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Biomedical subjects

Thomas Horn

Publications and source records attributed to Thomas Horn.

At least 19 recordsLinked to original sources

GenomeRNAi: a database for cell-based RNAi phenotypes.

RNA interference (RNAi) has emerged as a powerful tool to generate loss-of-function phenotypes in a variety of organisms. Combined with the sequence information of almost completely annotated genomes, RNAi technologies have opened new avenues to conduct systematic genetic screens for every annotated gene in the genome. As increasing large datasets of RNAi-induced phenotypes become available, an important challenge remains the systematic integration and annotation of functional information. Genome-wide RNAi screens have been performed both in Caenorhabditis elegans and Drosophila for a variety of phenotypes and several RNAi libraries have become available to assess phenotypes for almost every gene in the genome. These screens were performed using different types of assays from visible phenotypes to focused transcriptional readouts and provide a rich data source for functional annotation across different species. The GenomeRNAi database provides access to published RNAi phenotypes obtained from cell-based screens and maps them to their genomic locus, including possible non-specific regions. The database also gives access to sequence information of RNAi probes used in various screens. It can be searched by phenotype, by gene, by RNAi probe or by sequence and is accessible at http://rnai.dkfz.de.

Animals↗

[A severe case of interstitial nephritis caused by sodium valproate].

A case of acute interstitial nephritis caused by sodium valproate is reported. The sodium valproate treatment was continued after initial diagnosis and the patient developed end-stage renal failure. After transplantation, interstitial nephritis was demonstrated in the renal graft.

Adult↗

Ultrasound characteristics and histological dating of the endometrium in a natural cycle in infertile women compared with fertile controls.

OBJECTIVE: To compare endometrial dating and ultrasound texture in a natural cycle before IVF and relate these to outcome and to fertile references. DESIGN: Prospective study with a fertile reference group. SETTING: Four university IVF clinics. PATIENT(S): Seventy-five IVF patients and 21 fertile women. INTERVENTION(S): Ultrasound, biopsy, blood sampling. In vitro fertilization-ET in the following cycle. MAIN OUTCOME MEASURE(S): Endometrial evaluation, P, IVF outcome. RESULT(S): At day LH+7, 42% infertile vs. 67% fertile women demonstrated endometria that were in phase (statistically nonsignificant difference). Nine percent had an accelerated endometrium, and 47% (infertile) vs. 24% (fertile) had a delayed endometrium (statistically nonsignificant difference). Statistically significantly fewer women with tubal factor and no hydrosalpinges had an endometrium in phase (20%) than was the case in fertile women (67%). Dating could not predict outcome. Statistically significantly more women in the hydrosalpinx group had a visible midline at day LH+7 compared with the case in other infertile groups. Forty-three percent conceived after IVF-ET. Plasma P was statistically significantly lower in nonpregnant women compared with in women with ongoing pregnancies and with fertile controls. A periovulatory hyperechogenic endometrium resulted in no ongoing pregnancies. CONCLUSION(S): In a natural cycle preceding IVF, a low midluteal P level predicts a low implantation rate. A periovulatory hyperechogenic endometrium or hydrosalpinges visible at ultrasound may have some predictive value. Endometrial dating was of no help.

Adult↗

Eosinophilic cellulitislike reaction to subcutaneous etanercept injection.

BACKGROUND: Injection site reactions are well recognized in patients treated with etanercept. Previous reports describe histologic findings of a cell-mediated T(H)1 reaction, with CD8+ T cells composing the majority of the dermal infiltrate. OBSERVATIONS: A pruritic, erythematous, edematous patch occurred on the right thigh of a 57-year-old white woman treated for rheumatoid arthritis within 12 to 24 hours after her second dose of subcutaneous etanercept. The patient had a similar reaction to adalimumab injection 2 weeks prior to presentation. While benzyl alcohol is present in the etanercept preparation, and mannitol in both drugs, dermal injection revealed no reaction to these additives. Biopsy specimens from the etanercept injection site demonstrated papillary dermal edema accompanied by a brisk polymorphous infiltrate with a predominance of eosinophils and scattered flame figures. CONCLUSIONS: Histologic features of eosinophilic cellulitis as a response to etanercept have not been reported to date. Although most injection site reactions contain T cells and represent a T(H)1 immune response, the findings we report suggest a T(H)2-mediated phenomenon.

Antirheumatic Agents↗

Transitional cell bladder tumor: predicting recurrence and progression by analysis of microsatellite loss of heterozygosity in urine sediment and tumor tissue.

Transitional cell bladder tumors (TCT) is prone to recurrence (60-80%) after tumor resection. Up to 25% of these patients will progress, so it is important to find reliable predictive markers. We analyzed for loss of heterozygosity (LOH) with respect to 13 microsatellites located on 10 different chromosomal arms. This analysis was performed on the urine sediment and tumor tissue from 59 patients with bladder TCT and on the urine and normal-looking mucosa from 25 patients with a history of bladder TCT but no evidence of disease at the time of the study inclusion. The median follow-up period was 23.1 months (range, 2-48 months) for the 59 patients with bladder TCT and 25 months (range, 4-57 months) for the 25 patients without evidence of ongoing active disease. Correlation between LOH and eventual recurrence, progression, and mortality was investigated. In patients with noninvasive TCT, correlation between 11p tumor tissue LOH and recurrence was found. Similarly, 8p LOH in both urine sediment and tumor tissue correlated with progression. Finally, in the group of patients with a history of bladder TCT, normal tissue 8p and/or 11p LOH correlated with recurrence.

Aged↗

Human detrusor smooth muscle cells release interleukin-6, interleukin-8, and RANTES in response to proinflammatory cytokines interleukin-1beta and tumor necrosis factor-alpha.

OBJECTIVES: Recently, we have demonstrated that human detrusor smooth muscle cells in culture secrete the chemokine monocyte chemoattractant protein 1. In the present study, we extended these studies to include the effect of the proinflammatory cytokines tumor necrosis factor (TNF)-alpha and interleukin (IL)-1beta on IL-8, IL-6, and RANTES (regulated on activation, normal T cell expressed and secreted) release by human detrusor smooth muscle cells (HDSMCs) and examined their regulation. METHODS: With ethical approval, detrusor muscle biopsies were obtained from patients with benign noninvasive bladder diseases undergoing control cystoscopy. HDSMCs were cultured using an explant technique and used at maximum third passage. HDSMCs were cultured in the presence or absence of TNF-alpha and IL-1beta. Supernatants were collected after 6, 12, and 24 hours. IL-8, IL-6, and RANTES were measured using enzyme-linked immunosorbent assays. RESULTS: TNF-alpha and IL-1beta (0.01 to 100 ng/mL) induced secretion of IL-8, IL-6, and RANTES in a dose and time-dependent manner. The production of chemokines reached a maximum after 24 hours of incubation. In nonstimulated HDSMCs, the basal secretion of IL-8, IL-6, and RANTES was detectable. Induction of cytokine release by IL-1beta was synergistic with TNF-alpha. CONCLUSIONS: These findings for the first time demonstrate that HDSMCs release IL-8, IL-6, and RANTES in response to IL-1beta and TNF-alpha. The constitutive and cytokine-stimulated production of chemokines and cytokines suggest that the human detrusor may contribute to mast cell infiltration into the bladder interstitium. The new evidence that HDSMCs secrete immunomodulatory proteins makes the detrusor muscle cell a target for anti-inflammatory therapy.

Cells, Cultured↗

Colonic epithelial cell expression of ICAM-1 relates to loss of surface continuity: a comparative study of inflammatory bowel disease and colonic neoplasms.

OBJECTIVE: Intercellular adhesion molecule-1 (ICAM-1) is important in ulcerative colitis (UC) by mediating the arrest and further migration of neutrophils. In vitro studies have shown that colonocytes from chronically inflamed colon and cultured colon cancer cells are capable of expressing ICAM-1. The aim of this study was to assess the ICAM-1 expression in human colonic tissue representing UC, Crohn's disease (CD), adenomas, and adenocarcinomas, with special attention to the epithelium. MATERIAL AND METHODS: Formalin-fixed and paraffin-embedded tissue from the archives of the Department of Pathology of Rigshospitalet University of Copenhagen was examined. Colonic tissue from 10 patients with UC, 10 with CD, 32 adenomas, 27 adenocarcinomas, and 10 lymph node metastases were included. The expression of ICAM-1 was assessed by using the EnVision(+)technique (DakoCytomation). RESULTS: Endothelial ICAM-1 was up-regulated in areas with dense lymphocyte infiltration and near crypt abscesses and ulcerations. Ulcerations were covered by a continuous layer of macrophages and epithelial cells expressing ICAM-1. Similar observations were made in the case of adenomas and adenocarcinomas, but in adenocarcinomas the epithelial ICAM-1 was more diffuse and not related solely to sites of surface destruction. CONCLUSIONS: In the colon, endothelial cells, macrophages, and epithelial cells are in certain conditions capable of expressing ICAM-1. Although the ICAM-1 expression was related to both the degree and the nature of inflammation, the data indicate increased susceptibility of cancer cells to express ICAM-1. Epithelial and macrophage ICAM-1 might be involved in the immune surveillance and the first-line defense of the diseased colon.

Adolescent↗

Detection of the activating JAK2 V617F mutation in paraffin-embedded trephine bone marrow biopsies of patients with chronic myeloproliferative diseases.

The discovery of the activating V617F mutation in the JAK2 tyrosine kinase in a high proportion of patients with Ph- chronic myeloproliferative diseases (CMPD) represents a diagnostic breakthrough for these disorders. Trephine bone marrow biopsy is an essential part of the diagnostic workup of CMPD and represents a valuable archival source of DNA. Therefore, we studied 152 paraffin-embedded trephines with CMPD and related disorders for the presence of the V617F mutation, using both allele-specific polymerase chain reaction (PCR) and nested PCR with subsequent digestion with BsaXI. Only 6 of 152 (4%) samples were not evaluable because of poor DNA quality. The V617F mutation was detected in 27 of 28 (96%) cases of polycythemia vera, 17 of 23 (74%) cases of essential thrombocythemia, 28 of 45 (62%) cases of chronic idiopathic myelofibrosis, six of eight (75%) cases of CMPD unclassified, and two of four (50%) cases of myelodysplastic/myeloproliferative syndrome. Ph+ chronic myelogenous leukemia (four cases), reactive (secondary) erythrocytosis (14 cases), and thrombocytosis (one case) as well as normal controls (19 cases) all lacked the V617F mutation. Based on results of BsaXI digestion and sequencing, 24 of 54 (44%) evaluable V617F+ cases were considered homozygously mutated. Thus, detection of the V617F JAK2 mutation is feasible in paraffin-embedded trephine biopsies and represents a major advance in the diagnostic evaluation of CMPD.

Adult↗

Keratin expression profiling of transitional epithelium in the painful bladder syndrome/interstitial cystitis.

Painful bladder syndrome/interstitial cystitis (PBS/IC) is a severely debilitating condition. Its cause is poorly understood; therapy is symptomatic and often unsuccessful. To study urothelial involvement, we characterized the keratin phenotype of bladder urothelium in 18 patients with PBS/IC using a panel of 11 keratin antibodies recognizing simple keratins found in columnar epithelia (keratins 7, 8, 18, and 20) and keratins associated with basal cell compartments of squamous epithelia (keratins 5, 13, 14, and 17). We also tested 2 antibodies recognizing more than 1 keratin also directed against basal cell compartments of squamous epithelia (D5/16 B4 and 34betaE12). Bladder urothelium in PBS/IC showed distinct differences in the profiles of keratins 7, 8, 14, 17, 18, and 20 compared with literature reports for normal bladder urothelium. These were characterized by a shift from the normal bladder urothelial keratin phenotype to a more squamous keratin profile, despite the lack of morphologic evidence of squamous epithelial differentiation and a loss of compartmentalization of keratin expression. The severity of these changes varied between biopsy specimens. Whether these changes are primary or secondary to another underlying condition remains to be determined.

Cystitis, Interstitial↗

E-RNAi: a web application to design optimized RNAi constructs.

RNA interference (RNAi) has become a powerful genetic approach to systematically dissect gene function on a genome-wide scale. Owing to the penetrance and efficiency of RNAi in invertebrates, model organisms such as Drosophila melanogaster and Caenorhabditis elegans have contributed significantly to the identification of novel components of diverse biological pathways, ranging from early development to fat storage and aging. For the correct assessment of phenotypes, a key issue remains the stringent quality control of long double-stranded RNAs (dsRNA) to calculate potential off-target effects that may obscure the phenotypic data. We here describe a web-based tool to evaluate and design optimized dsRNA constructs. Moreover, the application also gives access to published predesigned dsRNAs. The E-RNAi web application is available at http://e-rnai.dkfz.de/.

Animals↗

Routine bladder biopsies in men with bladder outlet obstruction?

OBJECTIVES: To establish whether routine evaluation of light microscopic changes in bladder biopsies in men with graded bladder outlet obstruction correlates with urodynamic parameters and to evaluate the performance of two pathologists in bladder biopsy interpretation. METHODS: In 63 consecutive patients presenting with lower urinary tract symptoms suggestive of bladder outlet obstruction, the workup included bladder biopsies, which were semiquantitatively and independently evaluated by two pathologists for fibrosis, elastosis, muscle cell degeneration, inflammation, and additional remarkable findings. Furthermore, as determined by their general impression, the pathologists gave a diagnosis of normal or graded abnormality. The pathologists' performance was compared and the clinical and urodynamic data were correlated to the consensus histologic diagnoses. RESULTS: Fifty-four of 63 cases could be evaluated. The intraobserver and interobserver reproducibility were reasonable, with a kappa of 0.35 and 0.50, respectively. The consensus diagnosis of abnormal bladder biopsy correlated with impaired bladder compliance and capacity. However, no correlation was found between the presence and severity of histologic abnormalities and Schäfer class, urethral resistance factor, instability, postvoid residual urine volume, symptom score, and prostate volume. CONCLUSIONS: Although abnormal bladder biopsies correlated significantly with impaired bladder capacity and compliance, routine evaluation of bladder biopsies is not indicated in the evaluation of bladder outlet obstruction.

Biopsy↗

Monocyte chemoattractant protein-1 production by human detrusor smooth muscle cells.

PURPOSE: Most recently attention has turned to the secretory properties of smooth muscle cells. Monocyte chemoattractant protein-1 (MCP-1) is a potent chemokine that causes mast cells recruitment and provokes mast cells activation in vitro. We investigated whether MCP-1 is produced by human detrusor smooth muscle cells (HDSMCs) cultured under inflammatory conditions. MATERIALS AND METHODS: Using an explantation technique HDSMCs were isolated and short-term cultured. HDSMCs were incubated at 37C for 24 hours with the proinflammatory mediators interleukin-1 beta (IL-1 beta), tumor necrosis factor (TNF-alpha), lipopolysaccharide, histamine, leukotriene D4 and prostaglandin E2. The level of MCP-1 in cell supernatants were measured by enzyme linked immunoassay. RESULTS: There was basal secretion of MCP-1 in unstimulated cultures. Following 24-hour incubation with IL-1 beta or TNF-alpha (1 pg/ml to 100 ng/ml) the level of MCP-1 increased in a dose dependent manner. IL-1 beta was more potent at inducing MCP-1 release in 8 of 10 experiments. Lipopolysaccharide (10 microg/ml), histamine (100 microM), leukotriene D4 (50 nM), prostaglandin E2 (1 microM) and KCl (30 to 100 mM) failed to induce MCP-1 production. When IL-1 beta (10 ng/ml) and TNF-alpha (10 ng/ml) were given in combination, a highly synergistic effect on MCP-1 production was observed. CONCLUSIONS: To our knowledge this study shows for the first time that human detrusor smooth muscle cells cultivated under inflammatory conditions produce significant amounts of MCP-1. In addition to contractile function, HDSMCs have synthesis and secretory potential with the release of MCP-1. Thus, MCP-1 may contribute to the local inflammatory process by producing proinflammatory mediators. The release of cytokines and chemokines by human detrusor muscle even in small amounts may have important functional consequences.

Chemokine CCL2↗

A variant of nephrogenic fibrosing dermopathy with osteoclast-like giant cells: a syndrome of dysregulated matrix remodeling?

Nephrogenic fibrosing dermopathy (NFD) is a disorder characterized by dramatic thickening and hardening of skin in the extremities and trunk, which occurs in individuals on dialysis for renal disease. The pathophysiology is unknown. Increased transforming growth factor-beta (TGF-beta) and collagen deposition have been reported in a small group of patients studied by Jimenez et al.1 We report two patients with NFD and osteoclast-like giant cells in the fibrotic dermis; one patient also had dystrophic cutaneous calcification. These findings have been seen in a small percentage of NFD patients (estimated 2-5%) and may represent a variant of the disease. The hypothesis of altered matrix dysregulation due to altered TGF-beta, metalloproteinases, and activation of osteoclasts as an explanation for this variant is proposed.

Adult↗

Microsatellite analysis of urine sediment versus urine cytology for diagnosing transitional cell tumors of the urinary bladder.

The aim was to evaluate microsatellite analysis of urine sediment (MAUS) as an alternative method to urine cytology for routine diagnosis of patients with transitional cell tumors (TCT) of the urinary bladder. Urine cytology has the advantage of being non-invasive, fast and cheap, but is of limited value because of its low sensitivity. MAUS has previously been found to be a successful alternative method. However, the experimental set-up of such investigations implied exclusion of samples with unfavorable characteristics and use of a large number of markers. In the present study, MAUS was tested on all samples routinely available and a small panel of markers was selected. The urine sediments of 66 TCT patients and 24 controls were analyzed by MAUS with 16 fluorescent markers and by urine cytology. All samples were analyzed, including the ones of later micturition, with gross hematuria, leukocyturia or absence of visible sediment. In patients with tumors of low grade (grades I-II), MAUS was significantly more sensitive than urine cytology. The two methods were of equivalent diagnostic power in high-grade (grades III-IV), high-stage (pT1-pT4) tumors. A panel of the six most informative markers for MAUS was selected. Although MAUS has an advantage over routine cytology in low-grade, low-stage tumors, an overall sensitivity of 45% is not sufficient for routine clinical use.

Adult↗

The expression and activity of renal nitric oxide synthase and circulating nitric oxide in polycystic kidney disease rats.

Nitric oxide (NO) influences tubular fluid and electrolyte transport, and hence possibly also fluid accumulation in renal cysts. The expression and activity of intrarenal constitutive NO synthase (cNOS) [neuronal NOS, nNOS and endothelial NOS, eNOS] and inducible NOS (iNOS) and plasma nitrite/nitrate (PNOx) concentration were assessed in homozygous Han:SPRD polycystic kidney disease (PKD) rats (cy/cy), heterozygous Han:SPRD PKD rats (cy/+), homozygous normal Han:SPRD littermates (+/+) and Sprague Dawley rats (sd). The results showed: 1) nNOS expression was decreased in proximal tubules and thick ascending limbs of the loop of Henle in cy/cy and cy/+ rats compared to +/+ and sd rats (p<0.05). nNOS was weakly expressed in the epithelium of small cysts and unexpressed in epithelium of large cysts. 2) iNOS expression was increased in proximal tubular epithelial cells in cy/+ rats compared to +/+ rats and sd rats (p<0.01). iNOS expression in cyst epithelium was decreased in cy/+ rats (p<0.05) and absent in cy/cy rats. 3) eNOS expression was similar in the endothelium of intrarenal arteries in all groups. 4) The activity of renal cNOS was decreased in cy/cy and cy/+ rats; the activity of iNOS was decreased only in cy/cy rats, with no significant difference among the other three groups. 5) PNOx concentration was higher in cy/cy rats than in the other three groups, and correlated positively with plasma creatinine and urea. In conclusion, NOS expression and activity decreased as cysts developed, suggesting that NO downregulation is involved in the pathogenesis of PKD.

Animals↗

Expression of ICAM-1 in colon epithelial cells: an ultrastructural study performed on in vivo and in vitro models.

BACKGROUND: Studies have suggested that in ulcerative colitis (UC), intercellular adhesion molecule-1 (ICAM-1) is involved in migration of leukocytes toward the colonic epithelium. A suitable in vitro model of chronic colonic inflammation does not exist, and the role of the epithelium is based on monolayers of cancer cells. Conflicting results exist on epithelial ICAM-1 expression, and the aim of this study was to compare the expression in various models of colonic epithelium. MATERIALS AND METHODS: Colonic biopsies from four UC patients and four controls were examined by cryoimmuno-electron microscopy using ICAM-1-antibodies. In four other controls, the epithelium was isolated from colonic biopsies, embedded in collagen, and evaluated similarly. Isolated crypts and cultured cancer cells were stimulated with interferon-gamma (IFN-gamma) or tumor necrosis factor-alpha (TNF-alpha). RESULTS: ICAM-1 was not expressed in the biopsies. In contrast, HT29 cells and the collagen-embedded crypts expressed ICAM-1 on the apical membranes proximal to the junctional complexes when stimulated with IFN-gamma or TNF-alpha in a dose-related manner. CONCLUSIONS: ICAM-1 is not expressed on colonic epithelium in vivo. However, both colonocytes and HT29 cells were capable of expressing ICAM-1 on their apical membranes in response to supraphysiologic cytokine concentrations. These observations question the justification of extrapolating observations from colon cancer cell lines to in vivo inflammatory conditions.

Adult↗