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W Haase

Publications and source records attributed to W Haase.

At least 37 records · Page 2Linked to original sources
PubMed2000

[Radiotherapy of non-malignant diseases: principles and recommendations].

The plenty options and high quality of radiation therapy for non-malignant disorders is not well known outside the field of radiology. It is necessary to transfer this information to cooperating general practitioners, surgeons, orthopedics and other specialists. To warrant quality assurance and quality control and to allow a uniform performance of radiotherapy of non-malignant conditions, general guidelines and recommendations according to the German Working Group of Scientific Medical Societies are useful. This paper summarizes the essential aspects of radiotherapy for non-malignant diseases: indication of, informed consent for, documentation and conduct of radiation therapy for non-malignant diseases using orthovoltage equipment and specific recommendations for follow up examinations. Radiotherapy concepts for non-malignant diseases are summarized.

Arteriovenous Malformations↗
PubMed2000

The human ET(B) endothelin receptor heterologously produced in the methylotrophic yeast Pichia pastoris shows high-affinity binding and induction of stacked membranes.

The human endothelin B receptor (ET(B) receptor) was produced in the methylotrophic yeast Pichia pastoris under transcriptional control of the highly inducible alcohol oxidase 1 (AOX1) gene promoter. In the expression plasmids pPIC9KFlagET(B)Bio and pPIC9KFlag deltaGPET(B)Bio the ET(B) receptor coding region was fused in frame to the Saccharomyces cerevisiae alpha-factor prepropeptide and the FLAG-tag. In both constructs, the receptor was also fused to a biotinylation domain. Additionally, in pPIC9KFlag deltaGPET(B)Bio the putative N-glycosylation site and a protease site have been deleted by site directed mutagenesis. Crude membranes prepared from recombinant P. pastoris revealed specific and saturable binding of [125I]ET-1 with a K(D) of about 42 pM. Receptor levels of 60 pmol/mg and 35 pmol/mg for the Flag deltaGPET(B)Bio and the FlagET(B)Bio construct, respectively, were determined. The pharmacological profile for ET-1, ET-2 and ET-3 were as expected for a subtype B endothelin (ET) receptor. Immunoblot analysis showed an apparent molecular mass of 55 kDa for the Kex2-processed and about 74 kDa for the Kex2-unprocessed receptor. Contrary to the Flag deltaGPET(B)Bio construct, the FlagET(B)Bio construct was not correctly processed by the internal Kex2 endopeptidase. As was detected by ultrastructural analysis of recombinant yeast cells, high-level production of the receptor resulted in the formation of stacked membranes.

Amino Acid Sequence↗
PubMed1999

Oligomerization state of MIP proteins expressed in Xenopus oocytes as revealed by freeze-fracture electron-microscopy analysis.

The MIP (major intrinsic protein) family is a widespread family of membrane proteins exhibiting two major types of channel properties: aquaporins and solute facilitators. In the present study, freeze-fracture electron microscopy was used to investigate the oligomerization state of two MIP proteins heterologously expressed in the plasma membrane of Xenopus laevis oocytes: AQPcic, an aquaporin from the insect Cicadella viridis, and GlpF, a glycerol facilitator from Escherichia coli. Swelling assays performed on oocytes 48 and 72 h following cRNA microinjections showed that these proteins were functionally expressed. Particle density determinations indicated that expression of proteins is related to an increase in particle density on the P fracture face of oocyte plasma membranes. Statistical analysis of particle sizes was performed on protoplasmic fracture faces of the plasma membrane of oocytes expressing AQPcic and GlpF 72 h after cRNA microinjections. Compared to control oocytes, AQPcic-expressing oocytes exhibited a specific population of particles with a mean diameter of 8.7 +/- 0.1 nm. This value is consistent with the previously reported tetrameric organization of AQPcic. In addition, AQPcic particles aggregate and form orthogonal arrays similar to those observed in native membranes of C. viridis, consisting of homotetramers of AQPcic. On the protoplasmic fracture face of oocytes expressing GlpF, the particle density is increased by 4.1-fold and the mean diameter of specifically added particles is 5.8 +/- 0.1 nm. This value fits with a monomer of the 28-kDa GlpF protein plus the platinum-carbon layer. These results clearly demonstrate that GlpF is a monomer when functionally expressed in plasma membranes of Xenopus oocytes and therefore emphasize the key role of the oligomerization state of MIP proteins with respect to their function.

Animals↗
PubMed1999

[Radiotherapy of benign diseases: a pattern of care study in Germany].

BACKGROUND: Radiation therapy of benign diseases is controversially discussed and rarely applied in Anglo-American countries, while in other parts of the world, especially Central and East Europe, it is commonly practised for several benign disorders. Similar to the European Society of Therapeutic Radiology and Oncology survey, a patterns of care study was performed in Germany. METHOD: A questionnaire was mailed in 3 years (1994, 1995, 1996) to all radiation facilities in Germany, which assessed equipment, indications, number of patients and treatment concepts. A total of 134 (88%) institutions returned all requested data: 22 in East and 112 in West Germany; 30 in university and 104 in community/private hospitals. The average data of each institution and of all institutions were analyzed for frequencies and ratios between different regions and institutions. RESULTS: A mean of 2 (range 1 to 7) megavoltage (Linac/Cobalt 60) and 1.4 (range 0 to 4) orthovoltage units were available per institution; 32 (24%) institutions had no orthovoltage equipment. A mean of 20,082 patients were treated per year: 456 (2%) for inflammatory diseases (221 hidradenitis, 78 nail bed infection, 23 parotitis, 134 not specified), 12,600 (63%) for degenerative diseases (2,711 peritendinitis humeroscapularis, 1,555 epicondylitis humeri, 1,382 heel spur, 2,434 degenerative osteoarthritis, 4,518 not specified), 927 (5%) for hypertrophic diseases (146 Dupuytren's contracture, 382 keloids, 155 Peyronie's disease, 244 not specified), 1,210 (6%) for functional disorders (853 Graves' orbitopathy, 357 not specified), and 4,889 (24%) for other disorders (e.g. 3,680 heterotopic ossification prophylaxis). In univariate analysis, there were significant geographical (West vs East Germany) differences in the use of radiotherapy for inflammatory and degenerative disorders and institutional differences (university vs community/private hospitals) in the use of radiotherapy for hypertrophic and functional disorders (p < 0.05). The prescribed dose concepts were mostly in the low dose range (< 10 Gy), but varied widely and inconsistently within geographic regions and institution types. CONCLUSION: Radiotherapy is a well accepted and frequently practised treatment for several benign diseases in Germany, however, there are significant geographical and institutional differences. As the number of orthovoltage units decreases, an increasing patient load is in demand of more megavoltage units, which may compromise the cost-effectiveness of this treatment. Only 4% of all clinical institutions are involved in controlled clinical trials. To maintain a high level of radiotherapy service to other disciplines, radiotherapy treatment guidelines, quality control and continuing medical education are required.

Dose Fractionation, Radiation↗
PubMed1999

[Long-term outcome of gliomas of the visual pathway in type 1 neurofibromatosis].

BACKGROUND: Optic gliomas are frequently associated with neurofibromatosis type 1 (NF1) and belong to the diagnostic criteria of NF1. Different growth rates require differentiated strategies for screening and observation. PATIENTS AND METHODS: 29 patients (25 children < 11 years, 4 adults > 18 years) with visual pathway tumors and NF1 were examined neurologically, ophthalmogically, by means of MRI and VEP. Results were set into context with preceding investigations (mean follow up time 6.5 years). RESULTS: 11 children showed a stable condition, 14 an unfavorable process with substantial loss of vision. Children with an unfavorable process showed a lower age at diagnosis (3.2 versus 5.8 years; p < 0.05), more frequently strabism (11/14 versus 1/11; p < 0.05), optic atrophy (12/14 versus 1/11; p < 0.05), pathological VEP (9/9 versus 2/10; p = 0.001), visual field defects (9/9 versus 1/9) and involvement of the optic chiasm (11/14 versus 3/11; p < 0.05) than children with a stable condition. 3 of 4 adults had no visual symptoms despite involvement of the optic chiasm. CONCLUSIONS: The crucial prognostic factor is the patient's age at the time of diagnosis. Optic gliomas which become symptomatic in early childhood (< 6 years) grow rapidly and require frequent ophthalmologic investigations and MRI. Tumors diagnosed in late childhood (> 6 years) do not progress, allowing for gradual extension of intervals between ophthalmological investigations.

Adolescent↗
PubMed1998

Endogenous or overexpressed cGMP-dependent protein kinases inhibit cAMP-dependent renin release from rat isolated perfused kidney, microdissected glomeruli, and isolated juxtaglomerular cells.

An overactive renin-angiotensin-aldosterone system (RAAS) has a central role in the pathogenesis of hypertension and cardiac hypertrophy, precursors of cardiac failure. Natriuretic peptides and NO acting through their second messenger, cGMP, increase natriuresis and diuresis, and inhibit renin release; however the mechanism by which this inhibition of the RAAS system functions is obscure. We recently reported cloning of the cDNA for type II cGMP-dependent protein kinase (cGK II), elucidated its first known function of inhibiting the cystic fibrosis transmembrane conductance regulator in rat intestine, and initially described its location in rat kidney juxtaglomerular (JG) cells, the ascending thin limb, and the brush border of proximal tubules. Here, we demonstrate inhibition of isoproterenol- or forskolin-stimulated renin release by 8-para-chlorophenylthio-cGMP (8-pCPT-cGMP), a selective activator of cGK, and prevention of this inhibition by a selective inhibitor of cGK, Rp-8-pCPT-cGMPS. In systems of differing complexity, inhibition by 8-pCPT-cGMP was nearly complete in isolated perfused kidney and microdissected afferent arterioles but only approximately 25% in isolated JG cells. Expression of either cGK II or cGK I in JG cells by using adenoviral vectors enhanced the inhibition of forskolin-stimulated renin release by 8-pCPT-cGMP to 50%. Our results indicate that cGK II, and possibly cGK I, can mediate cGMP inhibitory effects on renin release and are physiological components of the cGMP signal transduction system which opposes the RAAS.

Animals↗
PubMed1998

Expression of NHE1 and NHE4 in rat pancreatic zymogen granule membranes.

We previously characterized a Na+/H+ exchange activity in rat pancreatic zymogen granules [Anderie, I., and Thévenod, F. (1996) J. Membrane Biol, 152, 195-205]. Here we have identified the Na+/H+ exchanger (NHE) isoforms present in zymogen granules by functional studies with NHE inhibitors. The NHE1 specific blocker HOE 694 [3-(methylsulfonyl-4-piperidino-benzoyl)-guanidine methanesulfonate] inhibited zymogen granule Na+/H+ exchange in a concentration dependent manner, maximally to 53 +/- 5% of controls at 100nM. The remaining Na+/H+ exchange activity was inhibitable by EIPA [5-(N-ethyl-N-isopropyl)amiloride] (EC50 approximately 25 microM) or benzamil (EC50 approximately 100 microM). Amiloride inhibited weakly suggesting that "amiloride-resistant" and "amiloride-sensitive" NHE are expressed in zymogen granules. cDNA sequences encoding NHE1- and NHE4-specific transmembrane domains were detected by RT-PCR in rat pancreatic tissue and in the rat pancreatic acinar cell line AR4-2J. The presence of NHE1 and NHE4 in zymogen granule membranes was confirmed by immunoblots of zymogen granule membranes and by pre-embedding immunogold labeling of purified rat pancreatic zymogen granules with polyclonal NHE1 and NHE4 antibodies. Therefore, we propose that NHE1 and NHE4 are expressed in zymogen granule membranes of rat exocrine pancreas.

Amiloride↗
PubMed1998

Phenotypic variability associated with 14 splice-site mutations in the NF2 gene.

Neurofibromatosis type 2 (NF2) is an autosomal dominant disorder caused by mutations in the NF2 gene. Patients carrying NF2 mutations are predisposed to cerebral and spinal tumors with bilateral vestibular schwannomas as the hallmark. Using single strand conformation polymorphism and temperature gradient gel electrophoresis analysis, we have screened 87 unrelated NF2 patients for mutations in the NF2 gene. In this study, we report phenotypes associated with 14 splice-site mutations carried by 14 propositi and 11 relatives. The mutations were distributed in exons 2, 3, 5, 7, 8, 14, and 15. These splice-site mutations were associated with various phenotypes, from severe to asymptomatic. Phenotypic variation was also observed within families. Mutations downstream from exon 8 resulted more often in mild phenotypes. No meningiomas were found in any of 13 affected or mutation bearing individuals from three families with splice-site mutations of exons 14 and 15. These data suggest that splice-site alteration is a relatively common cause of NF2, and that unlike other mutations the clinical outcomes of splice-site mutations in the NF2 gene are variable. These results add to the growing body of information on genotype-phenotype correlation in NF2.

Adolescent↗
PubMed1998

Comparative biochemical and pharmacological characterization of the mouse 5HT5A 5-hydroxytryptamine receptor and the human beta2-adrenergic receptor produced in the methylotrophic yeast Pichia pastoris.

Over the last few years, Pichia pastoris has been developed into a powerful expression system for a multitude of foreign genes. Here, we demonstrate that the P. pastoris expression system has similar power to the baculovirus expression system in high-level production of two G-protein-coupled receptors, the mouse 5HT5A 5-hydroxtryptamine receptor and the human beta2-adrenergic receptor. Different expression plasmids were constructed in which the cDNAs of the two receptors were cloned under the transcriptional control of the highly inducible promoter of the P. pastoris alcohol oxidase 1 (AOX1) gene. In three expression plasmids, the receptors were fused to the Saccharomyces cerevisiae alpha-factor prepropeptide and also to the c-myc tag or the FLAG tag to permit immunological detection of the receptors. After transformation into P. pastoris strains KM71 and SMD 1163, recombinant clones were selected and tested for the production of the 5HT5A receptor and the beta2-adrenergic receptor by radioligand binding using [N-methyl-3H]lysergic acid diethylamide and [5,7-3H](-)CGP-12177 respectively. The production level of the 5HT5A receptor was improved by a factor of three by fusion with the alpha-factor prepropeptide. Also, the higher gene dosage resulting from multiple insertions of the expression cassette led to an improvement in production by a factor of two for both receptors. The addition of the adrenergic antagonist alprenolol to the culture medium had a positive effect on the number of specific binding sites detectable in clones producing the beta2-adrenergic receptor. For the 5HT5A receptor the addition of yohimbine resulted in a similar but smaller effect. Binding assays revealed that approx. 25 pmol of beta2-adrenergic receptor and approx. 40 pmol of 5HT5A receptor per mg of membrane protein in crude membrane preparations were produced. The pharmacological profiles for the heterologously produced receptors, estimated by ligand-displacement analysis using certain adrenergic and serotoninergic agonists and antagonists, were comparable with those reported for the receptors expressed in mammalian systems. Immunoblot analysis of the 5HT5A receptor revealed an apparent molecular mass about 20 kDa higher than expected from the amino acid sequence. Here, the Kex2 endopeptidase failed to process the alpha-factor leader correctly. Blocking glycosylation in vivo by tunicamycin or in vitro deglycosylation of membranes by endoglycosidase H resulted in correct processing. In contrast, the beta2-adrenergic receptor fusion to the alpha-factor leader was correctly processed by the internal Kex2 endopeptidase. The Kex2-processed beta2-adrenergic receptor was not glycosylated. In conclusion, the high-level production of the two receptors in P. pastoris will allow their purification in quantities sufficient for subsequent biophysical and structural studies.

Adrenergic beta-Agonists↗
PubMed1998

[Fluorescein angiography of retinal changes in patients with neurofibromatosis 2].

BACKGROUND: Neurofibromatosis 2 (NF2) is a rare autosomal dominant disorder (prevalence 1:37.000) associated with changes in tumor suppressor genes. Intraocular manifestations have been reported as subcapsular cataract, retinal hamartomas, epiretinal membranes, keratopathy in facial palsy, and tumors of the nerves I-V are typical ocular manifestations of NF2. PATIENTS AND MATERIALS: We prospectively examined 7 patients who met the diagnostic criteria of NF2 with regard to retinal changes using fluorescence angiography and red-free fundus photography. RESULTS: In four patients, we found window defects of the pigment epithelium in the macular or paramacular areas. In one patient we observed a combined pigment epithelial and astrocytic hamartoma. A choked papilla was found in two patients. CONCLUSIONS: Presumably, retinal changes in NF2 occur more frequently than has been assumed previously. Our results confirm that in NF2 patients more attention should be paid to abnormalities of the optic disk, the retina and the choroid.

Fluorescein Angiography↗
PubMed1998

Endosomes: another extra-mitochondrial location of type-1 porin/voltage-dependent anion-selective channels.

Endocytotic vesicles (EV) isolated from rat renal cortex were subjected to SDS-polyacrylamide gel electrophoresis and Western blotting. A monoclonal antibody against human type-1 porin (31 kDa) detected a strong band of 31 kDa. The same antibody has been used as the primary antibody in indirect immunocytochemistry. Light microscopy of cryostat sections of rat renal cortex showed a heavy staining of EV underneath the brush-border membrane. Electron microscopy was performed by "preembedding immunogold staining" of rat renal cortex, the sections of which showed an extensive labelling of EV with gold particles. These results demonstrate that the expression of type-1 porin is not restricted to outer mitochondrial membranes. The biological function of endosomal type-1 porin has as yet to be ascertained.

Animals↗
PubMed1998

Characterization of the human dopamine transporter heterologously expressed in BHK-21 cells.

1. cDNA of the human dopamine transporter (hDAT) was cloned into a cloning vector based on the Semliki Forest virus. Electroporation of in vitro transcribed mRNA from this plasmid into BHK-21 cells resulted in production of the transporter as measured by [3H]dopamine uptake (Km = 2.0 +/- 0.4 microM), which was specifically inhibited in the presence of cocaine. 2. The recombinant transporter protein exhibited an apparent molecular mass of 56 kDa, which was reduced to 50 kDa after tunicamycin treatment of the producing BHK-21 cells. Tunicamycin treatment of the electroporated cells also resulted in a decrease in transport activity with no change in the Km value (2.1 +/- 0.4 microM). 3. The localization of the heterologously produced transporter in the BHK cells either with or without tunicamycin treatment was studied by electron microscopic immunogold staining. The glycosylated transporter was found to be localized at the plasma membrane, whereas in the case of the unglycosylated transporter, transport to the plasma membrane was blocked.

Animals↗
PubMed1998

Characterization of the human gonadotropin-releasing hormone receptor heterologously produced using the baculovirus/insect cell and the Semliki Forest virus systems.

1. Two eukaryotic viral systems, the baculovirus/insect cell and the Semliki Forest virus systems, were tested for heterologous expression of human gonadotropin-releasing hormone receptor (GnRHR) cDNA. 2. An unmodified as well as a c-myc epitope-tagged human GnRH receptor was produced in two insect cell lines (Spodoptera frugiperda, Trichoplusia ni) after infection with the respective recombinant baculoviruses. In both insect cell lines, the receptor was identified by immunoblot analysis as a triplet of bands between 35 and 40 kDa. After deglycosylation of the receptor the molecular mass decreased to 35 kDa. The GnRH receptor was localized in membrane compartments within the infected insect cells. However, only in membranes of infected Trichoplusia ni insect cells could approximately 2000 receptors per cell be detected. 3. Production of the GnRH receptor in BHK cells using the Semliki Forest virus system resulted in approximately 50,000 receptors per cell. A maximal yield of 0.42 pmol/mg membrane protein was obtained 24 hr after electroporation of BHK cells with in vitro synthesized RNA. Binding of the antagonist [125I]Cetrorelix was saturable with a KD of 1.3 nM. The receptor produced in the BHK cells was further characterized by ligand displacement studies. The rank order of agonist and antagonist affinities was Cetrorelix > Triptorelin > Antide > GnRH.

Amino Acid Sequence↗
PubMed1997

Radiotherapy in stage IIA and IIB testicular seminoma with reduced portals: a prospective multicenter study.

PURPOSE: A prospective multicenter study was carried out to estimate the treatment outcome of radiotherapy in Stage II seminoma after the application of modern staging and radiotherapy techniques. The lower margin of the iliac field was positioned on the upper rim of the acetabulum to reduce the amount of scattered irradiation to the remaining testicle. METHODS AND MATERIALS: The study was carried out in 25 centers in Germany. Patients with pure seminoma, negative AFP-values, and retroperitoneal lymph node metastases of less than 5 cm in diameter were entered into the study. All patients received a ventrodorsal opposed field irradiation of the para-aortic and the ipsilateral iliac lymph nodes. The fields extended from the top of the 11th thoracic vertebra to the top of the acetabulum. Patients in Stage IIA (lymph nodes <2 cm ) received 30 Gy, and patients with Stage IIB (lymph nodes between 2 and 5 cm) 36 Gy total dose. RESULTS: 39 patients in Stage IIA and 19 patients in Stage IIB were evaluated. After a median observation time of 37 months all patients are alive and disease free. Recurrence free survival in stage IIA was 100%. Two patients in Stage IIB experienced a recurrence 10 and 17 months after the end of radiotherapy. The actuarial recurrence free survival estimate in Stage IIB was 94.1% for 1 year and 87.4% for 2 years. One recurrence in Stage IIB occurred in the mediastinum, one in the mediastinum, and one the lung. Both patients could be salvaged by chemotherapy. There were no pelvic recurrences. The treatment was well tolerated, with nausea being the most common side effect (56.9% Grade 1, 15.5% Grade 2, and 8.6% Grade 3). Diarrhea occurred in 15.5% (Grade 1), 15.5% (Grade 2), and 5.2% (Grade 3) of the patients. CONCLUSIONS: The outcome of para-aortic and ipsilateral iliac irradiation in Stage IIA/B testicular seminoma is excellent with the currently available staging methods and treatment facilities. The treatment is well tolerated. The lower margin of the iliacal field can be placed at the acetabulum.

Adult↗
PubMed1997

Comparison of line and space bisection in evaluation of normal and amblyopic spatial vision.

BACKGROUND: Partitioning experiments have been used historically and in the recent past to evaluate space perception in visually normal and disturbed individuals. Specifically, amblyopic patients display notably distorted and/or uncertain spatial localization when assessed by either line or space bisection. METHODS: This investigation was concerned with the comparison of line bisection with space bisection. Normal and amblyopic subjects bisected horizontal lines and spaces extending 1, 2, 3 and 15 deg arc monocularly on a computer screen. Results of the two procedures were compared. RESULTS: Visually normal subjects bisected both lines and spaces without reproducible distortion, within uncertainties approximating 1-3% of their length. No differences were observed between the two procedures. Strabismic amblyopes bisected without constant distortion to either side of the geometrical mean, irrespective of direction or extent of the deviation; their uncertainty at bisecting ranged from 2% to 12%. Again, no distinction between line and space bisection could be made. CONCLUSION: We conclude that the two procedures yield comparable results.

Adolescent↗