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Biomedical subjects

M Mengel

Publications and source records attributed to M Mengel.

At least 19 recordsLinked to original sources
PubMed2006

Side effects of sirolimus.

The mTOR inhibitor sirolimus improves renal transplant function compared with the nephrotoxic calcineurin inhibitors. We evaluated retrospectively the adverse events in 119 of 134 patients getting sirolimus which seemed to be caused by sirolimus. Patients were converted to sirolimus because of malignancies (n = 47), a creeping creatinine (n = 33), or hypertension (n = 26). One cohort had started sirolimus from the time of transplantation (n = 28). A rise in serum lipids and a decrease in hemoglobin were seen relatively regularly, while arthralgia, peripheral edema, gastrointestinal complaints, skin disorders, electrolyte disturbances, and infections occurred only occasionally. Interestingly, 31% of patients developed doubling or more proteinuria. Among renal biopsies, 9/13 showed a glomerulopathy which in 6 cases was de novo and in 3 cases, a presumed recurrence of the primary kidney disease. Thus, we think that caution is required, particularly in connection with preexisting glomerular disease.

Biopsy↗
PubMed2006

[Embryonal rhabdomyosarcoma of the orbita].

A 2(1/2) year old girl was presented with an acute, painless orbital swelling without signs of local or systemic inflammation. CT and MRT scanning revealed a tumor which by open biopsy disclosed embryonal rhabdomyosarcoma. By means of this case we present the current diagnostic and therapeutic approaches for childhood soft tissue sarcomas. At present our patient receives a poly-chemotherapy which has already shown a good response. For local tumor control, a complete surgical resection as well as radiotherapy may be indicated and have to be considered carefully with respect to the possible late effects. This case demonstrates that in a child with a unilateral, progressive orbital tumor, the differential diagnosis of a soft tissue sarcoma has to be ruled out.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed2006

Nodular B-cell aggregates associated with treatment refractory renal transplant rejection resolved by rituximab.

Acute rejection episodes leading to treatment refractory early graft loss are increasingly rare events in living related renal transplantation today. Pathophysiologic pathways often remain unsolved. We report on tubulointerstitial and vascular rejection developing within 2 weeks after transplantation in a 12-year-old boy treated with cyclosporine, mycophenolate, steroids and double blinded basiliximab. Despite steroid pulses, switch to tacrolimus and ATG serum creatinine peaked at 347 micromol/L with imminent graft loss and ongoing C4d negative cellular vascular rejection. Permanent gain of function was only achieved after a single dose of rituximab. Retrospectively CD20+ nodular B-cell aggregates could be demonstrated in all three biopsies obtained prior to rituximab and resolved concomitantly with functional improvement. Our case for the first time demonstrates resolution of nodular CD20+ infiltrates and decline of OX40, NF-kappaB and CTL transcription shortly after rituximab indicating a B-cell facilitated C4d negative pathway. Single dose rituximab may effectively reverse even long-lasting refractory rejection.

Antibodies, Monoclonal↗
PubMed2006

A blue kidney--chronic renal failure as a consequence of siderosis in paroxysmal nocturnal hemoglobinuria?

Acute renal failure is a known complication during hemolytic crisis in paroxysmal nocturnal hemoglobinuria (PNH). However, chronic renal failure is rare despite the well-known spectacular hemosiderosis of the kidneys due to chronic hemolysis. Here, we report about a 74-year-old man with PNH who developed acute on chronic renal failure after an episode of intercurrent urinary tract infection and subsequent hemolytic crisis. Mild chronic hemolysis, well-documented over the past decade, had long been considered the cause of a constantly declining glomerular filtration rate. Accordingly, magnetic resonance imaging during admission demonstrated marked siderosis of both kidneys, supporting the hypothesis that chronic renal failure (CRF) was likewise related to PNH. However, a renal biopsy revealed acute tubular necrosis and distinct renal siderosis, as expected. Additionally, tubulointerstitial injury and global glomerular sclerosis, best classified as arterionephrosclerosis, were present. In retrospect, these findings were explained by a 15-year history of hypertension and a 4-year medication with cyclosporine. Careful diagnostic workup including a renal biopsy is mandatory, given a misleadingly suggestive correlation between chronic hemolysis and CRF. Chronic renal failure in PNH is a diagnosis of exclusion, even if radiologic evidence of heavy siderosis draws off the physician's attention.

Aged↗
PubMed2005

Correlation of bFGF expression in renal cell cancer with clinical and histopathological features by tissue microarray analysis and measurement of serum levels.

The prognostic value of bFGF for surgically treated renal cell cancer (RCC) patients was evaluated by immunohistochemistry (IHC) and the tissue microarray technique (TMA). Additionally, preoperative serum bFGF levels were correlated to tumour stage and the presence of metastases at initial diagnosis. Serum levels of bFGF were measured by ELISA in 39 healthy volunteers, in 37 patients with benign urologic diseases and in 74 RCC patients, 26 of whom revealed lymph node or distant metastases. bFGF expression as detected by IHC was investigated in 777 tissue cores from 259 different RCC patients [median follow-up: 138 (36-240) months]. Eighty eight patients died from tumour progression. For each patient, the TMA slides contained a tissue core from the primary tumour, its invasion front and the normal renal parenchyma. bFGF serum levels were higher in RCC patients vs healthy volunteers (P<0.01) and vs patients with benign urologic diseases (P<0.01). Metastasized patients revealed higher bFGF serum levels than organ-confined specimens (P<0.01). As detected by IHC only increased bFGF expression in the invasion front tissue correlated with the patients' long-term survival (log rank test) (P=0.03). In multivariate analysis regional LN metastases (P<0.01), the histological grading (P<0.01), and an increased bFGF expression in the invasion front (P=0.04) independently predicted the patients' clinical prognosis. Not the expression of bFGF in the primary tumour but in its invasion front reflects the aggressiveness of RCC, hereby indicating a different biological potential within both areas. The value of bFGF serum levels as indicators of systemic tumour dissemination remains to be determined.

Adult↗
PubMed2005

Compartment-specific quantitative gene expression analysis after laser microdissection from archival renal allograft biopsies.

BACKGROUND: Various immunological and non-immunological pathomechanisms are responsible for the cellular damage in renal allografts. Since the kidney is an anatomically complex organ with functional and morphological heterogeneous compartments (interstitium, tubuli, vessels, glomeruli), the local response to injury maybe variable, therefore, the identification of local pathomechanisms is important. AIM: To elucidate any discrepancies in quantitative mRNA expression profiles between a total specimen analysis and a cell-specific evaluation after laser microdissection. METHODS: Real-time RT-PCR was performed for complement component C3 and heme oxygenase-1 (HO-1) genes compared to the housekeeping gene beta-actin using whole section RNA extracted from formalin-fixed and paraffin-embedded archival material of 16 explanted, rejected renal allografts. Ten non-transplant nephrectomies served as controls. For five cases from each group, five different compartments of the organs (interstitium, proximal tubuli, distal tubuli, vessels, glomeruli) were microdissected and quantitative analysis for C3 and HO-1 was performed identically. RESULTS: Whole section mRNA expression analysis: the data showed a constant expression of the housekeeping gene beta-actin, a 7-fold increased expression of C3 and a 3-fold decreased expression of HO-1 in the allograft group as compared to the control group. mRNA expression results from microdissected compartments: in the control group, C3 and HO-1 expression could only be detected in the proximal tubuli of all cases whereas all five compartments analyzed from the rejecting kidneys showed expression of the two genes. In the allografts, expression levels of the investigated genes varied considerably not only among the different compartments but between individual cases as well. CONCLUSION: Laser microdissection combined with real-time RT-PCR is a feasible approach for retrospective quantitative gene expression analysis in formalin-fixed and paraffin-embedded renal allograft specimens. As shown for C3 and HO-1, cell-specific expression patterns ofpathogenetically relevant genes vary considerably between individual cases. A close correlation of morphology and cell-specific gene expression analysis will contribute to the elucidation of the complex pathogenesis of chronic renal allograft nephropathy.

Actins↗
PubMed2003

[Interlaboratory trial 2000 " Immunohistochemistry" of the German Society for Pathology and the Professional Association of German Pathologists].

Early in 2000 an interlaboratory trial on immunohistochemistry was held in Germany in which 172 pathologists took part. Each pathologist received one H&E stained and five unstained slides of five different tumors to reach a diagnosis based on immunohistochemical stains. Additionally, the diagnosis-independent staining quality was assessed by using a multi-tissue block. Altogether, 828 diagnoses were made, among which 57% (468) were correct. The individual steps of immunohistochemistry (tentative morphological diagnosis, choice of primary antibodies, technical staining quality, conclusions from the diagnosis and rendering a final diagnosis) were assessed independently. Although each of these steps was correlated to the correct final diagnosis, in the multivariate analysis only the tentative diagnosis, choice of primary antibodies and the conclusions drawn from individual stains were independent factors to reach the correct final diagnosis. In the diagnostic part of the interlaboratory trial, the technical quality of the immunostaining was not an independent variable to reach a correct diagnosis. In contrast, the results of the multi-tissue block proved that the immunohistochemical staining quality has to be standardized to reach reproducible results in defining the estrogen receptor expression as a basis for therapeutic decisions.

Coloring Agents↗
PubMed2002

CXCR4/CXCL12 expression and signalling in kidney cancer.

CXCL12 (SDF-1), a CXC-chemokine, and its specific receptor, CXCR4, have recently been shown to be involved in tumourgenesis, proliferation and angiogenesis. Therefore, we analysed CXCL12alpha/CXCR4 expression and function in four human kidney cancer cell lines (A-498, CAKI-1, CAKI-2, HA-7), 10 freshly harvested human tumour samples and corresponding normal kidney tissue. While none of the analysed tumour cell lines expressed CXCL12alpha, A-498 cells were found to express CXCR4. More importantly, real-time RT-PCR analysis of 10 tumour samples and respective adjacent normal kidney tissue disclosed a distinct and divergent downregulation of CXCL12alpha and upregulation of CXCR4 in primary tumour tissue. To prove that the CXCR4 protein is functionally active, rhCXCL12alpha was investigated for its ability to induce changes of intracellular calcium levels in A-498 cells. Moreover, we used cDNA expression arrays to evaluate the biological influence of CXCL12alpha. Comparing gene expression profiles in rhCXCL12alpha stimulated vs unstimulated A-498 kidney cancer cells revealed specific regulation of 31 out of 1176 genes tested on a selected human cancer array, with a prominent stimulation of genes involved in cell-cycle regulation and apoptosis. The genetic changes reported here should provide new insights into the developmental paths leading to tumour progression and may also aid the design of new approaches to therapeutic intervention.

Antigens, Surface↗
PubMed2002

Quality assurance in immunohistochemistry: results of an interlaboratory trial involving 172 pathologists.

The practicability of quality assurance in immunohistochemistry and its integration into the diagnostic process were both tested in this Germany-wide interlaboratory trial. One hundred seventy-two pathologists received one hematoxylin and eosin and five unstained slides from five cases; all cases were selected by a panel because immunohistochemistry was required for their final diagnosis. Participants rendered a morphologic diagnosis and then substantiated it immunohistochemically. Stained slides and evaluation sheets were reviewed by the panel, and the diagnostic process was analyzed in individual steps: morphologic diagnosis, selection of antibodies, staining quality, interpretation of stained slides, conclusions, and final diagnosis. Diagnosis-independent immunohistochemical performance was tested using a multisample tissue block (30 samples) that was stained and evaluated for six common antigens. For individual cases, corresponding to their difficulty, 21-89% of the final diagnoses (altogether 57% from 828 diagnoses) were correct. In a statistical analysis, the tentative diagnosis, the interpretation of stains and conclusions drawn from immunohistochemistry, were independent factors in reaching the diagnosis. Sensitivity to detect estrogen receptors on the multisample tissue block was only 48%. However, 24% of the stains were interpreted as falsely negative. The low staining sensitivity was not correlated to the number of correct diagnoses. The major problem of applying immunohistochemistry in surgical pathology appears to be its integration into the diagnostic process and not the staining quality. Both future quality control projects and training will have to regard these integrative requirements. Multisample tissue blocks provide a promising tool to standardize quantitative immunohistochemical parameters, such as receptor or proliferation scores.

Coloring Agents↗
PubMed2002

Nodular fasciitis, erythema migrans, and oligoarthritis: manifestations of Lyme borreliosis caused by Borrelia afzelii.

We describe a 35-year old patient with nodular fasciitis, erythema migrans, and gonarthritis four months after a bite of a Borrelia afzelii infected tick. The Borrelia afzelii infection was identified by a polymerase chain reaction and direct sequencing of the amplification product. Borrelia-specific DNA was also detectable in nodular fasciitis tissue. We therefore conclude that Borrelia afzelii can be a causative agent of nodular fasciitis and Lyme arthritis in a highly endemic region of Northern Germany.

Adult↗
PubMed2001

Diagnostic impact of fluorescence in situ hybridization in the differentiation of hepatocellular adenoma and well-differentiated hepatocellular carcinoma.

Histopathological differentiation between hepatocellular adenoma and well differentiated hepatocellular carcinoma (HCC) may be a difficult task in small biopsies and occasionally in resected tumor specimens. Whether the analysis of chromosome aberrations can contribute to a more precise discrimination has not been analyzed systematically up to now. Therefore, fluorescence in situ hybridization was applied to 28 cases of adenoma and well differentiated carcinoma, using centromeric probes for chromosomes 1, 6, 7, 8, and X. None of 14 adenomas revealed an aberrant count in the analyses performed. By contrast, 13/14 carcinomas demonstrated aberrations for 2-5 chromosomes/case. Chromosome 1 was aberrant in 8/12 cases informative for this probe (67%), chromosomes 6 and 7 were aberrant in 9/14 cases (64%), chromosome 8 was aberrant in 11/14 cases (79%), and chromosome X in 7/14 cases (50%). Taking results for chromosomes 1 and 8 together, 13/14 HCC revealed aberrations for at least one of these chromosomes. Probes for 6, 7, and X revealed no additional aberrant cases.Thus, FISH for chromosomes 1 and 8, extended by probes for chromosomes 6, 7 and X, represents a promising approach toward a more accurate differentiation between hepatocellular adenoma and carcinoma.

Adenoma, Liver Cell↗
PubMed2001

Nephrotoxicity of selective COX-2 inhibitors.

We describe 2 male patients, a 49-year-old with psoriatic arthritis and impaired renal function and a 43-year-old renal transplant recipient, who both sustained a marked decline in glomerular filtration rate in conjunction with a selective inhibitor of cyclooxygenase-2 (COX-2), rofecoxib. In the second patient, acute renal failure necessitated hemodialysis. Both patients made an uneventful recovery. Our report lends further support to the assumption that COX-2 inhibitors, as a class, can be as nephrotoxic as their nonselective predecessors. Therefore, COX-2 inhibitors should be used with caution in renal transplant recipients and in patients with salt depletion and renal insufficiency.

Acute Kidney Injury↗
PubMed2000

[Primary leiomyosarcoma of the pulmonary artery--a case report].

A case of a primary pulmonary leiomyosarcoma originating in the right pulmonary artery in a 61-year-old woman is reported. Patient's complaints were non-specific and after non-invasive diagnostics a chronic thromboembolic event was suspected to have occurred a long time ago. During a heart catheter investigation prior to planned surgical embolectomy a small specimen was taken from the pulmonary artery. Histological examination revealed malignant the tumour and by immunohistological staining its smooth muscle differentiation was confirmed. Complete resection of the tumour was achieved by radical surgery, including pneumonectomy and extensive resection of pulmonary vessels with subsequent implantation of a Goretex prosthetic. There was no evidence of recurrence or metastasis of the primary leiomyosarcoma of the pulmonary artery in a 14-month follow-up period after operation.

Biopsy↗
PubMed2000

Complete sequencing and mRNA expression analysis of the MEN-I gene in adrenal myelolipoma.

The molecular pathogenesis of adrenal myelolipoma is unclear. Endocrine activity of these tumors and association with other endocrine tumors have stimulated the hypothesis that it may belong to the group of sporadic tumors caused by defects of the gene responsible for multiple endocrine neoplasia type I (MEN-I). DNA of blood and tumoral sections from two patients with adrenal myelolipoma were analyzed by examination of variable number of tandem repeats (VNTR) loci PYGM, D11S987, D11S480, and D11S449 on chromosome 11q13 and by complete direct DNA sequencing of all coding exons and splice junctions of the MEN-I gene. Menin expression was examined by RT-PCR. RT-PCR did not detect menin expression in one adrenal myelolipoma. No loss of heterozygozity on chromosome 11q13 was identified. Intragenic heterozygozity was retained in codon 418 of the menin gene in both patients. No mutation was identified in the coding exons of the menin gene. Complete DNA sequencing yielded no hint that defects of the MEN-I gene are responsible for the formation of adrenal myelolipomas. Adrenal myelolipomas do not share the loss of heterozygozity on chromosome 11q13 observed in some benign adenomatous and many malignant adrenocortical tumors.

Adrenal Gland Neoplasms↗
PubMed2000

Complete sequencing and messenger ribonucleic acid expression analysis of the MEN I gene in adrenal cancer.

Adrenal cancer is a rare sporadic disease that has also been observed in the context of multiple endocrine neoplasia type I (MEN I). Adrenal lesions occur in up to 40% of MEN I patients. Loss of heterozygosity of the 11q13 band harboring the menin gene has been reported in more than 50% of patients with adrenal cancer. Despite this high index of suspicion, former screening studies did not reveal mutations of the MEN I gene in 28 patients. We identified loss of heterozygosity of 11q13 microsatellites in five of five patients (100%). In 40%, heterozygosity was retained in codon 418 of the MEN I gene. Complete direct DNA sequencing data of the entire coding region and adjacent splice sites of the MEN I gene were obtained in 14 patients with sporadic adrenal cancer. In only one of them a heterozygous missense mutation, R176Q (exon 3), was identified. Due to the heterozygous pattern and unknown biological effect of this mutation, it is not clear whether there is a causal relationship with adrenal cancer. The total mutation frequency in sporadic adrenal cancer is 1 of 14 (7%). Menin messenger RNA expression was identified in 14 of 14 patients (100%). Transcriptional inactivation of the menin gene is, hence, unlikely to cause loss of its tumor suppressor function in adrenal cancer. Furthermore, we examined three patients who presented adrenal cancer in the context of sporadic multiglandular endocrine tumor disease previously diagnosed on clinical grounds to be MEN I syndrome. An opal stop codon mutation was identified in codon 126 (exon 2) in the adrenal cancer of one of these patients. Formation of the adrenal cancer in this patient may be rather coincidental because the mutation was present in a heterozygous pattern. There was no mutation of the menin gene in the two other patients. This may mean that formation of adrenal cancer in the context of multiglandular endocrine disease denotes an entity different from MEN I in some patients.

Adolescent↗
PubMed1999

Molecular and functional characterization of the small Ca(2+)-regulated K+ channel (rSK4) of colonic crypts.

Colonic crypt cells possess basolateral Ca(2+)-regulated K+ channels which support Cl- secretion by providing the necessary driving force. The pharmacological characteristics of these channels were examined in Ussing chamber experiments of rat and rabbit colon mucosa by the use of blockers. The chromanol 293B, a blocker of KVLQT1 channels, and clotrimazole (CTZ), a blocker of small Ca(2+)-activated K+ channels, blocked stimulated Cl- secretion completely. Small-conductance Ca(2+)-activated K+ channels (SK) in excised basolateral patches of rat colonic crypts were inhibited concentration dependently by the imidazoles CTZ, NS004 and NS1619 and activated by 1-EBIO. These properties are similar to those of the known human SK channel (hSK4). hSK4-expressing Xenopus laevis oocytes showed ionomycin-activated and CTZ-inhibited K+ currents. When P2Y2 receptors were coexpressed these currents were also activated by ATP. The concentration/response curve was identical to that of rat SK channels. In human colonocytes (T84) exposed to hSK4 antisense probes, but not to sense probes, carbachol-induced K+ currents were attenuated. With RT-PCR an hSK4 could be demonstrated in human colon and in T84 colonocytes. By homology cloning the SK of the rat colon (rSK4) was identified. This protein has a high homology to hSK4 and mouse IK1. These data indicate that the Ca(2+)-activated and imidazole-inhibited basolateral K+ current in the colon is caused by SK4 channels.

Animals↗