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Biomedical subjects

M Werner

Publications and source records attributed to M Werner.

At least 55 records · Page 3Linked to original sources
PubMed2002

Which factors influence therapeutic decisions in Parkinson's disease?

Development of dyskinesia is a common phenomenon during the long-term course of Parkinson's disease. During the last few years, some but not all pathogenetic mechanisms causing dyskinesias in PD have become better understood. Severity of Parkinson's disease and levodopa dosing are the main clinical risk factors. Most concepts underline the significance of pulsatile D1-receptor stimulation for the development of dyskinesias. The interactions between D1- and D2-mediated STR-Gpi pathways and colocalized neuropeptides are important but not fully understood. Glutamatergic overactivity might also be a significant pathogenetic factor. According to these pathophysiological concepts, therapeutic strategies focus mainly on continuous postsynaptic DA-receptor stimulation by long-acting DA-agonists or highly selective D2-agonists. Another strategy is the use of NMDA antagonists.

Age Factors↗
PubMed2002

[Risk estimation in Barrett's esophagus: biomolecular marker and histopathologic classification].

The diagnosis of Barrett's esophagus and the different degrees of intraepithelial neoplasia appear to be demanding in several aspects. Current data on genetic alterations involved in the carcinogenesis of Barrett's esophagus are discussed. Several new biomarkers are being tested to help better to determine the risk of cancer development. However, a few immunohistochemical markers have emerged which could be helpful for the differential diagnosis of low- and high-grade intraepithelial neoplasia. Markers which could predict the progression of premalignant Barrett's epithelium to carcinoma are still to be established. At present, the "gold standard" for classifying the malignant potential in Barrett's esophagus is the degree of intraepithelial neoplasia found on standard biopsy protocols.

Barrett Esophagus↗
PubMed2002

Urogenital abnormalities in male children with cystic fibrosis.

BACKGROUND: Congenital bilateral absence of the vas deferens (CBAVD) is presumed to occur prenatally and is present in over 99% of adult males with cystic fibrosis (CF). AIMS: To describe ultrasonic features in male children with CF. We aimed to describe urogenital anomalies, comparing pancreatic sufficient and insufficient CF patients. METHODS: Pelvic and scrotal ultrasonography were performed in 12 boys with CF aged 2-12 years and 16 age matched healthy controls. RESULTS: Nine patients had pancreatic insufficiency (PI): seven had two severe mutations and two had unknown mutations. Three boys were pancreatic sufficient (PS), two with splicing mutations (5T and 3849+10kb C-T respectively) and borderline sweat tests. Seminal vesicles were visualised in 5/12 patients and 8/16 controls, compared to non-visualisation reported in all adults with CBAVD. Testicular microlithiasis was found in 4/18 PI, 0/6 PS, and 0/32 control testes, compared to 0.6-1.4% in healthy males and 15% in CF adults; 7/18 PI, 4/6 PS, and 0/32 control testes were smaller than predicted for age. The epididymal head was non-homogeneous with cysts, hypo-, or hyper-echogenicity in 5/18 PI, 1/6 PS, and 0/32 control testes. CONCLUSIONS: Genital abnormalities may occur early in CF, but are less common than described in adults. They are found more often in pancreatic insufficient than in pancreatic sufficient CF patients. However, a positive finding, if present, may aid in the diagnosis of the latter. A larger longitudinal study is recommended to better define the onset and progression of urogenital abnormalities.

Child↗
PubMed2001

Lymphatic vessel invasion is an independent prognostic factor in patients with a primary resected tumor with esophageal squamous cell carcinoma.

BACKGROUND: Little data exist about the prognostic role of a lymphatic vessel invasion (LVI) in patients with esophageal carcinoma. The objective of this study was to clarify the presence and prognostic impact of LVI in a large group of patients resected for esophageal squamous cell carcinoma (SCC) at one surgical center. METHODS: Three hundred sixty-six patients, who had a primary resection for SCC, were analyzed by univariate and multivariate analysis. Follow-up was complete for 93.7% patients with a median follow-up of 8.3 years. RESULTS: The total rate of LVI was 39.1% (n = 143). Univariate analysis revealed a significant relation between LVI and different T classifications (P = 0.001), N classifications (P < 0.0001), M classifications (P < 0.0001), International Union Against Cancer (UICC) stages (P < 0.0001), and residual tumor (P < 0.0001). Multivariate analysis of the patients with R0-resected tumors proved LVI as an independent prognostic factor. The 2-, 5- and 10-year survival rates in patients with LVI were 28.5%, 11.1%, and 9.2% compared with 63.4%, 46.6%, and 27%, respectively, without LVI (P < 0.0001). Patients with LVI had a median survival time of 11.4 months compared with 28.6 months without LVI (P < 0.0001). Patients with R0-resected tumors without LVI had a median survival time of 54.1 months compared with 12.1 months in patients with LVI (P < 0.0001) and compared with 11.3 months in patients with R1-resected tumors P < 0.0001). CONCLUSIONS: These data clearly show that LVI is an independent prognostic factor in patients with SCC and confirm the importance of a systematic pathohistologic workup. The prognosis of patients with R0-resected tumors with LVI is equal to patients with an incomplete tumor resection. This supports the inclusion of LVI in the UICC classification system for esophageal carcinoma.

Adult↗
PubMed2001

Mapping the chromosome 16 cadherin gene cluster to a minimal deleted region in ductal breast cancer.

The cadherin family of cell adhesion molecules has been implicated in tumor metastasis and progression. Eight family members have been mapped to the long arm of chromosome 16. Using radiation hybrid mapping, we have located six of these genes within a cluster at 16q21-q22.1. In invasive lobular carcinoma of the breast frequent LOH and accompanying mutation affect the CDH1 gene, which is a member of this chromosome 16 gene cluster. CDH1 LOH also occurs in invasive ductal carcinoma, but in the absence of gene mutation. The proximity of other cadherin genes to 16q22.1 suggests that they may be affected by LOH in invasive ductal carcinomas. Using the mapping data, microsatellite markers were selected which span regions of chromosome 16 containing the cadherin genes. In breast cancer tissues, a high rate of allelic loss was found over the gene cluster region, with CDH1 being the most frequently lost marker. In invasive ductal carcinoma a minimal deleted region was identified within part of the chromosome 16 cadherin gene cluster. This provides strong evidence for the existence of a second 16q22 suppressor gene locus within the cadherin cluster.

Base Sequence↗
PubMed2001

Kinetic modeling and simulation of in vitro transcription by phage T7 RNA polymerase.

This study provides a mathematical model of T7 RNA polymerase (T7 RNAP) kinetics under in vitro conditions targeted at application of this model to simulation of dynamic transcription performance. A functional dependence of transcript synthesis rate is derived based on: (a) essential reactant concentrations, including T7 RNAP and its promoter, substrate nucleotides, and the inhibitory byproduct inorganic pyrophosphate; (b) a distinction among vector characteristics such as recognition sequences regulating transcription initiation and termination, respectively; and (c) specific properties of the nucleotide sequence including both transcript length and nucleotide composition. Inactivation kinetics showed a half-life of T7 RNAP activity of 50 min under the conditions applied in vitro using the isolated enzyme. Model parameters and their precision are estimated using dynamic simulation and nonlinear regression analysis. The particular novelty of this model is its capability to incorporate linear genomic sequence information for simulation of nonlinear in vitro transcription kinetics.

Computer Simulation↗
PubMed2001

[Accelerated rehabilitation after colon resection].

INTRODUCTION: The stay in hospital after colonic resection is usually 7-12 days, with a complication rate of 20%. A multi-modal rehabilitation regimen, comprising epidural analgesia, early mobilisation, and oral nutrition, reduced the hospital stay to 2-3 days after colonic resection. METHODS: One hundred patients underwent elective colonic resection with a planned postoperative stay of two days in hospital and a regimen with epidural analgesia, oral nutrition, and mobilisation. Anaesthesia, the surgical technique, and nursing care programme were standardised. Postoperative follow-up visits were arranged for day 8 and day 30. RESULTS: The median age was 73 years. Forty patients were at high risk, ASA III-IV. Gastrointestinal function (defecation) occurred within 48 hours, except for five patients, and the median hospital stay was two days. The readmission rate was 18% with no acute, potentially lethal conditions. The total hospital stay was three days. None of the patients had cardiopulmonary complications, except for one patient, who died from cardiac failure 36 hours after surgery. Three patients had anastomotic dehiscence, two of whom were treated conservatively. CONCLUSION: The usual postoperative ileus, "medical complications", and hospital stay were reduced in high-risk patients undergoing colonic resection with a multi-modal rehabilitation programme. These results call for further comparative studies with conventional care programmes and laparoscopic colonic resection.

Adult↗
PubMed2001

A man with hereditary exostoses and high-grade non-Hodgkin's lymphoma of the bone.

Multiple cartilaginous exostoses (MCE) is an autosomal dominant disorder that can lead to malignant transformation from exostoses to a secondary chondrosarcoma. We present a case report of a 52-year-old man with MCE who had a palpable mass at the left shoulder. At the site of the left proximal humerus, a cartilaginous exostosis was localized, suggesting that the tumor developed by a malignant transformation of an exostosis into a secondary chondrosarcoma. Interestingly, a biopsy showed a diffuse large B-cell lymphoma with Burkitt-like features. To our knowledge, the association of high-grade lymphoma and hereditary exostoses has not been described previously. This case demonstrates that a malignant tumor at the location of a cartilaginous exostosis is not necessarily a chondrosarcoma and that a biopsy is an essential part of the diagnostic work-up.

Bone Neoplasms↗
PubMed2001

[Histological characteristics and prevalence of secondary osteoporosis in systemic mastocytosis. A retrospective analysis of 158 cases].

Mastocytosis is characterized by abnormal proliferation of mast cells especially within the skin and bone marrow and is often associated with osteoporosis. Mast cells can synthesize a variety of cytokines that are known to affect the skeletal system, but the cellular and pathophysiological mechanisms leading to osteoporosis in systemic mastocytosis remain poorly understood. To further characterize mastocytosis-associated osteoporosis we compared bone histomorphometric findings in iliac crest biopsy specimens from 158 untreated patients with mastocytosis. The overall prevalence of mastocytosis in the specimens diagnosed with osteoporosis was 1.25%, but that in patients younger than 45 years was 2.25%. The male-to-female ratio was 1:1, in contrast to 1:2 in osteoporosis. Osteopenia was present in 64% of the patients with mastocytosis, while osteosclerosis was rare (3%). Histological criteria are the concentric increase in mast cells in the perivascular tissue and the increase in elongated mast cells within the marrow space. Histomorphometry showed mastocytosis to be associated with moderate hyperosteoidosis and increased perforating bone resorption, indicated by a significant decrease in bone volume, trabecular thickness, and trabecular number as compared to controls. Osteoclast number was not altered, pointing to a functional effect of mast cells and/or its product on osteoclasts, rather than an effect on osteoclast differentiation. We conclude that although the prevalence of mastocytosis seems to be low, its correct and early diagnosis is crucial for at least 2.25% of younger patients with osteoporosis.

Adult↗
PubMed2001

Tissue microdissection techniques in quantitative genome and gene expression analyses.

Current advances in quantitative genome and gene expression analyses allow precise molecular genetic fingerprinting of tumor tissues. A crucial factor for the reliability of the data obtained with these refined techniques is the use of morphologically well-defined cell populations. Microdissection technology has been developed to procure pure cell populations from specific areas of tissue sections under microscopic control. This review covers techniques of tissue microdissection in the context of commonly used methods of quantitative genome and gene expression analysis. The first part of the review will summarize the technical aspects of various methods developed for tissue microdissection. In the latter part, current applications of quantitative genome and gene expression analysis techniques employed in microdissected tissue samples will be described.

Animals↗
PubMed2001

TO-PRO-3 is an optimal fluorescent dye for nuclear counterstaining in dual-colour FISH on paraffin sections.

Confocal laser scanning microscopy (CLSM) is an extensive but reliable tool for assessing the hybridisation signals in fluorescence in situ hybridisation (FISH). Most CLSMs are equipped with an argon-laser and a helium/neon-laser illumination system with excitation wavelengths of 488, 543 and 633 nm. A protocol for an optimal nuclear counterstaining in combination with dual-colour FISH for these laser illumination systems has not been established so far. Here, we determined the suitability of eleven dimeric and monomeric cyanine nucleic acid stains on paraffin sections of breast carcinoma specimens in combination with dual-colour FISH (Her-2/neu and centromere 17) for CLSM application. Strong staining of cell nuclei was observed for TO-PRO-3 and YO-PRO-3, YOYO-1 and propidium iodide (PI), but only TO-PRO-3 showed specific staining of nuclei without any staining of the cytoplasm. A specific emission in exclusively one distinct fluorescence channel was shown for TO-PRO-3 (633 nm excitation) as well as YOYO-1, BO-PRO-1 and Sytox Green (488 nm excitation), evaluated by a CLSM and confirmed by 3-D fluorescence spectra. High stability of fluorescence intensity was shown for the far-red dyes TO-PRO-3, YO-PRO-3, YOYO-3 and Syto-59 as well as YOYO-1 and PI. Only TO-PRO-3 was due to its high specificity and stability suitable for detection of an amplification of the Her-2/neu gene by dual-colour FISH and CLSM evaluation.

Breast Neoplasms↗
PubMed2001

Characterization of two tomato aquaporins and expression during the incompatible interaction of tomato with the plant parasite Cuscuta reflexa.

A subtractive suppression hybridization technique was used to identify genes that were induced during early phases of the interaction between Cuscuta reflexa, a phanerogamic plant parasite and the incompatible host tomato (Lycopersicon esculentum Mill.). One of the identified genes encodes a new aquaporin (LeAqp2) from tomato. Its function was concluded from the swelling kinetics of LeAqp2-expressing Xenopus laevis oocytes under hypo-osmotic conditions. It was shown that, 6 h after attachment of the plant parasite, the corresponding mRNA accumulated in cells at and adjacent to the attachment site of Cuscuta, while artificial wounding did not modify steady-state LeAqp2- RNA levels. Expression of a close homologue named TRAMP (tomato-ripening-associated protein) was not affected by the plant-plant interaction. Levels of indole-3-acetic acid (IAA) in tomato tissue after infection by Cuscuta have been found to increase at a similar stage of infection. In contrast to the different behavior with respect to infection, IAA induced both LeAqp2 and TRAMP expression. The observed pattern of LeAqp2 expression during the interaction at a stage where cell elongation occurs together with the water-channel activity in the heterologous expression system suggest a function for LeAqp2 during the tomato-Cuscuta interaction.

Aquaporins↗
PubMed2001

Gsalpha gene mutations in monostotic fibrous dysplasia of bone and fibrous dysplasia-like low-grade central osteosarcoma.

A series of nine cases with monostotic fibrous dysplasia (FD) and five cases of fibrous dysplasia-like low-grade central osteosarcoma (fd-like lgcOSA) were applied in a mutational analysis. Restriction digestion analysis, single-stranded conformational polymorphism (SSCP) analysis, and repeated sequencing demonstrated a R201H mutation in six cases and a R201C mutation in three cases of patients with monostotic FD. These results demonstrate that the presence of Gsalpha gene mutations is a constant finding in monostotic FD. To our knowledge, this is the first report in the literature investigating Gsalpha gene mutations in lgcOSA, which is one of the most important differential diagnoses of FD because of its low-grade malignant behavior. In four of five cases of fd-like lgcOSA, no mutation has been detected. In one case of this tumor, a R201C mutation could be demonstrated. Because our results demonstrate a low prevalence of Gsalpha gene mutations in this tumor in contrast to monostotic FD, mutational analysis may be an additional helpful parameter in individual cases for the differential diagnosis of FD and fd-like lgcOSA.

Adolescent↗
PubMed2001

Gastric adenocarcinoma: pathomorphology and molecular pathology.

Two types of gastric adenocarcinoma can be distinguished histopathologically: the diffuse and the intestinal type. Molecular pathology supports this theory by showing differences in the genetic pathways of both tumor types. In addition to known pathomorphological factors of prognosis, e.g., depth of tumor infiltration, number of lymph node metastases and resection margins, a few genes have been suggested to have prognostic impact in gastric carcinoma. Clinically relevant molecules whose expression or structure is altered include the plasminogen activator (uPA) and its inhibitor PAI-1 (plasminogen activator inhibitor type 1), the cell cycle regulator cyclin E, epidermal growth factor (EGF), the apoptosis inhibitor bcl-2, the cell adhesion molecule E-cadherin, and the multifunctional protein beta-catenin. Gene amplification and protein overexpression of the growth factor receptors c-erbB-2 and K-sam may be prognostic factors for intestinal-type and diffuse-type gastric cancer, respectively. In addition, genetic instability is commonly seen. There has long been evidence for a genetic predisposition to gastric cancer by epidemiological studies and case reports. Very recently, germ line mutations of E-cadherin have been identified that are responsible for a dominantly inherited form of diffuse-type gastric cancer and could be used to identify individuals that are at high risk.

Adenocarcinoma↗
PubMed2001

The nature of giant cell tumor of bone.

Giant cell tumor of bone (GCT) is a locally osteolytic tumor with variable aggressiveness. In rare cases, pulmonary metastasis can be observed. The lesion most frequently occurs in the epiphysis of long tubular bones of the knee region, predominantly affecting young adults after closure of the growth plate. The characteristic histological appearance of GCT displays a high number of osteoclast-like multinucleated giant cells, which resulted in the classification "osteoclastoma" or "giant cell tumor". Apart from the multinucleated giant cells, there are two mononuclear cell types in GCT. The first one has a round morphology and resembles monocytes. The second cell type is the spindle-shaped, fibroblast-like stromal cell. Cell culture experiments with GCT cells revealed the stromal cell to be the proliferating component of the GCT. The other two cell types, the monocyte and the multinucleated giant cell, were lost after a few cell culture passages. Furthermore, latest results from GCT reveal that the stromal cells secrete a variety of cytokines and differentiation factors, including MCP1, ODF, and M-CSF. These molecules are monocyte chemoattractants and are essential for osteoclast differentiation, suggesting that the stromal cell stimulates blood monocyte immigration into tumor tissue and enhances their fusion into osteoclast-like, multinucleated giant cells. The multinucleated giant cell itself resembles a normal osteoclast that is able to resorb bone leading to extended osteolysis. This new model of GCT genesis supports the hypothesis that the stromal cell is the neoplastic component whilst the monocytes and the multinucleated giant cells are just reactive components of this tumor. Taking this into consideration, the nomenclature of the "giant cell tumor" needs to be reconsidered.

Bone Neoplasms↗
PubMed2001

Quantitative gene expression analysis in microdissected archival formalin-fixed and paraffin-embedded tumor tissue.

Formalin-fixed, paraffin-embedded tissue is the most widely available material for retrospective clinical studies. In combination with the potential of genomics, these tissues represent an invaluable resource for the elucidation of disease mechanisms and validation of differentially expressed genes as novel therapeutic targets or prognostic indicators. We describe here an approach that, in combination with laser-assisted microdissection allows quantitative gene expression analysis in formalin-fixed, paraffin-embedded archival tissue. Using an optimized RNA microscale extraction procedure in conjunction with real-time quantitative reverse transcriptase-polymerase chain reaction based on fluorogenic TaqMan methodology, we analyzed the expression of a panel of cancer-relevant genes, EGF-R, HER-2/neu, FGF-R4, p21/WAF1/Cip1, MDM2, and HPRT and PGK as controls. We demonstrate that expression level determinations from formalin-fixed, paraffin-embedded tissues are accurate and reproducible. Measurements were comparable to those obtained with matching fresh-frozen tissue and neither fixation grade nor time significantly affected the results. Laser microdissection studies with 5-microm thick sections and defined numbers of tumor cells demonstrated that reproducible quantitation of specific mRNAs can be achieved with only 50 cells. We applied our approach to HER-2/neu quantitative gene expression analysis in 54 microdissected tumor and nonneoplastic archival samples from patients with Barrett's esophageal adenocarcinoma and showed that the results matched those obtained in parallel by fluorescence in situ hybridization and immunohistochemistry. Thus, the combination of laser-assisted microdissection and real-time TaqMan reverse transcriptase-polymerase chain reaction opens new avenues for the investigation and clinical validation of gene expression changes in archival tissue specimens.

Animals↗