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W Berger

Publications and source records attributed to W Berger.

At least 37 records · Page 2Linked to original sources
PubMed2001

Overexpression of the human major vault protein in astrocytic brain tumor cells.

Evidence has shown that the major human vault protein (MVP), which is identical to lung resistance-related protein (LRP), may be causally involved in a special type of multidrug resistance (MDR). The purpose of this study was to investigate the expression and cellular localization of MVP in cells derived from brain tumors and other tumors of neuroectodermal origin. Using both established cell lines (n = 22) and primary explants (n = 30), we show that a distinct overexpression of the MVP gene at the mRNA (RT-PCR) and protein (Western blot) levels is a characteristic feature of cells derived from astrocytic brain tumors. Primary cultures obtained from meningioma specimens also expressed high MVP levels, in contrast to neuroblastoma and medulloblastoma cells, which rarely contained detectable amounts of MVP. Normal human astrocytes cultured in vitro expressed MVP, although at low amounts compared with most malignant cell types. Basal MVP expression correlated with resistance against diverse antineoplastic drugs including anthracyclins, cisplatin and etoposide. By Western blot, MVP was also detected in all tumor samples taken from 7 glioma and 3 meningioma patients. Taken together, these data suggest overexpression of MVP as one explanation for the low efficacy of chemotherapeutic treatment of astrocytic brain tumors.

Antibodies, Monoclonal↗
PubMed2001

Mutations in the X-linked RP2 gene cause intracellular misrouting and loss of the protein.

Mutations in RP2 cause the second most frequent form of X-linked retinitis pigmentosa, a severe retinal degeneration that leads to loss of visual acuity and blindness. The RP2 gene encodes a protein with homology to cofactor C, a tubulin-folding chaperone. By searching protein sequence databases, we identified a whole set of similar molecules from diverse organisms. Protein sequence alignments show that RP2 and cofactor C represent members of two distinct orthologous groups. All previously identified missense mutations affect amino acid residues which are conserved in all RP2 orthologues or both orthologous groups. Intracellular localization of the wild-type protein and mutated variants was determined by fluorescence microscopy of cells expressing RP2 with a green fluorescent protein tag. A mutation in the N-terminus of RP2 abolishes localization to the plasma membrane in HeLa cells. C-terminal protein truncation mutations, which account for 2/3 of the pathogenic RP2 variants, lead to scattered fluorescent foci in the cytoplasm of COS-7 and HeLa cells. Analysis of protein extracts from the respective cells with anti-RP2 antibodies identified truncated proteins of expected size in a low-speed centrifugation pellet while the wild-type protein appeared in the supernatant. Moreover, no protein was detected in immortalized cell lines from patients with protein truncation mutations while mRNA was still present. Thus, loss of the protein and/or aberrant intracellular distribution might be the basis for the photoreceptor cell degeneration in most RP2 cases.

Amino Acid Sequence↗
PubMed2001

A small upstream open reading frame causes inhibition of human major vault protein expression from a ubiquitous mRNA splice variant.

Overexpression of the major vault protein (MVP) has been linked to a multidrug resistance (MDR) phenotype. We describe a ubiquitously expressed MVP mRNA splice variant (long (L)-MVP) differing from the regular isoform (short (S)-MVP) within the 5'-leader. Only L-MVP mRNA contains a small upstream open reading frame which was proven to inhibit in vitro and in vivo MVP expression in cis. L-MVP represented an almost constant portion of total MVP mRNA in diverse normal tissues, but was more variable in malignant cell types. MDR sublines with altered MVP expression displayed changed S-MVP/L-MVP ratios as compared to their drug-sensitive counterparts. Our results suggest alternative splicing as one mechanism for regulation of MVP expression.

5' Untranslated Regions↗
PubMed2001

Accreditation and recognition of soil sampling evidence of competence for testing laboratories in Germany.

Quality assurance is an essential requirement in many areas of soil testing. Soil sampling plays an important role in soil investigation. One important quality assurance measure is evidence of the competence of institutions offering sampling services (testing laboratories) to carry out appropriate sampling. A special quality assurance procedure has been developed in the course of the investigation and assessment of suspected and contaminated sites on federal property. Testing laboratories are granted official recognition by an independent competent institution, based on well-defined criteria with regard to testing methodology and the qualifications held by the personnel. A prerequisite for such recognition is an effective accreditation procedure. Currently only testing laboratories with recognised status are commissioned for work on contaminated sites on federal property.

Accreditation↗
PubMed2001

Liver carcinoma prevention among Asian Pacific Islanders. Getting hepatitis B shots into arms.

BACKGROUND: For the past 20 years, the hepatitis B virus (HBV) has infected at least 250,000 persons annually in the United States. Persons with chronic HBV infection are at increased risk for liver carcinoma. Among immigrants to the United States from countries with high HBV endemicity, high rates of chronic HBV infection account in large part for their high incidence rates of liver carcinoma. Among those who have not been infected, hepatitis B and hepatitis B-related liver carcinoma can be prevented through hepatitis B vaccine immunizations. In this article, the authors examine hepatitis B vaccine coverage rates from surveys of Asian and Pacific Islander children in Houston, Texas and Los Angeles County, California. METHODS: In Houston, the authors surveyed the parents of 300 students aged 10 to 18 years at a Vietnamese-language school. In Los Angeles County, they surveyed parents of 471 fourth grade students from 6 different Asian and Pacific Islander ethnic groups in 8 public elementary schools. RESULTS: In Houston, 55% of responding parents submitted immunization records indicating that their child had had 3 hepatitis B shots; 3% reported that their child had had no shots. In Los Angeles County, 37% (Filipino) to 67% (Japanese) had had 3 shots; proportions of children having had no shots ranged from 5% to 15%. CONCLUSIONS: Under current immunization practices, the authors estimate that nearly 13,000 Asian and Pacific Islander children living in the United States today will become infected with HBV in the future, resulting in more than 600 liver carcinoma deaths. It is essential that cancer control agencies in the United States take leadership in raising awareness about the role of HBV in the etiology of liver carcinoma and that of the hepatitis B vaccine in preventing it.

Adolescent↗
PubMed2001

X chromosome-specific cDNA arrays: identification of genes that escape from X-inactivation and other applications.

Mutant alleles are frequently characterized by low expression levels. Therefore, cDNA array-based gene expression profiling may be a promising strategy for identifying gene defects underlying monogenic disorders. To study the potential of this approach, we have generated an X chromosome-specific microarray carrying 2423 cloned cDNA fragments, which represent up to 1317 different X-chromosomal genes. As a prelude to testing cell lines from patients with X-linked disorders, this array was used as a hybridization probe to compare gene expression profiles in lymphoblastoid cell lines from normal males, females and individuals with supernumerary X chromosomes. Measurable hybridization signals were obtained for more than half of the genes represented on the chip. A total of 53 genes showed elevated expression levels in cells with multiple X chromosomes and many of these were found to escape X-inactivation. Moreover, the detection of a male-viable deletion encompassing three genes illustrates the utility of this array for the identification of small unbalanced chromosome rearrangements.

Alleles↗
PubMed2001

DNA sequence comparison of human and mouse retinitis pigmentosa GTPase regulator (RPGR) identifies tissue-specific exons and putative regulatory elements.

Retinitis pigmentosa 3 (RP3) is a progressive retinal degeneration due to mutations in the X-linked RPGR gene. Transcription studies in human and mouse tissues have revealed ubiquitously expressed transcripts and also an exceptional high number of tissue-specific alternative splice variants. However, regulation of tissue-specific expression and splicing is unclear, but this is of particular interest as mutations in this ubiquitously expressed gene lead to severe retinal degeneration, while other tissues are unaffected. To elucidate the conservation pattern of RPGR and to identify additional tissue-specific exons and putative regulatory elements we performed comparative genomic sequencing of the human and mouse RPGR gene. Each of the genes spans a region of nearly 59 kb, and all previously identified exons are conserved between the two species. DNA sequence comparison identified 28 conserved sequence elements (CSEs) in introns, upstream of exon 1, within the promotor region, and downstream of the most 3' exon. Some of the intronic CSEs flank tissue-specific exons and therefore may represent important regulatory elements for alternative splicing. Comparative northern blot hybridization of ubiquitous and tissue-specific RPGR probes identified high molecular weight transcripts with similar expression patterns in both human and mouse. These transcripts range from 6 to 15 kb in size and suggest the presence of additional transcribed sequences within RPGR. Our cross-species sequence comparison enables us to define candidate regions that may explain these large transcripts and will therefore contribute to the understanding of RPGR expression and splicing.

Alternative Splicing↗
PubMed2001

Consecutive geoelectric measurements reveal the downward movement of an oxidation zone.

An investigation program for monitoring pyrite oxidation on a conveyer bridge dump used geoelectric measurement for monitoring the progress of pyrite oxidation within the dump. The results of the geoelectric measurement show that low soil-pH and high pore water conductivity correlate with low soil resistivity values. The soil resistivity values are dominated by high pore water conductivity. The influence of changes in water saturation on resistivity was comparably low. An increase in pyrite oxidation was observed in areas with high porosity due to low dump density. Consecutive geoelectric measurements revealed locally differentiated downward movement of an oxidation zone caused by dump heterogeneity.

Electric Conductivity↗
PubMed2001

Percutaneous colonoscopic cecostomy for management of chronic constipation in children.

BACKGROUND: Chronic constipation and encopresis are common problems in children with spina bifida and anorectal anomalies. Commonly used therapies include complicated bowel regimens and antegrade continence enemas delivered via surgically placed appendicostomies and radiologically placed cecostomies. METHODS: A technique is described for percutaneous placement of cecostomies for the delivery of continence enemas or venting. RESULTS: Percutaneous cecostomies were placed in 12 patients. Improvement in bowel management occurred in all patients. CONCLUSIONS: Percutaneous endoscopic cecostomy is a safe and effective method for the treatment of intractable constipation.

Adolescent↗
PubMed2001

Effect of bilateral subthalamic nucleus stimulation on gait in Parkinson's disease.

The fundamental disturbance of the parkinsonian gait is the reduction in walking velocity. This is mainly due to reduction in stride length, while cadence (steps/min) is slightly enhanced. Treatment with L-dopa increases stride length while cadence is unchanged. Chronic stimulation of the thalamus has no effect on Parkinsonian gait. The efficacy of electrical stimulation of the subthalamic nucleus (STN) on gait in advanced Parkinson's disease has been clearly demonstrated clinically. The aim of the present study was to quantify the changes in gait measures induced by STN stimulation and L-dopa and to assess possible differential or additive effects. Eight Parkinson's disease patients (mean +/- SD age 48.1 +/- 7.3 years) with chronic bilateral STN stimulation (mean duration of disease 13.3 +/- 2.4 years, mean stimulation time 15.4 +/- 10.6 months) and 12 age-matched controls were investigated. Subjects walked on a special treadmill with a closed-loop ultrasound control system that used the subject's position to adjust treadmill speed continuously for the actual walking velocity. In an appropriate crossover design, spatiotemporal gait measures and leg joint angle movements were assessed for at least 120 stride cycles in four treatment conditions: with and without stimulation and with and without a suprathreshold dose of L-dopa. With STN stimulation, there were increases of almost threefold in mean walking velocity (from 0.35 to 0.96 m/s) and stride length (from 0.34 to 0.99 m). Cadence remained constant. The range of motion of the major leg joints also increased. L-Dopa alone had a slightly weaker effect, with an increase in walking velocity to 0.94 m/s and in stride length to 0.92 m at a similar cadence. These increased values were in the range of those for healthy age-matched subjects performing the same task. The combination of both treatments further increased the mean walking velocity to 1.19 m/s and stride length to 1.20 m at an unchanged cadence. However, not all patients receiving STN stimulation improved further when they also received L-dopa. These results demonstrate that chronic bilateral STN stimulation, like treatment with L-dopa, improves walking velocity by increasing stride length without changing cadence. STN stimulation almost exclusively affects mechanisms involved in the control of spatial gait measures rather than rhythmicity. The gait measures obtained with STN stimulation alone are in the range of control subjects.

Adult↗
PubMed2001

Peroxisome proliferators do not increase DNA synthesis in purified rat hepatocytes.

There have been numerous reports that chemicals which induce peroxisomes in rodent liver increase DNA synthesis in isolated hepatic parenchymal cells, but not as well in vitro as in vivo. It is also known that tumour necrosis factor alpha (TNFalpha) is mitogenic in isolated hepatocytes. Since Kupffer cells are a major source of TNFalpha in the liver and have recently been shown to be activated by peroxisome proliferators, the possibility exists that the effect of peroxisome proliferators on DNA synthesis in parenchymal cells is via Kupffer cell contamination of isolated hepatocyte preparations. The purpose of this study was to evaluate this hypothesis by studying the effect of model peroxisome proliferators on purified hepatocyte preparations. Hepatocytes were prepared from rat liver by standard calcium-free and collagenase perfusion. Subsequently, cells were centrifuged through Percoll to remove contaminating non-parenchymal cells. Cells were at least 99.9% pure as assessed by cell counting using specific markers for hepatocytes (resorufin O-glucoside) and Kupffer cells (FITC-labelled latex beads). Hepatocytes were cultured in Williams medium + 10% fetal bovine serum for 24 h followed by culture for 48 h in Williams medium plus or minus drug or mitogen additions. Under these conditions epidermal growth factor stimulated DNA synthesis assessed by incorporation of [3H]thymidine approximately 5-fold over control levels. The peroxisome proliferators WY,14-643 and nafenopin, however, had no effect on DNA synthesis, although they did increase acyl-CoA oxidase as expected. In contrast, TNFalpha increased cell proliferation nearly 10-fold in purified hepatocytes, an effect nearly doubled by WY-14,643. Further, when conditioned medium from purified Kupffer cells incubated with WY-14,643 was added to pure hepatocytes, DNA synthesis was increased over 2-fold in a time-dependent manner. Collectively, these data support the hypothesis that peroxisome proliferators do not influence DNA synthesis in isolated hepatocytes per se. Rather, they stimulate cytokine production by Kupffer cells which in turn increases DNA synthesis in parenchymal cells. An increase in mitogenic cytokine production by Kupffer cells is necessary for stimulation of DNA synthesis in purified rat parenchymal cells.

Animals↗
PubMed2001

Analysis of sporadic neuroendocrine tumours of the enteropancreatic system by comparative genomic hybridisation.

BACKGROUND: Chromosomal instability is observed in a wide spectrum of human cancer syndromes. However, to date, little is known of the characteristic genetic changes in sporadic neuroendocrine tumours of the gastroenteropancreatic system. AIMS AND METHOD: We have studied copy number aberrations (CNAs) in 26 sporadic neuroendocrine tumours of the enteropancreatic system (12 foregut and 14 midgut tumours) by comparative genomic hybridisation (CGH), allowing simultaneous evaluation of the entire tumour genome. RESULTS: Nearly all tumours (25/26; that is, 96%) showed chromosomal imbalances, including full chromosomal aneuploidies, losses and gains of chromosome arms, interstitial deletions, and amplifications. Whereas gains of chromosomes 4, 5, and 19 were found in both foregut and midgut tumours, gains of chromosomes 20q (58%), 19 (50%), as well as 17p (50%), and partial losses of chromosomes 1p (42%), 2q (42%), 3p, 4q, and 6q (25% each) were frequently observed only in foregut tumours. In contrast, midgut tumours displayed less CNAs. Gains were detected for chromosomes 17q and 19p (57%). Most frequent losses affected chromosomes 18 (43%) and 9p (21%). CONCLUSIONS: The results of our CGH analyses revealed new distinct candidate regions in the human genome associated with sporadic neuroendocrine tumours. Some of the genetic alterations were shared by foregut and midgut tumours while others discriminated between the two groups. Thus our results allude to the involvement of identical as well as discriminative genetic loci in tumorigenesis and progression of neuroendocrine neoplasms of the foregut and midgut. Based on these findings potential new candidate genes will be discussed.

Adolescent↗
PubMed2001

Treatment of childhood asthma with anti-immunoglobulin E antibody (omalizumab).

BACKGROUND AND OBJECTIVE: There seems to be a strong causal relationship between allergy and the origins of asthma. Susceptibility to both is determined by a combination of genetics and environment acting through a complex network of cytokines. Nearly 90% of affected children have positive skin tests indicating the presence of specific immunoglobulin E (IgE), with sensitivity to house dust mite, Alternaria, cockroach, cat, and dog most closely linked to the disease. Greater exposure to house dust mite during infancy leads to earlier onset of wheezing, and elevated serum IgE levels correlate with the appearance of asthma symptoms. Specific IgE binds to high-affinity (FcepsilonRI) receptors on mast cells and basophils. The IgE-mediated reactions that follow exposure of sensitized mast cells to an allergen are designated early- and late-phase asthmatic responses (EAR and LAR). EAR is characterized by release of histamine and other preformed mediators within 1 hour of allergen exposure. It is often followed by LAR, an infiltration of the airways by inflammatory cells associated with an episode of more prolonged, and usually more severe airflow obstruction, 4 to 8 hours after antigen exposure. Chronic airway symptoms result from persistent LAR caused by continuous allergen exposure. IgE antibodies are capable of passive transfer of both EAR and LAR sensitivity. IgE-mediated mast cell activation contributes to chronic tissue eosinophilia and airway remodeling, with permanent loss in pulmonary function. Omalizumab (rhuMAb-E25) is a recombinant, humanized, monoclonal anti-IgE antibody of mouse origin developed for the treatment of IgE-mediated diseases. Omalizumab binds to free IgE at the same site as the high-affinity receptor. Although it attaches to free IgE, it does not bind to IgA, IgG, or cell-bound IgE. It therefore does not induce cross-linking of cell-bound IgE, which would lead to the release of allergic mediators. It has been reported to decrease serum IgE levels in a dose-dependent manner, inhibit EAR and LAR, and cause a down-regulation of FcepsilonRI receptors on basophils. Omalizumab has been reported to be safe and effective in improving asthma control and reducing the requirement for oral and inhaled corticosteroids. This double-blind, randomized, placebo-controlled study evaluated the safety, steroid-sparing effects, and impact on disease exacerbations of omalizumab in the treatment of childhood asthma. Methods. Participants were 334 males and premenarchal females aged 6 to 12 years, with moderate to severe allergic asthma requiring treatment with inhaled corticosteroids. During a run-in phase, all children were switched to equivalent doses of beclomethasone dipropionate (BDP), and the dose was adjusted to assure maintenance of asthma control achieved with previous corticosteroid treatment. Children were randomized to subcutaneously administered placebo (N = 109) or omalizumab (N = 225) at a dose based on body weight and initial serum IgE (0.016 mg/kg/IgE [IU/mL] per 4 weeks). BDP dose (initial range 168-420 microg/d) was kept stable for 16 weeks (stable-steroid phase), reduced over 8 weeks to the minimum effective dose (steroid-reduction phase), and maintained constant for the final 4 weeks. RESULTS: More participants in the omalizumab group decreased their BDP dose, and their reduction was greater than that of the placebo group (median reduction 100% vs 66.7%). BDP was withdrawn completely in 55% of the omalizumab group versus 39% of the placebo group. The incidence and the frequency of asthma exacerbations requiring treatment with doubling of BDP dose or systemic corticosteroids were lower in the omalizumab group. The treatment differences were statistically significant during the steroid-reduction phase, during which fewer participants in the omalizumab group had asthma exacerbation episodes (18.2% vs 38.5%), and the mean number of episodes per patient was smaller than with placebo (0.42 vs 2.72). Five asthma exacerbations requiring hospitalization all occurred in the placebo group. Participants' and investigators' global evaluations of treatment effectiveness were more favorable for omalizumab than placebo. Investigators rated effectiveness excellent for 31.5% of the omalizumab group versus 16.3% of the placebo group and good for 44.7% of the omalizumab group versus 32.7% of the placebo group. There was little change in asthma symptom scores or spirometry measurements during either the stable-steroid or steroid dose-reduction phase, with minimal differences between the treatment groups. The requirement for rescue medication in the omalizumab group during both the stable-steroid and steroid dose-reduction phases was consistently lower than at baseline. At week 28, the median number of puffs of rescue medication taken daily was 0 in the omalizumab group and 0.46 in the placebo group. The change from baseline was significant in favor of omalizumab. (ABSTRACT TRUNCATED)

Acute Disease↗
PubMed2001

Complete form of X-linked congenital stationary night blindness: refined mapping and evidence of genetic homogeneity.

A number of distinct, partly non-overlapping genetic loci have been reported for the complete type of X-linked congenital stationary night blindness (CSNB1), suggesting genetic heterogeneity. In order to refine the localization of the CSNB1 gene and to demonstrate genetic homogeneity, linkage analysis was performed in two large CSNB1 families. Clinical features consistent with the diagnosis of CSNB1 were documented in five patients from a German seven-generation kindred by full ophthalmological examination including psychophysical and electroretinographical testing. Haplotype analysis in 30 members of the large German family was performed with 38 polymorphic markers predominantly covering the critical region. Linkage analyses defined a locus for CSNB1 with flanking markers DXS8042 and DXS228, refining the interval to 2.5 cM in Xp11.4. In addition, two-point linkage analysis was carried out using the MLINK computer program. In agreement with meiotic breakpoints, lod scores of 3.0 and greater were obtained for markers located to the proximal site of the former 5 cM CSNB consensus interval. A large Dutch CSNB1 family was re-evaluated with markers from the Xp11.4 region, and supports the CSNB1 minimal interval found in the German family. Together with previous results from three unrelated families from Sweden, Sardinia and Great Britain, our results provide evidence of genetic homogeneity in the disorder. Subsequent mutation analyses in CSNB1 patients revealed no pathogenic sequence alterations in DFFRX and CASK genes, but retain candidates for other diseases mapping to that region.

Calcium-Calmodulin-Dependent Protein Kinases↗
PubMed2000

Expression of the major vault protein LRP in human non-small-cell lung cancer cells: activation by short-term exposure to antineoplastic drugs.

Non-small-cell lung cancer (NSCLC) cells are characterised by resistance to the toxic impact of antineoplastic drugs both in vivo and in vitro. The lung resistance-related protein (LRP), identical with the human major vault protein, is over-expressed in a variety of tumour cells characterised by intrinsic or acquired chemoresistance. We investigated the expression and cellular localisation of LRP in 16 unselected NSCLC cell lines, immortalised bronchial epithelial cells and embryonic lung fibroblasts. All cell lines analysed expressed LRP mRNA, while protein expression ranged from undetectable up to high levels. Cell fractionation and immunofluorescence staining in selected cell lines localised LRP almost exclusively to the cytoplasm. LRP was contained in the 100, 000 g pellet and absent in the soluble, cytosolic fraction and nuclei. A small proportion of LRP, however, was shown to be loosely associated with the outside of the nuclei. Sucrose gradient equilibrium centrifugation revealed presence of LRP exclusively in the fraction known to accumulate purified vault particles. Short-term exposure (16 hr) to subtoxic daunomycin (DM)-, and bleomycin (BM)-concentrations significantly (up to 4-fold) enhanced LRP expression in 2/4 cell lines tested. Cisplatin (CDDP) had a minor effect while vinblastine (VBL) was ineffective. At cytotoxic conditions all drugs rather decreased than increased LRP expression. When basic LRP expression was compared with chemosensitivity, a significant correlation was detected for resistance to CDDP but not DM, doxorubicin (DOX), etoposide (VP-16), VBL and BM. Summing up, our data suggest a role of vaults both in basic CDDP resistance and, additionally, in an short-term defensive response of NSCLC cells against several other drugs.

Antineoplastic Agents↗