these genes.

Adult↗
PubMed1998

Epstein-Barr virus-infected B cells of males with the X-linked lymphoproliferative syndrome stimulate and are susceptible to T-cell-mediated lysis.

Primary infection with the Epstein-Barr virus (EBV) results in fatal infectious mononucleosis in up to 70% of males affected by the X-linked lymphoproliferative syndrome (XLP). This rare disease is often associated with diverse natural killer (NK)-, B- and T-cell deficiencies. We describe experiments testing whether the B lymphocytes of affected males play a role in the pathogenesis of XLP due to a low susceptibility to T-cell-mediated immunity. Using reverse transcription-polymerase chain reaction (RT-PCR) and immunohistochemistry we detected in these B cells the expression of viral proteins EBNA-1, EBNA-2, EBNA-3A, EBNA-3C, LMP-1 and LMP-2A, which provide targets for cytotoxic T cells. Major histocompatibility complex (MHC) class I, MHC class II and the B7 costimulatory molecule were present on the cell surface. Accordingly, the EBV-infected B cells were lysed in 51Cr-release assays by T lymphocytes sharing MHC determinants with the targets. This MHC-restricted and specific lysis was confirmed in competition experiments using MHC-specific monoclonal antibodies (MAbs) and synthetic peptides. XLP-derived LCLs could also induce MHC class I-restricted memory and cytotoxic T lymphocytes. Thus, these XLP-derived B cells resembled normal LCIs in vitro with respect to induction of EBV-specific cytotoxic T cells (CTL), the ability to present EB viral antigens and the susceptibility to EBV-specific and MHC-restricted CTL-mediated killing. The failure of the immune system to eliminate these virus-infected B cells in XLP is clearly not caused by a B-cell-specific defect.

Antigens, Viral↗
PubMed1998

Cytotoxic T cells and neutralizing antibodies induced in rhesus monkeys by virus-like particle HIV vaccines in the absence of protection from SHIV infection.

HIV Pr55gag has in the absence of other viral components the capacity to self assemble in budding noninfectious virus-like particles (VLP). The immunological spectrum of the HIV-1IIIB gag-derived VLP was expanded either by stable anchoring of chimeric modified gp 120 on the surface of the VLP (type 1) or by replacing sequences of the Pr55gag precursor by the V3 loop and a linear portion of the CD4 binding domain (type 2). This noninfectious antigen delivery system was evaluated for immunogenicity and efficacy in rhesus macaques without adjuvants. Intramuscular immunization with both types of VLP induced high titers of gag-specific antibodies ranging from 1/8000 to 1/510,000 for type 1 VLP and from 1/4000 to 1/16,000 for type 2 VLP. Only animals immunized with type 1 VLP developed substantial endpoint titers of env-specific antibodies (1/2000-1/32,000) with a neutralizing capacity at serum dilutions of 1/32-1/128. Gag- and env-specific cytotoxic T lymphocyte (CTL) activity was induced by both types of VLP at similar levels. Four weeks after the last immunization animals were challenged intravenously with 20 MID50 of the cell free homologous envelope simian/HIV-1IIIB chimeric challenge stock Despite HIV-1-specific neutralizing and CTL responses, all vaccinated animals became infected.

AIDS Vaccines↗
PubMed1998

The prognosis of mild cognitive impairment in the elderly.

PURPOSE: To determine whether or not subtypes of intellectual functioning are suitable to predict further cognitive decline in individuals with mild cognitive impairment. DESIGN: Naturalistic longitudinal study (mean interval 2.7 years). PATIENTS: 41 subjects with mild cognitive impairment who attended a memory clinic. METHODS: SIDAM, CT, SPECT, and ApoE genotype. RESULTS: At follow-up, 8 out of 41 patients (19.5%) with MCI had progressed to dementia, 8 patients (19.5%) had improved to normal levels of cognitive functioning, 25 patients (61%) had remained stable within the MCI group. At baseline the two prognostic groups differed significantly with regard to age, memory functions, orientation, and the degree of atrophy of the left medial temporal lobe on CT scan. CONCLUSION: The majority of MCI patients in this study remained cognitively stable within the observation period. Patients with older age, poorer test performance on memory tasks and orientation deficits are at higher risk of progressive decline to dementia. CT measures of medial temporal lobe atrophy may be a sensitive parameter of group discrimination.

Aged↗
PubMed1998

Molecular alterations in bladder cancer.

In recent years, significant information has been accumulated on the molecular alterations that take place during development of transitional cell carcinoma (TCC). A number of studies aimed at defining loss of heterozygosity have shown a general chromosomal instability in TCC with loss of parts of chromosome 9 at early stages of papillomas, and of chromosomes 11, 13, 3, 4, 8, 17 and 18 during further development of the tumor. Oncogenes are activated, exemplified by mutations in the ras gene family and overexpression of the c-erbB-2 gene, in a minor fraction of tumors. Alterations of tumor suppressors (involved in control of the cell cycle, DNA quality control and activation of apoptosis) seem to be frequently involved. Among these p53 has a key role, and one p53 allele is frequently lost in TCC followed by mutation of the remaining allele.These alterations are correlated with survival, disease progression, invasion and recurrence. Also frequently lost are the cell cycle control genes p16 and p15. The predictive value of this has not yet been determined. Studies of glycosylation genes have shown downregulation of the ABO gene, followed by loss of ABO blood group structures and accumulation of the Lewis cell adhesion molecules in high grade tumors. Functional proteome analysis has furthermore identified biomarkers that are correlated with grade and stage. Molecular models for TCC development can now be built, and clinical testing of these is urgently needed.

Blood Group Antigens↗
PubMed1998

Regulation of the Epstein-Barr viral immediate early BRLF1 promoter through a distal NF1 site.

The immediate early BRLF1 and BZLF1 promoters of Epstein-Barr virus are crucial for triggering the replicative cycle of the virus. To better understand the cell type dependence of the lytic cycle we conducted an analysis of the BRLF1-promoter in the epithelial cell line HeLa and the lymphoid cell line IM9. To analyze promoter activities, transient transfections with 5'-deletions of the BRLF1-promoter in front of luciferase as reporter gene were conducted. Besides the already known cis-acting elements of the promoter close to the TATA-box, more distal elements were located and functionally tested. A nuclear factor 1 consensus site was found to act positively in HeLa cells, but did not in lymphoid IM9 cells. The NF1 site was shown to bind protein by electrophoretic mobility shift assays, antibody-supershifts and in vitro footprinting. Thus, a protein belonging to the nuclear factor 1 family of proteins was identified as additional cellular trans-acting factor for the BRLF1-promoter besides the already described factors Sp1, Zta and Zif268.

Binding Sites↗
PubMed1998

Fetal and maternal diurnal rhythms during the third trimester of normal pregnancy: outcomes of computerized analysis of continuous twenty-four-hour fetal heart rate recordings.

OBJECTIVE: We quantified the presence of diurnal rhythms in various computerized fetal heart rate parameters in normal pregnancies to assess their clinical relevance. STUDY DESIGN: Modified cosine analysis was applied to the outcomes of computerized analysis of continuous 24-hour fetal heart rate recordings in 26 normal pregnancies. Diurnal rhythms in maternal heart rate and plasma hormones were assessed in 15 and 17 pregnancies, respectively. Correlations between maternal and fetal rhythms were calculated. RESULTS: A significant diurnal rhythm in basal heart rate was present in 73% of the fetuses and was closely related to the maternal heart rate rhythm. Diurnal rhythms in heart rate variability, accelerations, and activity were present in only 30% to 50% of the fetuses. CONCLUSIONS: The mother entrains fetal diurnal rhythms. The normal variability in neural development may account for the absence of diurnal rhythms in some fetuses.

Circadian Rhythm↗
PubMed1998

Urinary symptoms, potency, and quality of life in patients with localized prostate cancer followed up with deferred treatment.

OBJECTIVES: To evaluate urinary symptoms, potency, and quality of life in a group of patients with prostate cancer followed up with deferred treatment. METHODS: A self-administered questionnaire was mailed to patients with localized prostate cancer who were followed up with deferred treatment. Data regarding clinical stage, pathologic grade, and treatment after diagnosis were obtained from patient files. RESULTS: A total of 71 consecutive patients (age 79 years or less) were included. Of the 52 patients (73%) who responded, 31% had undergone transurethral resection of the prostate, 8% underwent radiation therapy, and 44% underwent hormonal deprivation during the follow-up period. With respect to incontinence, 21% were using pads and 37% leaked urine daily; in 21% of the patients, urine dripping or leaking was a substantial problem. Before the diagnosis of their prostate cancer, 81% stated they were able to have an erection. At the time of the questionnaire, 77% stated that their ability to have erections was reduced and only 29% had had an erection after the prostate cancer was diagnosed. For 12%, impotence was a problem. With respect to quality of life, 52% of the patients rated their health as excellent or good and 61% would be happy to spend the rest of their life feeling the way they did at the time of the questionnaire. Eighty-five percent were satisfied with the treatment policy for their prostate cancer, and 96% would choose deferred treatment again if faced with the decision. CONCLUSIONS: By use of a self-administered questionnaire, a high frequency of incontinence and impotence was found in a group of patients with prostate cancer followed up with deferred treatment. Despite these problems, more than half of the patients rated their health as good and would undergo expectant management again if faced with the decision.

Aged↗