Biomedical subjects

Hans Wolf

Publications and source records attributed to Hans Wolf.

47 records · Page 3Linked to original sources

PubMed2002

Immunohistochemical study of the expression of cell cycle regulating proteins at different stages of bladder cancer.

PURPOSE: The cell cycle is known to be deregulated in cancer. We therefore analyzed the expression of the cell cycle related proteins p21, p27, p16, Rb, and L-myc by immunohistochemical staining of bladder tumors. METHODS: The tissue material consisted of bladder tumors from three groups of patients; group 1, 23 patients with recurrent stage Ta (non-invasive) tumors; group 2, 22 patients presenting at their first admission with T2-4 (muscle invasive) tumors; group 3, 24 patients who experienced disease progression from Ta or T1 (invasive in connective tissue) to a higher stage. By immunohistochemical staining the protein expression was compared to allelic deletions of the corresponding genes. The allelic deletions were detected by PCR-based microsatellite analyses. RESULTS: We detected a significant reduction in the expression levels of the cell cycle related proteins p21(waf1) ( P=0.002), p27(kip1) ( P=0.03), Rb ( P=0.00002), and L-myc ( P=0.00000007) in muscle invasive tumors compared to noninvasive tumors. Tumors presenting as muscle invasive at first diagnosis had significantly lower levels of p16/CDKN2A ( P=0.01) when compared to muscle invasive tumors that followed Ta or T1 precursor lesions. We found no general correlation between allelic deletion of a gene and its immunohistochemical protein expression, indicating that the remaining allele may be capable of encoding a normal or even increased protein level. CONCLUSIONS: Our results support the hypothesis that bladder tumors with invasion at first diagnosis differ from those in which invasion follow superficial tumors. This difference is reflected as a different level in cell cycle related protein expression. The data also indicate that allelic deletions of cell cycle related genes do not correlate with an altered level of protein expression.

Cell Cycle Proteins↗

PubMed2002

Allelic imbalances in human bladder cancer: genome-wide detection with high-density single-nucleotide polymorphism arrays.

BACKGROUND: Bladder cancer is characterized by genomic instability. In this study, we investigated whether genome-wide screening using single-nucleotide polymorphism (SNP) arrays could detect allelic imbalance (loss or gain of at least one allele) in bladder cancers. METHODS: For microarray analysis, DNA was isolated from microdissected bladder tumors and leukocytes from 11 patients. The stage T1 tumor (connective tissue invasive) and the subsequent stage T2-4 tumor (muscle invasive) were available from eight of these patients, and only the first muscle-invasive stage T2-4 tumor was available from three of the 11 patients. The microarray contained 1494 biallelic polymorphic sequences. For microsatellite analyses, DNA was isolated from tumors and leukocytes of nine patients with primary T2-4 tumors and 13 patients with Ta (noninvasive) tumors. All statistical tests were two-sided. RESULTS: We assigned a genotype to 1204 loci, 343 of which were heterozygous. Allelic imbalance was detected in known areas of imbalance on chromosomes 6, 8, 9, 11, and 17, and a new area of imbalance was detected on the p arm of chromosome 6. Microsatellite analysis of nine other T2-4 tumors and 13 Ta tumors showed that allelic imbalance was more frequent in T2-4 tumors than in Ta tumors (P<.001). We detected 8.5 allelic imbalances (median) in 348 informative loci in T1 tumors and 28 allelic imbalances (median) in 329 informative loci in T2-4 tumors. When pairs of T1 and T2-4 tumors were analyzed from eight patients, 68% of imbalances detected in T1 tumors (146 imbalances) occurred in the subsequent T2-4 tumors (99 imbalances). Homozygous TP53 mutations were more often associated (P =.005) with high allelic imbalance than with low allelic imbalance. CONCLUSION: SNP arrays are feasible for high-throughput, genome-wide scanning for allelic imbalances in bladder cancer.

Allelic Imbalance↗

PubMed2002

Long-term follow-up of infants after transcervical chorionic villus sampling and after amniocentesis to compare congenital abnormalities and health status.

OBJECTIVES: Next to procedure-related fetal loss, other adverse effects of invasive prenatal diagnosis have been reported: limb defects after chorionic villus sampling (CVS) or early amniocentesis and respiratory distress after amniocentesis (AC). Because minor abnormalities may be overlooked in routine follow-up, we obtained long-term follow-up data after CVS and AC. METHODS: 1509 women with a singleton pregnancy who had transcervical CVS were matched by age and season of conception with 1509 women with singleton pregnancies who had AC. All procedures were performed during 1985-1991 for advanced maternal age >35 years. Data regarding congenital malformations (classified according Eurocat), neonatal and paediatric morbidity and complications of motor development, speech, hearing and visual function were obtained by questionnaire in 1993-1995. RESULTS: Short-term outcome was known in all but ten infants. Questionnaires with a structured design were mailed to all women with a surviving infant (n=2810); 86.7% responded. No difference was detected between infants after CVS compared with infants after AC regarding congenital malformations (7.2% versus 6.3%), neonatal morbidity (15.1% versus 15.9%), paediatric morbidity with clinical treatment (7.7% versus 6.3%) or outpatient treatment only (43.9% versus 40.3%) and evident function disturbance (2.0% versus 2.0%) or doubtful function disturbance (6.3% versus 6.8%). The number of infants with physical growth <10th centile for Dutch infants was equal (10.1%). Sub-analysis for limb abnormalities or respiratory complications did not demonstrate differences between infants after CVS and AC. Only 10% of all congenital malformations were already known through routine post-partum follow-up. CONCLUSIONS: An extensive long-term survey could not demonstrate differences of health status between infants after prenatal diagnosis by transcervical CVS and AC.

Adult↗

PubMed2002

Genome-wide study of gene copy numbers, transcripts, and protein levels in pairs of non-invasive and invasive human transitional cell carcinomas.

Gain and loss of chromosomal material is characteristic of bladder cancer, as well as malignant transformation in general. The consequences of these changes at both the transcription and translation levels is at present unknown partly because of technical limitations. Here we have attempted to address this question in pairs of non-invasive and invasive human bladder tumors using a combination of technology that included comparative genomic hybridization, high density oligonucleotide array-based monitoring of transcript levels (5600 genes), and high resolution two-dimensional gel electrophoresis. The results showed that there is a gene dosage effect that in some cases superimposes on other regulatory mechanisms. This effect depended (p < 0.015) on the magnitude of the comparative genomic hybridization change. In general (18 of 23 cases), chromosomal areas with more than 2-fold gain of DNA showed a corresponding increase in mRNA transcripts. Areas with loss of DNA, on the other hand, showed either reduced or unaltered transcript levels. Because most proteins resolved by two-dimensional gels are unknown it was only possible to compare mRNA and protein alterations in relatively few cases of well focused abundant proteins. With few exceptions we found a good correlation (p < 0.005) between transcript alterations and protein levels. The implications, as well as limitations, of the approach are discussed.

Carcinoma, Transitional Cell↗

PubMed2002

Proteomic strategies to reveal tumor heterogeneity among urothelial papillomas.

Proteomics and immunohistochemistry were used to reveal tumor heterogeneity among urothelial papillomas (UPs) with the long term goal of predicting their biological potential in terms of outcome. First, we identified proteins that were deregulated in invasive fresh lesions as compared with normal urothelium, and thereafter we immunostained UPs with a panel of antibodies against some of the markers. Twenty-two major proteins showing variations of 2-fold or more in at least one-third of the invasive lesions were selected. Specific antibodies against several of the proteins were obtained, but only a few reacted positively in immunostaining. A panel consisting of antibodies against keratinocytes (CKs) 5, 13, 18, and 20 and markers of squamous metaplasia (CKs 7, 8, and 14) was used to probe normal urothelium and 30 UPs collected during a period of five years. Four UPs showed a normal phenotype, whereas the rest could be grouped in five major types that shared aberrant staining with the CK20 antibody. Type 1 heterogeneity (n = 4) showed preferred staining of the umbrella cells with the CK8 antibody. Type 2 (n = 11) was typified by the staining of the basal and intermediate layers with the CK20 antibody. Type 3 (n = 7) was characterized by the predominant staining of the basal cell layer with the CK5 antibody. Type 4 (n = 1) showed areas of CK7 negative cells, whereas type 5 (n = 3) showed loss of staining of the basal cells with the CK20. 29% of the patients experienced recurrences, but none progressed to invasive disease. Patients harboring phenotypic alterations in the basal cell compartment (types 3 and 5) showed the highest number of recurrences (4/7 and 2/3, respectively), and all type 3 lesions progressed to a higher degree of dedifferentiation. Even though a long term prospective study involving a larger sample size is required to assess the biological potential of these lesions, we believe that this approach will prove instrumental for revealing early phenotypic changes in different types of cancer.

Antibodies↗

PubMed2002

Comparison of Portapres with standard sphygmomanometry in pregnancy.

BACKGROUND: Continuous beat-to-beat noninvasive blood pressure (BP) measurement is possible with Portapres. It constructs finger arterial waveforms beat-to-beat. Dedicated software is used to analyze the arterial waveforms. A new technique has been developed to reconstruct brachial intra-arterial pressure that uses return to flow (RTF). This method has been validated against invasive intra-arterial measurements in nonpregnant individuals. OBJECTIVES: To validate Portapres in normal and preeclamptic pregnant women against standard aneroid sphygmomanometry according to Riva-Rocci-Korotkoff (RRK). METHODS: In 30 normotensive (10 in each trimester) and 20 preeclamptic women, two trained observers blinded from each other's results took BP measurements with a standard sphygmomanometer. These measurements were compared with sequential same-arm averaged measurements obtained during 30 sec by Portapres, following protocols from the Association for the Advancement of Medical Instrumentation (AAMI, mean accepted difference < or = 5 mmHg, SD < or = 8) and British Hypertension Society (BHS, gradings A down to D). RESULTS: A total of 150 measurement pairs were analyzed. Cumulative percentages of absolute pressure differences for all women (BHS) and mean pressure differences (SD) for different trimesters and preeclampsia (AAMI) between sphygmomanometry and Portapres were calculated. Overall, mean difference (SD) for systolic BP was 5 (SD 8) and for diastolic BP was -3 (SD 8), although analysis of variance revealed a significant effect for preeclampsia on diastolic differences between the two methods of BP measurement ( p<0.001). CONCLUSIONS: Portapres with RTF, developed to equal intra-arterial brachial pressure, compares reasonably well to RRK and overall meets the criteria set by the AAMI. According to the BHS, Portapres receives a B-grading for diastolic BP and a C-grading for systolic BP. As Portapres measures BP and calculates cardiac output continuously and noninvasively, it would appear worthwhile to further evaluate this device in pathological pregnancies.

Adolescent↗

PubMed2002

Non-invasive assessment of autonomic cardiovascular control in normal human pregnancy and pregnancy- associated hypertensive disorders: a review.

PURPOSE: Pre-eclampsia is a major complication of pregnancy. Although the disorder usually becomes apparent only in the third trimester of pregnancy, evidence is available that underlying pathophysiological abnormalities are already present early in pregnancy. The association between alterations in autonomic cardiovascular control and the development of hypertension in pregnancy has been investigated for some time. Non-invasive methods are especially of interest, since they have the advantage of minimal risk for the mother and the conceptus and enable repeated measurements during pregnancy. If non-invasive tests for autonomic cardiovascular control could demonstrate the increased sympathetic activity, as observed by microneurography than this method is a candidate for early identification of pre-eclampsia. Therefore, the literature on non-invasive testing of autonomic cardiovascular control in normal pregnancies and pre-eclampsia was summarized. DATA IDENTIFICATION AND SELECTION: Medline was searched and 36 articles on autonomic cardiovascular control in human pregnancy by non-invasive test methods were reviewed. For each test method, data of different studies were summarized to evaluate if the method could discriminate between healthy pregnancy and pre-eclampsia. CONCLUSION: Although small differences have been observed between normal pregnancy and pre-eclampsia in individual studies using non-invasive methods, the consistency in the available data is insufficient to discriminate between normal pregnancy and pre-eclampsia. The failure to demonstrate the increased sympathetic activity, as observed by direct microneurography, might be due to methodological factors of the non-invasive studies. Alternatively, sympathetic activity to resistance vessels in skeletal muscle may not be a proper reflection of autonomic cardiovascular control in pregnancy. Well-designed longitudinal research could be useful to test these suppositions.

Autonomic Nervous System↗

PubMed2002

Nucleoprotein structure of immediate-early promoters Zp and Rp and of oriLyt of latent Epstein-Barr virus genomes.

Genomic footprints across Rp, Zp, and oriLyt of Epstein-Barr virus (EBV) have been conducted in a panel of latently infected B-cell lines. Close protein-base contacts were found about 360 nucleotides upstream of the Zp initiation site. Gel shifts and transient transfection assays indicated that an Sp1-NF1 locus may serve as a repressive transcriptional element against Zp induction from latent EBV genomes.

B-Lymphocytes↗

PubMed2001

The VP1-unique region of parvovirus B19: amino acid variability and antigenic stability.

The unique region of structural protein VP1 of parvovirus B19 (erythrovirus B19) is important for eliciting neutralizing antibodies that are responsible for eliminating the virus from the peripheral blood and for inducing lifelong immunity. Neutralizing human MAbs bind a conformationally defined epitope spanning VP1 residues 30-42. The DNA sequence encoding the VP1-unique region was determined in parvovirus B19 isolated from peripheral blood and amniotic fluid of nine acutely infected pregnant women, five arthritis patients and two chronically infected children. The amino acid sequences of the VP1-unique region exhibited higher variability in comparison with other B19-specific proteins. To analyse the influence of amino acid variations on antibody binding and protein conformation, two variants of the VP1-unique region were selected and expressed in E. coli as intein-fusion proteins. The selected variants displayed a number of amino acid exchanges in the VP1-unique region and had mutations in the determined epitope and adjacent regions. After purification via affinity chromatography, the dissociation constants K(D) of VP1-specific human MAbs interacting with the variant antigens and a viral prototype of the VP1-unique region were determined with a quartz crystal microbalance biosensor. A value of 5.4 x 10(-8) M was determined for the prototype isolate pJB; the affinity constants for the variant VP1-unique regions were similar. Comparable values were obtained for interaction of antibodies with non-infectious VP1/VP2 capsids produced by recombinant baculovirus and with B19 virions from amniotic fluid. It is concluded that the conformation of the epitope is unaffected by mutations or the environment of the VP1-unique region in virus capsids.

Amino Acid Sequence↗

PubMed2001

Cellular transcription factors that interact with p6 promoter elements of parvovirus B19.

All transcripts of the human parvovirus B19 identified so far are regulated by a single promoter at map unit 6 of the viral genome, the so-called p6 promoter. This promoter is active in a wide variety of different cells. In order to identify cellular transcription factors involved in regulating promoter activity, we performed gel-retardation and supershift assays using the parts of the p6 promoter sequence shown previously to be protected in footprint experiments. Thereby, binding was demonstrated of the Oct-1 protein to an octamer motif within the p6 promoter and of the transcription factor Sp1 to three GC boxes. A specific preferential interaction of the factor Sp3 with one of these boxes was observed, indicating that the ratio Sp1:Sp3 may be involved in the regulation of promoter activity. Consensus sites for the regulatory protein YY1 are located close to the GC boxes and the octamer motif, to which this factor binds efficiently.

Antibodies↗

PubMedDate not supplied

Allelic deletions of Rb and L-myc in urine sediments from patients with bladder tumors or carcinoma in situ.

In a previous study we found allelic imbalances of Rb and L-myc associated with disease stage and disease course in bladder cancer. The primary aim of the present study was to determine whether the changes found in tumors were reflected in urine sediments. Secondly we wanted to test if Rb and L-myc were frequently lost in urine sediments from patients with carcinoma in situ and no bladder tumor at present. Based on this we examined allelic deletions of the Rb and L-myc genes in tumor and urine from 55 patients with bladder tumors or carcinoma in situ. Deletions were examined on extracted DNA from tumors and urine sediments by the use of microsatellite markers located as close to the genes as possible. Fifty-five patients and 10 controls were included. We found no strict correlation between allelic deletions in bladder tumors and urine sediments from the same patient. Allelic deletions in urine sediments were at least as common in patients with carcinoma in situ and no bladder tumor (32%) as in patients with bladder tumors (20%). It was possible to identify allelic deletions in urine sediment from 1 patient with cystitis and no history of malignant bladder disease (6%). In conclusion we found no strict correlation between allelic deletions in bladder tumors and urine sediments. Allelic deletions in urine sediments seem to be at least as common in patients with carcinoma in situ as in patients with bladder tumors.

Alleles↗