PubMed Health⌕ Search

Biomedical subjects

G Schuler

Publications and source records attributed to G Schuler.

At least 19 recordsLinked to original sources

Characterization of the canine 3beta-hydroxysteroid dehydrogenase and its expression in the corpus luteum during diestrus.

3beta-Hydroxysteroid dehydrogenase (3betaHSD) is a key enzyme in the synthesis of bioactive steroid hormones. Objectives of the present study were to clone canine 3betaHSD and to investigate its expression in dog corpora lutea (CL) covering the periods of their formation, early and late regression (days 5, 15, 25, 35, 45, 65 after ovulation). Complete complementary DNA sequence was amplified by RACE PCR. Subsequent cloning revealed that the canine ovarian 3betaHSD transcript was composed of a 5'-untranslated region (5'-UTR) of 126 nucleotides, an open reading frame (ORF) of 1122 nucleotides and a 3'-UTR of 441 nucleotides. The putative ORF encoded a 374 amino acid protein which remains highly conserved (79-85% identity) between species. The transient expression of the cloned canine 3betaHSD in a mammalian heterologous cell expression system (HEK293T cells) identified the 3betaHSD activity as the only activity of this canine enzyme (absence of any detectable 17-hydroxysteroid dehydrogenase activity). Qualitative RT-PCR revealed expression of 3betaHSD on all days investigated and the signals were strongest on days 5 and 15, with day 25 intensity tending to decrease. However, variability between individual animals was high. The significant decrease in the expression of 3betaHSD towards the end of diestrus as indicated by Real Time PCR (p<0.01) and immunhistochemistry may indicate that the provision of progesterone is controlled by availability of the enzyme rather than the substrate.

17-Hydroxysteroid Dehydrogenases↗

[Peri-interventional risk in 1,384 cardiac catheterizations in patients aged 80 years or older].

BACKGROUND AND OBJECTIVE: Because of the rising life expectancy in the industrialized countries, ever more cardiac catheterizations are performed in patients aged 80 years or older. Little is known about the incidence of peri-interventional events in this age group. PATIENTS AND METHODS: Between January 1996 and September 2000, a total of 1,085 patients of that age (mean 82.6 +/- 2.6 years) underwent cardiac catheterization and intervention (3% of a total of 43,517 cardiac catheterizations). RESULTS: 827 patients (77%) had significant coronary artery stenoses. 373 of them (45%) were treated with balloon angioplasty, with or without stenting, and 331 (40%) underwent aortocoronary bypass procedures. 31 patients died while in hospital, 17 of them having been in cardiogenic shock on admission. Peri-interventional events, including damage to artery at the site of catheter entry occurred in 2.1% of patients undergoing diagnostic cardiac catheterization and in 11.6% in connection with a percutaneous interventional procedure. CONCLUSION: Both cardiac catheterization and interventional procedures can be done with a justifiable risk in patients aged 80 years or older. These cardiac investigations/interventions should not be withheld in this group of patients for reasons of age.

Age Factors↗

Dacarbazine (DTIC) versus vaccination with autologous peptide-pulsed dendritic cells (DC) in first-line treatment of patients with metastatic melanoma: a randomized phase III trial of the DC study group of the DeCOG.

BACKGROUND: This randomized phase III trial was designed to demonstrate the superiority of autologous peptide-loaded dendritic cell (DC) vaccination over standard dacarbazine (DTIC) chemotherapy in stage IV melanoma patients. PATIENTS AND METHODS: DTIC 850 mg/m2 intravenously was applied in 4-week intervals. DC vaccines loaded with MHC class I and II-restricted peptides were applied subcutaneously at 2-week intervals for the first five vaccinations and every 4 weeks thereafter. The primary study end point was objective response (OR); secondary end points were toxicity, overall (OS) and progression-free survival (PFS). RESULTS: At the time of the first interim analysis 55 patients had been enrolled into the DTIC and 53 into the DC-arm (ITT). OR was low (DTIC: 5.5%, DC: 3.8%), but not significantly different in the two arms. The Data Safety & Monitoring Board recommended closure of the study. Unscheduled subset analyses revealed that patients with normal serum LDH and/or stage M1a/b survived longer in both arms than those with elevated serum LDH and/or stage M1c. Only in the DC-arm did those patients with (i) an initial unimpaired general health status (Karnofsky = 100) or (ii) an HLA-A2+/HLA-B44- haplotype survive significantly longer than patients with a Karnofsky index <100 (P = 0.007 versus P = 0.057 in the DTIC-arm) or other HLA haplotypes (P = 0.04 versus P = 0.57 in DTIC-treated patients). CONCLUSIONS: DC vaccination could not be demonstrated to be more effective than DTIC chemotherapy in stage IV melanoma patients. The observed association of overall performance status and HLA haplotype with overall survival for patients treated by DC vaccination should be tested in future trials employing DC vaccines.

Cancer Vaccines↗

Expression of cyclooxygenase-II (COX-II) and 20alpha-hydroxysteroid dehydrogenase (20alpha-HSD)/prostaglandin F-synthase (PGFS) in bovine placentomes: implications for the initiation of parturition in cattle.

The chain of events leading to prepartal luteolysis in cattle is not yet fully understood. Prostaglandin F(2alpha) (PGF(2alpha)) seems to be a major factor involved. However, only little information is available about the underlying regulatory mechanisms. Consequently, the expression of cyclooxygenase-II (COX-II) and 20alpha-hydroxysteroid dehydrogenase (20alpha-HSD), an enzyme recently shown to be most likely responsible for the production of luteolytic PGF(2alpha) in the endometrium of cyclic cows, was investigated in bovine placentomes. Immunohistochemical methods were applied to placentomes from 17 pregnant cows between days 100 and 284, from three cows during the prepartal progesterone decrease (days 273-282) and from five parturient cows. COX-II was found in uninucleated trophoblast cells (UTC) from day 100 until parturition. However, between days 100 and 235 expression was only weak to moderate, focal and mainly restricted to the chorionic plate and adjacent basal parts of chorionic stem villi. In placentomes from a 270 and a 284 day pregnant cow, in which the prepartal decline of progesterone levels had not started yet, staining had substantially increased and extended to secondary and tertiary chorionic villi. In prepartal and parturient cows strong to intense staining was present in UTC all over the villous tree. Real time RT-PCR confirmed an extensive pre- and intrapartal rise of COX-II expression in bovine placentomes with a 70-100-fold increase of COX-II-mRNA levels. 20alpha-HSD/PGFS was widely expressed in UTC of chorionic villi. Like COX-II it was down-regulated in UTC differentiating into trophoblast giant cells. Immunostaining pattern did not change remarkably during the period under investigation, and 20alpha-HSD/PGFS-mRNA levels increased only 2.6-fold in the prepartal phase. Thus, in UTC PGF(2alpha) may be produced via COX-II and 20alpha-HSD/PGFS, but only COX-II may be substantially involved in the control of a putative prepartal placentomal output of luteolytic PGs, whereas 20alpha-HSD/PGFS seems to be expressed in a more constitutive manner.

20-alpha-Hydroxysteroid Dehydrogenase↗

[Refractory cutaneous necrotizing vasculitis. Successful sulfone therapy].

The clinical picture in vasculitis varies from few self-limiting symptoms to life-threatening illnesses affecting multiple organs. We describe the course of a woman patient who had had a severe cutaneous necrotizing vasculitis for more than 10 years. Various immunsuppressants, including cyclophosphamide, had failed to improve the clinical course, although adequate doses were given for a sufficient period. Treatment with DADPS (diaminodiphenylsulfone, dapsone), however, finally led to complete remission of the severe and chronic vasculitic ulcerations. Indications for DADPS treatment of inflammatory cutaneous diseases are discussed, and an overview of cutaneous vasculitis is provided.

Adult↗

[Rosacea fulminans, pyostomatitis and pyovulvitis in Crohn's disease: dapsone as key factor in combination therapy].

Rosacea fulminans (also known as pyoderma faciale) has been reported to occur in association with Crohn's disease. It is still unclear whether the papulopustules and confluent nodules of rosacea fulminans represent a manifestation of mucocutaneous Crohn's disease or whether this association is a mere coincidence. A 46-year-old woman presented with the spontaneous outbreak of rosacea fulminans and pyostomatitis/pyovulvitis. Complete remission of the mucocutaneous symptoms was achieved with 2 months combination therapy with methylprednisolone, isotretinoin and dapsone. The patient's Crohn's disease, already diagnosed for 3 years, did not flare during this period.

Anti-Infective Agents↗

[Interventional treatment of extracranial carotid stenoses: current status, requirements and indications].

Interventional treatment of extracranial carotid stenoses: current status, requirements and indications Around 30000 strokes per year in Germany are caused by extracranial obstructions of the carotid arteries. Besides the well established surgical endatherectomy, which has been proven to be superior to medical treatment alone in randomized multicenter trials, percutaneous treatment by balloon angioplasty and stent placement is increasingly performed. This consensus paper summarizes the present status of scientific studies and controlled treatment registries of carotid angioplasty and stenting and yields to recommendations regarding its performance and indication. A Medline search was done until August 2005 including all randomized comparative studies with clinical endpoints and all controlled registries with more than 500 patients included. Both completed randomized trials comparing angioplasty and stenting with surgery (CAVATAS and SAPPHIRE) did not show a significant difference with respect to stroke and death within 30 days. The incidence of this combined endpoint was between 3.3 and 6.9% in large multicenter registries. Thus, the current endovascular treatment results in a perlinterventional complication rate comparable to that which is commonly accepted for vascular surgery. A systematic preferably external quality monitoring as well as interdisciplinary cooperation most importantly with neurologists is recomendedfor all interventionalists. Based on available clinical data, this consensus paper defines recommendation classes I or II with a level of evidence B or C depending on symptoms, operative risk status of the patient and severity of the underlying stenosis.

Angioplasty, Balloon↗

The highly attenuated vaccinia virus strain modified virus Ankara induces apoptosis in melanoma cells and allows bystander dendritic cells to generate a potent anti-tumoral immunity.

Vaccinia virus (VV) has been tested as oncolytic virus against malignant melanoma in clinical trials for more than 40 years. Until now, mainly strains comparable to viral strains used for smallpox vaccination have been probed for anti-tumoral therapy. We have shown recently that the wild-type strain Western Reserve (WR) can interfere with crucial functions of monocyte-derived dendritic cells (DCs). Our aim was to examine whether viral immune evasion mechanisms might be responsible for the ineffectiveness of WR-based vaccination strategies and whether the highly attenuated strain modified virus Ankara (MVA) differs from WR with respect to its possible immunostimulatory capacity after intratumoral injection. Using in vitro experiments, we compared the effect of both strains on melanoma cells and on local bystander DCs. We found that both VV-strains infected melanoma cells efficiently and caused disintegration of the actin cytoskeleton, as shown by fluorescence microscopy. In addition, both VV-strains caused apoptotic cell death in melanoma cells after infection. In contrast to MVA, WR underwent a complete viral replication cycle in melanoma cells. Bystander DCs were consecutively infected by newly generated WR virions and lost their capacity to induce allogeneic T cell proliferation. DCs in contact with MVA-infected melanoma cells retained their capacity to induce T cell proliferation. Immature DCs were capable of phagocytosing MVA-infected melanoma cells. Priming of autologous CD8(+) T cells by DCs that had phagocytosed MVA-infected, MelanA positive melanoma cells resulted in the induction of T cell clones specifically reactive against the model antigen MelanA as shown by enzyme-linked immunospot (ELISPOT) analysis. We conclude that the clinical trials with oncolytic wild-type VV failed probably because of suppression of bystander DCs and consecutive suppression of T cell-mediated anti-melanoma immunity. The attenuated VV-strain MVA facilitates the generation of tumour associated antigen (TAA)-specific T cell response as it is oncolytic for melanoma cells, but non-toxic for DC, and should be a promising candidate for intralesional metastatic melanoma therapy.

Actins↗

Psoriasis confined strictly to vitiligo areas--a Koebner-like phenomenon?

Vitiligo and psoriasis are both common skin disorders. However, psoriasis strictly confined to pre-existing vitiligo areas is rare and suggests a causal relationship. We report here on two patients with a strict anatomical colocalization of vitiligo and psoriasis. The histopathological examinations showed typical changes for both diseases together with a dense infiltrate of CD4+ and CD8+ T cells. By immunohistochemistry, intracytoplasmatic granzyme B and tumour necrosis factor alpha (TNF-alpha) were detected within the T-cell population, suggesting the functional activity of these cells and the creation of a local T helper 1 (Th1)-cytokine milieu. Additionally, in one patient we could identify anti-melanocytic T cells by tetramer staining and enzyme-linked immunospot (ELISPOT) analysis. These skin-infiltrating lymphocytes might trigger, by the local production of Th-1 cytokines such as TNF-alpha and interferon-gamma (IFN-gamma), the eruption of psoriatic plaques in patients with a genetic predisposition for psoriasis.

Adult↗

Treatment of inflammatory dermatoses by tumour necrosis factor antagonists.

BACKGROUND: The treatment of inflammatory skin diseases is at present often empirical as causal therapeutic approaches, based on an incomplete knowledge of the immune pathogenesis, are mostly unavailable. The currently applied treatments can in fact lead to remission of the disease; however, under certain circumstances undesirable side-effects must be expected. On the basis of experience gained in cytokine modulation therapy of chronic inflammatory diseases such as rheumatoid arthritis and psoriasis, the application of TNF-alpha inhibitors represents a novel, more specific, and effective therapeutic option for distinct chronic inflammatory diseases. PATIENTS AND METHODS: The current status of the therapeutic effect of TNF-alpha blockers is discussed based on our own observations and a review of the current literature. Also discussed are potential undesirable side-effects and possible contraindications of this therapy. RESULTS AND CONCLUSIONS: Based on recent findings, the use of TNF-alpha blockers seems to be promising in the treatment of therapy-resistant inflammatory dermatoses. At present, guidelines for indications and contraindications of anti-TNF-alpha treatment of inflammatory skin disorders are rare. Such guidelines are necessary to improve the efficacy of anticytokine treatment and the reduction of side-effects.

Dermatologic Agents↗

The glycosylation of pregnancy-associated glycoproteins and prolactin-related protein-I in bovine binucleate trophoblast giant cells changes before parturition.

Binucleate trophoblast giant cells (BNC) in the bovine placenta produce glycoproteins, which are delivered into the mother after fusion of BNC with uterine epithelial cells. During most time of pregnancy, BNC produce pregnancy-associated glycoproteins (PAGs) and prolactin-related protein-I (PRP-I) with asparagine-linked lactosamine-type glycans terminating with N-acetyl-galactosamine. We show by lectin histochemistry that terminal N-acetyl-galactosamine (detected by Dolichos biflorus agglutinin, DBA) in placentomal BNC is greatly reduced prior to parturition, while lactosamine-type N-glycans (detected by Phaseolus vulgaris leucoagglutinin, PHA-L) remain unaltered. The change in DBA-staining showed no statistically significant differences between placentomes of cows with and without retention of fetal membranes. Western blots revealed that, at parturition the apparent molecular mass of PAGs and PRP-I is 1-2 kDa lower than in late pregnancy. These changes are due to alterations of asparagine-linked glycans, since the molecular weight of the peptide backbones after enzymatical release of asparagine-linked glycans is identical at late pregnancy and parturition. Lectin western blots showed a reduction of terminal N-acetyl-galactosamine on PAGs at parturition. A lectin sandwich-ELISAwas used to differentiate DBA- and PHA-L-binding PAGs in sera of pregnant and non-pregnant cows. The values for DBA-binding PAGs at parturition were not significantly different from non-pregnancy, while the values for PHA-L-binding PAGs were significantly higher at parturition. The peripartal changes of PAG- and PRP-I-glycosylation could alter functional properties of these proteins and might therefore be considered for functional studies. The differentiation of PAG glycoforms in maternal serum could be valuable for a further optimization of PAG-based pregnancy diagnosis in cattle.

Animals↗

Reciprocal expression of 17alpha-hydroxylase-C17,20-lyase and aromatase cytochrome P450 during bovine trophoblast differentiation: a two-cell system drives placental oestrogen synthesis.

No definitive information is yet available on the steroidogenic capacity of the two morphologically distinct cell types forming the bovine trophoblast, the uninucleated trophoblast cells (UTCs) and the trophoblast giant cells (TGCs). Hence, in order to localise 17alpha-hydroxylase-C17,20-lyase (P450c17) on a cellular level and to monitor its expression as a function of gestational age, placentomes from pregnant (days 80-284; n = 19), prepartal (days 273-282; 24-36 h prior to the onset of labour; n = 3) and parturient cows (n = 5) were immunostained for P450c17 using an antiserum against the recombinant bovine enzyme. At all stages investigated, P450c17 was exclusively found in the UTCs of chorionic villi (CV), where staining was ubiquitous between days 80 and 160, but was largely restricted to primary CV and the branching sites of secondary CV between days 160 and 240. Thereafter, a distinct ubiquitous staining reoccurred in the UTCs of all CV in late pregnant, prepartal and parturient animals. Using an antiserum against human aromatase cytochrome P450 (P450arom), specific cytoplasmic staining was observed in TGCs. In placentomes from pregnant cows, staining intensity was higher in mature compared with immature TGCs and was more pronounced in the trophoblast covering big stem villi compared with the trophoblast at other sites of the villous tree. In placentomes of a parturient cow, specific staining was only found in mature TGCs that survived the normal, but substantial, prepartal decline in TGC numbers. These results clearly showed that bovine UTCs and TGCs exhibit different steroidogenic capacities, constituting a 'two-cell' organisation for oestrogen synthesis. P450c17 expression appears to be quickly down-regulated and P450arom is up-regulated when UTCs enter the TGC differentiation pathway.

Animals↗

Retrospective interactive rigid fusion of (18)F-FDG-PET and CT. Additional diagnostic information in melanoma patients.

AIM: This study investigates whether interactive rigid fusion of routine PET and CT data improves localization, detection and characterization of lesions compared to separate reading. For this purpose, routine PET and CT scans of patients with metastases from malignant melanoma were used. PATIENTS, METHODS: In 34 patients with histologically confirmed malignant melanoma, FDG-PET and spiral CT were performed using clinical standard protocols. For all of these patients, gold standard was available. Clinical and radiological follow-up identified 82 lesions as definitely pathological. Two board-certified nuclear medicine physicians and two board-certified radiologists analyzed PET and CT images independently from each other. For each patient up to 32 anatomical regions (24 lymph node regions, 8 extranodular regions) were systematically classified. Discordant areas were interactively analyzed in manually and rigidly registered images using a commercially available fusion tool. No side-by-side reading was performed. RESULTS: Image fusion disclosed that the evaluation of the PET images alone led to a mislocalization in 26 of 91 focally FDG enhancing lesions. The overall sensitivities of PET, CT, and image fusion were 85, 88, and 94%, respectively; the overall specificities of PET, CT and image fusion were 98, 95 and 100%, respectively. Image fusion exhibited statistically significant higher specificity values as compared with CT. Ten definitely malignant sites were false-negative in CT, but could be detected by PET. On the other hand, twelve metastases were false-negative in PET, but could be detected by CT. These included two lesions, which had a clear correlate on the PET image when the fused images were evaluated. On the whole, registration of the PET and CT images yielded additional diagnostic information in 44% of the definitely malignant lesions. CONCLUSION: Retrospective image fusion of independently obtained PET and CT data is particularly valuable in exactly localizing foci of abnormal FDG uptake and improves the detection of metastases of malignant melanoma.

Adult↗

Fibroblast growth factor (FGF)-1, FGF2, FGF7 and FGF receptors are uniformly expressed in trophoblast giant cells during restricted trophoblast invasion in cows.

The bovine placenta is characterized by a limited invasion of trophoblast giant cells (TGC). In contrast to mononuclear trophoblast cells (MTC), TGC are non-polarized cells, which migrate and fuse with single uterine epithelial cells throughout gestation. Fibroblast growth factors (FGF) were shown to be associated with the migratory activity of cells, cell differentiation and angiogenesis, and due to its localization in trophoblast cells were proposed as important regulating factors in hemochorial placentae of rodents and humans, and the (syn)epitheliochorial placenta of pig and sheep. Since migrating bovine TGC are of epithelial origin, but exhibit similarities to mesenchymal cells we hypothesize that the restricted trophoblast invasion in cattle is characterized by a specific FGF expression pattern. Therefore, the spatiotemporal expression of specific FGF factor:receptor pairs, either acting on cells of mesenchymal origin or on epithelial cells was examined in bovine placental tissues throughout gestation and prepartum by immunohistochemistry, semiquantitative RT-PCR and in situ hybridization. FGF1 protein was found in trophoblast, caruncular epithelium (CE) and stroma (CS), stroma of chorionic villi (SCV), and in fetal and maternal blood vessels. FGF2 signals dominated in maternal vascular endothelia (VE), immature TGC, and MTC, whereas staining in other cell types was clearly weaker. FGF7 protein was detected in fetal and maternal blood vessel as well as in immature TGC and MTC predominantly at the chorionic plate. FGFR immunoreaction was localized in immature TGC, MTC, and to a clearly lesser extent in CS, CE and fetal and maternal blood vessels. Mature TGC stained negatively for all examined factors and FGFR. The corresponding mRNAs specific for FGF1, -2, -7, total FGFR, and FGFR2 isoforms IIIb and IIIc were colocalized in immature TGC, whereas hybridization was substantially lower in CE and absent in CS, SCV and mature TGC throughout gestation, but switched to CS and VE immediately prepartum. Semiquantitative RT-PCR revealed higher mRNA levels for FGF1, FGFR, and FGFR2IIIc in cotyledons compared to caruncles (p<0.05), whereas it was the opposite with FGF2 (p<0.001). FGF7 and FGFR2IIIb mRNA levels did not differ between caruncles and cotyledons. Significant changes (p<0.05) of mRNA levels related to gestational age were found for FGF1 and FGFR2IIIc, but not for FGF2, -7, total FGFR, and FGFR2IIIb. The specific localization of all examined FGF family members in TGC suggests that TGC, apart from their classical function as producers of hormonal products, play other important roles in the regulation of bovine placentomal growth, differentiation and angiogenesis.

Animals↗