PubMed Health⌕ Search

Biomedical subjects

H A Müller

Publications and source records attributed to H A Müller.

At least 19 recordsLinked to original sources
PubMed2006

[Clinical pathways. Implementation in a urological department].

BACKGROUND: Clinical pathways are directions for standardised treatment processes for different diseases or procedures in a hospital. These pathways are developed within a team of several professions and are used as order and procedure sheets. Experiences with this element of quality management are limited in Germany. METHODS: The development and the implementation process of 15 pathways in a urological department are described. A clinical pathway for female incontinence surgery (suburethral tape) is presented as an example. The effects of the pathways are evaluated on a routine basis. RESULTS: Seventy-two percent of the patients were treated according to a clinical pathway. The advantages of clinical pathways are a better structuring and transparency of medical processes, a reduction of documentation, improvements in medical education and savings in time, hospital stay of the patients and costs. Expenses for pharmaceuticals were significantly reduced in connection with development of the pathways. CONCLUSIONS: The implementation of clinical pathways is a complex but rewarding project. It can be expected that clinical pathways will be rapidly distributed in the near future and that they will contribute to improvements of health care quality.

Critical Pathways↗
PubMed2005

Lethal LPS-independent side effects after microfilaricidal treatment in Acanthocheilonema viteae-infected rodents.

Mastomys coucha and jirds infected with Acanthocheilonema viteae, a filarial species free of endosymbiontic bacteria of the genus Wolbachia, suffer lethal side effects after effective microfilaricidal therapy with diethylcarbamazine and levamisole, whereas, M. coucha infected with the Wolbachia-infested species Brugia malayi or Litomosoides carinii tolerate corresponding treatment. Mortality in A. viteae infected, treated animals varied with microfilariae density in the blood. It was up to 100% in highly microfilaraemic M. coucha and jirds, but low or absent in animals with low microfilariae counts. Deaths occurred in most cases 5-24 h after treatment. Characteristic symptoms in animals, which died subsequently were a rapid drop in body temperature by 4-7 degrees C, an increase in hematokrit values by up to 10% and a moderate blood acidosis. Lethal effects in A. viteae infections did not depend on a particular status of hypersensitivity of the animals since desensitization procedures, which protected infected M. coucha against an otherwise lethal intravenous challenge with A. viteae homogenate did not protect against adverse reactions to a subsequent microfilaricidal treatment. The animals were protected from treatment induced death by injection of N-LMMA. Thus the final morbific agent seems NO. The data show that adverse effects after effective microfilaricidal therapy may be caused by microfilariae derived components different from Wolbachia-released LPS.

Animals↗
PubMed2001

Of mice, frogs and flies: generation of membrane asymmetries in early development.

Embryonic development begins with cleavage of the fertilized egg. Cleavage comprises two major processes: cytokinesis and formation of a polarized epithelial cell layer. The focus of this review is comparison of the generation of membrane polarity during embryonic cleavage in three different developmental model systems. In mammalian embryos, as exemplified by analysis of the mouse, generation of distinct membrane domains is uncoupled from cleavage divisions and is initiated in a specific developmental phase, called compaction. In Xenopus laevis embryos, generation of polarized blastomeres occurs simultaneously with cytokinesis. The origin of specific membrane domains of X. laevis polar blastomeres, however, can be traced back to oogenesis. Finally, in Drosophila melanogaster, generation of polarized cells occurs at cellularization. The relevance of cell adhesion, cell junctions and cytocortical scaffolds will be discussed for each of the model systems. Despite enormous morphologic differences, the three models share many common features; in particular, many important molecular interactions are conserved.

Animals↗
PubMed2001

Transcriptional regulation of cytoskeletal functions and segmentation by a novel maternal pair-rule gene, lilliputian.

Transcriptional control during early Drosophila development is governed by maternal and zygotic factors. We have identified a novel maternal transcriptional regulator gene, lilliputian (lilli), which contains an HMG1 (AT-hook) motif and a domain with similarity to the human fragile X mental retardation FMR2 protein and the AF4 proto-oncoprotein. Embryos lacking maternal lilli expression show specific defects in the establishment of a functional cytoskeleton during cellularization, and exhibit a pair-rule segmentation phenotype. These mutant phenotypes correlate with markedly reduced expression of the early zygotic genes serendipity alpha, fushi tarazu and huckebein, which are essential for cellularization and embryonic patterning. In addition, loss of lilli in adult photoreceptor and bristle cells results in a significant decrease in cell size. Our results indicate that lilli represents a novel pair-rule gene that acts in cytoskeleton regulation, segmentation and morphogenesis.

Actins↗
PubMed2000

Genetic control of epithelial cell polarity: lessons from Drosophila.

The cell biology of polarized epithelial cells is a field of major interest to cell and developmental biologists. In addition to the study of epithelial cells in tissue culture, genetically tractable systems have been employed to examine the functional importance of individual molecules. Here I review recent progress that has been made using Drosophila as a model system to study apical-basal epithelial cell polarity. In this system, a large number of genes have been identified that are essential for the development and maintenance of the apical-basal polarity of epithelial cells in different developmental contexts. In this article, the recent progress in three models, i.e., establishment of the ectoderm and midgut epithelia during embryogenesis, epithelial polarity of imaginal discs, and epithelial development of the follicle cells during oogenesis will be discussed.

Animals↗
PubMed1999

The Drosophila caspase inhibitor DIAP1 is essential for cell survival and is negatively regulated by HID.

Drosophila Reaper (RPR), Head Involution Defective (HID), and GRIM induce caspase-dependent cell death and physically interact with the cell death inhibitor DIAP1. Here we show that HID blocks DIAP1's ability to inhibit caspase activity and provide evidence suggesting that RPR and GRIM can act similarly. Based on these results, we propose that RPR, HID, and GRIM promote apoptosis by disrupting productive IAP-caspase interactions and that DIAP1 is required to block apoptosis-inducing caspase activity. Supporting this hypothesis, we show that elimination of DIAP1 function results in global early embryonic cell death and a large increase in DIAP1-inhibitable caspase activity and that DIAP1 is still required for cell survival when expression of rpr, hid, and grim is eliminated.

Acridine Orange↗
PubMed1999

Wingless signaling in the Drosophila embryo: zygotic requirements and the role of the frizzled genes.

Wingless signaling plays a central role during epidermal patterning in Drosophila. We have analyzed zygotic requirements for Wingless signaling in the embryonic ectoderm by generating synthetic deficiencies that uncover more than 99% of the genome. We found no genes required for initial wingless expression, other than previously identified segmentation genes. In contrast, maintenance of wingless expression shows a high degree of zygotic transcriptional requirements. Besides known genes, we have identified at least two additional genomic regions containing new genes involved in Wingless maintenance. We also assayed for the zygotic requirements for Wingless response and found that no single genomic region was required for the cytoplasmic accumulation of Armadillo in the receiving cells. Surprisingly, embryos homozygously deleted for the candidate Wingless receptor, Dfrizzled2, showed a normal Wingless response. However, the Armadillo response to Wingless was strongly reduced in double mutants of both known members of the frizzled family in Drosophila, frizzled and Dfrizzled2. Based on their expression pattern during embryogenesis, different Frizzled receptors may play unique but overlapping roles in development. In particular, we suggest that Frizzled and Dfrizzled2 are both required for Wingless autoregulation, but might be dispensable for late Engrailed maintenance. While Wingless signaling in embryos mutant for frizzled and Dfrizzled2 is affected, Wingless protein is still internalized into cells adjacent to wingless-expressing cells. Incorporation of Wingless protein may therefore involve cell surface molecules in addition to the genetically defined signaling receptors of the frizzled family.

Animals↗
PubMed1996

Acquired C 1-inhibitor deficiency with angioedema due to pleomorphic immunocytoma in a patient with three malignant tumors: long-term follow-up data and presentation of an additional case.

Two cases of lymphoma-associated acquired C 1-inhibitor deficiency are described. In both patients, C 1-inhibitor deficiency and related symptoms preceded the diagnosis of the underlying neoplasm by several months. C 1-inhibitor deficiency was most likely due to consumption following immunocomplex formation. In both patients, a close relationship between low levels of C 1-inhibitor and tumor relapse was observed during follow-up. These findings indicate that measurement of C 1-inhibitor and complement factor C4 can be used as markers of disease activity in affected patients.

Angioedema↗
PubMed1996

armadillo, bazooka, and stardust are critical for early stages in formation of the zonula adherens and maintenance of the polarized blastoderm epithelium in Drosophila.

Cellularization of the Drosophila embryo results in the formation of a cell monolayer with many characteristics of a polarized epithelium. We have used antibodies specific to cellular junctions and nascent plasma membranes to study the formation of the zonula adherens (ZA) in relation to the establishment of basolateral membrane polarity. The same approach was then used as a test system to identify X-linked zygotically active genes required for ZA formation. We show that ZA formation begins during cellularization and that the basolateral membrane domain is established at mid-gastrulation. By creating deficiencies for defined regions of the X chromosome, we have identified genes that are required for the formation of the ZA and the generation of basolateral membrane polarity. We show that embryos mutant for both stardust (sdt) and bazooka (baz) fail to form a ZA. In addition to the failure to establish the ZA, the formation of the monolayered epithelium is disrupted after cellularization, resulting in formation of a multilayered cell sheet by mid-gastrulation. SEM analysis of mutant embryos revealed a conversion of cells exhibiting epithelial characteristics into cells exhibiting mesenchymal characteristics. To investigate how mutations that affect an integral component of the ZA itself influence ZA formation, we examined embryos with reduced maternal and zygotic supply of wild-type Arm protein. These embryos, like embryos mutant for both sdt and baz, exhibit an early disruption of ZA formation. These results suggest that early stages in the assembly of the ZA are critical for the stability of the polarized blastoderm epithelium.

Animals↗
PubMed1995

Epithelial cell polarity in early Xenopus development.

The Xenopus blastula consists of two morphologically distinct cell types. Polarized epithelial cells build up the embryonic surface and fence off an inner non-polarized cell population. We examined the establishment of this early functional cell diversification in the embryo by single cell analysis, in vitro cell culture, and transplantation experiments. Single blastomeres from a 64-cell embryo (1/64 cells) exhibit several features of polarized cells. The plasma membrane of 1/64 cells consists of an apical domain, which is inherited from the original egg membrane, and a basolateral domain derived from newly formed membrane during cleavage. These are inherent, cell-autonomous properties of the blastomeres, as they form and are maintained in blastomeres raised in the absence of any cell interactions in calcium free medium. Upon in vitro culture a single 1/64 cell gives rise to an aggregate of two different cell types. Cells carrying a part of the former egg membrane domain differentiate into polarized epithelial cells, whereas cells lacking this membrane domain are not polarized. These results demonstrate that the inclusion of the egg membrane, rather than external signals related to the position of a cell in the intact embryo, is required for the apical/basolateral differentiation of the surface epithelium. This view is supported by cell transplantation studies. A single 1/64 cell was implanted into the blastocoel of a stage 8 blastula embryo. The progeny of the implanted cell proliferate within the host embryo and split into two morphologically distinct populations with different cell behaviours. Cells incorporating a part of the egg membrane form coherent patches of polarized epithelial cell sheets in the interior of the host embryo. In contrast, cells lacking egg membrane do not exhibit any characteristics of polarized cells and eventually spread into different regions of the host embryo. Our results show that the egg membrane and/or components of the submembrane cortex play a determinative role in the formation of the blastula epithelium.

Animals↗
PubMed1995

Impediments to developing wide area networks in health care.

The availability and prominence of telecommunication technology has spurred research into generic wide area health care networks. Electronic exchange of patient data supposedly results in cost efficiencies, increased accessibility to health care resources, and improved delivery of health care services. Although a number of pilot networks have been built, none yet have a broad, heterogeneous base of users and applications. Properties of the health care process and delivery system delay the acceptance of generic wide area networks and end-user computer applications. As the technical problems seem well understood, it seems advisable to investigate these factors in telemedical research.

British Columbia↗
PubMed1994

DNA-ploidy, G2M-fractions and prognosis of stages B and C prostate carcinoma.

Paraffin embedded tissue of 49 stage C and 27 stage B prostate adenocarcinomas was investigated by flow cytometry. All patients were treated by radical prostatectomy with pelvic lymphadenectomy and followed up for 5-10 years. The tumour was separated from the benign tissue to increase the proportion of tumour cells. Ten stage C and seven stage B carcinomas had to be excluded because of poor fixation. Six of the 39 (15%) stage C and 1/20 (5%) stage B carcinomas were aneuploid. Cell cycle analysis was done with correction for sliced nuclei and background subtraction. The threshold between carcinomas with low and with increased ("tetraploid") G2M-fraction was determined by comparing carcinomas with and without tumour progression. Sixty-seven percent of the patients with non-euploid stage C carcinomas and 11% of those with euploid carcinomas suffered from tumour progression (P < 0.01). The respective values for the stage B carcinomas were 67% and 6% (P < 0.01). These results demonstrate the strong prognostic impact of DNA-ploidy and G2M-fractions for each individual patient.

Adult↗
PubMed1994

Xenopus cadherins: the maternal pool comprises distinguishable members of the family.

Three maternal cadherins have been reported to occur in the pregastrula Xenopus embryo. EP- and XB-cadherin are distinguished by their distinct cDNA sequences. U-cadherin has been characterized by its reaction with a specific monoclonal antibody (mAb 6D5). Thus far, lack of specific probes that discriminate between these molecules has prevented their identification as distinct cadherins. We now demonstrate by means of RNase protection assays that both EP- and XB-cadherin mRNAs are present in oocytes and mature eggs. By use of the Xenopus cadherin proteins expressed in mammalian cell lines, we find that mAb 6D5 crossreacts with XB-cadherin, but not with EP-cadherin. The major fraction of the maternal cadherins does not contain the 6D5 epitope and probably represents EP-cadherin. A minor fraction carries the 6D5 epitope indicative for the XB- and U-type of cadherins. We have termed this fraction XB/U-cadherin. The function of maternal cadherins was examined by in vitro cell adhesion assays. A newly developed antiserum with a broad specificity for various Xenopus cadherins efficiently blocks all calcium dependent cell adhesion in the early embryo. We conclude that the maternal cadherins play a central role in interblastomere adhesion in the early embryo and comprise at least two discrete cadherin forms, EP- and XB/U-cadherin.

Amino Acid Sequence↗
PubMed1994

Similarities in structure and expression between mouse P-cadherin, chicken B-cadherin and frog XB/U-cadherin.

By immunological methods, we show that the monoclonal antibody 6D5 which reacts specifically with Xenopus laevis XB/U-cadherin, also binds to mouse P-cadherin and to chicken B-cadherin but not to the respective E-cadherins (L-CAM) or other "classical" cadherins in these species. In the first extracellular domain, three amino acid residues are identified that are shared by frog XB/U-cadherin, chicken B-cadherin and mammalian P-cadherins but not by the other "classical" cadherins. With few exceptions, the other cadherins possess residues at these positions that are also characteristic of each type of cadherin. Moreover, the expression patterns of P-, B-, and XB/U-cadherin in mouse, chicken and frog are more similar to each other than they are to those of the E-cadherins, L-CAM or other classical cadherins. Taken together, our results suggest that mammalian P-cadherins, chicken B-cadherin and frog XB/U-cadherin are closely related, if not homologous, molecules. A number of differences in the expression patterns between P-, B-, and XB/U-cadherin indicate that these molecules assume differential morphogenetic roles in different species.

Amino Acid Sequence↗
PubMed1992

[Herpes simplex-associated exacerbation of Crohn's disease. Successful treatment with acyclovir].

Seven years ago, a now 25-year-old man was found to have Crohn's disease of the terminal ileum as well as of the transverse and sigmoid colon. Despite treatment with both corticosteroids and mesalazine the disease progressed and led to almost complete stenosis of the lumen of the sigmoid colon so that surgical intervention was planned. But because immunohistological examination of the small and large intestinal mucosa had demonstrated herpes simplex virus (HSV I + II) DNA, additional treatment with acyclovir appeared worth-while. The morphological and clinical findings indeed changed decisively, obviating surgery. If a virus infection is found to be a pathogenetic co-factor in a case of Crohn's disease, a therapeutic trial with a suitable antiviral agent seems reasonable.

Acyclovir↗